There is a hypothesis that eating natural yogurt on a daily basis could potentially protect women from breast cancer. Researchers from the UK’s Lancaster University noted that yogurt contains beneficial lactose-fermenting bacteria similar to the bacteria found in the breasts of women who have breastfed their babies. They theorize that these micro-organisms protect against breast cancer, because we know that each year of breast feeding reduces the risk of breast cancer by 4.3 percent and that these bacteria occupy the breast ducts of women while they are breast feeding and for some time after they stop.
The team also made the point that each birth reduces a woman’s risk of breast cancer by seven percent and suggested that the incidence of the disease in developed countries would drop by more than half – from 6.3 to 2.7 per 100 by age 70 – “if women had the average number of births and lifetime duration of breast feeding that had been prevalent in developed countries until recently.”
The team noted that one of the causes of breast cancer may be inflammation, a process which might be influenced by harmful bacteria, a theory that has not yet been proved.
Several studies have shown that consuming yogurt is linked to a reduction in the risk of breast cancer, possibly due to the displacement of harmful bacteria by beneficial species. High and moderate dairy consumption also reduce breast cancer risk. High consumption is more than 600 grams daily (about four cups) while low consumption is less than 400 grams (less than two cups).
Yogurt also appears to help protect against other types of cancer. I reported last year (2019) that the risk of lung cancer is lower for people who consume a high-fiber diet that includes three to four ounces (about a half cup) of yogurt daily. The researchers, from Vanderbilt University, combined data from 10 studies that looked at diet and the incidence of lung cancer and included information on more than 1.4 million adults in the U.S., Europe, and Asia.
Other evidence from 2019 suggests that consuming yogurt regularly may help reduce development of polyps in the colon that can become cancerous. Those findings came from a study showing that men who ate yogurt at least twice a week developed fewer of these than men who didn’t eat any yogurt. No such results were seen in women. Compared to men who didn’t eat yogurt, those who consumed at least two servings per week were 19 percent less likely to develop the most common types of colorectal polyps and had a 26 percent lower risk of developing the type of polyps most likely to become malignant.
Andrew Weil, M.D.
R.J. Rigby et al, “Hypothesis: Bacterial induced inflammation disrupts the orderly progression of the stem cell hierarchy and has a role in the pathogenesis of breast cancer,” Medical Hypothesis, March 2020, doi.org/10.1016/j.mehy.2019.10953