Vitamin and mineral supplements are widely touted as the panacea for a long and active life. Vitamin C is presumed to fight off colds, betacarotene is touted as a cancer-beating drug, and vitamin E is supposed to defeat ageing and reduce the risk of a heart attack. Alarming new evidence, however, suggests that rather than helping us fight off disease, certain supplements may actually increase the risks of cancer and a range of debilitating diseases.

It appears that taking vitamin supplements in high doses may shunt the body’s biochemistry off in the wrong direction. Scientists are especially worried about people taking high doses of the antioxidant betacarotene, which the body converts into vitamin A.

Researchers are unsure exactly why vitamins, which are so essential to health, can be toxic in high doses. The most likely explanation is that the body is only equipped to deal with the levels found naturally in the environment. If the intake is too far outside the normal range, then the body’s internal chemistry can be shunted out of alignment.

Despite the slowly accruing evidence that certain vitamins in high doses can be damaging, the majority of scientists working in the field are still virtually unanimous in recommending – and taking – a good all round multi-vitamin and mineral supplement containing optimum levels of each vitamin and mineral. This is because overall there’s a lot of evidence that as long as the dose is not dangerously high vitamins and mineral supplements can improve health.

In short, it’s excessively high doses that are toxic; not the doses generally contained in quality vitamin and mineral supplements. So if you are taking a good quality multi vitamin or thinking about supplementing it is safe to do so, as long as the dose is not excessive.

There is a strong and frequently repeated argument that we should be able to get all the nutrients we need from ‘a well balanced diet’. Yes, we should. The problem is, all too often, we can’t.

Food rich in nutrients needs to be grown in soil rich in nutrients, but much of our soil has been over-farmed to the point that it no longer contains the nutrients we need. Pesticides and other chemicals reduce the nutrient content of the food, and as food is processed it is stripped of its key nutrients even more. The additional chemicals in our processed food put an additional strain on our bodies, increasing our need for more key nutrients.

Nowadays it is not easy to get everything you need from your diet. With the dominance of supermarket shopping, there’s no way of knowing the freshness or nutritional content of our food. A Which? Report found, for instance, that one pack of sliced green beans contained only 11% of the vitamin C it should have done. And a recent national study showed that 74% of women were falling woefully short on nutrients in their diet. The National Diet and Nutritional survey published in 2003 which looked at adults aged 19-64 showed that only 15% of women and 13% of men actually ate the five-a-day target for fruit and vegetables. With vitamins and minerals, 74% of women failed to achieve the Reference Nutrient Intake (RNI – this term replaced the old RDA, Recommended Daily Allowance) for magnesium, 45% for zinc, 84% for folic acid and 15% for vitamin D.

So food supplements can be helpful if:

• You don’t eat well: If you eat less than five total servings of fruits and vegetables daily, it may be difficult to get all of the vitamins and minerals your body needs. Also, if you eat only one or two times a day, you may be limiting the number and variety of servings you eat from the various food groups.
• You’re a vegan: If you’re a vegan you may not consume enough calcium, iron, zinc and vitamins B-12 and D. You can get these nutrients naturally from non-meat sources, such as, green leafy vegetables, legumes, whole-grain products and nuts. If you aren’t able to regularly consume these foods, food supplements can be helpful.
• You consume less than 1,200 calories a day: Low-calorie diets limit the types and amounts of foods you eat and, in turn, the types and amounts of nutrients you receive. Unless monitored by a doctor, a low-calorie diet isn’t recommended.
• You’re a postmenopausal woman: After the menopause, women experience a drop in oestrogen levels, which increases bone loss. To keep bones strong and to decrease bone loss, you need calcium as well as vitamin D – the vitamin essential for absorbing calcium. Women who don’t obtain enough calcium and vitamin D through foods could benefit from taking a calcium supplement with vitamin D.
• You have a medical condition that affects how your body absorbs, uses or excretes nutrients: If your diet has limited variety because of food allergies or intolerance to certain foods, you can benefit from food supplements.
• You’re a woman who has heavy menstrual bleeding: If you have heavy menstrual bleeding, you may need additional iron to replace the iron depleted by blood loss. Iron deficiency can lead to anaemia, a condition in which blood is low in haemoglobin, the substance which carries oxygen to tissues. Symptoms of anaemia can include exhaustion, shortness of breath, dizziness, sore tongue and headaches. If tests suggest that you are iron-deficient, take extra iron (as amino acid chelate or citrate). Vitamin C is essential for the body to absorb iron, so for maximum absorption take vitamin C with your iron supplement on an empty stomach. Avoid taking iron and vitamin C alongside any other supplements you may be taking.

Avoid taking iron in the form of ferrous sulphate (also called iron sulphate), which is less easily absorbed by the body. Only 2 to 10 percent of the iron from this type of iron supplement is actually absorbed by your body, and even then, half is eliminated, causing blackening of your stools and constipation.

Ferrous sulphate is classed as an inorganic iron. Organic irons are much more easily absorbed and do not affect the bowels in the same way. Look for iron in the form of ascorbates, malates or amino acid chelates.

• You’re pregnant or trying to become pregnant: During this time, you need more of certain nutrients, especially calcium, zinc and folic acid. Folic acid is needed very early in pregnancy to help protect your baby against neural tube birth defects, such as incomplete closure of the spine (spina bifida).
• You smoke: Tobacco decreases the absorption of many vitamins and minerals, including vitamin C, folic acid, magnesium and calcium. But dietary supplements can’t make up for the major health risks caused by smoking. The safest option is to stop smoking.
• You drink excessively: Long-term excessive alcohol consumption can impair the digestion and absorption of several vitamins and minerals, eg the B vitamins, including folic acid, iron, zinc, calcium and magnesium. In addition, you may be substituting alcohol for food, resulting in a diet lacking in essential nutrients. Excessive drinking is defined as more than two drinks a day for men under age 65 and more than one drink a day for men over 65 and women. Taking food supplements can be helpful but they can’t make up for the major health risks caused by excessive alcohol consumption.

It’s time to ease up on heavy winter root vegetables and switch to light spring greens instead.

Why not make a pot of fresh strong green soup with nettle and garlic to flush out your liver and boost your vitality levels? Or you could throw together a salad containing watercress which is brimming with both zinc and calcium, minerals crucial to boost your energy.