Cancer Prevention in Primary Care: Diet and cancer
Authors: J Austoker
Journal: BMJ (1994)

Frequent consumption of fruit and vegetables is consistently associated with a lower risk of cancers of the digestive and respiratory tracts * Reductions in levels of total and unsaturated fat should relate to reducing the risk of cardiovascular disease, not specifically to cancer * Avoid obesity * The evidence that dietary fibre protects against large bowel cancer is inconclusive.Substituting fibre rich carbohydrates to compensate for reducing dietary fat may be desirable * Vitamin and mineral supplements are not needed for people eating good balanced diets, and there is no conclusive evidence that they prevent cancer * There is no evidence that artificial sweeteners or other food additives cause cancer in humans * Consumption of smoked, cured, pickled, and barbecued foods is unlikely to be a hazard in the United Kingdom but should not be increased above current levels * Avoid mouldy foods Box 3-Strategies for prevention: some of the problems * The total impact of dietary factors on incidence of and mortality from cancer is difficult to determine * Insufficient knowledge is available on the best means to affect dietary change * The precise effect of implementing dietary changes on the risk of cancer is difficult to quantify * Any recommendation should reflect the relative importance of a risk factor in terms of the proportion of cancer that might be prevented by its modification * Evidence of a beneficial effect of a dietary change should outweigh any potential harmful effects * A population approach has the potential for major reductions in incidence of and mortality from cancer * The effect of any intervention may be delayed for many years, possibly a whole generation * Measures that are beneficial to the population as a whole are not necessarily beneficial to each person * An individual based approach would result in a very small reduction in overall risk of cancer in the population * It is not possible at present to predict which individuals will benefit-the evidence is based on probabilities rather than certainties Box 5-Key issues for primary care teams in diet and cancer * With the exception of the protective effect of fruit and vegetables, the evidence linking diet and cancer is inconclusive * Consistent, accurate messages are needed * Dietary interventions must be relevant for all lifestyle issues (healthy eating)-that is, part of a more general prevention of chronic disease and not specific to cancer * Brief validated assessment questionnaires need to be developed * People who are most likely to benefit should be targeted * Incorporating the principles of the "process of change" model and the techniques of 'motivational interviewing" may lead to improved outcomes * Advice from the general practitioner should be tailored to the needs of the individual patient as much as is possible * Simple information, advice, and support may be more useful than more detailed and sophisticated approaches * Advice should be practical, positive, and relevant * Practice nurses may have an important role in providing follow up to advice from the general practitioner * Dietitians have a part to play, but more in educating doctors and nurses than in advising individual patients * Oral advice could be supplemented with simple leaflets emphasing basic dietary issues and with good illustrations