UVitamins are micronutrients, that is, they are needed by the body in small quantities and measured in milligrams, micrograms. Like minerals, they are needed daily and are readily available from food. Vitamins are grouped into two namely fat-soluble vitamins (A, D, E, K) and water-soluble vitamins (B and C). Unlike water-soluble vitamins, fat-soluble vitamins cannot be dissolved in the watery environment of the gastrointestinal tract.
Vitamin A, the first fat-soluble vitamin to be recognized, are of three different forms in the body but are collectively known as retinoids and which are commonly found in foods of animal origin. Plants especially yellow and green fruits and veggies provide carotenoids (e.g. beta carotene), some of which can be converted to vitamin A. Beta-carotene, which can be split to form retinol in the intestine and liver. Several proteins participate in the digestion and absorption of vitamin A. Fat is needed for proper digestion and metabolism.
Vitamin A does a lot to help in keeping the body healthy, being known to regulate the expression of hundreds of genes although its major roles are promoting vision, protein synthesis, development of cells so they can perform specialized functions, maintaining health of epithelial tissues and skin, regulating growth especially of the bone and teeth, supports reproduction and promotes immunity. Retinoic acid inhibits cell growth in tumors and can stimulate cell growth in the skin.
Good sources of retinol, the active form of vitamin A include fortified milk, cheese, cream, butter, fortified margarine, eggs, liver. Meanwhile, beta-carotene, which will need to be converted into retinol in the body, can be sourced out from spinach and other dark green, leafy vegetables, broccoli, deep orange, fruits like cantaloupe, and vegetables such as squash, carrots, sweet potatoes.
When the body is lacking vitamin A for a prolonged period of time, night blindness or difficulty seeing in the dark or dim light starts. It can progress to drying of the cornea (xerosis), appearance of triangular gray spots on eye (Bitot’s spots), softening of the cornea (keratomalacia), and corneal degeneration leading to blindness. Simultaneously, resistance to infectious diseases weaken. The hair follicles may also get plugged with keratin forming white lumps. The skin becomes dry. Excessive intake can lead to toxicity as vitamin A can accumulate in the body.
Vitamin A deficiency (VAD) remains one of the country’s malnutrition problems. One solution is the bi-annual administration of vitamin A capsule (VAC) among children starting at age six months. This is available at the barangay health center. Children when severely undernourished, have diarrhea or measles need therapeutic supplementation as the body uses more vitamin A at these times. Much as everyone may need VAC, insufficiency of supply limit the coverage of supplementation. Supplements are in active forms and can contribute to toxicity which is harmful to pregnant women, thus they are advised to consume natural foods, not supplements. Even topical vitamin A solutions or those applied to the skin, should be avoided by pregnant women. Adolescents and adults better seek medical consultation prior to taking supplements.
