Multi-vitamin/mineral supplements (also known as MVM supplements, multis, multiples and mega-vitamins in the USA) contain a combination of vitamins and minerals, and sometimes other ingredients as well.
There are many types of multi-vitamin/mineral supplements in the marketplace. Manufacturers choose which vitamins, minerals, and other ingredients, as well as their amounts, to include in their products.
We found a wide range of multi-vitamin/mineral supplements when we did an online search of major UK suppliers on 19 September 2017. The number of ingredients in these supplements varied from 18 to 36.
Some multi-vitamin/mineral supplements are designed for specific functions. For example, some supplements are designed to provide more energy, to protect your immune system or to control your weight.
Some multi-vitamin/mineral supplements are designed for specific audiences. For example, multi-vitamin/mineral supplements for older people usually provide more calcium and vitamins D and B12 and less iron than multi-vitamin/mineral supplements for younger adults. Multi-vitamin/mineral supplements for pregnant women often provide vitamin A in the form of beta-carotene.
Some manufacturers claim to have produced multi-vitamin supplements specifically for people on the autism spectrum but the formulations of these vary from one manufacturer to another. For example, the multi-vitamin/mineral supplement used in the study by Adams et al (2011) contained 30 different ingredients including vitamin A, vitamin C, vitamin B6, vitamin B12, calcium, iron, lithium, zinc etc.
Multi-vitamin/mineral supplements are available in a wide range of forms including tablets, capsules, pastilles, powders, liquids and injectable formulations.
Because they come in some many varieties and forms and because they are produced by so many different manufacturers, it is important to check the label to see what each supplement actually contains.
Multi-vitamin/mineral supplements are sold under a variety of brand names, each of which may come in different strengths and be administered in different ways.
The dosage will depend to a certain extent on the characteristics of the specific multi-vitamin/mineral supplement being used (trace elements such as zinc should only be given in very, very small doses) and the characteristics of the individual taking the supplement (children generally need smaller doses than adults).
However, care should be taken not to exceed recommended dosages set by organisations such as the Food Standards Agency or the Medicines and Healthcare Regulatory Agency. This is because high dosages of some substances can cause problems. For example, according to Bazian (2011), levels of vitamin C above 1,000mg a day can cause abdominal pain and diarrhoea.
Dietary supplements in the UK carry labels denoting the percentage of the RNIs (Reference Nutrient Intakes) contained in the product.