There is a possible relationship between milk and breast cancer, according to a new study conducted by researchers at Loma Linda University Health. The researchers found that even relatively moderate amounts of such products in womenBreast cancer risk, dependentof the amount consumed, can increase by up to 80%.
Link between milk and breast cancer
The observational study provides “fairly strong evidence that either milk or another factor closely related to milk drinking is a cause of breast cancer in women.” This is what the first author of the paper, Gary Fraser, claims.
“Consuming just 1/4 to 1/3 cup of milk per day was associated with a 30% increased risk of breast cancer. Drinking up to one cup per day increased the associated risk to 50%. For those who drink two to three cups per day, the risk increased further to 70% to 80%.” Nutritionists recommend three cups of milk per day. “However, the results of this study suggest that people should view this recommendation with caution,” Fraser said.
The scientists evaluated the dietary intake of nearly 53,000 women, all of whom were initially cancer-free, for almost eight years. They estimated milk consumption using food frequency questionnaires. The test subjects also repeated this around the clock. A basic questionnaire included questions about demographics, family history of breast cancer,physical activity, alcohol consumption, hormonal and other medication use, breast cancer prevention, and reproductive and gynecological history.
Research results
At the end of the study period, there were 1,057 new breast cancer cases during follow-up. No clear associations have been found between soy products and breast cancer, regardless of dairy. However, higher intake of dairy calories and milk was associated with a higher risk of breast cancer. This was also independent of soy intake. Fraser found that results showed minimal variation when comparing full-fat intake with reduced or fat-free milk. No important associations with cheese and yogurt were found.
“However, dairy products, particularly milk, were associated with increased risk and the data predicted a significant reduction in risk. This is associated with replacing milk with soy milk. It increases the possibility that alternating dairy products are optimal.”
A dangerous effect of dairy products is consistent with the recent AHS-2 report that vegans, but not lacto-ovo vegetarians, had lower rates of breast cancer than non-vegetarians.
Fraser said the possible reasons for these associations between breast cancer and milk could be the sex hormone content of milk, as cows naturally breastfeed and often about 75% of the dairy herd are pregnant. Breast cancer in women is a hormone-sensitive cancer. Additionally, dairy and other animal protein intake is also linked in some reports to higher blood levels of a hormone, insulin-like growth factor 1 (IGF-1), which is thought to promote certain types of cancer.
“Milk has some positive nutritional benefits,” Fraser said, “but these need to be weighed against other possible, less helpful effects. The work in thisStudysuggests the urgent need for further research.”
