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http://slidepdf.com/reader/full/funcfood1198 1/12FOOD TECHNOLOGY 61VOL. 52, NO. 11 • NOVEMBER 1998

S C I E N T I F I C S T A T U S S U M M A R Y

Functional Foods:Their role in disease prevention

and health promotion

A P U B L I C A T I O N O F

T HE I N S T I T U T E OF F OOD T E C HN OL OGI S T S ’

E X P E R T P A N E L O N F O OD S A F E T Y A N D N U T R I T I O N

NOVEMBER 1998

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62 FOOD TECHNOLOGY NOVEMBER 1998 • VOL. 52, NO. 11

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FOOD TECHNOLOGY 63VOL. 52, NO. 11 • NOVEMBER 1998


A P U B L I C A T I O N O F

T HE I N S T I T U T E OF F OOD T E C H N OL OGI S T S ’

E X P E R T P A N E L O N F O OD S A F E T Y A N D N U T R I T I O N

This Scientific Status

Summary addresses

the primary plant

and animal foods

that have been

linked with

physiological

benefits

he tenet “Let food be thy medicine and

medicine be thy food,” espoused byHippocrates nearly 2,500 years ago, is receiving

renewed interest. In particular, there has been

an explosion of consumer interest in the health

enhancing role of specific foods or physiologi-

cally-active food components, so-called func-

tional foods (Hasler, 1998). Clearly, all foods are

functional, as they provide taste, aroma, or

nutritive value. Within the last decade, however,

the term functional as it applies to food has

adopted a different connotation—that of

providing anadditional physiological benefit

beyond that of meeting basic nutritional needs.

This Scientific Status Summary reviews the

literature for the primary plant and animal

foods that have been linked with physiological

benefits. Although a plethora of biologically-

active compounds have been identified in this

regard (Kuhn, 1998), this review focuses on

foods, rather than specific compounds isolated

from foods.

Defining Functional FoodsThe term functional foods was first intro-

duced in Japan in the mid-1980s and refers toprocessed foods containing ingredients that aidspecific bodily functions in addition to being nu-tritious. To date, Japan is the only country that hasformulated a specific regulatory approval processfor functional foods. Known as Foods for Specifi ed

Health Use (FOSHU), these foods are eligible tobear a seal of approval from the Japanese Ministryof Health and Welfare (Arai, 1996). Currently, 100products are licensed as FOSHU foods in Japan.

Functional Foods:Their role in disease prevention

and health promotion

In the United States, the functional foods categoryis not recognized legally. Irrespective of this, manyorganizations have proposed definitions for thisnew and emerging area of the food and nutritionsciences. The Institute of Medicine’s Food andNutrition Board (IOM/FNB, 1994) defined func-tional foods as “any food or food ingredient thatmay provide a health benefit beyond the tradi-tional nutrients it contains.”

Health-conscious baby boomers have madefunctional foods the leading trend in the U.S. foodindustry (Meyer, 1998). Estimates, however, of themagnitude of this market vary significantly, as thereis no consensus on what constitutes a functionalfood. Decision Resources, Inc. (Waltham, 1998) es-

timates the market value of functional foods at$28.9 billion. More significant, perhaps, is the po-tential of functional foods to mitigate disease, pro-mote health, and reduce health care costs.

Functional Foods From Plant SourcesOverwhelming evidence from epidemiologi-

cal, in vivo, in vitro, and clinical trial data indi-cates that a plant-based diet can reduce the risk of chronic disease, particularly cancer. In 1992, a re-view of 200 epidemiological studies (Block et al.,1992) showed that cancer risk in people consum-ing diets high in fruits and vegetables was only

one-half that in those consuming few of thesefoods. It is now clear that there are components ina plant-based diet other than traditional nutrientsthat can reduce cancer risk. Steinmetz and Potter(1991a) identified more than a dozen classes of these biologically active plant chemicals, nowknown as “phytochemicals.”

Health professionals are gradually recognizingthe role of phytochemicals in health enhancement(ADA, 1995; Howard and Kritcheveky, 1997), aid-ed in part by the Nutrition Labeling and Educa-tion Act of 1990 (NLEA). The NLEA required nu-tr it ion labeling for most foods and allowed dis-ease- or health-related messages on food labels.

Oats. Oat products are a widely studied di-

T

CLARE M.HASLER, PH.D.Executive Director, Functional

Foods for Health Program,

University of Illinois, Dept. of Food

Science and Human Nutrition,

10 3 ABL (M/C 640 ) ,

1302 W. Pennsylvania Ave.,

Urbana, IL 61 80 1.

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etary source of the cholesterol-loweringsoluble fiber b-glucan. There is now sig-nificant scientific agreement that con-sumption of this particular plant foodcan reduce total and low density lipopro-tein (LDL) cholesterol, thereby reducingthe risk of coronary heart disease(CHD). For this, the Food and Drug Ad-ministration (FDA) awarded the firstfood-specific health claim in January1997 (DHHS/FDA, 1997), in response toa petition submitted by the Quaker OatsCompany (Chicago, Ill.).

In its health claim petition, theQuaker Oats Company summarized 37human clinical intervention trials con-ducted between 1980 and 1995. The majority of these studies revealed statistical-ly significant reductions in total andLDL-cholesterol in hypercholesterolemicsubjects consuming either a typicalAmerican diet or a low fat diet. The dailyamount of oat bran or oatmeal con-sumed in the above studies ranged from34 g to 123 g. Quaker Oats determinedthat 3 g of b-glucan would be requiredto achieve a 5% reduction in serum cho-lesterol, an amount equivalent to ap-proximately 60 g of oatmeal or 40 g of oat bran (dry weight). Thus, a food bear-ing the health claim must contain 13 g of oat bran or 20 g oatmeal, and provide,without fortification, at least 1.0 g of b-glucan per serving. In February of 1998,the soluble fiber health claim was ex-tended to include psyllium fiber.

Soy. Soy has been in the spotlightduring the 1990s. Not only is soy a highquality protein, as assessed by the FDA’s“Protein Digestibil it y Corrected Amino

Acid Score” method, it is now thought toplay preventive and therapeutic roles incardiovascular disease (CVD), cancer,osteoporosis, and the alleviation of menopausal symptoms.

The cholesterol-lowering effect of soy is the most well-documented physio-logical effect. A 1995 meta-analysis of 38separate studies (involving 743 subjects)found that the consumption of soy pro-tein resulted in significant reductions intotal cholesterol (9.3%), LDL cholesterol(12.9%), and triglycerides (10.5%), with

a small but insignificant increase (2.4%)

in high density lipoprotein (HDL) cho-lesterol (Anderson et al., 1995). Linearregression analysis indicated that thethreshold level of soy intake at which theeffects on blood lipids became signifi-cant was 25 g. Regarding the specificcomponent responsible for the cholester-ol-lowering effect of soy, recent attention

has focused on the isoflavones (Potter,1998). Isoflavones, however, were not ef-fective in lowering cholesterol in two re-cent studies (Hodgson et al., 1998; Nestleet al., 1997). The exact mechanism bywhich soy exerts its hypocholesterolemiceffect has not been fully elucidated.

On May 4, 1998, Protein Technolo-gies International (PTI, St. Louis, Mo.)petitioned the FDA for a health claim onsoy protein containing products pertain-ing to reduced risk of CHD. Based on aneffective daily level of 25 g soy protein,

PTI proposed that the amount of soyprotein required to qualify an individualfood to bear the health claim is 6.25 gwith a minimum of 12.5 mg of totalisoflavones (aglycone form) per referenceamount customari ly consumed. On Au-gust 12, the FDA accepted PTI’s petitionand is in the process of formulating aproposed rule.

Several classes of anticarcinogens havebeen identified in soybeans, includingprotease inhibitors, phytosterols, sa-ponins, phenolic acids, phytic acid, andisoflavones (Messina and Barnes, 1991).Of these, isoflavones (genistein and daid-zein) are particularly noteworthy becausesoybeans are the only significant dietarysource of these compounds. Isoflavonesare heterocyclic phenols structurally simi-lar to the estrogenic steroids. Because theyare weak estrogens, isoflavones may act asantiestrogens by competing with themore potent, naturally-occurring endoge-nous estrogens (e.g., 17b-estradiol) forbinding to the estrogen receptor. This mayexplain why populations that consumesignificant amounts of soy (e.g., Southeast

Asia) have reduced risk of estrogen-de-pendent cancer. However, the epidemio-logical data on soy intake and cancer riskare inconsistent at the present time (Mes-sina et al., 1997). To date, there are nopublished clinical intervention trials in-vestigating the role of soy in reducingcancer risk.

Soy may also benefit bone health(Anderson and Garner, 1997). A recentclinical study involving 66 post-meno-pausal women conducted at the Univer-sity of Illinois (Erdman and Potter, 1997)

found that 40 g isolated soy protein

(ISP) per day (containing 90 mg totalisoflavones) significantly increased (ap-proximately 2%) both bone mineralcontent and density in the lumbar spineafter 6 months.

The theory that soy may alleviatemenopausal symptoms was prompted bythe observation that Asian women report

significantly lower levels of hot flushesand night sweats compared to Westernwomen. Most recently, 60 grams of ISPdaily for 3 months reduced hot flashes by45% in 104 postmenopausal women (Al-bertazzi et al., 1998). Although these ob-servations are exciting, there is a sig-nificant placebo effect in these studies,and it is too premature to suggest thatsoy may substitute for hormone replace-ment therapy.

Flaxseed. Among the major seed oils,flaxseed oi l contains the most (57%) of

the omega-3 fatty acid, a-linolenic acid.Recent research, however, has focusedmore specifically on fiber-associatedcompounds known as lignans. The twoprimary mammalian lignans, enterodioland its oxidation product, enterolactone,are formed in the intestinal tract by bac-terial action on plant lignan precursors(Setchell et al., 1981). Flaxseed is therichest source of mammalian lignan pre-cursors (Thompson et al., 1991). Becauseenterodiol and enterolactone are struc-turally similar to both naturally-occur-ring and synthetic estrogens, and havebeen shown to possess weakly estrogenicand antiestrogenic activities, they mayplay a role in the prevention of estrogen-dependent cancers. However, there areno epidemiological data and relativelyfew animal studies to support this hy-pothesis. In rodents, flaxseed has beenshown to decrease tumors of the colonand mammary gland (Thompson, 1995)as well as of the lung (Yan et al., 1998).

Fewer studies have evaluated the ef-fects of flaxseed feeding on risk markersfor cancer in humans. Phipps et al.

(1993) demonstrated that the ingestionof 10 g of flaxseed per day elicited severalhormonal changes associated with re-duced breast cancer risk. Adlercreutz etal. (1982) found that the urinary l ignanexcretion was significantly lower in post-menopausal breast cancer patients com-pared to controls eating a normal mixedor a lactovegetarian diet.

Consumption of flaxseed has alsobeen shown to reduce total and LDLcholesterol (Bierenbaum et al., 1993;Cunnane et al., 1993), as well as platelet

aggregation (Allman et al., 1995).

FunctionalFoods

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Tomatoes. Selected byEating Well

magazine as the 1997 Vegetable of the Year,tomatoes have received significant atten-tion within the last three years because of interest in lycopene, the primary caro-tenoid found in this fruit (Gerster, 1997),and its role in cancer risk reduction (Weis-burger, 1998).

In a prospective cohort study of morethan 47,000 men, those who consumed to-mato products 10 or more times per weekhad less than one-half the risk of develop-ing advanced prostate cancer (Giovannuc-ci et al., 1995). Interestingly, lycopene isthe most abundant carotenoid in the pros-tate gland (Clinton et al., 1996). Othercancers whose risk have been inversely as-sociated with serum or tissue levels of ly-copene include breast, digestive tract, cer-vix, bladder, and skin (Clinton, 1998) andpossibly lung (Li et al., 1997). Proposed

mechanisms by which lycopene could in-fluence cancer risk are related to its anti-oxidant function. Lycopene is the most ef-ficient quencher of singlet oxygen in bio-logical systems (Di Mascio et al., 1989).The antioxidant function of lycopene mayalso explain the recent observation in amulti-center European study that adiposetissue levels of carotenoids were inverselyassociated with risk for myocardial infarc-tion (Kohlmeier et al., 1997b).

Garlic. Garlic (Al lium sativum) is likelythe herb most widely quoted in the litera-ture for medicinal properties (Nagourney,1998). Thus, its not surprising that garlichas ranked as the second best selling herbin the United States for the past two years(Anon., 1998). The purported health ben-efits of garlic are numerous, includingcancer chemopreventive, antibiotic, anti-hypertensive, and cholesterol-loweringproperties (Srivastava et al., 1995).

The characteristic flavor and pungencyof garlic are due to an abundance of oil-and water-soluble, sulfur-containing ele-ments, which are also likely responsible forthe various medicinal effects ascribed to

this plant. However, intact, undisturbedbulbs of garlic contain only a few medici-nally active components. The intact garlicbulb contains an odorless amino acid, alli-in, which is converted enzymatically by al-linase into allicin when the garlic clovesare crushed (Block, 1992). This latter com-pound is responsible for the characteristicodor of fresh garlic. Allicin then spontane-ously decomposes to form numerous sul-fur-containing compounds, some of which have been investigated for theirchemopreventive activity.

Garlic components have been shown

to inhibit tumorigenesis in several ex-perimental models (Reuter et al., 1996).However, additional reports haveshown garlic to be ineffective. Incon-clusive results are likely due to di ffer-ences in the type of garlic compoundsor preparations used by various investi-gators. Considerable variation in the

quanti ty of organosulfur compoundsavailable in fresh and commerciallyavailable garlic products has been dem-onstrated (Lawson et al., 1991).

Several epidemiologic studies showthat the garl ic may be effective in re-ducing human cancer risk (Dorant etal., 1993). A relatively large case-con-trol investigation conducted in Chinashowed a strong inverse relationshipbetween stomach cancer risk and in-creasing allium intake (You et al.,1988). More recently, in a study of

more than 40,000 postmenopausalwomen, garlic consumption was asso-ciated with nearly a 50% reduction incolon cancer risk (Steinmetz et al.,1994). Not all epidemiological studies,however, have shown garlic to be pro-tective against carcinogenesis. A 1991review of 12 case-control studies(Steinmetz and Potter, 1991b), foundthat eight showed a negative associa-tion, one showed no association, andthree studies showed a positive associa-tion. A more recent review of 20 epide-miological studies (Ernst, 1997) sug-gests that allium vegetables, includingonions, may confer a protective effecton cancers of the gastrointestinal tract.

Garlic has also been advocated forthe prevention of CVD, possiblythrough antihypertensive properties.According to Silagy and Neil (1994a),however, there is still insufficient evi-dence to recommend it as a routineclinical therapy for the treatment of hy-pertensive subjects. The cardioprotec-tive effects are more likely due to itscholesterol- lowering effect. In a meta-

analysis, Warshafsky et al. (1993) sum-marized the results of five randomized,placebo-controlled clinical tr ials, in-volving 410 patients. They showed thatan average of 900 mg garlic/day (as lit-tle as one half to one clove of garl ic)could decrease total serum cholesterollevels by approximately 9%. In a sec-ond meta-analysis involving 16 trials,Silagy and Neil (1994b) reported that800 mg garlic/day reduced total choles-terol levels by 12%. The validity of bothof these reports, however, is reduced by

methodological shortcomings, includ-

ing the fact that dietary intake, weight,and/or exogenous garlic ingestion was notalways well-controlled. In a recent multi -center, randomized, placebo-controlledtrial in which dietary assessment and su-pervision were strictly controlled, 12weeks of garlic treatment was ineffectivein lowering cholesterol levels in subjects

with hypercholesterolemia (Isaacsohn etal., 1998). It is currently unclear whichcomponent in garlic is responsible for itscholesterol-lowering effect.

Broccoli and other Cruciferous Veg-etables. Epidemiological evidence has as-sociated the frequent consumption of cruciferous vegetables with decreasedcancer risk. In a recent review of 87 case-control studies, Verhoeven et al. (1996)demonstrated an inverse association be-tween consumption of total brassica veg-etables and cancer risk. The percentages

of case-control studies showing an in-verse association between consumptionof cabbage, broccoli, cauliflower, andBrussels sprouts and cancer risk were 70,56, 67, and 29%, respectively. Verhoevenet al. (1997) attributed the anticarcino-genic properties of cruciferous vegetablesto their relatively high content of glucos-inolates.

Glucosinolates are a group of glyco-sides stored within cell vacuoles of allcruciferous vegetables. Myrosinase, anenzyme found in plant cells, catalyzesthese compounds to a variety of hydroly-sis products, including isothiocyanatesand indoles. Indole-3 carbinol (I3C) iscurrently under investigation for i ts can-cer chemopreventive properties, particu-larly of the mammary gland. In addit ionto the induction of phase I and II detoxi-fication reactions, I3C may reduce can-cer risk by modulating estrogen metabo-lism. The C-16 and C-2 hydroxylationsof estrogens involve competing cyto-chrome P-450-dependent pathways, eachsharing a common estrogen substratepool. Studies suggest that the increased

formation of 2-hydroxylated (catechol)estrogen metabolites relative to 16-hy-droxylated forms, may protect againstcancer, as catechol estrogens can act asantiestrogens in cell culture. In contrast,16-hydroxyestrone is estrogenic and canbind to the estrogen receptor. In humans,I3C administered at 500 mg daily (equiv-alent to 350-500 g cabbage/day) for 1week significantly increased the extent of estradiol 2-hydroxylation in women(Michnovicz and Bradlow, 1991), sug-gesting that this compound may be a

novel approach for reducing the risk of

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C O N T I N U E D


FunctionalFoods

breast cancer. However, since I3C hasalso been shown to enhance carcinogen-esis in vivo, caution has been urged be-fore proceeding with extensive clinicaltrials (Dashwood, 1998), although suchphase I trials are currently ongoing(Wong et al., 1998).

Although a wide variety of naturallyoccurring and synthetic isothiocyanateshave been shown to prevent cancer inanimals (Hecht, 1995), attention hasbeen focused on a particular isothiocy-anate isolated from broccoli, known as

sulforaphane. Sulforaphane has beenshown to be the principal inducer of aparticular type of Phase II enzyme,quinone reductase. Fahey et al., (1997)recently demonstrated that 3-day-oldbroccoli sprouts contained 10-100 timeshigher levels of glucoraphanin (the glu-cosinolate of sulforaphane) than did cor-responding mature plants. However, inview of the importance of an overall di-etary pattern in cancer risk reduction,the clinical implications of a single phy-tochemical in isolation has been ques-tioned (Nestle, 1998).

Citrus Fruits. Several epidemiologicalstudies have shown that citrus fruits areprotective against a variety of human can-cers. Although oranges, lemons, limes,and grapefruits are a principal source of such important nutr ients as vitamin C,folate, and fiber, Elegbede et al. (1993)have suggested that another component isresponsible for the anticancer activity.Citrus fruits are particularly high in aclass of phytochemicals known as the li-monoids (Hasegawa and Miyake, 1996).

Over the last decade, evidence has

been accumulating in support of the can-cer preventative effect of limonene(Gould, 1997). Crowell (1997) showedthis compound to be effective against avariety of both spontaneous and chemi-cally-induced rodent tumors. Based onthese observations, and because it has lit-tle or no toxicity in humans, limonenehas been suggested as a good candidatefor human clinical chemoprevention trialevaluation. A metabolite of limonene,perrillyl alcohol, is currently undergoingPhase I clinical tr ials in patients with ad-

vanced malignancies (Ripple et al., 1998).

Cranberry. Cranberry juice has beenrecognized as efficacious in the treat-ment of urinary tract infections since1914, when Blatherwick (1914) reportedthat this benzoic acid-rich fruit causedacidification of the urine. Recent investi-gations have focused on the ability of cranberry juice to inhibit the adherence

of Escherichia coli to uroepitheial cells(Schmidt and Sobota, 1988). This phe-nomenon has been attributed to twocompounds: fructose and a nondialyz-able polymeric compound. The lattercompound, subsequently isolated fromcranberry and blueberry juices (Ofek etal., 1991), was found to inhibit adhesinspresent on the pili of the surface of cer-tain pathogenicE. coli .

Avorn et al. (1994) published the re-sults of the first randomized, double-blind, placebo-controlled clinical trial de-

signed to determine the effect of a com-mercial cranberry juice beverage on uri-nary tract infections. One hundred-fiftythree elderly women consuming 300 mLcranberry beverage per day had signifi-cantly reduced (58%) incidence of bacte-riuria with pyuria compared to the con-trol group after six months. Based on theresults of these studies, prevailing beliefsabout the benefits of cranberry juice onthe urinary tract appear to be justi fied.

Tea. Tea is second only to water asthe most widely consumed beverage inthe world. A great deal of attention hasbeen directed to the polyphenolic con-stituents of tea, particularly green tea(Harbowy and Balentine, 1997).Polyphenols comprise up to 30% of thetotal dry weight of fresh tea leaves. Cat-echins are the predominant and mostsignificant of all tea polyphenols (Gra-ham, 1992). The four major green teacatechins are epigallocatechin-3-gallate,epigallocatechin, epicatechin-3-gallate,and epicatechin.

In recent years, there has been a greatdeal of interest in pharmacological ef-

fects of tea (AHF, 1992). By far, most re-search on health benefits of tea has fo-cused on its cancer chemopreventive ef-fects, although the epidemiological stud-ies are inconclusive at the present time(Katiyar and Mukhtar, 1996). In a 1993review of 100 epidemiological studies(Yang and Wang, 1993), approximately2/3 of the studies found no relationshipbetween tea consumption and cancerrisk, while 20 found a positive relation-ship and only 14 studies found that teaconsumption reduced cancer risk. A

more recent review suggests that benefits

from tea consumption are restricted tohigh intakes in high-risk populations(Kohlmeier et al., 1997a). This hypothe-sis supports the recent finding that theconsumption of five or more cups of green tea per day was associated with de-creased recurrence of stage I and IIbreast cancer in Japanese women (Naka-

chi et al., 1998).In contrast to the inconclusive results

from epidemiological studies, researchfindings in laboratory animals clearlysuppor t a cancer chemopreventive effectof tea components. In fact, Dreosti etal.(1997) stated that “no other agenttested for possible chemoprevention ef-fects in animal models has elicited suchstrong activity as tea and its componentsat the concentrations usually consumedby humans.”

There is some evidence that tea con-

sumption may also reduce the risk of CVD. Hertog and coworkers (1993) re-ported that tea consumption was themajor source of flavonoids in a popula-tion of elderly men in the Netherlands.Intake of five flavonoids (quercetin,kaempferol, myricetin, apigenin, and lu-teolin), the majority of which was de-rived from tea consumption, was signifi-cantly inversely associated with mortalityfrom CHD in this population. Althoughseveral other prospective studies havedemonstrated a substantial reduction inCVD risk with tea consumption, the evi-dence is not presently conclusive(Tijburg et al., 1997).

Wine and Grapes. There is growingevidence that wine, particularly red wine,can reduce the risk of CVD. The link be-tween wine intake and CVD first becameapparent in 1979 when St. Leger et al.(1979) found a strong negative correla-tion between wine intake and death fromischemic heart disease in both men andwomen from 18 countries. France in par-ticular has a relatively low rate of CVDdespite diets high in dairy fat (Renaud

and de Lorgeril, 1992). Although this“French Paradox” can be partly ex-plained by the ability of alcohol to in-crease HDL cholesterol, more recent in-vestigations have focused on the non-al-cohol components of wine, in particular,the flavonoids.

The high phenolic content of redwine, which is about 20-50 times higherthan white wine, is due to the incorpora-tion of the grape skins into the ferment-ing grape juice during production. Kan-ner et al. (1994) showed that the black

seedless grapes and red wines (i.e., Cab-

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ernet Sauvignon and Petite Sirah) con-tain high concentrations of phenolics:920, 1800, and 3200 mg/L, respectively,while green Thomson grapes containonly 260 mg/kg phenolics. Frankel andcoworkers (1993) attributed the posi-tive benefits of red wine to the abilityof phenolic substances to prevent the

oxidation of LDL, a critical event in theprocess of atherogenesis.

Although the benefits of wine con-sumption on CVD risk reduction seempromising, a recent prospective studyof 128,934 adults in Northern Cali for-nia concluded that the benefits of alco-hol consumption on coronary riskwere not especially associated with redwine (Klatsky et al., 1997). Moreover, anote of caution is in order, as alcoholicbeverages of all kinds have been linkedto increased risk of several types of

cancer, including breast cancer (Bowlinet al., 1997). Moderate wine consump-tion has also been associated with a de-creased risk of age-related macular de-generation (Obisesan et al., 1998).

Those who desire health benefits of wine without potential risk may wishto consider alcohol-free wine, whichhas been shown to increase total plas-ma antioxidant capacity (Serafini et al.,1998). Furthermore, Day et al. (1998)showed that commercial grape juice iseffective in inhibiting the oxidation of LDL isolated from human subjects.Red wine is also a significant source of trans -resveratrol, a phytoalexin foundin grape skins (Creasy and Coffee,1988). Resveratrol has also been shownto have estrogenic properties (Gehm etal., 1997) which may explain in partthe cardiovascular benefits of winedrinking, and it has been shown to in-hibit carcinogenesis in vivo (Jang et al.,1997).

Functional Foods From AnimalSources

Although the vast number of natu-rally occurring health-enhancing sub-stances are of plant origin, there are anumber of physiologically-active com-ponents in animal products that de-serve attention for their potential rolein optimal health.

Fish. Omega-3 (n-3) fatty acids arean essential class of polyunsaturatedfatty acids (PUFAs) derived primarilyfrom fish oil. It has been suggested thatthe Western-type diet is currently defi-cient in n-3 fatty acids, which is reflect-

ed in the current estimated n-6 to n-3

dietary ratio of 20:25-1, compared to the1:1 ratio on which humans evolved (Si-mopoulos, 1991). This has prompted re-searchers to examine the role of n-3 fattyacids in a number of diseases—particu-larly cancer and CVD—and more re-cently, in early human development.

That n-3 fatty acids may play an im-

portant role in CVD was first brought tolight in the 1970s when Bang and Dyer-berg (1972) reported that Eskimos hadlow rates of this disease despite consum-ing a diet which was high in fat. The car-dioprotective effect of fish consumptionhas been observed in some prospectiveinvestigations (Krumhout et al., 1985),but not in others (Ascherio et al., 1995).Negative results could be explained bythe fact that although n-3 fatty acidshave been shown to lower triglyceridesby 25-30%, they do not lower LDL cho-

lesterol. In fact, a recent review of 72 pla-cebo-controlled human trials, showedthat n-3 fatty acids increased LDL cho-lesterol (Harris, 1996).

Although eating large amounts of fish has not unequivocally been shownto reduce CVD risk in healthy men, con-sumption of 35 g or more of fish dailyhas been shown to reduce the risk of death from nonsudden myocardial inf-arction in the Chicago Western ElectricStudy (Daviglus et al., 1997), and as littleas one serving of fish per week was asso-ciated with a significantly reduced risk of total cardiovascular mortality after 11years in more than 20,000 U.S. male phy-sicians (Albert et al., 1998).

Dairy Products. There is no doubtthat dairy products are functional foods.They are one of the best sources of calci-um, an essential nutrient which can pre-vent osteoporosis and possibly coloncancer. In view of the former, the Na-tional Academy of Sciences recently in-creased recommendations for this nutri-ent for most age groups. In addition tocalcium, however, recent research has fo-

cused specifically on other componentsin dair y products, part icularly fermenteddairy products known as probiotics. Pro-biot ics are defined as “ live microbial feedsupplements which beneficially affect thehost animal by improving its intestinalmicrobial balance” (Fuller, 1994).

It is estimated that over 400 speciesof bacteria, separated into two broad cat-egories, inhabit the human gastrointesti -nal tract. The categories are: those con-sidered to be beneficial (e.g., Bifidobacte- rium and Lactobacillusand those consid-

ered detrimental (e.g., Enterobacteriaceae

and Clostridium spp.). Of the beneficialmicroorganisms traditionally used infood fermentation, lactic acid bacteriahave attracted the most attention (Sand-ers, 1994). Although a variety of healthbenefits have been attributed to probiot-ics, their anticarcinogenic, hypocholes-terolemic and antagonistic actions

against enteric pathogens and other in-testinal organisms have received themost attention (Mital and Garg, 1995).

The hypocholesterolemic effect of fermented milk was discovered morethan 30 years ago during studies con-ducted in Maasai tribesmen in Africa(Mann et al., 1964). The Maasai have lowlevels of serum cholesterol and clinicalcoronary heart disease despite a highmeat diet. However, they consume daily4 to 5 L of fermented whole milk. Al-though a number of human clinical

studies have assessed the cholesterol-lowering effects of fermented milk prod-ucts (Sanders, 1994), results are equivo-cal. Study outcomes have been compli-cated by inadequate sample sizes, failureto control nutrient intake and energy ex-penditure, and variations in baselineblood lipids.

More evidence supports the role of probiotics in cancer risk reduction, par-ticularly colon cancer (Mital and Garg,1995). This observation may be due tothe fact that lactic acid cultures can alterthe activity of fecal enzymes (e.g., b-glu-curonidase, azoreductase, nitroreduc-tase) that are thought to play a role inthe development of colon cancer. Rela-tively less attention has been focused onthe consumption of fermented milkproducts and breast cancer risk, al-though an inverse relationship has beenobserved in some studies (Talamini et al.,1984; van’t Veer et al.,1989).

In addition to probiotics, there isgrowing interest in fermentable carbohy-drates that feed the good microflora of the gut. These prebiotics, defined by Gib-

son and Roberfroid (1995) as “nondi-gestible food ingredients that beneficiallyaffect the host by selectively stimulatingthe growth and/or activity of one or alimited number of bacteria in the colonand thus improves host health,” may in-clude starches, dietary fibers, other non-absorbable sugars, sugar alcohols, andoligosaccharides (Gibson et al., 1996). Of these, oligosaccharides have received themost attention, and numerous healthbenefits have been attributed to them(Tomomatsu, 1994). Oligosaccharides

consist of short chain polysaccharides

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FunctionalFoods

C O N T I N U E D


Pathogen Temperature Time to toxin Food° C ° F formation (h)

composed of three and 10 simple sugarslinked together. They are found naturallyin many fruits and vegetables (includingbanana, garlic, onions, milk, honey, arti-chokes). The prebiot ic concept has beenfurther extended to encompass the con-cept of synbiotics, a mixture of pro- andprebiotics (Gibson and Roberfroid,1995). Many synbiotic products are cur-rently on the market in Europe.

Beef. An anticarcinogenic fatty acidknown as conjugated linoleic acid (CLA)was first isolated from grilled beef in

1987 (Ha et al., 1987). CLA refers to amixture of positional and geometric iso-mers of l inoleic acid (18:2 n-6) in whichthe double bonds are conjugated insteadof existing in the typical methylene inter-rupted configuration. Nine different iso-mers of CLA have been reported as oc-curring naturally in food. CLA is uniquein that it i s found in highest concentra-tions in fat from ruminant animals (e.g.,beef, dairy, and lamb). Beef fat contains3.1 to 8.5 mg CLA/g fat with the 9-cis

and 11-trans isomers contributing 57-85% of the total CLA (Decker, 1995). In-terestingly, CLA increases in foods thatare cooked and/or otherwise processed.This is significant in view of the fact thatmany mutagens and carcinogens havebeen identified in cooked meats.

Over the past decade, CLA has beenshown to be effective in suppressingforestomach tumors in mice, aberrantcolonic crypt foci in rats, and mammarycarcinogenesis in rats (Ip and Scimeca,1997). In the mammary tumor model,CLA is an effective anticarcinogen in therange of 0.1-1% in the diet, which is

higher than the estimated consumptionof approximately 1 g CLA/person/day inthe United States. These results are notdue to displacement of linoleic acid incells, suggesting that there may beunique mechanism(s) by which CLAmodulates tumor development. Thus,there has been research designed to in-crease the CLA content in dairy cowmilk through dietary modification (Kellyet al., 1998).

More recently, CLA has been investi-gated for its ability to change body com-

position, suggesting a role as a weight re-

duction agent. Mice fed CLA-supple-mented diets (0.5%) exhibited 60% lowerbody fat and 14% increased lean bodymass relative to controls (Park et al.,1997), possibly by reducing fat depositionand increasing lipolysis in adipocytes.

Safety Issues

Although “ increasing the availabilityof healthful foods, including functionalfoods, in the American diet is cri tical toensuring a healthier population” (ADA,1995), safety is a critical issue. The opti-mal levels of the majority of the biologi-cally active components currently underinvestigation have yet to be determined.In addition, a number of animal studiesshow that some of the same phytochemi-cals (e.g., allyl isothiocyanate) highlight-ed in this review for their cancer-pre-venting properties have been shown to

be carcinogenic at high concentrations(Ames et al., 1990). Thus, Paracelsus’15th century doctrine that “All substanc-es are poisons . . . the right dose differen-tiates a poison from a remedy” is evenmore pert inent today given the proclivityfor dietary supplements.

The benefits and risks to individualsand populations as a whole must beweighed carefully when considering thewidespread use of physiologically-activefunctional foods. For example, what arethe risks of recommending the increasedintake of compounds (e.g., isoflavones)that may modulate estrogen metabo-lism?Soy phytoestrogens may representa “double-edged sword” because of re-ports that genistein may actually promote

certain types of tumors in animals (Raoet al., 1997). Knowledge of toxicity of functional food components is crucial todecrease the risk:benefit ratio.

ConclusionMounting evidence supports the ob-

servation that functional foods contain-ing physiologically-active components,

either from plant or animal sources, mayenhance health. It should be stressed,however, that functional foods are not amagic bullet or universal panacea forpoor health habits. There are no “good”or “bad” foods, but there are good or baddiets. Emphasis must be placed on over-all dietary pattern—one that follows thecurrent U.S. Dietary Guidelines, and isplant-based, high in fiber, low in animalfat, and contains 5-9 servings of fruitsand vegetables per day. Moreover, diet isonly one component of an overall life-

style that can have an impact on health;

other components include smoking,physical activity, and stress.

Health-conscious consumers are in-creasingly seeking functional foods in aneffort to control their own health andwell-being. The field of functional foods,however, is in its infancy. Claims abouthealth benefits of functional foods must

be based on sound scientific criteria(Clydesdale, 1997). A number of factorscomplicate the establishment of a strongscientific foundation, however. Thesefactors include the complexity of thefood substance, effects on the food, com-pensatory metabolic changes that mayoccur with dietary changes, and, lack of surrogate markers of disease develop-ment. Additional research is necessary tosubstantiate the potential health benefitsof those foods for which the diet-healthrelationships are not sufficiently scientif-

ically validated.Research into functional foods willnot advance public health unless thebenefits of the foods are effectively com-municated to the consumer. The Har-vard School of Public Health (Boston,Mass.) and the International Food Infor-mation Council Foundation (Washing-ton, D.C.) recently released a set of com-munication guidelines, aimed at scien-tists, journal editors, journalists, interestgroups, and others for improving publicunderstanding of emerging science. Theguidelines are intended to help ensurethat research results about nutrition,food safety, and health are communicat-ed in a clear, balanced, and non-mislead-ing manner (Fineberg and Rowe, 1998).

Finally, those foods whose healthbenefi ts are supported by sufficient sci-entific substantiation have the potentialto be an increasingly important compo-nent of a healthy lifestyle and to be bene-ficial to the public and the food industry.

REFERENCESADA. 19 95 . Position of the American Dietetic Associa-

tion: Phytochemicals and functional foods. J. Am. Diet.Assoc. 95 : 49 3 -49 6 .

AHF.1 99 2. Physiological and pharmacological effects ofCamellia snensis (Tea): Implications for cardiovasculardisease, cancer, and public health. American HealthFoundation, Valhalla, New York, Prevent. Med. 21:3 2 9 - 3 9 1 a n d 5 0 3 - 5 5 3 .

Adlercreutz, H., Fotsis, T., Heikkinen, R., Dwyer, J.T.,Woods, M., Goldin, B.R., and Gorbach, S.L. 1982. Ex-cretion of the lignans enterolactone and enterodiol andof equol in om nivorous and vegetarian postmenopausalwom en and in wom en with breast cancer. Lancet ii:1 2 9 5 - 1 2 9 9 .

Albert, C.M., Hennekens, C.H., O’Donnell, C.J., Ajani,U.A., Carey, V.J., Willett, W.C., Ruskin, J.N., and Man-son, J.E. 1998. Fish consumption and risk of sudden

card iac death. J. Am. Med. Assoc. 279 : 23 -28 .

8/13/2019 funcfood_1198




Albertazzi, P., Pansini, F., Bonaccorsi G., Zanotti, L., Fori-ni, E., and De Aloysio, D. 19 98 . The effect of dietarysoy supplementation on hot flushes. Obstet. Gynecol9 1 : 6 - 1 1 .

Allman, M.A., Pena, M.M., and Pang, D. 1995. Supple-mentation with flaxseed oil versus sunflowerseed oil inhealthy young m en consuming a low fat diet: Effects onplatelet composition and function. Eur. J. Clin. Nutr 49:1 6 9 - 1 7 8 .

Ames, B.N., Magaw, R., and Gold, L.W. 1990. Ranking

possible carcinogenic hazards. Science 236: 271-2 8 0 .

Anderson, J.W., Johnstone, B.M. , and Cook- Newell, M.E.19 95 . M eta-analysis of the effects of soy protein in-take on serum lipids. New Engl. J. Med. 333: 276-2 8 2 .

Anderson, J.J.B. and Garner, S.C. 1997. The effects ofphytoestrogens on bone. Nutr. Res. 17: 1617-1632.

Anonymous. 19 98 . U.S. topselling herbs and supple-ments. Nutraceuticals Intl. 3 (2): 9.

Arai, S. 19 96 . Studies on functional foods in Japan–State of the art. Biosci. Biotech. Biochem. 60 : 9 -15 .

Ascherio, A., Rimm, E.B., Stam pfer, M .J., Giovannucci,E.L., and Willett, W.C. 1 99 5. Dietary intake of m arinen-3 fatty acids, fish intake, and the risk of coronary dis-ease among men. New Eng. J. Med. 332 : 977 -98 2.

Avorn, J., Mo nane, M ., Gurwitz, J.H., Glynn, R.J., Chood-novskiy, I., and Lipsitz, L.A. 1 99 4. Reduction of bacte-riuria and pyuria after ingestion of cranberry juice- AReply. J. Am. Med. Assoc. 272 : 58 9-5 90 .

Bang, H.O. and Dyerberg, J. 19 72 . Plasma lipids and li-poproteins in Greenlandic w est-coast Eskimos. Acta.Med . Scand 192 : 8 5 -94 .

Bierenbaum, M.L., Reichstein, R. and Watkins, T.R.1993. Reducing atherogenic risk in hyperlipemic hu-mans with flax seed supplementation: A preliminary re-por t. J. Am. Col l. Nutr. 12 : 50 1-5 04 .

Blatherwick, N.R. 19 14 . The specific role of foods in re-lation to the composition of the urine. Arch. Int. Med.1 4 : 4 0 9 - 4 5 0 .

Block, E. 1992. The organosulfur chemistry of the genusAllium -- Implications for the organic chem istry of sulfur.

Angew. Chem. Int. Edn. Engl. 31: 1 13 5-1 17 8.Block, G., Patterson, B. and Subar, A. 19 92 . Fruit, vege-tables, and cancer prevention: A review of the epidemi-ological evidence. Nutr. Cancer 18: 1-29.

Bowlin, S.J., Leske, M.C., Varma, A., Nasca, P., Wein-stein, A. and Caplan, L. 19 97 . Breast cancer r isk andalcohol consumption: Results from a large case-controlstudy. Intl. J. Epidemiol. 26: 915-923.

Clinton, S.K. 19 98 . Lycopene: Chem istry, biology, andimplications for human health and disease. Nutr. Rev.5 6 : 3 5 - 5 1 .

Clinton, S.K., Emenhiser, C., Schwartz, S.J., Bostwick,D.G., Williams, A.W., Moore, B.J. and Erdman, Jr, J.W.19 96 . Cis-trans lycopene isomers, carotenoids, andretinol in the human prostate. Cancer Epidemiol. Biom-arkers Prev. 5: 8 23 -83 3.

Clydesdale, F.M. 19 97 . A proposal for the establishmentof scientific criteria for health claims for functionalfoods. Nutr. Rev. 55 (12) : 413 -42 2.

Creasy, L.L. and Coffee, M.1 98 8. Phytoalexin productionof grape berries. J. Am. Soc. Hort. Sci. 113: 230-234.

Crowell, P.L. 1 99 7. M onoterpenes in breast cancerchemoprevention. Breast Cancer Res. Treatment 46 :1 9 1 - 1 9 7 .

Cunnane, S.C., Ganguli, S., Menard, C., Liede, A.C., Ha-madeh, M.J., Chen, Z-Y., Wolever, T.M.S. and Jenkins,D.J.A. 199 3. H igh-linolenic acid flaxseed (Linum usi- tatissimum ): some nutritional properties in humans. Br.J. Nutr . 69: 443-453.

DHHS/FDA. 1997. Food labeling: Health claims; oatsand coronary heart disease. Dept. Health and HumanServices/Food and Drug Adm inistration. Fed. Reg. 62 :3 5 8 4 - 3 6 0 1 .

Dashwood, R.H. 1998. Indol-3-carbinol–Anticarcinogen

or tumor promoter in B rassica vegetables. Chem.- Biol.Ineractions 11 0: 1-5 .

Daviglus, M.L., Stamler, J., Orencia, A.J., Dyer, A.R., Liu,K., Greenland, P., Walsh, M., Morris, D., and Shekelle,R.B. 1997. Fish consumption and the 30-year r isk offatal myocardial infarction. New Eng. J. Med. 3 36 :1 0 4 6 - 1 0 5 3 .

Day, A. P., Kemp, H.J., Bolton, C., Hartog, M., Stansbie,D. 1998. Effects of concentrated red grape juice con-sumption on serum antioxidant capacity and low-densi-

ty lipoprotein oxidation. Ann. Nutr. Metab. 41 : 35 3-3 5 7 .

Decker, E.A. 1 99 5. The role of phenolics, conjugated li-noleic acid, carnosine, and pyrroloquinoline quinone asnonessential dietary antioxidants. Nutr. Rev. 5 3: 49 -5 8.

Di Mascio, P., Kaiser, S., and Sies, H. 1989. Lycopene asthe m ost efficient biological carotenoid singlet oxygenquencher. Arch. Biochem. Biophys. 27 4: 5 32 -53 8.

Dorant, E., van den Brandt, P.A., Goldbohm, R.A., Her-mus, R.J.J., and Sturmans, F. 19 93 . Garlic and its sig-nificance for the prevention of c ancer in humans: Acritical review. Br. J. Cancer 67: 424-429.

Dreosti, I.E., Wargovich, M.J., and Yang, C.S. 1 99 7. Inhi-bition of carcinogenesis by tea: The evidence from ex-perimental studies. Crit. Rev. Food Sci. Nutr. 37 : 7 61 -7 7 0 .

Elegbede, J.A., Maltzman, T.H., Elson, C.E., and Gould,M.N. 1993. Effects of anticarcinogenic monoterpeneson phase II hepatic metabolizing enzymes. Carcinogen-es is 14 : 1221 -1223 .

Erdman, J.W., Jr., and Potter, S.M. 19 97 . Soy and bonehealth. The Soy Connection 5 (2): 1 , 4.

Ernst, E. 19 97 . Can allium vegetables prevent cancer?Phytomed . 4 : 7 9 -83 .

Fahey, J.W., Zhang, Y., and Talalay, P. 1997. Broccolisprouts: An exceptionally r ich source of inducers of en-zymes that protect against chemical carcinogens. Proc.Natl . Acad. Sci . 94: 10366-10372.

Fineberg, H.V. and Rowe, S. 19 98 . Improving public un-derstanding: Guidelines for com municating emergingscience on nutrition, food safety and health. J. Natl.Cancer Inst. 90: 194-199.

Frankel, E.N., Kanner, J., German, J.B., Parks, E. and Kin-sella, J.E. 19 93 . Inhibition of oxidation of human low-density lipoprotein by phenolic substances in red wine.The Lance t 341 : 45 4 -45 7 .

Fuller, R. 1 99 4. History and development of probiotics. In“Probiotics,” ed. R. Fuller, pp. 1 -8 . Chapman & Hall,N.Y.

Gehm, B.D., McAndrews, J.M. , Chien, P.-Y., and Jame-son, J.L. 1997. Resveratrol, a polyphenolic compoundfound in grapes and wine, is an agonist for the estro-gen receptor. Proc. Natl. Acad. Sci. 94: 14138-1 4 1 4 3 .

Gerster, H. 1 99 7. The p otential role of lycopene for hu-man health. J. Am. Coll. Nutr. 16: 109-126.

Gibson, G. and Roberfroid, M.B. 19 95 . Dietary modula-tion of the human colonic mibrobiota: Introducing theconcept of prebiot ics. J. Nutr. 12 5: 1 40 1-1 41 2.

Gibson, G.R., Williams, A., Reading, S., and Collins, M.D.19 96 . Fermentation of non-digestible oligosaccharides byhuman colonic bacteria. Proc. Nutr. Soc. 55: 899-912.

Giovannucci, E., Ascherio, A., Rimm, E.B., Stampfer,M.J., Colditz, G.A., and Willett, W.C. 19 95 . Intake ofcarotenoids and retinol in relation to risk of prostatecancer. J. Natl. Cancer Inst. 87: 1767-1776.

Gould, M.N. 1997. Cancer chemoprevention and therapyby monoterpenes. Environ. Health Perspec. 105: 977-9 7 9 .

Graham, H.N. 1992. Green tea composition, consump-tion and polyphenol chemistry. Prev. Med. 21: 334-3 5 0 .

Ha, Y.L., Grimm, N.K., and Pariza, M. W. 19 87 . Anticar-cinogens from fried ground beef: Health-altered deriva-tives of linoleic acid. Carcinogenesis 8: 1881-1887.

Harbowy, M.E. and Balentine, D.A. 19 97 . Tea Chemistry.

Crit. Rev. Plant Sci. 16: 415-480.Harris, W.S. 19 96 . N-3 fatty acids and lipoproteins–Co m-

parison of results from human and animal studies.Hasegawa, S. and Miyake, M. 1996. Biochemistry and

biological functions of citrus limonoids. Food Rev. Intl.1 2 : 4 1 3 - 4 3 5 .

Hasler, C.M. 19 98 . A new look at an ancient concept.Chem. Industry Feb. 2: 84-89.

Hecht, S.S. 19 95 . Chemoprevention by isothiocyanates.J. Cel l. Biochem. Suppl. 22: 19 5-2 09 .

Hertog, M.G.L., Feskens, E.J.M., Hollman, P.C.H., Katan,M.B., and Krum hout, D. 199 3. Dietary antioxidant fla-vonoids and risk of coronary heart disease: The Zut-phen Elderly Study. The Lancet 342 : 10 07 -10 11 .

Hodgson, J.M ., Puddey, I.B., Beilin, L.J., M ori, T.A., andCroft, K.D. 19 98 . Supplementation with isoflavonoidphytoestrogens does not alter serum lipid c oncentra-tions: A randomized controlled trial in humans. J. Nutr.1 2 8 : 7 2 8 - 7 3 2 .

Howard, B.V. and Kritchevsky, D. 19 97 . Phytochemicalsand c ardiovascular disease–A statement for healthcareprofessionals from the American Heart Association. Cir-cu la tion 95 : 2 591 -259 3 .

IOM/NAS. 19 94 . “Opportunities in the Nutrition and FoodSciences”, ed. P.R. Thomas and R. Earl, p. 1 09 . Insti-tute of Med icine/National Academy o f Sciences, Na-

tional Academy Press, Washington, D.C.Ip, C. and Scim eca, J.A. 19 97 . Conjugated linoleic acid

and linoleic acid are distinctive modulators of m amma-ry carcinogenesis. Nutr. Cancer 27: 131-135.

Isaacsohn, J.L., Moser, M., Stein, E.A., Dudley, K., Davey,J.A., Liskov, E., and Black, H.R. 1998. Garlic powderand plasma lipids and lipoproteins: A multicenter, ran-domized, p lacebo-controlled tr ial. Arch. Int. Med.1 5 8 : 1 1 8 9 – 1 1 9 4 .

Jang, M., Cai, J., Udeani, G.., Slowing, K.V., Thomas,C.F., Beecher, C.W.W., Fong, H.H.S., Farnsworth, N.R.,Kinghorn, A.D., Mehta, R.G., Moon, R.C., and Pezzuto,J.M. 1 99 7. Cancer chem opreventive activity of resver-atrol, a natural product derived from grapes. Science2 7 5 : 2 1 8 - 2 2 0 .

Kanner, J., Frankel, E., Granit, R., German, B., and Kin-

sella, J.E. 1 99 4. Natural antioxidants in grapes andwines. J. Agric. Food Chem. 42: 64-69.Katiyar, S.K. and Mukhtar, H. 1996. Tea in chemopreven-

tion of cancer: Epidemiologic and experimental studies(review). Intl. J. Oncol. 8: 221-238.

Kelly, M. L., Berry, J.R., Dwyer, D.A., Griinari, J.M.,Chounard, P.Y., Van Amburgh, M.E., and Bauman, D.E.19 98 . Dietary fatty acid sources affect conjugated li-noleic acid conc entrations in milk from lactating dairycows. J. Nutr . 128: 881-885.

Klatsky, A.L., Armstrong, M.A., and Friedman, G.D. 19 97 .Red wine, white wine, liquor, beer, and risk for coronaryartery disease hospitalization. Am. J. Cardiol. 80 : 41 6-4 2 0 .

Kohlmeier, L., Weerings, K.G.C., Steck, S., and Kok, F.J.19 97 . Tea and cancer prevention–An evaluation of theepidemiologic literature. Nutr. Cancer 27 : 1 -1 3.

Kohlmeier, L., Kark, J.D., Gomez-Gracia, E., Martin, B.C.,Steck, S.E., Kardinaal, A.F.M. , Ringstad, J., Thamm,M., Masaev, V., Riemersma, R. , Martin-Moreno, J.M. ,Huttunen, J.K., and Kok, F.J. 19 97 . Lycopene and my-ocardial infarction risk in the EURAMIC study. Am. J.Epidemiol .146 : 618 -626 .

Kuhn, M.E. 1998. Functional foods overdose? FoodProc. 59 (5) : 21-48.

Krumhout, D., Bosschieter, E.B., and de Lezenne Cou-lander, C. 1985. The inverse relation between fish con-sumption and 20-year mortality from coronary heartd isease. New Eng. J. Med. 312 : 12 05 -12 09 .

Lawson, L.D., Wang, Z-Y.J., and Hughes, B.G. 19 91 .Identification and HPLC quantitation of the sulfides anddialk(en)ylthiosulfinates in commercial garlic products.P lanta Med . 57 : 3 63 -3 70 .

Li, Y., Elie, M., Blaner, W.S., Brandt-Rauf, P., and Ford, J.

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1997. Lycopene, smoking and lung cancer. Proc. Am.Assoc.. Cancer Res. 38: 113 (abstract #758).

Mann, G.V., Schaffer, R.D., Anderson, R.D., and Sand-stead, H.H. 1964. Cardiovascular disease in the Maa-sai. J. Atheroscler. Res. 4: 289-312.

Messina, M. and Barnes, S. 19 91 . The role of soy prod-ucts in reducing risk of cancer. J. Natl. Cancer Inst. 83:5 4 1 - 5 4 6 .

Messina, M., Barnes, S., and Setchell, K.D.R. 19 97 . Phy-tooestrogens and breast cancer. Lancet 350: 971-9 7 2 .

Meyer , A. 1998. The 1998 top 100 ® R&D survey. FoodProcessing 58(8) : 32-40.

Michnovicz, J.J. and Bradlow, H.L. 1991. Altered estrogenmetabolism and excretion in humans following con-sumption of indole carbinol. Nutr. Cancer 16: 59-66.

Mital, B.K. and Garg, S.K. 19 95 . Anticarcinogenic, hypoc-holesterolemic, and antagonistic activities of Lactobacil- lus acidophilus . Cr it . Rev. Micro. 21 : 17 5-2 14 .

Nakachi, K., Suemasu, K., Suga, K., Takeo, T., Imai, K.,and Higashi, Y. 19 98 . Influence of d rinking green teaon breast cancer malignancy among Japanese pa-tients. Jap. J. Cancer Res. 89: 254-261.

Nagourney, R.A. 1 99 8. Garlic: Medicinal food or nutri-tious medicine? J. Medicinal Food 1: 13-28.

Nestle, P.J., Yamashita, T., Sasahara, T., Pom eroy, S.,Dart, A., Komesaroff, P., Owen, A., and Abbey, M.1997. Soy isoflavones improve systemic arterial com-pliance but not plasma lipids in m enopausal and peri-menopausal women. Arterioscler. Thromb. Vasc. Biol.1 7 : 3 3 9 2 - 3 3 9 8 .

Nestle, M. 1 99 8. Broc coli sprouts in cancer prevention.

Nutr. Rev. 56 : 127 -13 0.Obisesan, T.O., Hirsch, R., Kosoko, O., Carlson, L., andParrott, M. 1998. Moderate wine consumption is asso-ciated with decreased odds of developing age-relatedmacular degeneration in NHANES-1. J. Amer. GeriatricsSoc. 46 : 1 - 7 .

Ofek, I., Goldhar, J., Zafriri, D., Lis, H., Adar, R., andSharon, N. 1991. Anti- Escherichia coli adhesin activityof cranberry and blueberry juices. New Eng. J. Med.3 2 4 : 1 5 9 9 .

Park, Y., Albrigh, K.J., Liu, W., Storkson, J.M., Cook,M.E., and Pariza, M.W. 19 97 . Effect of conjugated li-noleic acid on body composition in mice. Lipids 32:8 5 3 - 8 5 8 .

Phipps, W.R., Martini, M.C., Lampe, J.W., Slavin, J.L.,and Kurzer, M. S. 199 3. Effect of flax seed ingestion onthe menstrual cycle. J. Clin. Endocrin. Metab. 77:1 2 1 5 - 1 2 1 9 .

Potter, S.M. 1 99 8. Soy protein and cardiovascular dis-ease: The impact of bioactive components in soy. Nutr.Rev. 56(8) :231-235.

Rao, C.V., Wang, C.X., Simi, B., Lubet, R., Kellogg, G.,Steele, V., and Reddy, B.S. 19 97 . Enhancement of ex-perimental colon cancer by genistein. Cancer Res. 57 :3 7 1 7 - 3 7 2 2 .

Reuter H.D., Koch, H.P, and Lawson, L.D. 19 96 . Thera-peutic effects and applications of garlic and its prepa-rations. In: Garlic. The Science and Therapeutic Appli-cation of Allium sativum L. and Related Species, 2ndEd., ed., H.P. Koch and L.D. Lawson, Williams &Wilkins, Baltimore.

Renaud, W. and de Lorgeril, M. 1 99 2. W ine, alcohol,platelets, and the French paradox for coronary heart

d isease. The Lancet 339: 1523-1526.

Ripple, G.H., Gould, M.N., Stewart, J.A., Tutsch, K.D., Ar-zoomanian, R.Z., Alberti, D., Feierabend, C., Pomplun,M., W ilding, G., and B ailey, H.H. 19 98 . Phase I clinicaltrial of peillyl alcohol administered daily. Clin. CancerRes. 4 : 1159 -1164 .

Sanders, M.E. 1994. Lactic acid bacteria as promotersof human health. In: “Functional Foods— DesignerFoods, Pharmafoods, Nutraceuticals”, ed. I. Goldberg,pp. 294-322. Chapman & Hall, N.Y.

Schmidt, D.R. and Sobota, A.E. 1988. An examination of

the anti-adherence activity of cranberry juice on urinaryand nonurinary bacterial isolates. Microbios. 55: 17 3-1 8 1 .

Serafini, M., M aiani, G., and Ferro-Luzzi, A. 19 98 . Alco-hol-free red w ine enhances plasma antioxidant capaci-ty in humans. J. Nutr. 12 8: 1 00 3-1 00 7.

Setchell, K.D.R., Lawson, A.M., Borriello, S.P., Harkness,R., Gordon, H., Morgan, D.M.L, Kirk, D.N., Adlercreutz,H., Anderson, L.C., and Axelson, M. 1 98 1. Lignan for-mation in man— microbial involvement and possibleroles in relation to cancer. The Lancet ii: 4-7.

Silagy, C.A. and Neil, H.A.W. 1 99 4a. A m eta-analysis ofthe effect of garlic on blood pressure. J. Hyper. 12:4 6 3 - 4 6 8 .

Silagy, C. and Neil, A. 1994b. Garlic as a lipid-loweringagent— a meta- analysis. J. Royal Coll. Physicians

Lond . 28 : 39 -45 .Simopoulos, A.P. 19 91 . Omega-3 fatty acids in health

and disease and in growth and development. Am. J.Cl in . Nutr. 54: 4 38 -46 3.

Srivastava, K.C., Bordia, A., and Verma, S.K. 1995. Garlic(Allium sativum ) for disease prevention. S. Afr. J. Sci.9 1 : 6 8 - 7 7 .

St. Leger, A.S., Cochrane, A.L., and M oore, F. 1 97 9.Factors associated with cardiac mortality in developedcountries with particular reference to the consum ptionof wine. The Lancet i: 10 17 -10 20 .

Steinmetz, K.A. and Potter, J.D. 1991a. Vegetables, fruitand cancer II. Mechanisms. Cancer Causes Control 2 :4 2 7 - 4 4 2 .

Steinmetz, K.A. and Potter, J.D. 1991b. Vegetables, fruitand cancer I. Cancer Causes Control 2: 325-357.

Steinmetz, K.A., Kushi, H., B ostick, R.M. , Folsom, A.R.,and Potter, J.D. 1994. Vegetables, fruit, and colon can-cer in the Iowa W omen’s Health Study. Am. J. Epidemi-o l. 1 3 9 : 1 - 1 5 .

Talamini, R., L a Vecchia, C., Decarli, A., et al. 19 84 . So-cial factors, diet and breast cancer in a northern Italianpopulation. Br. J. Cancer 49: 723-729.

Thompson, L.U., Robb, P., Serraino, M., and Cheung, F.1991. Mammalian lignan production from variousfoods. Nutr. Cancer 16: 43-52.

Thompson, L.U. 1995. Flaxseed, lignans, and cancer. In:“Flaxseed in Human Nutrition,” ed. S. Cunnane and L.U.Thompson, pp. 21 9- 23 6. AOCS Press, Champaign, IL.

Tijburg, L.B.M. Mattern, T., Folts, J.D., Weisgerber, U.M.,and Katan, M.B. 1 99 7. Tea flavonoids and cardiovas-cular diseases: A review. Crit. Rev. Food Sci. Nutr. 37:7 7 1 - 7 8 5 .

Tomom atsu, H. 19 94 . Health effects of oligosaccharides.Food Technol. 48 : 61 -65 .

van’t Veer, P., Dekker, J.M., Lamers, J.W.J., Kok, F.J.,Schouten E.G., Brants, H.A.M., Sturmans, F., and Her-mus, R.J.J. 1989. Consumption of fermented milkproducts and breast cancer: A case-c ontrol study inthe Netherlands. Cancer Res. 49: 4020-4023.

Verhoeven, D.T.H., Goldbohm, R.A., van Poppel, G., Ver-hagen, H., and van den Brandt, P.A. 1996. Epidemio-logical studies on brassica vegetables and c ancer r isk.Cancer Epidemiol. Biomarkers Prev. 5: 733-748.

Verhoeven, D.T.H., Verhagen, H., Goldbohm, R.A., vanden Brandt, P.A., and van Poppel, G. 19 97 . A reviewof m echanisms underlying anticarcinogenicity by bras-sica vegetables. Chem. Bio. Interactions 103: 79-129.

Waltham, M.S. 1998. Roadmaps to Market: Commer-

cializing Functional Foods and Nutraceuticals, DecisionResources, Inc., p. 5.

Warshafsky, S., Kamer R.S., and Sivak, S.L. 1 99 3. Effectof garlic on total serum cholesterol. A meta-analysis.Ann. Int . Med . 119 : 59 9 -60 5 .

Weisburger, J.H. (ed.). 1 99 8. International symposium onlycopene and tom ato products in disease prevention.Proc. Soc. Exp. Bio l. Med. 2 18 : 93 -14 3.

Wong, G.Y.C., Bradlow, L., Sepkovic, D., Mehl, S., Mail-man, J., and Osborne, M.P. 1998. Dose-ranging studyof indole-3 -carbinol for breast cancer prevention. J.Cel l . Biochem. 22 (Suppl. 28-29) : 111-116.

Yan, L., Yee, J.A., Li, D., McGuire, M.H., and Thompson,L.U. 19 98 . Dietary flaxseed supplementation and ex-perimental metastasis of melanoma c ells in mice. Can-ce r Le tt . 124 : 181 -186 .

Yang, C.S. and Wang, Z-Y. 1993. Tea and cancer. J. Natl.Cancer Inst. 85: 1038-1049.You, W-C., Blot, W.J., Chang, Y-S., Ershow, A.G., Yang,

Z.-T., An, Q. Henderson, B., Xu, G.-W., Fraumeni, J.F.,and Wang, T.-G. 19 88 . Diet and high risk of stomachcancer in Shandong, China. Cancer Res. 48: 3518-3 5 2 3 .

FunctionalFoods

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S C I E N C E C O M M U N I C AT I O N S

JOHN A. MILNER, PH.D.

Nutrition Department and Graduate Programin Nutrition, The Pennsylvania State Univ.

By

Belief in the medicinal power of foods is not a recent event. While

Hippocrates may not have started this movement, he proclaimed

almost 2,500 years ago to “Let food be thy medicine and medi-

cine be thy food.” Today, while such a statement might result in

severe reprimands, if not litigations, these penalties have not

deterred consumers from seeking the health benefits of foods.

Increasingly, scientists are being charged with the responsibility

of clarifying the role that foods play in maintaining and promot-

ing health. The Scientific Status Summary, “Functional Foods:

Their Role in Disease Prevention and Health Promotion” (pp.

63–70) prepared for IFT’s Expert Panel on Food Safety and Nu-trition by Clare Hasler, reviews the primary plant and animal foods

linked with physiological benefits.

A variety of foods and their components are emerging as

factors capable of modifying growth, development, performance

and disease resistance. Such discoveries may influence percep-

tions about what is appropriate nutrition, and necessitate a new

vocabulary including terms from apigenin to zeaxanthin. In the

process, a better understanding that adequate nutrition is more

than energy and essential nutrients will emerge.

The term “functional food” is surfacing as a generic descrip-

tor of the benefits from foods that go beyond those attributable

to essential nutrients. Interest in the health benefits of foods ispropelled by rising health care cost; legislative changes (i.e., the

Nutrition Labeling and Education Act and Dietary Supplement

Health and Education Act) that permit claims for foods and asso-

ciated components; and by new and exciting scientific discover-

ies. Although not a legal term, the concept of “functional foods”

is gaining consumer acceptance. Nevertheless, it is surrounded

by controversy and even condemnation. Much of the concern

arises from the view that while diets might justifiably be charac-

terized as “good or bad,” foods should not be so described. In

fact, the concept might create a false sense of security about

Do “Functional Foods” OfferOpportunities to OptimizeNutrition and Health?

eating behaviors. Furthermore, while total fruit and vegetable

consumption is increasingly linked to a reduction in risk of sev-

eral diseases, the association is far less impressive when a specific

food or component is considered. Regardless, there is little rea-

son to believe that consumer acceptance of this concept will

dwindle in the foreseeable future. Accepting this movement asan opportunity to “optimize nutrition” rather than to endorse

good or bad foods or as a gimmick to foster sales will surely

make it more acceptable to most scientists.

Unquestionably food components can have physiological

consequences. Diverse compounds including allyl sulfurs, indoles,

polyphenols and isothiocyanates have the potential to modify

metabolism and ultimately influence disease risk. While

phytochemicals in plants are increasingly respected for these at-

tributes, animal products also contain positive effectors. The ability

of omega-3 fatty acids in fish or conjugated linoleic acid in milk

and meat products to alter several physiological processes raises

questions about what intakes and proportions of animal and plant

foods are needed to optimize health and well-being.

Food processing and preparation procedures also impact the

physiological consequences of food. Fermented products, includ-

ing dairy products, have long been recognized to alter gastrointes-

tinal flora and even reduce circulating cholesterol. While heating

tomatoes may improve lycopene availability and thus improve

its antioxidant potential, results from our laboratory show that

heating of unpeeled garlic reduces its anticancer potential. Clari-

fication of the role of how processing impacts bioactive compo-

nents and their interactions in foods will become increasingly

important as consumers consider dietary shifts.

While it may be prudent to increase the intake of selected

foods it must not be done without considering potential nega-

tive consequences. Establishing an upper safe and permissible

intake for functional foods and their biologically active compo-nents will be exceedingly important for vulnerable segments of

society. Such information might allow for recommendations for

an amount of garlic that reduces the risk of heart disease and

cancer while minimizing chances of gastrointestinal bleeding.

Any claims about the benefits of foods must be based on sound

and accurate scientific information. Identification of sensitive and

reliable biomarkers will be key to adequately assessing the true

impact of foods and components. Universally accepted indicators

of intake and the biological response will surely be needed given

our global market. Finally, it is assumed that all individuals will not

equally benefit, or suffer, from the enhanced intake of specific foods

or components. To assess who might benefit most it, is imperative

that a series of susceptibility biomarkers be employed that takeinto account genetics and other environmental factors.

Ingestion of functional foods represents an effective strategy

to maximize health and reduce risk of diseases. However, it would

be foolish to consider them as “magic bullets” that function un-

der all circumstances. The positive message about foods, and

the inclusion rather than exclusion of items from the diet, may

encourage consumers to be more accepting of this “functional

foods” concept. Scientific advancements and effective commu-

nication strategies will be critical to the acceptance and success

of the “functional foods” movement.


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FOODTECHNOLOGY NOVEMBER1998 VOL 52 NO 11

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