We are often told that we should take much higher amounts of many vitamins than the doses that are usually recommended.
The late Linus Pauling was one of the most famous proponents of the idea of using huge amounts to Vitamin C to present colds and an array of other health problems. Over the years I have heard enough recommendations to confuse anyone: and one of my degrees is in biochemistry! The only answer with so many conflicting pieces of advice is to do some good research.
Vitamin A is an important fat-soluble vitamin involved in the maintenance of many of many key systems in the body. The recommended daily allowance for vitamin A is 5000 international units (IU) for adults and 8000 IU for pregnant or lactating women.
Vitamin A deficiency is one of the major nutritional problems worldwide and it threatens the survival and health of millions of children. According to a report published in 2002, 127 million preschool children and 7·2 million pregnant women are deficient in vitamin A.
Vitamin A deficiency can cause night blindness, drying and degeneration of the cornea that can lead on to total blindness, as well as impairment of the immune system.
Children living in regions where vitamin A intake is insufficient need to receive adequate amounts of vitamin A through breastfeeding, together with improved diets, food fortification and supplementation with vitamin A.
Providing vitamin A supplementation in countries where there is a deficiency of the vitamin has been proven to decrease mortality. As a result, most developing countries have adopted a standard World Health Organization (WHO) dosing schedule for vitamin supplementation, which calls for 200,000 IU to mothers early postpartum and then 200,000 IU every 4 to 6 months. For infants, the recommendation is 100,000 IU at 9 months and 200,000 IU at 12 months.
However, in 2002 the International Vitamin A Consultative Group (IVACG) Annecy Accord recommended a new high-dose regimen for mothers and infants which includes a doubling of the initial postpartum dose for mothers, and adding 50,000 IU at 2, 3 and 4 months for infants.
An article just published in the Lancet indicates that this high dose protocol does not have any benefit over the older recommendation.
Professor Andrew Prentice and a team of researchers at the International Nutrition Group at the London School of Hygiene and Tropical Medicine in London and colleagues, studied 220 women-infant pairs in an area of moderate vitamin A deficiency in Gambia. One group received the WHO recommended dose, while the other received the IVACG recommended dose.
They measured blood plasma levels of vitamin A, the incidence of Helicobacter pylori infection, how many of them had pneumococcus in the nasopharynx and the integrity of the infants’ intestines.
The problem is that too much vitamin A can also create problems, including nausea and vomiting, jaundice, irritability, anorexia, blurred vision and worst of all, increased intracranial pressure that can cause headaches, drowsiness and even death. These are not such big problems in well-nourished adults living in the Western world, but in malnourished infants, particularly if they are also being vaccinated, this can be a big problem.
There is one specific occasion when a high dose of Vitamin A can be helpful: if a child in a deficient area gets severe measles, the WHO recommendation is that two doses of 200,000 IU should be given to the child. It is easy to forget that in some parts of the world measles can be a killer.
The authors of the article, as well as an accompanying editorial suggest that we should be looking at lower, rather than higher doses of vitamin A.
The editorial is by Professor Bernard Brabin of the Child and Reproductive Health Group in Liverpool, England and he finishes by saying,
“Future trials should emphasize the importance of exclusive breastfeeding, because early feeding with formula milk might reduce potential benefits from early supplementation with vitamin A in infants."
This story shows us once again the extreme importance of having just the right amount of a vitamin or nutrient.
If someone claiming to be an expert in nutrition or vitamin therapy tells you to “take as much as you want” of anything, please be careful.
Just remember the story of Goldilocks and the Three Bears….