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Clinical Review ABC of complementary medicine

Unconventional approaches to nutritional medicine

BMJ 1999; 319 doi: (Published 27 November 1999) Cite this as: BMJ 1999;319:1419

This article has a correction. Please see:

  1. Andrew Vickers,
  2. Catherine Zollman

    Although nutrition, as a science, has always been part of conventional medicine, doctors are not taught, and therefore do not practise, much in the way of nutritional therapeutics. Dieticians in conventional settings tend to work mainly with particular patient groups—such as those with diabetes, obesity, digestive or swallowing problems, or cardiovascular risk factors. Apart from the treatment of gross nutritional deficiencies and rare metabolic disorders, other nutritional interventions generally fall outside the mainstream and can therefore be described as complementary medicine.

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    Conventional doctors only rarely make use of nutritional interventions, which is perhaps one reason why nutritional medicine has come to be regarded as part of complementary medicine


    There is a wide spectrum of complementary nutritional practices. These range from specific, well researched, biochemically understood treatments that are given by well trained practitioners to unresearched, biochemically implausible interventions popularised by spectacular claims in the lay press and largely used without professional supervision.

    Just which treatments are “conventional” and which are “complementary” is subject to debate. Some, such as fish oil supplements for patients with rheumatoid arthritis, have many of the features of a conventional medical treatment—a biochemical mechanism and support from randomised trials— but are, none the less, often considered unconventional. Other interventions were originally considered “complementary” but are now part of conventional practice. Probably the best example is the high fibre diet, rich in fruit and vegetables. “Alternative” practitioners of the 19th century, such as John Kellogg, advocated such a diet at a time when conventional nutritional authorities tended to see meat and potatoes as the best food, even to the extent of denigrating the importance of vegetables and describing wheat bran as “refuse.”

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    In the Hay diet proteins and starch must be eaten separately, though fruit and vegetables can be eaten with either

    Nutritional interventions

    Unconventional nutritional interventions can be …

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