Are you getting enough vitamin A?
Written by Dr Harold Gunatillake-Health writer
There are 4 fat soluble vitamins- A. D. E. K. They are referred to as fat soluble as fatty acids are required for absorption, in contrast to vitamin C which is water soluble, If you do not eat sufficient fatty food, these fat soluble vitamins may rush through the gut and get excreted. Thus – the importance of including fatty foods in your daily diet. Bile secreted in the liver too helps to absorb fat soluble vitamins, including cholesterol.
Further important fact is that fat soluble vitamins are retained and stored in the body and taking too much may lead to toxicity. Further fat soluble vitamins are not destroyed by heat, contrary to the water soluble ones are very unstable and you can take in excess with no toxic symptoms. They are easily destroyed by heat.
We all get adequate vitamin A requirement though we are not aware of it, unless you suffer from ill-nourishment or chronic gastro-intestinal disorders like coeliac disease, cystic fibrosis, cirrhosis among others. Rice eaters may not get sufficient vitamin A due to lack of carotene. Vitamin A deficiency is a common protein energynutrition as in Marasmus and Kwashiorkor.
Vitamin A is a great immune booster it keeps our cells that protect us against infections’ it also helps make the antibodies that fight off any threat to the defences. Vitamin A was the first vitamin to be identified and hence given the first letter A. It is also called retinol. Beta-carotene (pro-vitamin A) present in most leafy orange and yellow vegetables is converted into vitamin A (retinol) in the intestinal inner lining and stored in the liver as retinyl palmitate.
When your vitamin A requirement is inadequate in early stages -may not have any symptoms. With chronic vitamin A deficiency you can have problems like loss of hair, dry skins, dry eyes, night blindness and inability to drive in the night time, general tiredness and increased susceptibility for infections like respiratory infections, gastroenteritis and delayed growth and bone development with chronic deficiency of vitamin A.
The daily requirement of vitamin A is 900 mcg for men, 700 mcg for women and 300-600 mcg for children and growing teens.
The foods rich in vitamin A1 (retinol) are – Liver of animals like beef and lamb liver, Cod liver oil, Fish like Mackerels, Salmon, Tuna, Trout, among others.
Goat cheese has much vitamin A – 115 mcg in a thin slice. Other varieties of cheese too have similar amounts of vitamin A. Butter has about 97 mcg in a tablespoon
Boiled eggs too have approximately 74 mcg of vitamin A
Vegans get sufficient provitamins through vegetables such as sweet potatoes, Squash, Kale, Collards, Carrots, Peppers, and Spinach and so on. Peppers are high in vitamin A- only half cup gives you almost half of what you need for a day.
Plant foods do not seem to contain fat soluble vitamin A known as retinol instead exists as a pre-cursor called beta-carotene mostly found in vegies.
In our intestines beta-carotene is converted into vitamin A by an enzyme and retinol (vitamin A) is formed.
Animal foods, by contrast supply vitamin A in the form of retinyl palmitate which is converted to retinol in the small gut, which doesn’t require any gut enzymes for the conversion.
The bad news is that certain gene mutations can stop enzyme activity and prevent beta-carotene being converted to retinol. The enzyme that does this conversion is- 15,15′-monoxygenase (BCMO1)—
Vegans need to be aware of vitamin A deficiency and for peace of mind the blood levels should be checked by the pathology labs. Meanwhile those vegans who don’t lack the enzyme BCMO1 can produce enough vitamin A from plant foods to stay healthy.
Sweet potatoes have loads of vitamin A, One baked sweet potato gives more than 500% of the amount you need each day.
Fruits such as Mango, grapefruits, Watermelon, Papaya and many others have provitamin A converted to vitamin A in the intestines.
High levels of accumulated vitamin A can cause many problems. Water soluble vitamins are unstable, not stored in the organs and excreted in the urine, while fat soluble ones get accumulated in the liver and other fat cells.
Massive over-dosage of vitamin A can cause dry skin, dry hair, and enlarged liver and raised erythrocyte sedimentation rate (ESR), and raised serum calcium and serum alkaline phosphatase concentrations Deficiency of vitamin A also causes dry skin and loss of hair.
In this modern age you don’t have to think of vitamin A deficiency in affluent countries. If you feel you need some -vitamin A & D capsule daily as a supplement would suffice.
