If your diet is varied and balanced there is no reason to think that you need supplements. It’s also not known whether vitamins and minerals in supplement form can provide the same benefits as food, which contains all sorts of nutrients we can’t recreate in pill form. There are some situations where supplementation is recommended: * Women who are planning to get pregnant, or have just become pregnant, should take a daily supplement of 400mcg (micrograms) of folic acid to help prevent their baby from developing a neural tube defect such as spina bifida. * People who always cover their skin when outside and those who rarely get outdoors and have a limited exposure to sunlight may lack vitamin D, which could be taken in supplement form (10mcg a day). * Vegans who never eat meat or dairy products may need to take vitamin B12 in tablet form. It is possible to take too much of a particular vitamin. Fat-soluble vitamins that will be stored in the liver, like vitamin A, can reach toxic levels and cause liver damage. Pregnant women should avoid supplements containing vitamin A, including fish liver oil supplements, because too much vitamin A could harm their unborn baby. Of the water-soluble vitamins, taking large amounts of vitamin C can cause diarrhoea (2000mg a day) in some people.