What Are the Benefits of Vitamin A
Vitamin A helps form and maintain healthy skin, teeth, skeletal and soft tissue, mucus membranes, and skin. It is also known as Vitamin A Retinol because it produces the pigments in the retina of the eye. In addition to treating deficiency syndromes, vitamin A has several potential preventive and therapeutic uses. Vitamin A is important “medicine” for the immune system. It keeps skin and mucous membrane cells healthy. When membranes are healthy they stay moist and resistant to cell damage. The moistness inhibits bacteria and viruses from “putting down stakes” and starting infectious diseases.
Vitamin A promotes good vision, especially in low light. It may also be needed for reproduction and breast-feeding.
Retinol is an active form of vitamin A. It is found in animal liver, whole milk, and some fortified foods.
Carotenoids are dark-colored dyes (pigments) found in plant foods that can turn into a form of vitamin A. There are more than 500 known carotenoids. One such carotenoid is beta-carotene.
- Beta-carotene is an antioxidant. Antioxidants protect cells from damage caused by substances called free radicals. Free radicals are believed to contribute to certain chronic diseases and play a role in the aging processes.
- Food sources of carotenoids such as beta-carotene may reduce the risk for cancer.
- Beta-carotene supplements do not seem to reduce cancer risk.
Vitamin A comes from animal sources, such as eggs, meat, fortified milk, cheese, cream, liver, kidney, cod, and halibut fish oil. However, all of these sources — except for skim milk that has been fortified with Vitamin A — are high in saturated fat and cholesterol. In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to the retinol (chemically an alcohol) in the small intestine. The retinol form functions as a storage form of the vitamin, and can be converted to and from its visually active aldehyde form, retinal. The associated acid (retinoic acid), a metabolite that can be irreversibly synthesized from vitamin A, has only partial vitamin A activity, and does not function in the retina for the visual cycle.
Sources of beta-carotene include:
- Bright yellow and orange fruits such as cantaloupe, pink grapefruit, and apricots
- Vegetables such as carrots, pumpkin, sweet potatoes, and winter squash
- Other sources of beta-carotene include broccoli, spinach, and most dark green, leafy vegetables.
- The more intense the color of a fruit or vegetable, the higher the beta-carotene content. Vegetable sources of beta-carotene are fat- and cholesterol-free.
Lack of Vitamin A Means
If you don’t get enough vitamin A, you are more likely to get infectious diseases and vision problems.
If you get too much vitamin A, you can become sick. Large doses of vitamin A can also cause birth defects.
Vitamin A deficiency also diminishes the ability to fight infections. In countries where children are not immunized, infectious disease like measles have higher fatality rates. As elucidated by Dr. Alfred Sommer, even mild, subclinical deficiency can also be a problem, as it may increase children’s risk of developing respiratory and diarrheal infections, decrease growth rate, slow bone development, and decrease likelihood of survival from serious illness.
Acute vitamin A poisoning usually occurs when an adult takes several hundred thousand IUs of vitamin A. Symptoms of chronic vitamin A poisoning may occur in adults who regularly take more than 25,000 IU a day. Babies and children are more sensitive to vitamin A, and can become sick after taking smaller doses of vitamin A or vitamin A-containing products such as retinol (found in skin creams). Large amounts of beta-carotene will not make you sick. However, increased amounts of beta-carotene can turn the skin yellow or orange. The skin color will return to normal once you reduce your intake of beta-carotene.
In addition to dietary problems, there are other causes of vitamin A deficiency. Iron deficiency can affect vitamin A uptake. Excess alcohol consumption can deplete vitamin A, and a stressed liver may be more susceptible to vitamin A toxicity. People who consume large amounts of alcohol should seek medical advice before taking vitamin A supplements. In general, people should also seek medical advice before taking vitamin A supplements if they have any condition associated with fat malabsorption such aspancreatitis, cystic fibrosis, tropical sprue & biliary obstruction.
The best way to get the daily requirement of essential vitamins is to eat a wide variety of fruits, vegetables, fortified dairy foods, legumes (dried beans), lentils, and whole grains.
The Food and Nutrition Board of the Institute of Medicine — Dietary Reference Intakes (DRIs) Recommended Intakes for Individuals of Vitamin A:
Infants (average intake)
- 0 – 6 months: 400 micrograms per day (mcg/day)
- 7 – 12 months: 500 mcg/day
The Recommended Dietary Allowance (RDA) for vitamins is how much of each vitamin most people should get each day. The RDA for vitamins may be used as goals for each person.
- 1 – 3 years: 300 mcg/day
- 4 – 8 years: 400 mcg/day
- 9 – 13 years: 600 mcg/day
Adolescents and Adults (RDA)
- Males age 14 and older: 900 mcg/day
- Females age 14 and older: 700 mcg/day
How much of each vitamin you need depends on your age and gender. Other factors, such as pregnancy and your health, are also important. Ask your doctor what dose is best for you.
This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.