A study by Harvard Medical School researchers has disputed a commonly held belief that lower intake of total fat during mid-life can help reduce the risk of breast cancer.

According to a report in the Journal of the American Medical Association (JAMA), the research, conducted over 14 years and supported by the National Institute of Health, found no evidence that a lower fat intake can be associated with decreased risk of breast cancer.

``Our research indicates it's highly unlikely that women who consume a low-fat diet are protected against breast cancer,'' said Michelle Holmes, an instructor of medicine at the Harvard Medical School, who was the lead author of the study. ``At the same time, it appears a high-fat diet also poses no increased risk for the disease,'' she said.

Holmes and her colleagues studied 88,795 women who were free of cancer in 1980 and followed the cases for 14 years. They investigated the relative risk of invasive breast cancerfor an incremental increase of fat intake, ascertained by food frequency questionnaires in 1980, 1984, 1986 and 1990.``We found no evidence that lower intake of total fat or particular types of fat over 14 years of follow-up was associated with a decreased risk of breast cancer,'' the researchers reported.

``These findings suggest that reductions in total fat intake during mid-life are unlikely to prevent breast cancer and should receive less emphasis,'' said the report. ``Rather, women's decisions about fat intake should be guided primarily by risk of heart disease, which is strongly influenced by the type, but not total amount, of fat,'' it added.

The authors found no increase in the risk of breast cancer with increased intake of animal fat, polyunsaturated fat (vegetable fat), saturated fat or unsaturated fat in the women, who replaced carbohydrates with fat.

However, contrary to the predominant hypothesis, an increased risk of breast cancer was associated with omega-3 fats from fish, which isbelieved to be healthier. Omega-3 fats, which in previous studies, had been linked to breast cancer.

Breast cancer experts were divided over the results, with some questioning the methods and others saying they always doubted the benefits of diet.``I am still not convinced that fat content in diet may not play a role in cancer rates in this country,'' Bert Petersen, an oncologist at Beth Israel Medical Centre, was quoted as saying.

Medical experts warned that studies disputing the link between diet and cancer should not be interpreted as a licence to eat more fat and pointed out that other studies have shown a clear link between a high-fat diet and the top killer disease--heart attack.--IANS

Herbal immune stimulator

Results of a preliminary study indicate that echinacea, a herbal remedy for cold , boosts activity in white blood cells, immune cells that fight infection, according to a researcher at the University of Florida, reports Reuters Health.

``If for years we have been saying echinaceadoes this, it's nice to know that it does,'' said researcher Susan Percival of the University of Florida's Institute of Food and Agriculture Sciences. Echinacea, derived from the purple coneflower, has been used for centuries in the belief that it can reduce severity and duration of colds.

In the study, Percival gave 10 healthy, college age men an echinacea supplement for four days. Taking samples of their blood from day one and day four, she found that by day four, the men's white blood cells had a three times greater ability to kill bacteria. But in a statement issued by the University of Florida, Percival said her findings do not mean that people should take the herb regularly, in the absence of cold symptoms.

Percival noted that ``a stimulated immune system produces a lot of free radicals, and we know from other research that free radicals are not a good thing. We want the free radicals to kill microorganisms, but we don't want free radicals being produced all the time because they will damage healthytissues.''