Antioxidants and Diseases 4.ppsx

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DR.SAEED BAHRMEDICAL NUTRITIONAL CONSLUTANT

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Free Radicals and Diseases

ANTIOXIDANTS

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-1:a. b. c.Vitamin C

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Vitamin A&B-Carotene Vitamin E

-2 :

Lipase Transferase CatalaseProtease Glutathion Peroxidase

b. zinic a. Coppera.Selenium

Peroxidase

DNA Repair Enzyme

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Manganese

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: : GLUTATHONE o CATALASE o SUPER OXIDE DISMUTSE o :

: : ( ) C E ) A, ) B2 B6 Q10

E C .

Flavonoids .Carotenoids . . 4000 . Catechines . . .

; Soobrattee et al., 2005; Chen et al., (2004

).2006; Peschel et al., 2006

. ) Butylated hydroxytoluene (BHT

).(Soobrattee et al., 2005; Chen et al., 2006; Dawidowicz et al., 2006; Peschel et al., 2006

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: . . . . 20 %40 .

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THE MOST PUBLICIZED ANTIOXIDANTS HAVE BEEN:

fat-soluble antioxidants: vitamin A and carotenoids, vitamin E, Coenzyme Q10water-soluble antioxidants: vitamin C, minerals zinc, selenium, manganese

Some

antioxidants are made in the body and are poorly absorbed from the intestine. One example is glutathione, which is made from amino acids. Glutathion as a supplemet in the gut is broken down and have little effect on the concentration of glutathione in the body. Ubiquinol (coenzyme Q) is also poorly absorbed from the gut and is made in humans body.

The body has a limited ability to excrete vitamins and minerals, so excessive consumption may cause a number of health problems, even in relatively small dosages. Vitamin supplements may be necessary for individuals whose diets don't provide the recommended amounts of specific vitamins and especially important for pregnant and nursing women and people with specific illnesses. However, the benefits of vitamin supplements for the general population remain uncertain.

. E,C .ASCORBIC ACID

C

. . . (A ,E ,B.COMPLEX ( . . . LDL . ; Magalhaes (Block and Evans, 2001; 2004 ).and Churchs, 2006

VITAMIN C Sources:

fruits and vegetables vary in their vitamin C content Vitamin C, also known as ascorbic acid, is a water-soluble vitamin. Unlike most mammals, humans do not have the ability to make their own vitamin C. Therefore, we must obtain vitamin C through our diet. Vitamin C is known as a highly effective antioxidant in living organisms.

Supplements: Vitamin C (ascorbic acid) is available in many forms, but there is little scientific evidence that any one form is better absorbed or more effective than another. Natural vs. synthetic vitamin C: Natural and synthetic ascorbic acid are chemically identical and there are no known differences in their biological activities or bioavailability Toxicity: A number of possible problems with very large doses of vitamin C have been suggested, mainly based on in vitro experiments or isolated case reports, including: genetic mutations, birth defects, cancer, atherosclerosis, kidney stones, increased oxidative stress, excess iron absorption, vitamin B-12 deficiency, and erosion of dental enamel. However, none of these adverse health effects have been confirmed, and there is no reliable scientific evidence that large amounts of vitamin C (up to 10 grams/day in adults) are toxic.

TOCOPHEROLS E

:

o . o Tocopherols .Tocotrenols " o " .Radicals Scavenger o , , , , . o . o 77 . 47 o . o . o T . ; Sarkar and Das, (Ramel et al., 1986; 2004 ).2006

VITAMIN E Major

sources of alpha-tocopherol in the diet include vegetable oils (olive, sunflower, safflower oils), nuts, whole grains, and green leafy vegetables. The main function of alpha-tocopherol in humans appears to be that of an antioxidant. The term vitamin E describes a family of eight antioxidants:

four tocopherols, alpha-, beta-, gamma- and delta-, and four tocotrienols (also alpha-, beta-, gamma- and delta-).

Alpha-tocopherol

is the only form of vitamin E that is actively maintained in the human body.

Toxicity: High-dose vitamin E supplementation increases the risk of hemorrhage. Supplementation with 400 IU/day of vitamin E has been found to accelerate the progression of retinitis pigmentosa.

GOOD SOURCES (THE RDA FOR VITAMIN E WAS PREVIOUSLY AND 10 MG/DAY FOR MEN)

8 MG/DAY FOR WOMEN

Food Olive oil Soybean oil Corn oil Canola oil Safflower oil Almonds Hazelnuts Peanuts Spinach Carrots Avocado

Serving 1 tablespoon 1 tablespoon 1 tablespoon 1 tablespoon 1 tablespoon 1 ounce (30 g) 1 ounce (30 g) 1 ounce (30 g) cup, raw chopped cup, raw chopped 1 medium

Alpha-tocopherol (mg) 1.9 1.2 1.9 2.4 4.6 5.6 7.3 4.3 2.4 1.8 0.4 3.4

Sunflower oil 1 tablespoon

Vit A ,BETA_ CAROTENE

o . A o . o ) (DNA . o . o )(LDL . o o ( ) . o . o 25000 15 .

VITAMIN A

Vitamin A is a generic term for a large number of related compounds: Retinol (an alcohol) and retinal (an aldehyde) are often referred to as preformed vitamin A. Retinol, retinal, retinoic acid, and related compounds are known as retinoids. Beta-carotene and other carotenoids that can be converted by the body into retinol are referred to as provitamin A. Hundreds of different carotenoids are synthesized by plants, but only about 10% of them are provitamin A. The main function of vitamin A in humans appears to be that of an antioxidant, beta-carotene has stronger antioxidant activity than retinol.

The

combination of vitamin A and iron seems to reduce anemia more effectively than either iron or vitamin A alone. Toxicity: Vitamin A toxicity is relatively rare. Symptoms include nausea, headache, fatigue, loss of appetite, dizziness, and dry skin. Consumption of excess vitamin A during pregnancy is known to cause birth defects.

GOOD SOURCES, (RDA = 1000 MCG, OR 5000 IU, FOR ADULT MALES AND 800 MCG, OR 4,000 IU, FOR ADULT FEMALES)

Food Cod liver oil Fortified breakfast cereals Egg Butter Whole milk Carrot (raw) Spinach Squash, butternut

Serving 1 teaspoon 1 serving 1 large 1 tablespoon 1 cup (8 fl ounces) 1/2 cup, chopped

Vitamin A, 1,350 mcg 150-230 mcg 91 mcg 97 mcg 68 mcg 385 mcg 472 mcg 572 mcg

Vitamin A, IU 4,500 IU 500-767 IU 303 IU 323 IU 227 IU 1,283 IU 1,572 IU 1,906 IU

1/2 cup, cooked1/2 cup, cooked

CAROTENOIDS

The main carotenoids: Alpha-Carotene, Beta-Carotene, BetaCryptoxanthin, Lycopene, Lutein and Zeaxanthin Carotenoids are yellow, orange, and red pigments synthesized by plants. Fruits and vegetables provide most of the carotenoids in the human diet. Orange and yellow vegetables like carrots and winter squash are rich sources of alpha- and beta-carotene. Spinach is also a ri