As well as vitamin D and B12, the B vitamins, especially B6 and folate, are vital for a healthy brain, heart and immune system. Older people can also be low in calcium, zinc, potassium and magnesium.
It's true that we need higher levels of nutrients to protect against degenerative conditions and disease than to simply avoid a deficiency. But food is always better and safer than a pill. Food provides all the nutrients we need – the ones we have discovered and those we don't yet know about – in the perfect package for peak absorption.
Supplements are sometimes in a different form from what occurs naturally so may not be as effective. Large doses of vitamins, minerals and so-called 'natural' herbal remedies can have potent, drug-like effects, especially in older bodies which are less able to handle it. They can also interfere with medication. For example, taking fish oil or high doses of vitamin E (over 400µ) with aspirin or Warfarin may cause excessive bleeding as they both reduce clotting.
Taking just one vitamin or mineral can cause a deficiency in another, eg zinc and copper. A multi-vitamin minimises this risk and many people take one as a form of nutritional insurance. But popping a multi-vitamin with your cup of tea and jam sandwich doesn't make a balanced diet!
An expert panel, set up by the National Institutes of Health, recently analysed the research and concluded that there was a proven health benefit of supplements in just three cases: calcium and vitamin D to reduce bone fractures in post-menopausal women; vitamins C, E, beta-carotene, zinc and copper to reduce the risk of blindness in people with early signs of macular degeneration; and folic acid to prevent birth defects (not usually an issue for the over-65s!).
Always let your doctor know if you are taking nutritional supplements, especially if you are on medication.