The consumption of animal protein is a sensitive topic on many different levels. But from a purely scientific standpoint, the evidence weighs heavily in its favor. When compared gram for gram, scientific studies confirm that animal proteins are more easily and fully utilized than plant proteins. This makes sense given what we know about their biological value. Animal proteins contain not only a greater number, but a better balance of the eight essential amino acids.
What about meat?
From an evolutionary perspective, there’s some fairly conclusive evidence to support the idea that it’s a foundational component of the human diet. Isotope analysis from archaeological studies suggests that our hominid ancestors began eating meat at least 2.5 million years ago. While the digestive process of our even more primitive relatives (the chimpanzees) was dominated by the large intestine (which is good for breaking down fiber, seeds, and other hard-to-digest plant foods), modern humans have a larger small intestine, which suggests that we have since become adapted to eating more digestible, bioavailable, and energy-dense foods, like meat.
When examined in terms of sheer nutrient density, beef, lamb, pork, poultry, and fish all have an essential amino acid profile that is far superior to that of any plant. In the simplest and clearest of terms, animal proteins are complete, plant proteins are not.
Meat also tends to be high in several, key nutrients that are often lacking in plants.
Leading the list are iron and zinc which, ironically, are the two most commonly cited nutrient deficiencies among both male and female athletes. Vitamin B12 is another key nutrient for optimal health, performance, and recovery; it cannot be found in any plant. Docosahexaenoic acid or DHA is an essential omega-3 fat that’s abundant in fatty fish, but difficult to get from plants. The heme iron (found only in animals), is a particularly important mineral for menstruating women, and it’s much more readily absorbed than the non-heme form found in plants. Zinc is difficult to source from plants, but it’s abundant in beef, pork, and lamb. It’s also better absorbed and utilized when it comes from an animal.
In addition to more easily absorbed iron, zinc, and vitamin B12, there are a number of other key micronutrients, termed zoonutrients, that are only found in animals and cannot be obtained in optimal quantities without supplementing your diet.
These important nutrients found only in animals:
CoenzymeQ10 (CoQ10) which is so essential for the production of cellular energy that our bodies can actually make it. Our neurological, muscular, and cardiovascular function all rely on an adequate supply of CoQ10. It’s also a powerful antioxidant.
Creatine is an important cellular energy molecule that’s also stored in muscles and concentrated in the brain. Creatine functions as an easily accessible energy reserve for muscle cells, increasing their strength and endurance.
Carnosine is another antioxidant that’s concentrated in the muscles and brain. It contributes to improved, muscular endurance.
Conjugated linoleic acid (CLA) is a fatty acid found in grass-fed meat and full-fat dairy that has various health benefits. It is one of the key nutrients that make grass-fed butter and meat so much more beneficial to health including building muscle rather than storing fat, reducing inflammation and it may even help prevent cancer.
Other important zoonutrients include colostrum, alpha-lactalbumin, and lactoferrin in whey protein, growth factors, certain essential sugars, and cholesterol in lightly-cooked egg yolks; type II collagen in chicken cartilage, and nicotinamide adenine dinucleotide or NAD+ in fermented dairy products.
Keep in mind that we evolved to eat the entire animal, not just its flesh as the vast majority (of Americans) do today. Almost all other countries due to a combination of making the most of limited animal resources and due to adapted taste preferences consume, brain, tongue, intestines, tongue, ears, blood, feet etc.
It is also important to know that animal flesh contains an inflammatory amino acid called methionine which needs to be counterbalanced by the anti-inflammatory glycine and proline. Since these amino acids are found in the tendons, ligaments, and organs of animals, their intake probably isn’t in your culinary comfort zone (I know it’s not in mine).
Luckily, several palatable and relatively inexpensive alternatives exist. You can sip some bone broth, mix up a batch of gelatin blocks, or blend a scoop of grass-fed collagen into a smoothie in order to boost your body’s methionine level. There are a number of excellent plain, unflavored gelatin and collagen products as well as pre-packaged bone broths available at any natural foods store, although it’s not that difficult to make your own.
Of course there are many nutrients found in plants that can’t be found in animals. So the best course of action is to eat an adequate and balanced amount of both in order to nourish your body as deeply and broadly as possible. A healthy and balanced intake of zoonutrients can reduce the risk of heart disease, support healthy brain function, and speed muscular repair. In general, the healthiest animals raised under the best circumstances (pasture-raised beef and free-range chicken, or wild-caught fish), will contain the most zoonutrients.