On 14 December my blog highlighted some research linking higher insulin levels (or, more specifically, higher levels of related a substance known as C-reactive protein) and an increased risk of breast cancer. The lead investigator of this study had recommended that women wanting to temper their insulin levels should eat a diet low in fat, which I thought odd seeing as the major driver of insulin secretion is carbohydrate. Previous research, as I pointed out pointed to the consumption of certain carbohydrates as a risk factor for breast cancer, while at least some evidence suggested that fat intake was not an important risk factor for this particular condition.
Since that particular blog, I have become aware of some recently-published research which, again, appears to find that fat intake is not strongly linked with breast cancer risk. In this study, the relationship between fat intake and breast cancer risk was assessed in a group of about 45,000 Swedish women . The women were aged 30-49 at the beginning of the study, and each woman was tracked for an average of 13 years.
Looking at the entire group of women, the researches found no relationship between total fat intake and risk of breast cancer. The researchers went further, however, and looked at the relationship between specific types of fat and breast cancer risk. The results showed no significant relationship between intakes of saturated fat, polyunsaturated fat (essentially, a combination of omega-6 and omega-3 fats) or monounsaturated fat and breast cancer risk.
The researchers, perhaps in a quest to find any association, looked also at the relationship between fat intake and breast cancer risk in women of different ages. Here, they found that in women over the age of 50, those consuming the most polyunsaturated and monounsaturated fat had, compared to those eating the least, about half the risk of developing breast cancer.
Now, it is possible that polyunsaturated and monounsaturated fat do help to reduce breast cancer risk, but a ‘epidemiological’ study of this nature cannot tell us whether this is the case of not. What this study does support is the notion that overall fat intake is unlikely to be an important risk factor for breast cancer (and that women who want to reduce their risk of this condition may not be served by being recommended to cut back on fat).
Lof M, et al. Dietary fat and breast cancer risk in fhte Swedish women’s lifestyle and health cohort. British Journal of Cancer 2007;97:1570-1576