Sir, - I am writing to express our deep concern regarding an interview with Jane Plant, author of Your Life in your Hands (Features, June 12th). Her statement linking dairy products to breast cancer deserves to be challenged. There is no scientific basis for her argument. Her statements are based on one case study that has not been peer reviewed in the scientific press. A study describing just a single case-history, particularly when it is the author's own, is scientifically unacceptable on statistical grounds and on the grounds of objectivity.
It is impossible to link breast cancer risk with any one single dietary component; this would be far too simplistic. Risk of breast cancer is multi-factorial, involving family history, environmental and lifestyle factors, including diet.
In 20 years of research, scientists have failed to find simple relationships between diet and cancer. Recently, a review published in Nutrition Research concluded that there is no significant association of dairy foods with cancer of the breast. On the contrary, a protective effect of dairy products on breast cancer risk has been demonstrated in numerous studies. A recent long-term observational study of nearly 2,000 women with invasive breast cancer found that women with higher intakes of dairy foods are more likely to survive than those with low intakes. The reason for this may be that dairy foods are good sources of conjugated linoleic acid (CLA), a potent cancer preventive agent.
CLA was one of the topics discussed at "Nutrition Week 2000", an international conference in Dublin at the end of May. Dr Clement Ip, from the Roswell Cancer Institute in New York, presented data from several published studies carried out in his laboratory on CLA-enriched butter. Dr Ip has consistently shown CLA to significantly reduce tumour growth in models of breast cancer by as much as 50 per cent.
The consensus at the conference was that dairy products have many positive health benefits to offer consumers. They are the main dietary source of calcium, which is critical for bone health and the prevention of osteoporosis, a condition that affects one in four Irish women by the age of 60. It is imperative that all women consume three servings from the milk group daily (equivalent to one pint of milk) to meet calcium requirements.
The National Dairy Council therefore warns against following Jane Plant's advice. There is no evidence to promote the exclusion of specific foods to protect against breast cancer, and it is important not to highlight one person's personal experience to the detriment of strong proven health benefits. - Yours, etc.,
Dr Lean O'Flaherty, Senior Nutritionist, National Dairy Council, Lower Mount Street, Dublin 2.