Balanced is excited to bring to you our Nutrition Mythbusters series in which we debunk eight major myths about the links between diet and health! We believe that accurate, evidence-based nutrition information should be accessible to everyone. That’s why we created this educational series dispelling some of the most common and persistent misconceptions regarding healthy, balanced eating and diet-related disease. You can find the video episode of today's blog on our YouTube channel.
There are many people who continue to believe that animal proteins are not only good for you, but actually essential elements of a healthy diet. And who could blame them? Through food advertising and other media, we are bombarded with the notion that more protein is always better, especially from “high quality” animal sources.
But not only are animal proteins not essential, it is their “high quality” nature that makes them problematic for our health. Animal proteins, in the form of red meat, poultry, fish, dairy, and eggs, are very similar in structure and composition to the proteins in our own body. As such, animal proteins tend to fuel growth factor production even at moderate levels of consumption, which for us can spell the promotion of tumors. On the other hand, consuming plant proteins, even at high proportions of total calorie intake, fail to cause this cancer-promoting spike in growth factors.
In addition, the structural similarity between animal proteins and our own proteins poses a risk for autoimmune diseases. When we develop allergies to animal proteins that are analogous to our own, our bodies can end up attacking our own tissues. This is one of the proposed mechanisms by which dairy protein consumption among children is thought to trigger type 1 diabetes, where the body attacks the cells of the pancreas that produce insulin. Though the dairy industry often touts the calcium content of its products, the calcium in leafy greens like kale is more readily absorbed by the body.
Similarly, animal protein also comes with animal sex hormones, the same or similar to those in humans, including a range of estrogens. High-fat dairy products are particularly chock-full of mammalian estrogens, so much so that regular consumption has been associated with a decline in fertility in men and women, suggesting damage to or aging of testicular and ovarian tissues. But sex hormones aren’t the only chemicals we should worry about in animal products. Dozens of industrial pollutants, including ones that have since been banned, like DDT and PCBs, are present in significant amounts in red meat, poultry, fish, and dairy. Some of these, like PCBs, have endocrine-disrupting or estrogenic properties.
Fish, like salmon, is praised for its omega-3 fatty acid content, yet it is precisely within the fat that these fat-soluble pollutants like PCBs and dioxins accumulate. An article published by Harvard Medical School suggests that for those with family histories of cancer, fish consumption should be limited to once or twice per month. Given that the lifetime risk of having cancer in the United States is roughly one in two and the risk of dying from cancer is one in five, I would suggest, regardless of family history, we should all limit our seafood intake. A much safer way to consume more omega-3 fatty acids is through plant-based sources, such as walnuts, ground flax seeds, chia seeds, or an algae-derived supplement. This is especially important advice for pregnant women, who should steer clear of fish altogether.
Heavy metals in animal proteins pose yet another serious risk to health. Arsenic, cadmium, lead, mercury, and other harmful heavy metals tend to accumulate in animals, particularly fish, which live in highly contaminated oceans and waterways. Chicken is especially high in arsenic, as arsenic-containing compounds are added to chicken feed to prevent infection and speed up growth. Mercury, found at high levels in seafood, has deleterious effects on the developing brain and can increase risk of a child being epileptic, and for the consumption of most species of fish, the harms of mercury outweigh potential benefits of omega-3 fatty acid content. On the other hand, consuming more fiber- and phytate-rich plant-based foods, which bind heavy metals, can significantly reduce the absorption of heavy metals from food.
If you think industrial contaminants are alarming, then hold onto your hats for the microbiological contaminants of animal proteins. We’ve all witnessed the recalls of various grocery items for contamination with Salmonella, Campylobacter, or E. coli. While these pathogens originate with animal products contaminated with feces, many plant-based products (most recently, onions) can become tainted, too. But the contamination of animal products is so endemic that it begs the question: are these products truly safe?
One study, which sampled 316 packages of chicken from 26 states, concluded that these foods “pose a potential health threat to consumers because they are contaminated with extensively antibiotic-resistant and, presumably, virulent E. coli isolates,” (emphasis mine). Cooking-resistant endotoxins from these and other fecal bacteria damage the lining of our blood vessels over time, precipitating atherosclerosis and cardiovascular disease—our number one killer. Viruses also pose a significant threat, particularly “polyomaviruses” that are known to cause cancers in both farmed animals and, ultimately, people. For example, bovine leukemia virus, acquired through consumption of meat and dairy, may account for up to 37% of all breast cancer cases in the US.
As scary as all of this sounds, it is ultimately the saturated fat, cholesterol, naturally occurring trans fat, and added sodium found in red meat, dairy, fish, eggs, and poultry that contribute to our nation’s top killers—heart disease and stroke. Recent data show that, unfortunately, simply switching from red meat to white meat is not a solution. These proteins must be replaced with plant proteins to meaningfully reduce health risks.
To close with some useful advice, it’s a great idea for our health (on many levels, clearly) to opt for plant-based proteins most of the time and to reduce our consumption of animal proteins in both portion size and frequency. In general, Americans are consuming two to four times as much protein as we really need, and when this excess comes from animal sources specifically, it wreaks havoc on our kidneys, colons, hearts, and, well, virtually every organ in our bodies.
As far as protein recommendations go, I don’t find it helpful to tell people to eat X grams of protein per kilogram of bodyweight. As long as you are consuming enough calories, you are surely getting enough protein. Stick to eating a plethora of legumes, nuts, seeds, whole grains, and vegetables, and you’ll be set.