By Dr. Frank Sabatino

When European chemists in the 19^th century first used the Greek word proteios, meaning “of the first importance”, to label protein, this nutrient became the primary nutritional obsession and concern. Unfortunately we have all been sold the dangerous, unscientific lie that huge amounts of protein, primarily from animal sources, are necessary for life and health. Especially when studies going back decades show that animal-based protein diets, compared to diets of plant-derived protein, significantly promote the progression of cancer (1), and excessive protein in general can promote metabolic acidosis, inflammation and premature aging.

Protein is a significant and crucial macronutrient of any healthy diet. It is constructed as complex chain of building blocks, amino acids, nine of which are essential and must be provided by your diet. The production of amino acids requires the element nitrogen which makes up almost 80% of the air you breathe. However, no animal is capable of extracting nitrogen from the air to produce amino acids. Only plants working together with certain bacteria in the soil can trap atmospheric nitrogen and convert it to a form that can be utilized by all living organisms. So all amino acids, and therefore all protein,  is initially made by plants and all animal protein is actually nothing but recycled plant protein!

So there is no reason ever to consume animal protein, nor any reason to worry about your protein needs on a whole plant food diet. The largest land mammals on our planet, including elephants, hippos, rhinos, giraffes, and our closely related non-human primates (bonobos, gorillas), maintain huge muscle mass and meet their protein requirements from consuming plants.

You only need about 10% of your total daily calories from protein. The actual recommended dietary allowance for protein is 0.36 grams of protein per pound of body weight. If you weigh between 100-200 pounds, that’s 36-72 grams of protein per day. A diversity of whole plant foods comfortably satisfy these needs and provide all the essential and non-essential amino acids. Data from the US Department of Agriculture show that beans and lentils provide 14-18 grams of protein per cup, nuts and seeds provide 4-12 grams per ounce, oatmeal and quinoa provide 8 grams per cup, and a pound of broccoli , kale and spinach provide 11, 9 grams, and 12 grams respectively. Even a variety of fruits provide 1-4 grams a cup.

 In addition, while lentils and beans provide a percentage of their calories from protein that is on par with animal protein sources, beef, chicken, and salmon provide 50-74% of their calories from risky fat while the legumes only provide 3-5% of their calories from fat. As a result the animal sources are significantly more calorie dense, more loaded with dangerous saturated fats and more likely to promote increased weight, body fat, and serious degenerative, chronic disease.

It is important to consider that age related changes including the loss of muscle mass (sarcopenia), a decrease in digestive efficiency and absorption, chronic disease, dental issues, decreased appetite etc., can alter protein requirements with age. As many as 46% of elder adults may not be meeting their daily protein requirement (2)(3)These factors can increase the daily protein requirement from 0.36 to  0.45-0.54 grams per pound of body weight, and this increase has been associated with a significant improvement in functional integrity and a lower risk of  falls, fractures and frailty. (4)(5)(6)

Excesses of cooked and processed animal protein also promote exaggerations of a variety of certain nutrients and toxic compounds that promote serious health risks including chronic inflammation, heart disease, diabetes, obesity and cancer. These excesses include heterocyclic amines like Harmane, which increase tremors in Parkinson disease, excessive iron toxicity of the heart, liver, pancreas, and increased risk of colon cancer from heme iron, oxidized cholesterol (oxysterols) in processed dairy products associated with heart disease risk, excesses of the essential amino acid methionine that promotes a variety of cancers, and dysbiosis of the gut microbiome increasing TMAO associated with blood clots, heart attacks and mortality from heart disease. 

The combination and variety of whole plant foods provide all the essential amino acids that the body needs. The optimal diet for health, weight regulation, and the prevention/reversal of many chronic diseases requires modest but adequate protein from a diversity of whole plant foods without any animal products. 

References

Bauer J et al. Evidence-based recommendations for optimal dietary protein intake in older people: A position paper from PROT-AGE study group. JAMA. Aug, 2013;14(8):542-559.

Campbell TC. The China Study: Startling Implications For Diet, Weight Loss and Long-Term Health. (Dallas, TX. Benbella Books, 2004).

Krok-Schoen JL et al. Low dietary protein intakes and associated patterns and functional limitations in an aging population: a NHANES analysis. J Nutr Health and Aging, 2019;23:338-347.

Young VP. Amino acids and protein in relation to nutrition of the elderly. Ageing, 1990, July;19(4):S10-S24.

Volpi E et al. Is the optimal level of protein intake for older adults greater than the recommended daily allowance. J Gerontol A Biol Sci Med Sci.  2013;68(6):677-680.

Hruby A et al. Protein intake and functional integrity in aging: The Framingham Heart Study Offspring. J Gerontol Series, Jan 2020;75(1):123-130.