Milk Makes Estrogen Levels Rise

Moo-ve over, Reality; we've gotta make room for the dairy producers. And the dairy producers have a version of reality they'd really like us to believe. The California Milk Advisory Board has launched a beautiful new marketing campaign, "Return to Real." The commercials feature real farmers on real farms. The gentle music, natural lighting, and pastoral images of cows and farm families make the idea of eating dairy products seem downright healthy and natural and peaceful — like it's a good thing for all involved. The commercials make no mention of the rest of reality: dairy products are the single largest source of dietary estrogen for humans.

Excess estrogen raises the risk of cancer of the prostate, ovaries, and breast. It is implicated in lowering the age of puberty for girls, and in delaying puberty for boys. And it disrupts the lives of millions of women by causing heavy or painful monthly bleeding and an extended, difficult transition into menopause. 

Back to the Basics
To state the obvious, cows are female animals. As such, cows are subject to a natural hormonal cycle just as human women are. Cows naturally produce estrogen. When a cow becomes pregnant, the level of estrogen increases to help her body prepare for sustaining and nourishing new life. As a pregnant cow nears the time of delivery, estrogen rises dramatically, passing into her milk to help the baby grow strong and healthy. Estrogen is a growth hormone, and since baby calves are designed to double their birthweight in 50 to 60 days, they need that load of estrogen to help them reach their goal. By contrast, human babies usually take four to five months (roughly 150 days) to double birth weight.

However, most calves born to dairy cows don't get to enjoy their mother's milk. Calves are separated from their mothers forever during the first 2 to 48 hours of life. After that, they are bottle fed with either powdered milk or milk that has been deemed unfit for humans. The milk designed to grow the baby calf is diverted to human consumption instead. The estrogen is diverted, too.

Modern Dairy Practice Increases Our Estrogen Exposure
In order to keep dairy cows producing milk, farmers have to ensure a constant cycle of pregnancy and delivery. This is true for cows on an organic farm just as for cows on a large, commercial dairy. The amount of estrogen in a glass of milk will depend on how much estrogen a cow was producing when she was milked. The milk from a pregnant cow has 10 times the amount of estrogen as a non-pregnant cow. John McDougall, MD, reports the following amounts of estrogen in cow's milk: 

non-pregnant: 15 pg/ml
first half of pregnancy: 151 pg/ml
last days of pregnancy: 1000 pg/ml

Researchers estimate that 60 to 70 percent of our food-sourced estrogen comes from milk, yogurt, ice cream, cheese, and other dairy products. 

Modern Milk is More Dangerous
While it's true that dairy has long been part of the human diet, the amount of dairy consumed and the amount of estrogen it contains has all increased. In 2011, it was estimated that the average American ingested 630 pounds of dairy per year. Researchers have noted that "the milk that we are now consuming is quite different from that consumed 100 years ago. Unlike their pasture-fed counterparts of 100 years ago, modern dairy cows are usually pregnant and continue to lactate during the latter half of pregnancy, when the concentration of estrogens in blood, and hence in milk, increases." The researchers are finding corresponding increases in hormone-related cancers. "Among dietary risk factors, we are most concerned with milk and dairy products, because the milk we drink today is produced from pregnant cows, in which estrogen and progesterone levels are markedly elevated." 

Estrogen Makes Things Grow
Estrogen doesn't only cause baby calves to grow; it causes everything to grow — cancer cells included. The lining of the uterus, the endometrium, also grows when the cells in the uterus are bathed in estrogen. The thicker endometrium makes a woman's periods heavier and more painful. As a woman approaches menopause, excess estrogen prevents a woman from completing the transition. The longer menopause is delayed, the longer a woman is exposed to her own hormones, which raises her risk for cancer of the breast, uterus, and ovaries. Reaching menarche before age 12 is likewise a risk factor for these hormone-related cancers. Both early menarche and delayed menopause are driven by excess estrogen in a woman's dietary environment. Men are likewise at risk since prostate cancer is related to excess estrogen. 

Getting Real about Dairy
We can't let clever marketing and nostalgia-producing ad campaigns manipulate our nutritional decisions. It doesn't matter how melty the cheese looks or how beautifully the dairy-based smoothie swirls in the blender while the soft music plays and the camera records. If we want to lower our risk of disease, we are going to have to stop using dairy products. Milk is not designed for our needs; it is designed for the needs of calves. If we want to get back to real, old-fashioned food from the farm — as the milk marketers imply, then we should concentrate on the health-promoting produce that grows on farms. Strawberries, collard greens, potatoes, peas, and beets are just a tiny fraction of the farm foods that will fill our physical need for nutrition and fill our emotional desire to reconnect with the land. Eat food that goes From Sun - To Plant - To Plate. That's the "return to real" that we all need.

Other blogs in this series:  Eating Meat Raises Estrogen at Cellular Levels

Additional Information:

(1) Dr. Klaper's Q & A: This Doctor's Take on Dairy

(2) Dr. McDougall's When Friends Ask: Why Don't You Drink Milk

(3) PCRM's Health Concerns About Dairy Products

(4) NutritionFacts's Dairy Estrogen and Male Fertility

(5) TheVegan8's Fat-Free Vegan "Cheese" Sauce and Mac 'N' Cheese