IN THIS ARTICLE:
In my recent book, The Lyme Disease 30-Day Meal Plan, I mentioned that in my clinical practice, I’ve found most of my clients with Lyme disease do best including some sort of animal protein in their diets. While I attribute much of this benefit to the unique micronutrients found in animal proteins, including heme iron and vitamin B12, another reason animal proteins are so healing in Lyme disease is due to their beneficial effects on muscle mass maintenance. Read on to learn why maintaining and building muscle mass is essential for optimizing immunity and Lyme disease recovery, and why animal proteins are the best dietary proteins for achieving optimal muscle protein synthesis.
In This Article:
- Yes, Animal Protein is a Natural Part of the Human Diet
- Skeletal Muscle and Your Immune System
- Skeletal Muscle and Lyme Disease
- Animal Protein is Superior to Plant Protein for Supporting Muscle Synthesis
- Animal Protein: The Clear Winner for Building and Maintaining Muscle
- Beyond Protein: Additional Nutritional Benefits of Animal Proteins
Yes, Animal Protein is a Natural Part of the Human Diet
Before I dive into a discussion of animal protein, muscle protein synthesis, and the immune system, I want to clear the air regarding the role of animal proteins in the human diet. Recent vegan-centric documentaries, such as The Game Changers and What the Health, would have people believe that animal protein is not a necessary part of the natural human diet. I find it surprising that these documentaries made it all the way to the public, given their clear lack of understanding of evolutionary biology and the pivotal role animal proteins have played in human evolution.
The truth is that animal protein is not only a natural part of the human diet, but was essential for our evolution as a species. (1) Whatever your ideological perspective on animal protein consumption, these foods are inarguably crucial for human physiological function and health.
I still think that properly-prepared (soaked, sprouted, and fermented) gluten-free grains and legumes can play a role in my clients’ diets. However, I do not recommend these foods for their protein content, which can’t hold a candle to animal proteins – I recommend them for their carbohydrate content and for increasing the calorie density of my clients’ diets.
Side Note: The topic of dietary animal protein and environmental sustainability is a hot topic, albeit one that is greatly misrepresented in the mass media. I do not address the environmental aspects of meat consumption in this article. If you still think that all forms of animal agriculture “destroy the planet,” I encourage you to please go to Diana Rodgers RD’s website, Sustainable Dish, and learn about her fascinating documentary project Sacred Cow. This documentary explains all the reasons why regenerative animal agriculture is not only NOT harmful to the planet, but may actually help save our soils and our environment.
Skeletal Muscle and Your Immune System
Now that we’ve established that animal proteins are a natural, crucial part of the human diet, let’s talk a bit about muscle and immunity, and then tie them into the animal protein discussion.
Research shows that is skeletal muscle, or the muscles that allow you to move your body, engage in cross-talk with your immune system. White blood cells, called macrophages, within skeletal muscle assist in maintaining immune homeostasis and clearing pathogens. (1) Preclinical research indicates that skeletal muscle also confers protection during bacterial infection by activating innate immune pathways. (2) This has important implications in Lyme disease, a bacterial infection that manipulates the innate immune system to establish persistent infection. Maintaining a healthy skeletal muscle mass through the consumption of animal protein and exercise may thus aid in Lyme disease recovery.
Skeletal Muscle and Lyme Disease
Lyme disease is an infection and inflammatory illness caused by Borrelia burgdorferi (in the United States), a spirochete (spiral-shaped) bacterium transmitted by the bite of an infected tick. When not caught immediately, Borrelia burgdorferi induces changes in the immune system that allows it to evade your immune cells, establishing persistent infection.
Borrelia frequently affects the joints, causing joint stiffness, muscle pain, and even osteoarthritis. The magnitude of osteoarthritic pain, as well as the extreme fatigue and general discomfort caused by the disease, prohibit many Lyme patients from exercising. A lack of exercise, in turn, promotes sarcopenia, or skeletal muscle loss. Since skeletal muscle is critical for maintaining optimal immunity, the inactivity and loss of muscle caused by Lyme disease may further weaken the immune system. To compound matters, chronic inflammation and infection, key characteristics of Lyme disease, also promote muscle loss. (3) What can Lyme patients do to attenuate the loss of vital skeletal muscle, particularly if they are unable to exercise?
As a clinical nutritionist who works with the Lyme disease population, I recommend that Lyme-affected people focus on eating plenty of bioavailable animal protein, as an optimized protein intake has been found to diminish muscle loss. Sufficient bioavailable protein intake is especially important for middle-aged and older people with Lyme disease, as aging by itself causing a resistance to the stimulation of muscle protein synthesis following dietary protein intake – this is referred to as “anabolic resistance” – thus requiring people within these age groups to consume greater quantities of bioavailable protein in order to maintain healthy muscle mass. (4) Together, these findings make a compelling argument for why people with Lyme disease need to optimize their intake of highly bioavailable proteins, which by definition come from animal sources. Of course, this intake of bioavailable protein should be coupled with some sort of physical activity – whatever you can manage in your current stage of Lyme recovery. You do not need to be a body builder to reap the benefits of dietary animal protein on muscle mass – yoga, walking, and resistance exercise training are great, manageable options.
Animal Protein is Superior to Plant Protein for Supporting Muscle Synthesis
Numerous studies in the scientific literature indicate that animal proteins have a greater ability to enhance the rate of synthesis of muscle protein and support muscle mass compared to animal protein. (5, 6, 7) Animal protein is superior for supporting human health because it has a high dietary protein quality. The authors of a recent article in Nutrients define dietary protein quality clearly and succinctly:
Based on the concept of dietary protein quality, animal proteins are superior to plant proteins for several reasons:
Animal proteins are more bioavailable than plant proteins.
Bioavailability refers to the proportion of a substance (in this case, amino acids) that enters the circulation when introduced into the body, and so is able to have an active effect on biochemical processes such as muscle protein synthesis. Protein bioavailability is quantified by the DIAAS (Digestible Indispensable Amino Acid Score) system. DIAAS allows for a calculation of the amino acid quality of food proteins that are based on digestibility within the ileal portion of the small intestine, rather than total digestibility throughout the entire intestine (referred to as “true fecal digestibility;” the DIAAS system thus allows for more precise protein bioavailability calculations than the previously employed PDCAAS system, which utilizes true fecal digestibility.
Here are a few examples of animal and plant proteins ranked with the DIAAS system, from highest to lowest bioavailability.
Higher bioavailability is better:
Medium-rare beef steak: 1.39 (8)
Egg: 1.13 (9)
Chicken breast: 1.08 (9)
Whey protein concentrate: 1.33 (10)
Pea protein concentrate: 0.82 (11)
Green lentil: 0.65 (11)
Peanut butter: 0.46 (11)
Whole wheat: 0.20 (11)
So why are animal proteins more bioavailable than plant proteins? Well, simply put, plant proteins are difficult to digest! Poor digestion of plant proteins leads to poor absorption of the amino acids contained therein. Why are plant proteins difficult to digest? Plant proteins are characterized by a high content of amino acids in the beta-pleated sheet conformation, a secondary structure formed by strings of individual amino acids. The beta-pleated sheet conformation is resistant to proteolysis in the gastrointestinal tract, or breakdown by protein-degrading enzymes in the intestine. Conversely, most animal proteins are rich in the alpha-helix amino acid secondary structure, which is more easily deconstructed by proteolytic enzymes. (12)
Anti-nutritional Factors in Plant Proteins May Limit Protein Digestibility
Legumes and grains are also rich in antinutritional factors such as phytic acid, protease inhibitors, glucosinolates, and tannins, which may further inhibit protein digestibility. The non-starch polysaccharides and fiber in legumes and grains may also contribute to poor digestion of the protein contained in these foods. (13) Soaking and sprouting grains and legumes can reduce the antinutritional activity of phytic acid, but the extent to which these preparation processes improve the protein digestibility of these foods remains unclear.
Animal proteins have higher concentrations of essential amino acids than plant proteins.
Essential amino acids are amino acids that the human body needs to grow and function properly and that cannot be synthesized de novo in the body. Animal proteins contain greater amounts of essential amino acids crucial for building muscle, including leucine, lysine, and methionine. (12) Most plant proteins lack, or have very low levels, of one or more of these amino acids. Insufficient levels of leucine, lysine, and methionine insert a bottleneck into the process of muscle protein synthesis, reducing the efficiency of this critical physiological process.
Plant proteins lack carnosine, a dipeptide molecule that plays an important role in muscle function.
Animal Protein: The Clear Winner for Building and Maintaining Muscle
Based on the scientifically-validated, unbiased DIAAS data, animal proteins are clearly superior for building and maintaining a healthy skeletal muscle mass. If you have Lyme disease and are looking to optimize your recovery process, I urge you to optimize your intake of animal proteins to support your skeletal muscle mass and immune system. Self-experimentation, or working with a clinical nutritionist such as myself, can help you determine your unique protein needs and the best ways to fulfill those needs. If you could use some nutritional guidance in your healing journey, check out my services to learn more.
Beyond Protein: Additional Nutritional Benefits of Animal Proteins
Apart from their superior effects on muscle protein synthesis, animal proteins are also rich sources of several nutrients that cannot be found in plant proteins, including heme, vitamin B12 (not vitamin B12 analogs, such as those in chlorella), a brain-trophic B vitamin called nicotinamide, CoQ10, and conjugated linoleic acid (CLA). (ref) I will cover these animal protein-based nutrients in more detail in a later blog. Stay tuned!