Are you low in Selenium? Possibly, considering selenium is a naturally occurring trace mineral found in the soil, absorbed into plant life. Many countries including the UK have soils that are very low in selenium, hence this is reflected in the foods that we eat. There are no UK RDA set for this mineral. The recommend daily nutrient intake is 75 µg/d for men and 65 µg/ d for women. In my expert opinion I believe it is perfectly safe to have an selenium intake of 100ug to 200ug, especially since most most individuals are likely to be low and it also is needed for other vitamins and minerals to perform their duties. When combined with proteins in the body, selenium becomes a powerful antioxidant.
Recent surveys indicate that the average selenium intake may be as low as 30–40 µg/d (1). Vegetarians and the elderly particularly are at a higher risk of selenium deficiency. Moderate selenium deficiency has been linked to many conditions, including tumour growth, infections, infertility, decrease in immune and thyroid function, and several neurologic conditions: Alzheimer’s and Parkinson’s disease. Keshan disease is a potentially fatal form of cardiomyopathy (disease of the heart muscle), prevalent in children and endemic in parts of China with extremely low levels of selenium in the soil (intake, <10 µg/day) (2). Animal studies and some human intervention studies have shown inverse geographic correlations between intake and site-specific cancer incidence, an inverse association between serum selenium and subsequent risk of cancer. The experimental evidence linking selenium levels to cancer is compelling. It is still unclear as to how exactly how the selenoproteins work, however there could be an interplay of mechanisms involving cell signaling and transcription factors at the genetic level. It is too complex for me to explain here. But if anyone is interested in nutrient-gene interactions and the biochemical mechanisms I would recommend the following paper by Papp et al., (2007) which I have provided a link to. We know that selenium activates a family of glutathione peroxidase enzymes which also functions as antioxidants contributing to a healthy immune system and liver function.
Good dietary sources of this selenium are: Brazil nuts, walnuts, beef, chicken, turkey, kidney, liver and fish and seafood. If you are vegan or vegetarian than I would advise taking a good multivitamin mineral containing Selenium. I regard the importance of selenium for optimal health with the combination of other nutrients. This mineral is often undervalued and who knows what other health conditions it may play a preventive role in and I advocate supplementation of at least 100ug of selenium to bridge the gap of what may be missing in the diet.
If anyone would like to discuss anything in this article I have written or if you have any questions about your diet, health or supplementation please contact me: firstname.lastname@example.org
(1)Rayman, M. P. (1997) Dietary selenium: time to act. BMJ. 314: 387–388.
(2) Jackson MJ, Broome CS, F MCArdle., (2003) Marginal Dietary Selenium Intakes in the UK: Are There Functional Consequences? The American Society for Nutritional Sciences, J. Nutr. 133:1557S-1559S.