Supplements as a safeguard

The practice of taking supplements as a safeguard or protection may also be called a prophylactic use. Protection may be sought against inadequate diets or against a specific disease.

Protection against inadequate diet

Many people believe it’s impossible to obtain their vitamin and mineral requirements from the food they eat. Those whose diet includes a high proportion of refined foods, or a low intake of fresh vegetables and fruits may be the most concerned, but there is also a general suspicion that commercially produced and marketed produce is somehow nutritionally inferior.

Vitamin and mineral supplements are taken ‘just in case,’ as an insurance against micronutrient inadequacy. However, most people are not aware of their vitamin status, nor of the micronutrient content of their diet. The prophylactic use of supplements is generally a costly, unnecessary but usually harmless practice.

In Australia, clinical micronutrient deficiencies are rare, and when they do occur can be traced to the effects of poverty, disease, or poor food selection habits. Deficiencies arising from diet are best treated by improving the diet, while those resulting from a disease require medical diagnosis and treatment, possibly with prescription for a specific supplement.

There are cases where sub-clinical deficiencies could occur, and dietary supplementation may be appropriate. This can happen when people don’t eat enough food to supply the nutrients they need, for example habitual dieters, some elderly people, vegetarians who don’t select appropriate substitutes for their restriction of animal foods, individuals with anorexia nervosa or bulimia, and people suffering from gastrointestinal diseases or recovering from surgery.

Protection against a disease

Common prophylactic uses against a particular illness include taking:

• vitamin C or herbal preparations of echinacea to prevent cold and flu

• calcium and vitamin D supplements to prevent osteoporosis

• folic acid during pregnancy to prevent neural tube defects such as spina bifida in the developing foetus

• herbal preparations of ginko to prevent mental deterioration

• fibre preparations to protect against high cholesterol and colon cancer

• fish oil capsules to provide omega-3 and omega-6 fatty acids to lower cholesterol

• phytochemicals, for example garlic extracts, to prevent heart disease and cancer.

The prophylactic value of individual nutrients may not be as effective as when they are supplied in their natural food source, or even when they are added to foods as a way to fortify or enrich them, for example folic acid and vitamin B added to cereal products.

The best insurance against disease is a nutritionally balanced, widely varied diet. Prophylactic supplementation can be a way to reduce the risk of disease, where there is a need for micronutrient intake much higher than can be supplied by food. An example is risk reduction for osteoporosis, especially for menopausal women or for people with lactose intolerance. The inclusion of calcium-rich foods is important but calcium supplements may also be appropriate, in some cases with vitamin D.