Cows, Dairy Products, and Breast Cancer

New research has provided an interesting discovery—patients who consumed high-fat dairy products following breast-cancer diagnosis increased their chances of dying from the disease years later.

Who would ever have thought such a thing could be true? A study published in the Journal of the National Cancer Institute is the first of its kind to examine the relationship between high-fat and low-fat dairy consumption after a diagnosis of breast cancer, and then the long-term statistics on breast cancer survival.

Previous studies have shown that a higher lifetime exposure to estrogen is a probable causal pathway to breast cancer. because most of the milk consumed in the Western world comes from pregnant cows, elevated levels of estrogen are believed to be present in these dairy products. And since estrogen resides primarily in fat, high-fat dairy products contain higher levels of estrogen than do low-fat dairy products.

Kaiser Permanente in California conducted this research with breast-cancer survivors in the northern California and Utah region. The study reported that women consuming a larger amount of high-fat dairy (defined as 1 or more servings a day) had higher breast-cancer mortality, as well as higher all-cause mortality and higher non-breast cancer mortality as well.

How high were these mortality rates?

Compared to the group that consumed low-fat dairy products, those in the high-fat group had a 64 percent higher risk of dying from any cause, and a 49 percent increased risk of dying of their treatment cancer. Wow.

The dairy products considered in this study weren’t limited to milk. They included cream, whole milk, condensed or evaporated milk, puddings, ice cream (oh no!), custard, flan, and most cheeses and yogurts, unless a specific product was low-fat or nonfat.

When you think about it, though, a high-fat diet is not a healthy diet to begin with. And seeing this information laid out like this in these study results certainly gives you reason to pause. (And guess what? I grew up on a dairy farm!)

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