Are there more hormones in whole milk?

This article, entitled "Are There More Hormones in Whole Milk?," comes from Carolyn O'Neil at

We have so many choices in our grocery store's dairy case - whole milk, heavy whipping cream, 2% cheese, fat-free skim yogurt. But are there more steroid hormones in the full-fat versions of dairy products? If so, are high-fat dairy products, like whole milk and whipping cream, more likely to have more steroids than those dairy products with less fat, like fat free/skim milk?

To answer this question, we reached out to Dr. Ann Macrina, a research and teaching associate and dairy expert, at Penn State.

Dr. Ann Macrina:

"In general, higher fat dairy products contain a higher concentration of steroid hormones. However, the exact distribution between the fat and non-fat fractions really depends on the particular steroid hormone. Some steroids are more lipiphilic (more likely to combine with fat) than others.

  • Approximately 55% of estrone, one form of estrogen, is found in the fat fraction of milk with the remainder in the non-fat fraction.

  • Estradiol, another form of estrogen, and progesterone are more lipiphilic than estrone, and a greater proportion would associate with the fat fraction of milk.

"But, keep in mind that the overall quantity of steroid hormones in dairy products, even high-fat dairy products, is much lower than the amounts produced naturally by the body.

  • For example, butter is ~80% fat, and one serving contains 1.9 nanograms (billionth of a gram) of estrogen.

  • One 8-oz glass of whole milk contains 2.2 nanograms of estrogen.

  • One 8-oz glass of skim milk contains 0.8 nanograms.

  • The human body produces 54,000 nanograms (prepubertal boy) to 630,000 nanograms (woman) of estrogen per day."

Want to know more? Check out D is for Dairy for answers to many common questions about dairy including...

  • Do hormones in milk cause early puberty?

  • Should lactose-intolerant people avoid dairy?

  • Do dairy products cause weight gain?

  • Is organic milk healthier than non-organic milk?

About the Author...
Best Food Facts
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