Do Vegetarians Get Enough Protein?


· June 6th 2014 ·

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Nutritional quality indices show plant-based diets are the healthiest, but do vegetarians and vegans reach the recommended daily intake of protein?

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Animal Protein as a Carcinogen

Answer to a Reader’s Question:

Although there are many arguments favoring the nutritional imbalance explanation of cancer, one of the more striking for me was the experimental animal studies discussed in Chapter 3 in my book, The China Study. Namely, aflatoxin is a very potent carcinogen for the rat. However, after the Indian researchers showed that decreasing protein (casein) intake from the usual level of consumption of 20% to 5% completely prevented this very powerful carcinogen to cause cancer, we then began our work (references in our book). We explored that finding in great depth and eventually confirmed their initial observation. That is, simple adjustment of dietary protein (casein) within very normal ranges of protein intake controlled cancer growth and it worked not by one mechanism but by a large array of mechanisms. In other words, we proved this association beyond any doubt.

Further, over the years, this research required a lot of funding and our applications for funding were reviewed by other researchers highly experienced in this field. Every time we got high marks for the quality of the research. Then, when we submitted the results for publication, they were again reviewed by peers and these papers were published in the very best cancer research journals. Among the people who know the most about cancer, our work was entirely convincing.

Very simply, normal adjustment of protein intake was capable of enormously influencing the ability of a chemical carcinogen’s ability to promote cancer. Dietary protein trumped a very powerful carcinogen in a species that was exceptionally sensitive to this carcinogen.

Then we did much the same thing with a cancer caused by a virus, the hepatitis B virus.

If we follow the criteria of determining what is a carcinogen and what is not, these findings should shake up the entire world of cancer research and education because this is the way that other carcinogens (Alar, dioxin, DDT, etc.) also work–except the evidence favoring their carcinogenicity is far less than it is for aflatoxin!

But I was not comfortable taking the usual path of declaring that casein is a carcinogen that was far more powerful than aflatoxin (“the most potent carcinogen ever discovered” according to the people who favor the chemical carcinogen hypothesis). Instead, I was more interested in asking broader questions, involving the role of animal protein based foods in their association with human cancer, as well as to study the comparative associations of aflatoxin consumption and protein consumption in humans–this was the China Study.

I have given this story to many of the very best–and most critical audiences — that I can find (Harvard, Berkeley, Cornell, Emory, Yale, Duke, NIH, etc.) and I get no serious criticism. The only comment that seems to surface more than a few times is ‘I am taking on some very powerful interests and they won’t listen — regardless of the veracity of the evidence’, or words to that effect. In other words, this issue — first narrowly defined but later expanded into a much larger issue — is mostly about politics, economics, personal bias, etc., and not about rational science. Quite honestly, it depresses me because there is so much at stake for human health. Corporate America, who controls the agenda in this health research business, is more interested in their own health than they are in the health of the public!!

Dr. T. Colin Campbell has been at the forefront of nutrition research for over forty years. His legacy, the China Project, has been acknowledged as the most comprehensive study of health and nutrition ever conducted. Dr. Campbell is the Jacob Gould Schurman Professor Emeritus of Nutritional Biochemistry at Cornell University. Dr. Campbell also serves as the President of the Board for the T. Colin Campbell Center for Nutrition Studies and is featured faculty in our highly acclaimed, Plant-Based Certificate and our online heart course, Nutrition for a Healthy Heart.

How do you get enough protein on a plant-based diet?

This is a very popular question. And an important one, but even if you aren’t following a plant-based diet, do YU know how much protein you should be eating on a daily basis?

How much protein do we actually need?

Well, in the United States, the Dietary Reference Intake (DRI) for protein is 0.8 to 1.0 grams of protein per kilogram of body weight. To calculate your weight in kilograms, divide your weight in pounds by 2.2. That number is about how many grams you need each day. Approximately 15-25% of your total calories should be from protein sources. Although protein is certainly an essential nutrient, which plays many key roles in the way our bodies function, we do not need huge quantities of it.

Many Americans consume about twice the amount of protein necessary, and it’s important to note that excess protein can’t be stored in the body—ultimately, its elimination strains the liver and kidneys. Excessive protein consumption is linked to certain cancers (i.e.: colon, breast, prostate, pancreas), kidney disease and even osteoporosis. If you’re consuming a variety of clean, whole foods, you should get all the protein you need, without taxing your body.

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Why is protein so important?
As you may or may not know, proteins are made up of amino acids, and they are the “building blocks” of life. Our skin, muscles, tendons, cartilage, even hair and nails, are all thanks to protein. Protein helps form enzymes, hormones, antibodies and new tissues. It replaces old cells with shiny new ones, and it transports important nutrients in and out of those cells. The human body can manufacture all but nine of the 22 amino acids that make up proteins. These nine amino acids are known as “essential” amino acids, and therefore must be derived from what we eat. There’s a lot of overlap from the sources of these “essentials,” which further proves that variety is best for covering bases. You don’t have to sweat every detail, or spend a ton of time planning meals—eat an assortment of whole foods and you will get what you need.

* Arginine
Classified as a semi-essential or “conditionally” essential amino acid, depending on the developmental stage and health status of the individual.
Find it in: almonds, beets, Brazil nuts, buckwheat, carrots, cashews, celery, chickpeas, coconut, cucumbers, flax seed, garlic, green vegetables, hazelnuts, kidney beans, leeks, lentil, lettuce, nutritional yeast, onion, parsnips, pecans, pine nuts, potatoes, pumpkin seeds, radishes, sesame seeds, sprouts, sunflower seeds and walnuts.
. . .
Especially needed during infancy for proper growth and development—once was believed to be only essential for newborns, but is now known to be essential for adults, as well.
Find it in: apples, bananas, beans, beets, buckwheat, carrots, cantaloupe, cauliflower, celery, citrus fruits, cucumber, dandelion, endive, garlic, greens, legumes, mushrooms, pomegranates, radish, rice, seaweed, sesame, spinach, spirulina and turnip greens.
. . .
Necessary for muscle production, maintenance and recovery—especially post-workout. Involved in hemoglobin formation, regulating blood sugar levels, blood clot formation and energy.
Find it in: almonds, avocados, cashews, chickpeas, coconut, lentils, olives, papaya, seaweed and most seeds like sunflower.
. . .
Essential for growth hormone production, tissue production and repair. Prevents muscle wasting and is used in treating conditions such as Parkinson’s disease.
Find it in: almonds, asparagus, avocados, chickpeas, coconut, lentils, oats, olives, papayas, rice, sunflower seeds and walnuts.
. . .
Great for calcium absorption, bone development, nitrogen maintenance, tissue repair, hormone production, antibody production.
Find it in: amaranth, apples, apricots, beans, beets, carrots, celery, cucumber, dandelion greens, grapes, papayas, parsley, pears, peas, spinach and turnip greens.
. . .
The “cleaner”—important for fat emulsification, digestion, antioxidant (cancer prevention), arterial plaque prevention (heart health) and heavy metal removal.
Find it in: black beans, Brazil nuts, cashews, kidney beans, oats, sesame seeds, spirulina, spinach, sunflower seeds and watercress.
. . .
A precursor for tyrosine and the signaling molecules: dopamine, norepinephrine (noradrenaline) and epinephrine (adrenaline), as well as the skin pigment: melanin. Supports learning and memory, brain processes and mood elevation.
Find it in: apples, beets, carrots, cashews, flax seed, hazelnuts, nutritional yeast, parsley, pineapples, pumpkin seeds, sesame seeds, sunflower seeds, spinach and tomatoes.
. . .
Monitors bodily proteins for maintaining or recycling processes.
Find it in: almonds, beans, carrots, celery, chickpeas, collards, flax seed, greens, green leafy vegetables, kale, lentils, lima beans, nori, nuts, papayas, sesame seeds, sunflower seeds and walnuts.
. . .
Needed for niacin production, serotonin production, pain management, sleep and mood regulation.
Find it in: Brussels sprouts, carrots, celery, chives, dandelion greens, endive, fennel, nutritional yeast, pumpkin seeds, sesame seeds, snap beans, spinach, sunflower seeds, turnips and walnuts.
. . .
Helps muscle production, recovery, energy, endurance—balances nitrogen levels and is used in treatment of alcohol-related brain damage.
Find it in: apples, almonds, bananas, beets, broccoli, carrots, celery, dandelion greens, lettuce, nutritional yeast, okra, parsley, parsnips, pomegranates, potatoes, squash, tomatoes and turnips.

You may need more protein if you are…
• Mentally/physically tired (especially if you need daytime naps)
• Suffering from injuries/cramping/muscle soreness
• Unable to concentrate or focus
• Losing muscle, or unable to build it
• Losing hair
• Suffering from brittle/breaking nails
• Unusually susceptible to sunburn
• Suffering from headaches, fainting, nausea
• Cranky, anxious or moody or depressed

Remember, our bodies are designed, and biologically programmed, to survive. Symptoms are the way your body tries to communicate with you. If it doesn’t have enough of what it needs to thrive, it will do its best to get what it needs with what it has. If you are unable to build/retain muscle, that’s probably because you aren’t getting enough protein and your body is taking it from where it can—your muscle tissue. If you suffer from recurring/multiple injuries, your body probably doesn’t have the protein it needs for strength, rebuilding and recovery. Are your nails flimsy and breaking? Are you losing excessive hair? Your body may be holding onto what protein it has stored in the “bank,” versus using what little it has to create new nails or full hair.

This is also why nutrient-rich, whole foods are ideal, and why true health comes from these kinds of foods versus labels like “vegan.” Just because someone is vegan, vegetarian, or an omnivore for that matter, doesn’t make them healthy. Many folks make the mistake of “going vegan” and consuming a lot of processed, nutrient-void junk foods, pastas, etc. True health comes from the consumption of a variety of whole foods—the ones Mother Nature designed. It’s that simple.

Want to see how delicious plant-powerful recipes can be?

And here’s a helpful chart.
This chart is for reference only, since it’s recommended that you think of food in its “wholeness”—its natural, plant-based complexity. Excellent nutrition is truly about balance and variety. For example, everything that makes up a carrot is important for good health, not just the beta carotene, or the vitamin C, but the whole carrot. It’s packaged how Mother Nature designed—a symphony of nutrients, fiber and a large assortment of protective compounds, most of which still remain unnamed (and undiscovered). Imagine that.

Do I need to combine protein sources at each meal to make sure I get all essential amino acids?
No. It’s a myth. Nearly all whole foods (including greens and veggies) contain protein, and nearly all forms of protein contain all protein-forming amino acids in some quantity. If you eat a variety of nutrient-rich, whole foods, your body will work its magic to store what it needs to function optimally. Scientists used to claim that herbivores would develop protein deficiency if they didn’t get essential amino acids in proper, combined amounts at every meal. But our bodies are amazing. See, when we eat, amino acid “deposits” are made into a “storage bank,” and the body then takes what it needs as it’s needed. So, you don’t have to eat complementary proteins together with each meal in an effort to make complete protein. Your body has a system already set up; you just need to eat a variety of foods to fill the bank. By eating a variety of plant foods with “incomplete proteins” throughout the day, we can easily get enough “complete protein.”

Picture a giant 400lb gorilla. What does he eat to grow that strong, muscular body? Leaves, stems, roots, seeds and fruit (and maybe the occasional insect that lives on those foods). The body actually works less (uses less energy) to process protein from a vegetable-based diet than it does from a meat-based diet, too. This energy conservation is great for more efficient healing, building and overall optimal health. Most plant-based protein sources, contrary to animal-based sources, are also alkalizing for the body. Which means less aches and pains, freedom from disease, better sleep, happier moods, improved memory and concentration, stronger/more efficient digestion and an overall better state of health.

Complete Plant Protein Sources
Remember—variety. And if you want to make it even easier for yourself, here are a bunch of delicious, whole food options for complete plant-based proteins that you can keep in your pantry and fridge. Add them to salads, smoothies, wraps and more.

It’s also helpful to have a plant-based protein smoothie like Vega One once a day. It contains 15 grams of quality plant-based protein per serving (enter SHIPUSVEGA at checkout to get free shipping)—I usually have one a day with two scoops.

(These are gluten-free, too)
Amaranth: recipes | how to pop
Spirulina & Chlorella: add to smoothies, or take in powder or tablets
recipes | how to cook
Chia Seed: recipes
Hemp Seed: hemp milk recipe
Quinoa:  cooking tips and recipes
Sprouted Lentils (sprouting makes them complete):
how to sprout lentils
  |  lentil recipes

Print out this helpful Plant Protein Chart
 and keep it in your wallet or purse. Use it as a reference when planning meals for the week, or when shopping.

It’s all about variety.
While the protein question is a frequent one for plant-based eaters, don’t dismiss it in an uneducated haze of herbivore pride. It’s very important that we get enough protein each and every day, but as you can see, it’s not as difficult as most folks think—it’s actually quite easy (and did we mention delicious?). Variety is the key to acquiring all of the essential amino acids that we need, and YumUniverse shares an infinite collection of clean, whole food recipes that include this variety. Truly a universe of possibilities. Have fun with it.

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Answer to a Reader’s Question:

Many people are rightfully confused about the various ways that protein recommendations are established, and fail to know the main factors that have caused the confusion. Understanding the protein recommendations requires an understanding of the history of protein research and the serious bias that crept into the science over the years. From the beginning, there was a very strong bias that has emphasized the health importance of protein and this almost always meant animal-based protein. This bias arose even though the research results clearly showed in many cases that it SHOULD NOT be emphasized. Nonetheless nutrition researchers still emphasized higher consumption of protein because it was the “sign of civilization itself” as was said in the early 1900s and, further, that those who did not consume these generous amounts of protein (i.e., meat) were “of an effeminate nature”!

Researchers continually pushed the protein idea and continually found ways to develop methodologies and algorithms to ‘show’ that higher levels of protein were advisable. The whole concept of protein “quality” was devised so that it could be said that animal protein was high quality and plant proteins were low quality when, in fact, the concept of quality only indicated a biological efficiency of utilization per unit protein consumed. Naturally, animal-based proteins more nearly mimic our needs because they are composed of the right ratio of amino acids, thus are used more efficiently. But these studies were mostly based on animal production research that served the farm community (also served for my PhD thesis!) far more than it served the interests of human health. More efficiently used “high quality” proteins also efficiently grow cancer cells as well!

However, it’s important not to miss the really bizarre point that the current US dietary guidelines advocate an upper limit of 35% of calories as protein that is supposedly consistent with minimizing chronic diseases. The only way that one can go this high is to be a virtual carnivore. The correct recommended intake is around 8-10% protein (not 35%!) which can be easily supplied by a good whole foods plant based diet. Even potatoes will do the job alone.

So, it’s back to the question of how and why and who is recommending these ridiculous numbers. The first time that these new high limits appeared was when a top consultant to the dairy industry, was chairing the Food and Nutrition Board that was responsible for the report. That report was funded by the dairy industry-based Dannon Institute, among other corporate benefactors who, accidentally I suppose, rather liked these high protein recommendations.

This is where Dr. Caldwell Esselstyn’s research that was focused on low fat intake and my research that was initially focused on lower protein intake converged, pointing to the elimination of animal based food consumption that was so highly correlated in international studies with Western diseases.

“If All You Ate Were Potatoes, You’d Get All Your Amino Acids” aka Protein

The sentence above is haunting me.

Doug asked:

“I still don’t understand why more care isn’t necessary to avoid deficiencies of the essential amino acids. Is it the case that these amino acids are present in all fruits and vegetables? (I didn’t think this was so, but you mentioned on that other thread that thinking has changed in this regard.) Or is it simply that easy to avoid a deficiency of an essential amino acid by consuming any mixture of fruits and vegetables?”

Doug, I would answer “Yes.” to your last question. I thought it summed up the facts well.

Plants are capable of manufacturing all 20 amino acids, which include the essential amino acids (EAAs), although amounts vary. I checked a number of foods (potatoes, broccoli, tomatoes, asparagus, corn, rice, oatmeal, beans, and others) and found all EAAs in each of these foods. Even an apple which is listed as having 0 grams of protein has all the EAAs, albeit it small amounts.

Since I said in an earlier comment, “No mixing of foods is necessary. If all you ate were potatoes, you’d get all your amino acids,” I felt obliged to back it up. Below is my back-up.

  • The first column lists all 8 EAAs for adults.
  • The second column lists the World Health Organization’s recommended intake per body weight.
  • The third column lists the specific RDI for a 120 lb adult.
  • The fourth column lists the amount of each AA in a medium potato, with skin.
  • The fifth column lists the amount of each AA in 5 medium potatoes.
  • The last column lists the % of recommended intake (for a 120 lb adult) for each AA when 5 potatoes are consumed.


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