When it comes to hormonal balance, certain protein sources serve you better than others. Eating protein provides your body with amino acids that are used to produce specific hormones, including insulin and growth hormone. Some proteins are adaptogenic, such as lentils and wild steelhead trout, whereas others overstimulate the immune system and create inflammation, such as grain-fed beef. Not only that, but some proteins may shift the microbiome in a positive or negative direction, resulting in hormonal changes particularly to estrogen. While we do not yet understand the effect of all forms of protein on different hormones, we’ll explore the effect of certain protein sources on estrogen, thyroid, and insulin.
Estrogen effects of protein.
Estrogen is the hormone primarily responsible for making us uniquely women, with breasts, hips, curves, and glossy locks; that is, we’re not simply small men. Yet there’s something freaky that happens when you’re female and you eat grain-fed, hormone-injected, superbug-infected meat: It slows down your digestion and may make you bloated or constipated; it raises your body’s estrogen levels; and it messes with your microbiome, the collective DNA of the trillions of microbes that live in your gut and elsewhere in your body. Here is the biological principle: While it’s true that meat has a higher fat content than other sources of protein, the bigger problem is what’s hidden in the fat of most meats you find at your grocery store. You are anciently hard-wired by your own DNA and microbiome to eat mostly vegetables, nuts, seeds, the occasional fruit, and clean proteins, regardless of your blood type and ethical views. In fact, such native and unprocessed foods keep you lean and your hormones in balance, particularly estrogen.
When you eat conventionally raised red meat, estrogen overload is more likely. When you go meatless, your estrogen decreases. Not surprisingly, vegetarians have the edge here. That could be due to the hormones in the meat, the type of bacteria cultivated in the guts of people who eat a lot of meat, or a combination of factors. We do know that a meat-based diet is linked to higher body mass index and that too much of the wrong type of saturated fat raises estrogen.
Omnivorous women with estrogen excess don’t remove that excess in their bowel movements like women who eat a more plant-based diet—which contains more fiber and stimulates removal of excess estrogen. As a result, studies show that women who eat meat have higher estrogen levels than vegetarians. Vegetarians poop more volume and excrete three times the amount of estrogen as meat eaters, thereby preventing estrogen overload. In fact, estrogen levels in the blood of vegetarians are 15 to 20 percent lower than those of omnivores.
So one of the best ways of creating healthy estrogen levels is to limit alcohol and red meat and to eat more vegetables (1 to 2 pounds per day) and fiber (35 to 50 grams per day).
Thyroid effects of protein.
The major culprits here are mercury-toxic fish and protein sources that contain gluten. Gluten is associated with increased risk of autoimmune thyroiditis, the leading cause of hypothyroidism. Mercury is an endocrine disrupter to both estrogen and thyroid. The worst fish are tuna, shark, and swordfish. Mercury acts like a xenoestrogen by binding to your estrogen receptors. In the thyroid, mercury and iodine are biochemically similar, so your thyroid may absorb and store mercury at the expense of iodine. Women with mercury toxicity are twice as likely to test positive for thyroid antibodies.
Safe sources of marine protein include Alaskan salmon, cod, snapper, tilapia, mackerel, trout, sardines, anchovies, orange roughy, herring, flounder, sturgeon, clams, crab, oysters, and scallops.
Insulin effects of protein.
Eating sufficient fiber is an important part of stabilizing blood sugar and preventing insulin resistance or block. Meat eaters consume half as much fiber as vegetarians. On average, omnivores eat 12 grams of fiber each day, and vegetarians consume 26 grams per day. In other words, a plant-based diet may provide an advantage, although the jury is out on whether people who eat anti-inflammatory meat with adequate vegetables fare as well.
Women who eat red meat may have higher rates of blood sugar problems, as indicated in a recent large-scale observational study of red meat consumption, diabetes, and metabolic syndrome in nearly 150,000 people, published in the prestigious Journal of the American Medical Association. However, an observational study didn’t prove that red meat is the cause of blood sugar problems.
Other studies suggest that a paleo-based food plan may help reverse blood sugar problems in the short term, at least compared with the outdated low-fat American Diabetes Association (ADA) diet. Furthermore, despite the hype about nutritional ketosis and the ketogenic diet, I believe it’s most proven to benefit people with epilepsy and dementia and less proven to help reset insulin, although some studies show a decrease in insulin along with worsening athletic performance.
Mercury may also be associated with a modestly greater risk of insulin resistance, diabetes, and metabolic syndrome, according to a recent meta-analysis. Other studies confirm adverse effects on glucose disposal.
Adaptogenic vegan protein sources:
1. Pea protein:
I’m a big fan of pea protein because it’s a complete protein, i.e., it provides all of the amino acids you need. It’s also the least allergenic form of protein, so you are unlikely to develop intolerance as you might with other proteins (gluten and dairy). Choose a powder form of pea protein that’s free of gluten and dairy and low in sugar (less than 5 grams per serving).
2. Lentils and other legumes:
Some people tolerate them well; others experience inflammation, perhaps due to lectins or fermentation in the gut. See what’s true for you.
Especially flax, chia, sunflower.
4. Hemp protein:
One of the most digestible forms of protein if you have gut issues.
Macadamia and Brazil nuts are my favorites since they are less carby.
Avoid: gluten, and if grains are inflammatory, avoid grains.
Adaptogenic omnivore protein sources:
1. Wild-caught fish:
Salmon, anchovies, sardines, herring, and mackerel.
Particularly oysters, which are rich in copper.
3. Red meat:
Go for wild or grass-fed and grass-finished.
4. Pastured poultry and eggs.
5. Vegan sources:
Keep in mind that rotation of different foods and species helps to prevent intolerance over time.
Avoid: processed meat, grain-fed meat or poultry, dairy (if intolerant), mercury-toxic fish such as tuna, swordfish, and shark.
What's the right dose of protein?
I was taught that people should eat on average 0.75 to 1 gram of protein per pound of lean body mass.
For women of average size, aim for 75 to 125 grams per day, depending upon your level of activity and weight. So for a 150-pound woman with 25 percent body fat, that's 31 pounds of fat mass, and 119 pounds of lean body mass, so the range is 89 to 119 grams of protein per day. For an athlete, aim for the higher end of the range. If you're less fit, aim lower on the range. In general, that's about 8 to 12 ounces per day. When it comes to protein consumption, you want to determine the correct dose. Too little protein will mean you lose lean body mass, and in people who’ve lost weight, weight regain.
When you eat excess protein, it may be converted into sugar, raising blood sugar, through a process called gluconeogenesis. So make your best guess on how much to get, choose the best source for you and your lifestyle, then track your weight, blood sugar, and body composition over time.