Selenium: an under-rated micronutrient?
Selenium is an essential mineral but its importance in the diet often gets overlooked. Selenium is involved in a range of functions in the body including thyroid hormone production and immune system function.
Selenium also acts as an antioxidant. That means it may help to protect the body against oxidative damage. Since the ageing process, as well as certain diseases like cancer and cardiovascular disease (CVD), is associated with oxidative damage, having adequate selenium intake may provide some protection against these processes.
However, whilst selenium deficiency is a cause of cardiomyopathy (disease of the heart muscle), studies have shown inconsistent associations between selenium intake and CVD risk. The World Cancer Research Fund reports that the limited evidence available does not allow any firm conclusions with regards to selenium and cancer risk, although there is some suggestion that low blood levels of selenium increase risk of prostate cancer, and adequate selenium intake may decrease lung cancer risk.
Intakes for older adults
The latest dietary surveys of older people in the community reported that around 40 per cent had average daily intakes that are likely to be inadequate. Older adults living in residential care or nursing homes or being treated in hospital have also been found to have lower blood levels of selenium when compared with their ‘free-living’ counterparts.
Concerns have been raised for some years about the falling levels of selenium intake and the impact this may have on health. However, the health implications for low intakes remain uncertain. In addition, the references used to assess adequate intake are based on limited data and there is currently no established normal reference range for blood concentrations of selenium so it is hard to define deficiency and optimal status.
Nevertheless, as we age the body’s ability to absorb some nutrients becomes less efficient, so it can be harder to get all the necessary nutrients for good health. Therefore, it is vitally important that older adults eat a varied diet to ensure an adequate supply of all the essential vitamins and minerals including selenium.
Foods containing selenium
The amount of selenium in food actually depends on where it is grown, reared or produced, and the amount of selenium in plant foods is often affected by the selenium content of the soil. However, based on the current food composition information, the main contributors of dietary selenium in the UK population amongst those aged over 65 are fish, eggs, bread and poultry.
The Recommended Nutrient Intake (RNI) for the over 65s is 75 µg per day for men and 60 µg per day for women. Some foods to include in menus to ensure adequate intakes of selenium are:
As well as selenium, fish, eggs, poultry and nuts will also provide other important nutrients to the diet like protein, and wholegrain bread is a good source of fibre.
*All information is correct at the time of publishing