Nutritional medicine

Nutritional medicine involves modifying a person’s diet as well as recommending or prescribing vitamin and mineral supplements, usually taken by mouth, in the form of tablets or liquids. For any living organism to function properly, a number of vitamins (usually described by the letters A to E) and minerals (such as zinc, magnesium and chromium) are essential.

Their absence leads to disease, an observation first noted by James Lind in 1753. He was a naval doctor who observed that sailors on long voyages who had no access to fresh fruit and vegetables developed scurvy. This deficiency disease could kill a significant proportion of the crew, consequently reducing the navy’s ability to fight or man their ships. Lind observed that the addition of lime juice to the sailors’ diet could prevent scurvy. Vitamin C itself, however, was not chemically isolated until the twentieth century. A whole series of specific diseases, such as pellagra and beri-beri (both deficiency diseases of the vitamin B group), were carefully documented, and their cause isolated, in the 1920s and 1930s.

The dietary recommendations made by most Western govern­ments tend to be more focused on avoiding deficiencies rather than promoting optimal health. Most experts are sure about the nutritional requirements that are needed to avoid illness. However, there is often little information, and indeed much argument in the nutritional world, about the doses of nutritional supplements required to sustain optimal health. This is particularly so for the needs of people whose nutritional demands are raised for some reason, such as the presence of disease or when subject to unusual physical or mental demands, such as competitive sport.

This is perhaps illustrated by the differences in reference nutrient intakes (RNIs) between the USA and the UK – nearly all the RNIs in the USA are higher than those in the UK even though the Government has recently increased its recommended RNI for the UK population.

The table on page 82 shows the RNIs for some common vitamins and minerals and also shows how much of the average UK population falls below the recommended intakes. This suggests a somewhat worrying picture. Although many people in the UK certainly eat enough to suffer from obesity, a significant minority is probably also suffering from nutritional deficiencies. This is probably associated with the rise of high-fat, high-carbohydrate and low-nutrient junk food, as well as the increase in industrialised farming, which produces products with relatively lower levels of vitamins and minerals.

IS NUTRITIONAL MEDICINE CONVENTIONAL OR COMPLEMENTARY?

The various vitamins and minerals are a very important part of conventional medicine. However, many conventional doctors just assume that the average British diet is nutritionally adequate and other than in specific illnesses, such as eating disorders or anaemia, will rarely investigate a person’s nutritional status. There are some types of nutritional medicine, generally described as ortho­molecular medicine, in which very large doses of vitamins and minerals are used to treat illnesses varying from the common cold to cancer.

One of the underlying principles of nutritional medicine is that each person is unique and has unique nutritional requirements, so that what may be an adequate nut­ritional intake for one person may be inappropriate for another.

WHAT SHOULD NUTRITIONAL MEDICINE BE USED FOR?

Nutritional medicine has a range of uses spanning both conventional and complementary medicine. Some nutritional experts argue that everyone needs to take regular nutritional supplements on a daily basis, whereas others suggest that nutritional supplements are needed only where there is a proven deficiency, such as in iron-deficiency anaemia.

Certainly, nutritional supple­ments can be effectively used to modify the way some illnesses affect us. For example, there is evidence that zinc taken orally will shorten the duration of a cold or flu and alleviate the symptoms. Eating more polyunsaturated fatty acids, usually derived from plants or, more commonly, fish oils, can reduce the levels of harmful fats in the blood, control and reduce inflammation in rheumatoid arthritis and even ease symptoms and reduce relapse rates in inflam­matory bowel disease (such as ulcerative colitis and Crohn’s disease).

Studies suggest that vitamin C probably does treat (although it does not prevent) colds, vitamin B6 is of value in premenstrual syndrome and possibly autism, while vitamin E may be of value for people with angina. It is known that folic acid, taken before and during pregnancy, will reduce the rate of spina bifida (a neural tube defect) in babies. In general, the intake of folic acid in most Westernised industrialised nations falls well below the recommended nutritional intake – one American study suggested that most adults were taking only half the RNI for folate as part of their regular daily diet. Nutritional medicine, therefore, can be very important in the treatment and prevention of various problems.

The recommendations made by some nutritional medicine practitioners frequently involve quite complex and expensive supplement regimens. Many people claim that these regimens are beneficial and, indeed, these may be of genuine benefit. However, medical experts are often unclear about the scientific validity of the very specific recommendations made by some practitioners.

WHO PRESCRIBES SUPPLEMENTS?

Most people taking nutritional supplements do so on the advice of health magazines, friends or perhaps someone in a health food store or pharmacy selling nutritional supplements. Many people take cod liver oil or glucosamine for their arthritis, and women frequently take extra calcium during and after the menopause to avoid osteoporosis. In other words, most nutritional supplements are taken because people have prescribed them for themselves.

Nutritional supplements may also be used as part of the treatment regimens prescribed by many complementary practitioners, including herbalists, homeopaths, osteopaths and chiropractors. Some therapists specialise in the investigation and prescription of nutritional supplements, in particular those who are members of the British Association of Nutritional Therapists, registered naturopaths and medically qualified doctors who are members of the British Society for Allergy, Environmental and Nutritional Medicine (BSAENM).

WHAT DOES TREATMENT INVOLVE?

Although, in most cases, nutritional prescriptions are based on a detailed history from the patient, practitioners may use various individual nutritional tests to understand the person’s require­ments. Sometimes these tests are unconventional and unproven. The more conventional testing methods may be done on blood, hair or sweat and provide a clear and reproducible understanding of whether a person’s nutritional status, with respect to the sub­stances being tested, is within the normal range.
The laboratory that conducts most of these nutritional tests in the UK is called Biolab. Biolab will accept requests for tests made by someone who is properly qualified, but does not run investigations requested by members of the general public.

Using these various nutritional investigations enables a properly qualified person to then recommend a specific range of supplements and appropriate dietary changes. Treatments may be designed either to prevent illness or to treat and manage an ongoing complaint.

IS IT SAFE?

There has recently been a lot of discussion about the safety of nutritional supplements. There is no doubt that some supplements taken in high doses can produce adverse reactions. For example, extra vitamin A is not recommended in pregnancy because it may cause abnormalities in the developing baby. High doses of vitamin C can cause diarrhoea.

In general terms, nutritional supplements taken for two or three months are very unlikely to cause adverse reactions. However, some supplements taken over a long period of time can be harmful. For example, vitamin B6 taken for premenstrual syndrome has, in a very small number of cases, been reported to cause nerve damage. This has usually involved very high doses, far higher than those usually recommended by responsible nutritional therapists. Excessive doses of zinc and selenium have been reported in some cases to suppress the immune system and the prolonged use of evening primrose oil may make some forms of epilepsy slightly worse.

However, it is important to stress that, in general, nutritional supplements are very safe. There have, for example, been no reported deaths due to nutritional supplementation in the UK.

WHOM SHOULD I SEE?

Members of the British Society for Allergy, Environmental and Nutritional Medicine are all medically qualified doctors. The organisation can provide names and addresses of doctors giving nutritional advice and support. The regulation of doctors is the responsibility of the General Medical Council.
The General Council and Register of Naturopaths and the British Association of Nutritional Therapists are educational and regulatory bodies primarily for non-medically qualified people. Details may be found in ‘Useful addresses’.