Research scientists from the University of Newcastle (1) have found that up to about 50% of women in the UK might be suffering from a lack of vitamin A. This huge lack of this vital vitamin appears to be due to a genetic issue. It seems that about half of the women in the UK may suffer from a genetic variation which reduces their ability to produce enough vitamin A from beta-carotene. In the past it has been assumed that the body can convert beta-carotene into plentiful amounts of vitamin A, but this study indicates that this conventional wisdom may be misplaced.
Vitamin A is sometimes called retinol. It is an essential nutrient, a vital vitamin that is important for a strong and healthy immune system - important to help protect against common infections, colds and flu. Vitamin A is also crucial for healthy skin and mucous lined membranes in the nose, lungs and eyes.
In the past women were told to be careful not to consume too much vitamin A because in pregnancy too much of this vitamin seems to be associated with some birth defects. To prevent the problem of intoxication with vitamin A pregnant women were told to avoid vitamin A rich foods and to consume beta-carotene instead. Beta carotene is found in dark green vegetables such as Brussels sprouts, asparagus, watercress and spinach as well as orange vegetables, especially carrots, sweet potatoes and squash and orange fruits such as papaya, mangoes, cantaloupe melons, peaches, apricots. The thinking behind this was that the body would convert as much beta-carotene as it needed into vitamin A. This recent research (1) suggests, however, that for many women beta-carotene is not an effective substitute for vitamin A.
In a press release one of the research scientists commented (2) “Vitamin A is incredibly important -particularly at this time of year when we are all trying to fight off the winter colds and flu”. “It boosts our immune system and reduces the risk of inflammation such as that associated with chest infections”.”What our research shows is that many women are simply not getting enough of this vital nutrient because their bodies are not able to convert the beta-carotene.”
Further research is certainly needed as this was only a small and preliminary study. What the research showed (1) was that 47% of women in a volunteer group carried a genetic variation which prevented them from being able to effectively convert beta-carotene into vitamin A. The study scientists also found that all the volunteers only consumed about one third of the recommended intake of (preformed) vitamin A. Vitamin A is found ‘preformed’ in foods such as eggs, milk, liver, cheddar cheese, cod liver oil, salmon and mackerel.
This is a worrying statistic since many women may well be lacking enough vitamin A in their diet to reach optimal levels for body function, especially immune function. The authors explain (2): “Worryingly, younger women are at particular risk,” “The older generations tend to eat more eggs, milk and liver which are naturally rich in vitamin A whereas the health-conscious youngsters on low-fat diets are relying heavily on the beta-carotene form of the nutrient.”
The authors comment that they need to carry out larger studies that involve both men and women. In order to keep the immune system healthy this winter you may want to try and make sure you eat enough sources of preformed vitamin A, as well as including plenty of beta-carotene in the diet. Taking a low dose, food-state, multi-vitamin and mineral supplement could also help by preventing any shortfalls in the diet (but a supplement should never be seen as an alternative to a healthy diet). Until there is further evidence I don’t think it is necessary to supplement specifically with vitamin A. Vitamin A is a fat-soluble vitamin and it is possible to take too much, so taking a low-dose multi-nutrient supplement is more advisable. If you are pregnant always check with your doctor before taking any kind of supplement.
(1)Leung WC et al. 2009. Two common single nucleotide polymorphisms in the gene encoding β-carotene 15,15′-monoxygenase alter β-carotene metabolism in female volunteers. The FASEB Journal. 23:1041-1053
(2)Press release. Newcastle University (2009, November 18). UK women at risk from vitamin A deficiency. ScienceDaily. Retrieved November 19, 2009, from http://www.sciencedaily.com/releases/2009/11/091118072051.htm
Written by Ani Kowal
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