Dairy and Fertility: It Doesn't Do a Body Good!

One of the biggest dietary messages we ingest in this country is that dairy is not only health inducing, but in fact is an essential part of our diet. We have been bombarded with marketing campaigns from the dairy industry for so many years, that the marketing message of “Milk Does a Body Good” has been taken as absolute truth. But is it the truth? When looking at the biology of how the milk of a cow affects the body of a human, and all the decades of research on the topic, the answer is a resounding NO!

What’s wrong with milk? 

The Protein

There’s absolutely nothing wrong with cow’s milk, if you’re a baby cow. The milk of a mother cow is perfectly designed for her calf to grow quickly, much quicker than a human baby will grow in its first year. Both bovine and human milk contain a combination of casein and whey protein, but the bovine variety has 80% casein, while human milk has only 30%. The higher casein content allows the calf to double its birth weight after 40 days, while the human infant, the mammal with the slowest growth rate, doubles its birth weight after a long 180 days. Cow casein is a greasier and heavier molecule than its human counterpart, which is why it’s used in certain types of glue. For many people cow casein can be very hard to digest, and can lead to all sorts of gastrointestinal issues. Research shows that a specific variety of casein (A1), found in most commonly consumed dairy, is what can cause inflammation along the intestinal tract- leading to gut permeability, as well as stress to the liver, pancreas, and stomach. Although no studies prove per se that casein is a factor in infertility, since it has been proven to be inflammatory, and since there is research to prove that systemic inflammation can contribute to fertility issues, it is one of the many reasons dairy should be avoided when trying to conceive.

The Fat

The fat in dairy, as in meat and eggs, is saturated fat, which has been linked to cardiovascular disease, excess weight, and insulin resistance (a cause of diabetes). This type of fat has been shown to inflame and clog our blood vessels, which in turn negatively affects blood flow to all the major organs in the body, including the reproductive organs for both men and women. An example, proven by a recent study , is that the reproductive issue, Erectile Dysfunction (ED), is a symptom of a deeper cardiovascular issue that will typically show up within 3 years of an ED diagnosis.

Besides impairing blood flow, the amount of fat in dairy foods, especially butter and cheese, is extremely high, making these foods calorically dense, and a huge contributor to excess weight gain. Excess fat on the body can be problematic for two reasons: hormonal imbalances, and insulin resistance. Since fat cells turn hormones produced by ovaries and adrenal glands into sex hormones, acting like little hormone factories, too much body fat produces too much of these hormones, and also reduces the amount of Sex Hormone Binding Globulin (SHBG) in the bloodstream. SHBG holds on to hormones, keeping them inactive until needed, so too little of it can allow an imbalance of hormones to occur.

Insulin resistance occurs when the body’s cells become less responsive to the hormone insulin, which plays a key role in regulating blood sugar levels. Insulin is the key that allows glucose to enter the cells, yet the insulin can’t do its job if the cells are filled with excess fat (“intramyacellular lipids”) as a result of a diet too rich in saturated fat. Research  has shown that within just three hours of eating a high saturated fat meal, insulin can stop doing its job, thereby allowing excess glucose in the bloodstream. Chronic high blood sugar and high insulin levels can lead to diabetes, and fertility issues such as PCOS, and reduced sperm quality and testosterone imbalance.

The Hormones

Modern day dairy cows are impregnated a couple of months after giving birth, and milked continuously, except for 60 days prior to the next birth. Because so much of their milk is taken during pregnancy, the milk is filled with pregnancy hormones, which we, in turn, consume. Research has shown both estrogen and progesterone are found in very high concentrations in most milk, and especially high in milk’s concentrated forms: butter and cheese. Although little research has been done to prove the effect these pregnancy hormones have on fertility, there is a study that concludes that intake of full-fat dairy products inversely effects sperm motility and morphology. There is also evidence that the female fertility disorder, endometriosis, is caused in part by excessive estrogen, which could be linked to dairy consumption.

The Sugar

A recent study determined that women living in Thailand, where milk consumption is very low, had only a 25% fertility decline from their twenties to late thirties, compared to women in Finland, where milk consumption is high. The Finnish women had an 80% decline in fertility during the same age range, with statistics for other big milk-drinking countries, including the U.S, the same. The issue is within the sugar molecule, lactose, which breaks down into two smaller sugar molecules: glucose and galactose. The galactose has been found to be toxic to the ovaries, damaging the germ cells that turn into eggs. So all milk products are potentially damaging to the ovaries, including “lactose-free” products, which are simply milk products that have been treated to break the lactose into glucose and galactose in advance. They still very much contain the potentially damaging galactose molecule, and could negatively affect the ovaries.

The Toxins

A component of dairy that needs to be mentioned is the brew of toxins found within most milk products. The milk secretions of a dairy cow contain some amount of whatever that cow has consumed in their feed- pesticides, herbicides, or industrial contaminants, along with chemical substances they’re injected with- antibiotics, and hormones, including the genetically engineered bovine growth hormone. The most commonly used herbicide these days, glyphosate, is considered by the International Agency for Research on Cancer of the World Health Organization to be a probable carcinogen, as a comparative study found that it attaches to the estrogen receptors and pushes the cells to proliferate. And other toxins, leaching from plastics and old synthetic chemicals, such as PCBs, atrazine and dioxins, persist in the environment and are found in highest concentrations in fatty animal products, particularly dairy. PCBs have been proven to harm the reproductive system, along with the immune and endocrine systems.

The Advanced Glycation End Products

This declaration against dairy wouldn’t be complete without a mention of Advanced Glycation End Products (AGEs), and their impact on the reproductive system. AGEs are compounds formed when sugars attach to proteins, and can be made internally as well as taken in from outside sources, such as smoking cigarettes and eating animal-based foods. They are a known risk factor for heart disease and stroke as they can stiffen our arteries, but they are also associated with decreased male and female fertility.

Our bodies have receptors that AGEs can attach to, including throughout the male and female reproductive tract. When the AGEs attach to these receptors they can cause damage to cells and DNA, and cause inflammation. For men, a study has shown the AGEs can damage the DNA in sperm, and reduce sperm quality, and for women, another study shows AGEs can accumulate around the ovaries and inside the uterus, leading to early ovarian aging and failure of the embryo to implant. Women with PCOS have been shown to have twice the circulating levels of AGEs, partially due to AGEs increasing insulin resistance, which can be a cause of PCOS. Reducing dietary AGEs is an important recommendation for all women and men trying to conceive, but especially for women with PCOS.

Conclusion

Although our culture has led us to believe that dairy foods are beneficial for our health, and could be a healthful option for those trying to conceive, the research proves otherwise. Leave the cow’s milk for their calves, and find other plant-based sources of food to replace it. Got soy milk, anyone? :)