The Truth about Dairy
There’s a lot of buzz around dairy as a food group, as it seems increasing numbers of people are choosing to cut dairy from their diets. I am not one to classify foods as “good” or “bad,” but I believe it’s important to consume a diet that makes you feel your best. Lately, there have been a lot of claims that dairy is “bad” for you; I’ve heard people say that it is full of bad fat, unhealthy chemicals, hormones, and indigestible proteins, of which can harm your GI tract, cause acne, increase your cancer risk, and cause other detrimental effects. If you enjoy having dairy products as part of your diet, this may concern you. So, is dairy “bad” for you? Let’s look at the research.
Spoiler: the known health benefits outweigh the suspected harms (on average).
Dairy is a massive food group. The milk that creates the dairy products we consume can come from many different animals, including cows, goats, sheep, buffalo, yaks, horses, and more. The nutrient content varies based on the animal the milk comes from and how it is processed. In addition to recognizing the wide array of dairy products (and corresponding nutrient profiles) available, it is important to remember that we are all different human beings, as well. Some people tolerate and digest dairy better than others, and taste preference can be a just as important factor.
The Nutritional Content of Dairy
Milk is rich in fat, proteins, and nutrients, as it is specifically designed to be a complete source of nutrition for baby mammals. It’s made up of fatty acids, carbohydrates, proteins, minerals, fat-soluble vitamins, B vitamins, and iodine. The level of fatty acids in milk varies based on many factors because milk-producing mammals convert feed to fatty acids during digestion. This means that the animal’s diet has a large effect on the composition of its milk. This explains why grass-fed beef is more nutrient dense (contains more conjugated linoleic acid and omega-3s) than conventionally fed cows.
The protein content of dairy is primarily casein, which is a slow-digesting, high-quality protein that may have antioxidant effects, immune boosting properties, and the ability to reduce triglycerides and high blood pressure. Whey is the other type of protein in milk. You’ve probably heard of it, because it’s the most popular protein supplement on the market. Many people use it as a muscle-building supplement, but it can also provide other benefits such as lowered blood pressure, improved glucose control, increased antioxidant capacity, and more. There has been some buzz in the industry around the idea that whey protein can promote cancer development. However, more research indicates anti-cancer properties than cancer promoting properties. So, the benefits that come from including whey protein in your diet likely outweigh the possible risks. Milk is also an excellent source of calcium and vitamins A and D. Calcium in important for healthy bones, and it is vital for functions such as muscle contraction, blood clotting, and nerve impulse transmission. Milk and other dairy products are fortified with added vitamins A and D.
So, how does the nutritional content of dairy affect your health? Dairy seems to help people lose fat and maintain a healthy weight, which is likely due to the high-quality protein content, the high nutrient-density of calcium and magnesium, and the compound that have been shown to improve metabolic health, gut health, and other contributing factors to a normal body composition (in products such as yogurt and cultured dairy). Dairy also seems to help people gain and maintain muscle mass, which is likely due to the high-quality protein content that contains the essential amino acids our bodies need. Dairy consumption can help bone health, and might also decrease the risk for cardiovascular disease and stroke. According to current research, dairy intake doesn’t increase the risk for cancer.
Although the research on this subject is limited, it seems as if there are many benefits to incorporating dairy into your diet (if you enjoy it and choose to do so).
Hormones in Milk
Why does everyone talk about hormones in milk? Are they dangerous? Yes, milk contains naturally-occurring hormones, supplemental hormones, and hormones our own bodies make naturally. Spoiler: “dairy contains bad hormones” is not a scientifically-backed concern.
Naturally-occurring hormones come from the mammals that produce the milk. In order to lactate, the animal must have been pregnant at one point or another (in most cases). Mammals in various stages of pregnancy and lactation often have higher hormone levels. That being said, dairy definitely has estrogens in it. Although we know that higher blood levels of estrogen have been linked to breast cancer in women and prostate cancer in men, we also know that our livers break down steroid hormones after they are absorbed. In conclusion, consuming hormones can only have an effect on levels in our blood if we take incredibly high dosages.
Some farmers also use supplemental hormones to stimulate milk production. You may have heard of bovine growth hormone (bGH) or somatotropin (bST) causing concern in the health and fitness industries. However, although these hormones are in the milk and dairy products we consume, they are also broken down into peptides by our liver (so they never reach our bloodstream). These hormones are not biologically active in humans, anyways.
IGF-1 is the hormone in milk that actually does seem to increase hormone levels in humans. This is a hormone that our own bodies make naturally, and it supports muscle, bone, and tissue growth. If you’re trying to build muscle or bone density, this can have a positive effect. Uncontrolled growth can also have negative effects, though. Although IGF-1 is likely not responsible for tumor development, it is possible that higher levels can help existing tumors grow more rapidly. There isn’t a lot of research on this topic, and what research is available is often conflicting. In fact, some research has shown that low-fat dairy is associated with a lower risk of colorectal cancer in people with boosted levels of IGF-1. You should also note that all protein-rich foods increase IGF-1 levels: it is not isolated to milk and dairy. So, dairy’s IGF-1 connection to cancer is not consistent or strong by any means.
Intolerances to Dairy Products
Dairy allergies, intolerances, and sensitivities are some of the most common in the world. Allergies are usually constituted by an immediate immune response. You’ll likely feel the response in your immune system, as well as potentially in your respiratory system, skin, mouth, throat, and more. If you have a dairy allergy, you should avoid dairy.
Many people also suffer from lactose intolerance. Lactose is a simple sugar in milk, and some people have a difficult time digesting this. These people may lack the enzymes needed to break the lactose down. This can depend on genetics, age, intestinal health, our microbial environment, and more. With lactose intolerance, the lactose isn’t digested in the small intestine, so it passes to the large intestine. There, it ferments. This can cause symptoms such as gas production, bloating, stomach cramps, diarrhea, and more. If you can’t digest galactose properly, you likely suffer from a genetic disorder called “galactosemia,” which is more serious. Newborns are often screened for this.
Dairy sensitivities can also stem from factors other than lactose and galactose. For example, people can have sensitivities to things like casein, whey, or other proteins in milk. Sensitivities to these compounds can cause symptoms such as inflammation, skin rashes, an irritated respiratory system, and more.
So, Should You Include Dairy in Your Diet?
It depends! What matters to you? Does consuming dairy align with that? Can you tolerate dairy? Do you like dairy products? Does it fit into your routine and life, and does it cause you joy? There are many ways and reasons to consume dairy (or not). Ultimately, it is your decision! If you choose to consume dairy, that’s great. You can consider consuming fermented or cultured dairy more often to reap the health benefits. If you choose not to consume dairy, no worries! You don’t need dairy to be healthy.
