Health Experts
Nutritionist
Q&A with Saga's nutritionist
Dr Pamela Mason answers online readers questions about vitamin safety and low potassium foods
Safe vitamin E dosage
Q: I have been taking vitamin E tablets, one daily, which I bought from Boots. The nutritional info states 67mg per tab.(100iu); RDA670. I now find Boots have replaced these tablets with capsules with nutritional info stating per capsule 268mg (400iu); RDA2684.This suggests that by taking one capsule daily I will be in effect taking four times my original dose daily! Could you explain this discrepancy and who decides what the RDA should be? Can vitamin pills increase the risk of early death?
A: I don't know why Boots has stopped doing the lower dose vitamin E tablets. I assume you have checked availability and the reasons for this with a pharmacist in one of the stores? The Recommended Daily Amount (RDA) is decided by official bodies in different countries and regions of the world.
In the UK, we have dietary standards called Reference Nutrient Intakes (RNI). These are similar to RDAs in that they define requirements of each nutrient (vitamins, minerals and proteins) sufficient for most of the population by age and gender. The RDA appearing on pots of food supplements is an EU figure which must appear by law on food supplements sold in the EU including the UK.
The RDA is a very imprecise figure. Several methods are used to set it depending on the vitamin concerned. For vitamin C, for example, the RDA is the level required to prevent scurvy plus a margin. The RDA for vitamin E is 10mg.
The UK Expert Vitamin and Mineral Group (details of which you will find on the Food Standards Agency website) has set safe upper levels for vitamins and minerals and for vitamin E, this is 727mg and an amount that is suggested to be safe for long term supplementation. The dose of both the products you have taken falls within this safe upper limit.
In relation to your question about vitamin pills and risk of early death, I think you are referring to the recent newspaper reports. These were based on a review paper by the Cochrane collaboration which analysed results from 67 trials looking at the influence of antioxidant vitamin pills on mortality. This paper did conclude that antioxidant pills increased risk of early death, but there are a few things to note about the study. Firstly, around 400 trials of antioxidants were not included in the review. Secondly, the doses of vitamins used in the trials included in the review were very high. What the results of the review would have been if it had included lower dose supplements and also the other trials is unknown, but what can be said is that many people in the UK have poor diets and an all round vitamin supplement containing the RDA of a variety of vitamins and minerals is helpful in making up these dietary gaps.
Low potassium foods
Q: Where can I find a list of everyday food with a low potassium content please?
A: You will find a list of low potassium foods on the following website: National Kidney Foundation. As the site warns, be careful about portions as eating large amounts of a low potassium food can make it a high potassium snack or meal. Also be sure to get help and advice from a dietitian or doctor on your need for low potassium foods.
More information
Information on this site is for interest only and is not a substitute for professional medical advice. You should consult your own doctor about any specific health concerns.
