The topic of hormones in our food is a hot button issue, and for good reason, as these ingested hormones can be deleterious to our health. However, dairy is often left out of this discussion when it should be the first food we examine. A research paper titled “The Milk We Drink, Food For Thought” penned by a small team of doctors at the Hadassah Hebrew University Medical Center addressed this issue and not only found a correlation between dairy and consumed hormones but also found that these hormones could negatively affect fertility.^[1] The following is a summary of their findings. The full paper is available on the Fertility and Sterility journal website.

Due to a number of socio-political and economic factors, the modern dairy industry is in the business of producing large quantities of cows’ milk at an increasingly rapid pace. This necessitates that dairy cows be impregnated while still giving milk to reduce the time between her “dry” period and another lactation cycle. A pregnant animal naturally produces a significant amount of sex hormones, which are consequently transferred into the milk consumers drink (you can’t filter out hormones).

Researchers who have studied hormones in cows’ milk have expressed concern over the amount of estrone, estrogen sulfate, and progesterone found in milk and milk products. Some are particularly concerned with the hormone content of whole-fat milk, butter, and cheese, as estrogen and progesterone are fat soluble and cholesterol-based, and these foods are higher in cholesterol than lower-fat dairy products. Preliminary studies were conducted to see if the human body actually absorbs and is affected by these foreign hormones, ultimately concluding that yes, it is.^[2] After consuming 600 mL/m2 of cows’ milk, participants plasma E1 and P4 levels increased while FSH, LH, and testosterone levels dropped significantly. What this means is that the sex hormones in the cows’ milk were absorbed by the body and threw the human body’s hormones off balance. The decrease in testosterone suggests that cows’ milk could negatively impact male fertility.

In the US, Iran, and Spain, participants’ sperm were found to be negatively impacted by the consumption of dairy.

To further their hypothesis regarding cows’ milk and fertility, the researchers in the paper “The Milk We Drink, Food For Thought” cited another cross-sectional study which analyzed the impact that full-fat dairy had on sperm production and shape.^[3] In the US, Iran, and Spain, participants’ sperm were found to be negatively impacted by the consumption of dairy.

Fertility has become a multi-billion dollar industry in the US alone, but given recent findings linking dairy with suppressed fertility, there may not be such a dire need for this enormous business complex. If consumers would eliminate dairy from their diets, they may be able to eliminate the drugs and clinic visits. More research is underway, but if there is an opportunity to avoid fertility drugs (and embarrassing to dangerous side effects that come with them), why not take it?

References

1. Haimov-Kochman R., Shore L.S., Laufer N. The milk we drink, food for thought. Fertility and Sterility. 2016; 106(6): 1310-1311. 1310-1311. https://www.fertstert.org/article/S0015-0282(16)62851-0/abstract
2. Maruyama K , Oshima T , Ohyama K. Exposure to exogenous estrogen through intake of commercial milk produced from pregnant cows. Pediatr Int 2010;52:33–8.
3. Afeiche, M., Williams, P.L., Mendiola, J., Gaskins, A.J., Jørgensen, N., Swan, S.H. et al. Dairy food intake in relation to semen quality and reproductive hormone levels among physically active young men. Hum Reprod. 2013; 28: 2265–2275