Vitamins capsules in a daily dispenser

Do we need to take vitamins?

Separate food fibs from food facts

well-balanced diet will usually meet the recommended daily intake for vitamins and minerals. A few people with digestive problems will be prescribed vitamin supplements, but hardly anyone else needs them.

One exception is vitamin D, which, like folic acid, is recommended as a supplement for pregnant women in the UK because it is required for growth and development, especially of bones. Supplementary vitamin D is also recommended for those living in northern latitudes during the winter months, and throughout the year in northern areas for those with darker skin tones. 

Vitamins taken as supplements are often in a slightly different form from those found in foods, and are less effective. Taking large doses of some can even be harmful.

Vitamin C is one of the most widely taken vitamins. It is not stored in the body, and we need a regular intake. Big doses do not have much effect on how many colds you catch, unless you are under extreme physical stress, like training for a marathon.

Vitamin C is an antioxidant, a chemical that can help block the action of particular highly reactive chemicals in the body. Swallowing antioxidants is no guarantee that they will end up inside cells where oxidative damage is happening, and it has been shown that mega-doses of some of the other antioxidant vitamins, including vitamin A, vitamin E and beta-carotene, probably increase death rates a little. Exposure to high amounts of vitamin A in pregnancy increases the risk of birth defects. Extra-large doses of minerals can also be harmful: calcium supplements, for example, taken by some women to protect them from the bone depletion known as osteoporosis, have been shown to increase risk of heart attacks.

Lead image:

Daniel R Blume/Flickr CC BY


Further reading

About this resource

This resource was first published in ‘Food and Diet’ in June 2011 and reviewed and updated in August 2016.

Microbiology, Health, infection and disease
Food and Diet
Education levels:
16–19, Continuing professional development