Some minerals are thought to be lacking in the modern diet because of local variations of the mineral content in the soil used to grow food. Bio-Health's Extra Selenium capsules contain biologically active Selenium Yeast, so providing it in an organic food form. In the U.K. the availability from vegetables is low compared to that of countries where growing conditions give rich results. Seafoods probably account for dietary source & where shellfish or other seafood is lacking regularly from the diet it may result in inadequate intake. One capsule daily will provide an adequate dose of this trace element which is present in a medium upon which primary grown yeast feeds & is taken up into the cells during the growth cycle. It is then more easily absorbed into the bloodstream than inorganic forms because it is a natural biological food source. Careful laboratory trial & batch testing helps ensure accuracy of product content. The herbal ingredients are from organic, wild crafted (non-threatened species) or cultivated plants & conform to accepted scientific standards, British Pharmacopoeia, European Pharmacopoeia & British Herbal Pharmacopoeia. Bio-Health Extra Selenium Capsules are free from gluten, corn, wheat, soya & dairy. They do not contain any GM ingredients. Suitable for vegetarians & vegans.