The protein question
The frequently asked questions that people following a Whole Food Plant Based Diet is - But where do you get your protein? I first discuss the basic structure of proteins before delving further into this question.
Amino acids- the building blocks of protein
There are 21 amino acids in the human body. These comprise the building blocks for proteins with an almost infinite number of combinations possible. There are 8 essential amino acids in adults, and one more that is essential in children and occasionally older adults. “Essential” means we need to actually consume them in food - they can then be used to make the other amino acids, which are therefore not “essential”. So what are these 8 essential amino acids?
1.Leucine is used in the liver, adipose tissue and muscle tissue. It strongly activates mammalian target of rapamycin kinase (mTOR), which regulates cell growth. It directly stimulates muscle protein synthesis. Food sources include soybeans, hemp seeds, peanuts, wheatgerm and almonds.
2.Isoleucine assists in wound healing, stimulates the immune system and promotes secretion of several hormones. We need it to make hemoglobin and it regulates blood sugar and energy levels. Plant sources include soy protein, seaweed and nuts and seeds.
3.Lysine is responsible for proper growth and tissue repair. It is found in lentils, adzuki beans, soybeans, pumpkin seeds and peas. Deficiency may contribute to blindness.
4.Methionine is important in angiogenesis (growth of new blood vessels). Overconsumption, as is typical with the Standard American Diet (but not a vegan diet) is related to cancer growth. Good plant sources include sesame seeds, brazil nuts, and cereal grains.
5.Phenylalanine - once ingested it turns into tyrosine and is used to make dopamine and norepinephrine neurotransmitters. Deficiency can result in brain fog, lack of energy, depression and lack of appetite. Good sources include spirulina and other seaweed, soybeans, leafy greens and tofu.
6.Threonine is an important part of many proteins such as collagen and elastin. Important for the nervous system and fat metabolism it also helps prevent fat build up in the liver. Best sources are lentils, sesame seeds, spinach, pumpkin, figs, raisins and quinoa.
7. Tryptophan Known as the relaxing amino acid, tryptophan is vital to a healthy nervous system and overall brain health along with sleep, muscle growth and repair and overall neurotransmitter function. It is precursor to melatonin. It also converts to serotonin in the brain, which creates a happy feeling tied to lower levels of stress and depression. It is one of the most prominent amino acids found in turkey, milk and cheese, causing those foods to make you feel sleepy and relaxed - think post-Thanksgiving dinner. However, there are better plant based sources such spirulina, soybeans, sesame and oats.
8. Valine is needed for optimal muscle growth and tissue repair. Higher levels are associated with insulin resistance and diabetes. Plant sources include soy, beans and legumes.
Note: Meat, dairy and eggs are all sources of amino acids too, but since I am advocating a whole food plant based diet for optimal health I have emphasised the plant based sources only.
SO - HOW MUCH PROTEIN DO YOU REALLY NEED?
Ever since the discovery of protein as a macronutrient in food in 1839, it has been considered to be an exceptionally important nutrient. Its name even comes from the Greek work “Proteus” meaning of “prime importance”. The assumption has been that the more we consume the better.
The biggest myth around protein is that it is only found in animal products. We have actually known since the late 1800s that protein is also present in plant foods. Meat eaters often ask vegans “Where do you get your protein?”. Well, the answer is, simplistically, “the same place cows gets their protein - from plants!”
Research findings that showed that animal based proteins were “more efficiently used by the body” helped to make meat the protein of choice in most Western diets. This efficiency actually referred to increased body growth rate which may be useful for farm animal production but for humans, it also comes with the unwanted effect of growing cancer cells faster , promoting heart disease and accelerating the aging process.
So how much protein do we need? The Health Canada Guidelines have an average minimum protein requirement called the Estimated Average Requirement (EAR). For adults this is 0.66g/kg/day. That is, 0.66g of protein per kg body weight, per day. Because it is an average, about half of us need less and about half need more. Therefore, the Guidelines also have a Recommended Dietary Allowance for protein, the RDA, which includes a buffer and suggests getting 0.8g/kg/day. At that level, 98% of people will be getting more protein than they need. So for example, an 80kg (176lb) man needs only 53 g - 64g of protein a day.
A Whole Food Plant Based diet of mixed vegetables, fruits, legumes, grains and tubers can easily provide the RDA of protein.
For example, if we compare a 500 calorie serve of mixed grains, vegetables, legumes and fruit with a 500 calorie serve of mixed animal products, the plants group provides 29g protein compared with 51g for the animal products. If we multiply by 4 to get a 2000 cal diet for a 175lb person, the WFPB diet provides 116g of protein, which easily surpasses the 64g of protein a day recommended for a 175 pound person. It also has only 24g of fat and no cholesterol, but has lots of healthy fibre and multiple different vitamins and minerals.
The animal products 2000 calorie diet provides 200g of protein, way more than the recommended, and with 1600mg of cholesterol and 128g of fat it is also contributing massively to heart disease, stroke and cancer risks amongst many other chronic and debilitating conditions. The animal protein also provides zero fibre, less calcium, less iron and less vitamin, A, C and K.
So rest assured - unless someone is unable to eat sufficient calories (likely due to illness), protein deficiency is unheard of in the Western world. Most of us get way too much protein, which contributes to many of the “diseases of affluence” afflicting our society.