Multivitamins contain a mixture of micronutrients that are fundamental for proper functioning of the body. Only small quantities of these are needed, contrary to macronutrients like carbohydrates, fat and protein. They consist mainly of vitamins and minerals, but can also contain other extracts with phytotherapeutic properties. Supplements like these are often used to treat or prevent vitamin or mineral deficiencies, either in the general population or in risk groups, e.g. pregnant women, athletes, vegetarians, people with gastrointestinal conditions or smokers.