vitamin a and its funtions

VITAMIN A FUNCTIONS AND DEFICIENCIES

VITAMIN A

DEFINITION:

VITAMIN A IS RETINOL. CAROTENE COMPOUNDS (FOUND, FOR EXAMPLE, IN EGG YOLK, BUTTER AND

CREAM) ARE GRADUALLY CONVERTED BY THE BODY TO VITAMIN A (RETINOL). A FORM OF VITAMIN A CALLED RETINAL IS RESPONSIBLE FOR TRANSMITTING LIGHT

SENSATION IN THE RETINA OF THE EYE.

SOURCES OF VITAMIN A

THERE ARE TWO SOURCES:• PLANT SOURCES: B-CAROTENE • ANIMAL SOURCES: RETINOL (RETINOID)

BASIC FORMS OF VITAMIN A

• RETINOID:THIS CLASS OF COMPOUNDS PLAYS AN IMPORTANT ROLE FOR HEALTHY VISION, CELL AND BONE TISSUE GROWTH, AND IMMUNE FUNCTION.

• CAROTENOIDS:IN CONTRAST, FOUND IN PLANT SOURCES LIKE VEGETABLES AND FRUITS.

SOURCES OF FOOD

SOURCES OF ANIMAL FOOD:• EGGS, MEAT AND DAIRY PRODUCTS

SOURCES OF PLANT FOOD:• GREEN LEAFY VEGETABLE, INTENSELY COLORED FRUITS AND

VEGETABLES

BENEFITS• PROTECTS EYE HEALTH: HEALS DRY EYE AND FIGHT AGAINST EYE INFECTIONS

• PROVIDES IMMUNE SUPPORT:VITAMIN A HELPS TO REGULATE THE GENE OF YOUR BODY IMMUNE SYSTEM.

• FIGHT INFLAMMATION:VITAMIN HAS OXIDANTS PROPERTY TO NEUTRALIZE FREE RADICALS IN THE BODY THAT CAUSE TISSUE AND CELLULAR DAMAGE.

• SUPPORT SKIN HEALTH AND CELL GROWTH:1. NECESSARY FOR WOUND HEALING AND SKIN RE-GROWTH. IT ALSO DECREASES

THE SIGNS OF AGING.

2. IT KEEPS YOUR HAIRS HEALTHY AND THICK.

BENEFITS

• HELPS PREVENT CANCER:1. IT CONTROLS MALIGNANT CELLS IN THE BODY.

• IN EYES:1. IT IS ALSO KNOWN AS RETINOL BECAUSE IT

PRODUCES THE PIGMENTS IN THE RETINA OF THE EYE.

2. VITAMIN A PROMOTES GOOD VISION, ESPECIALLY IN LOW LIGHT.

EYE VISION FUNCTION: RODS CONES SENSES DARK VISION SENSES LIGHT VISION

RHODHOPSIN (VISUAL PURPLE) IODOPSIN (VISUAL VIOLET)

VITAMIN A

RETINALDEHYDE

DEFICIENCYVITAMIN A DEFICIENCY MAY CAUSE:• COLOR BLINDNESS• XEROPHTHALMIA• NIGHT BLINDNESS

EFFECTS • IMMUNE SYSTEM• EFFECTS SKIN CELLS • GROWTH CELLS

DISEASES

• XEROPHATHALMIA:DRYNESS OF EYES, OFTEN DUE TO DECREASED TEAR SECRETION,

• NIGHT BLINDNESS PEOPLE WITH NIGHT BLINDNESS EXPERIENCE POOR VISION.

• COLOR BLINDNESS:A PERSON WITH COLOR-BLINDNESS HAS TROUBLE SEEING RED, GREEN, BLUE, OR MIXTURES OF THESE COLORS. THE MOST COMMON TYPE IS RED-GREEN COLOR-BLINDNESS, WHERE RED AND GREEN ARE SEEN AS THE SAME COLOR.

TREATMENT1. USING THE VITAMIN A IN YOUR DIET. LIVER, BEEF, CHICKEN, EGGS, WHOLE

MILK, FORTIFIED MILK, CARROTS, MANGOES, ORANGE FRUITS, SWEET POTATOES, SPINACH, KALE AND OTHER GREEN VEGETABLES ARE AMONG FOODS RICH IN VITAMIN A.

2. VARIOUS FOODS, SUCH AS BREAKFAST CEREALS, PASTRIES, BREADS, CRACKERS AND CEREAL GRAIN BARS, ARE OFTEN FORTIFIED WITH VITAMIN

3. FOR MORE SEVERE FORMS OF VITAMIN A DEFICIENCY CAUSING SYMPTOMS, TREATMENT INCLUDES TAKING DAILY ORAL VITAMIN A SUPPLEMENTS.