The purpose here is to highlight the nutritional deficiencies of plant-based diets but most specifically plant-exclusive diets such as veganism (important nutrients are listed below). Not all of these deficiencies involve essential nutrients, but our knowledge is limited on what is essential. There are deficiencies that will kill you quickly, others slowly, and still others that simply will cause deteriorating health or less than optimal functioning. Also, some of these nutrients or their precursors can be found in plant foods or otherwise produced by the body, but there can be several problems. The plant-based sources may be inadequate or not in the most bioavailable form, antinutrients in the plants may block the absorption of certain nutrients (e.g., phytates block mineral absorption), gut and microbiome problems related to a plant-based diet might interfere with absorption, and most people have severely limited capacity to turn certain precursors into the needed nutrients.
So, when eating a supposedly healthy diet, many vegans and vegetarians still have major deficiencies, even with nutrients that should be in their diet according to standard food intake calculations — in those cases, the nutrients are there in theory but for some reason not being absorbed or utilized. For example, raw spinach has a lot of calcium, but it is almost entirely unavailable to the body. Adding raw spinach to your smoothie or salad might be a net loss to your health, as the antinutrients will block the nutrients in other foods as well. Another factor is that, on a plant-based diet, nutrients can get out of ratio. Nutrients work together with some acting as precursors, others as catalysts, and still others like master hormones — such as vitamin K2 determining where calcium is transported to, preferably the bones as opposed to arteries, joints and the brain; or think about how the body can produce vitamin D3 but only if there is adequate cholesterol. As such, besides deficiencies, sometimes there can too much of a nutrient which interferes with another nutrient, as seen with copper in relation to zinc.
That is the advantage to an animal-based diet, which could even include a well-balanced vegetarian diet that emphasized dairy and eggs (Vegetarianism is an Animal-Based Diet), but unfortunately many vegetarians are near-vegan in limiting even those non-meat animal foods. Here is the reason why animal foods are so important. Other animals have similar nutritional needs as humans and so, when we eat animal foods, we are getting not only the nutrients our bodies need but in the required form and ratio for our own optimal functioning. Without animal foods, one has to study nutrition to understand all of this and then try to artificially re-create it through careful calculations in balancing what one eats and supplements, an almost impossible task that requires someone to have a scientific mindset. Even then, one is likely to get it wrong. Regular testing of nutritional levels would be absolutely necessary to ensure everything is going according to plan.
As for supplements and fortification, the nutrients aren’t always in the best form and so wouldn’t be as bioavailable nor would likely have all the needed cofactors in just the right amounts. Besides, a diet dependent on supplementation and fortification is not healthy by definition, in that the food itself in natural form lacksing those nutrients. The fact that most vegans in particular and vegetarians as well have to be extremely obsessive about nutrition just to maintain a basic level of health is not high praise to the health-giving benefits of such a plant-based diet — and hence the reason even vegetarians should emphasize the allowed animal foods (there are even vegans who will make exceptions for some animal foods, such as fish). This is probably why most people quit these diets after a short period of time and why most people who quit, including those who quit after years or decades, do so for health reasons. Among those who remain on these diets, their responses on surveys show that most of them cheat on occasion and so are getting some minimal level of animal-based nutrition, and that is a good thing for their health even as it calls into question the validity of health claims about plant-based diets (Being “mostly vegan” is like being “a little pregnant.”).
There has long been a bias against meat, especially red meat. It goes back to the ancient Greek thought of Galen and how it was adapted to Medieval society in being Christianized for purposes of maintaining social hierarchy and social control. This Galenic bias was carried forward in the Christian tradition and then modernized within nutrition studies through the surprisingly powerful influence of the Seventh Day Adventists who continue to fund a lot of nutritional studies to this day. This has had practical consequences. It has long been assumed, based on a theology of a sinful world, that eating animals would make us beastly. It’s similar to the ancient idea that eating the muscles or heart of a fallen warrior would make one strong or courageous. A similar logic was applied to plants, that they have inherent qualities that we can imbibe.
So, it has been long believed that plant foods are somehow healthier for both body and soul, somehow more spiritual and so would bring humans closer to God or else closer to their divine natural state before the Fall of Man. That has been the moral concern of many Christians, from Medieval Catholics to modern Seventh Day Adventists. And in secularized form, it became internalized by mainstream nutrition studies and dietary guidelines. Part of the purpose of eating plants, according to Christianized Galenism, was that a strong libido was considered bad and it was understood that a plant-based diet suppressed libido, which admittedly doesn’t sound like a sign of health but their idea of ‘health’ was very different. It was also worried that, along with firing up the libido, meat would heat up the entire body and would lead to a shorter lifespan. Pseudo-scientific explanations have been used to rationalize this theological doctrine, such as concerns about mTOR and IGF-1, although this requires contorting the science and dismissing other evidence.
The problem is this simply became built into mainstream nutritional ideology, to such an extent that few questioned it until recently. This has led to most researchers, nutritionists, dieticians, and other health experts to obsess over the nutrients in plants while overlooking the nutrients in animal foods. So, you’ll hear something along the lines of, “meat is not an important source of vitamin E and with the exception of liver, is not a particularly good source of fat-soluble vitamins” (Nutrients in Meat, from the Meat We Eat). Keep in mind that assertion comes from a project of the American Meat Science Association — not likely to be biased against meat. It’s sort of true, depending on how one defines meat. From Galenic thought, the notion of meat is still associated with red meat. It is true that muscle meat, particularly lean muscle meat, from beef, pork and veal doesn’t have much vitamin E compared to plant foods (M. Leonhardt et al, Vitamin E content of different animal products: influence of animal nutrition). This is why some vegetarians and even vegans see no contradiction or conflict, much less hypocrisy, in eating fish and fowl — culturally, these have for millennia been considered a separate category from meat.
Yet adequate amounts of vitamin E are found in many animal foods, whether or not we label them as ‘meat’: chicken, goose meat, fish, seafood, crayfish, butter, and cheese; and some vitamin E is also found in liver and eggs (Atli Anarson, 20 Foods That Are High in Vitamin E). We have to be clear what we mean by ‘meat’. On a meat-based diet, even to the degree of being carnivore, there are plentiful good sources of every essential nutrient, including vitamin E, and many that aren’t essential but highly conducive to optimal health. Besides animal foods, there is no other source of such immense nutrient-density and nutrient-biavailability. Plant foods don’t come close in comparison.
Also, as vitamin E is an antioxidant, it’s important to note that animal foods contain many other antioxidants that play a similar role in maintaining health, but animal-sourced antioxidants have been mostly ignored because they don’t fit the dominant plant-based paradigm. Plant foods lack these animal-sourced antioxidants. So why do so few talk about a deficiency in them for vegans and vegetarians? And why have researchers so rarely studied in depth the wide variety of nutrients in animal foods to determine their full health benefits? This is particularly odd when considering, as I already stated, every known essential nutrient can be found in animal foods but not in plant foods. Isn’t that an important detail? Why is there a collective silence among mainstream health experts?
Think about how plant antinutrients can block the absorption of nutrients, both in plant foods and animal foods, and so require even more nutrients to counteract this effect which might simply further increase the antinutrient intake, unless one is careful in following the food selection and preparation as advised by those like Steven Gundry (The Plant Paradox). Or think about how glucose competes with the antioxidant vitamin C causing an increase of scurvy if vitamin C is not increased, and yet a low-carb diet with far lower intake of vitamin C is not linked to scurvy — maybe the reason ancient Vikings and Polynesians could remain healthy at sea for months, but once a high-carb diet was introduced modern sailors were plagued by scurvy (Sailors’ Rations, a High-Carb Diet). Similarly, a plant-based diet in general might require greater amounts of vitamin E: “Plant-based foods have higher concentrations of vitamin E. And for good reason. A plant-based diet requires additional protection from oxidation of PUFA which Vitamin E helps provide through its antioxidant properties. It’s still found in adequate supply in meat” (Kevin Stock, Vitamins and Minerals – Plants vs Animals).
What is adequate depends on the diet. A diet low in carbs, seed oils, and other plant foods may require fewer plant-based antioxidants, especially if this is countered by an increase of animal-based antioxidants. It is reminiscent of the fiber debate. Yes, fiber adds bulk that supposedly will increase regularity, ignoring the fact that the research is divided on this topic. No doubt bulking up your poop makes you have larger poops and more often, but is that really a good thing? People on a low-residue carnivore diet more easily digest and absorb what the eat, and so they don’t have bulky poops — then again they don’t usually have constipation either, not if they’re getting enough dietary fat. The main cause of constipation is plant foods. So, why are people advised to eat more plant foods in the hope of resolving this issue caused by plant foods? It’s absurd! We keep looking at problems in isolation, as we look at nutrients in isolation (Hubris of Nutritionism). This has failed us, as demonstrated by our present public health crisis.
Let me throw in a last thought about antioxidants. It’s like the fiber issue. People on plant-based diets have contipation issues and so they eat more plant foods in the form of fiber in trying to solve the problem plant foods cause, not realizing that constipation generally resolves itself by eliminating or limiting plant foods. So, in relation to antioxidants, we have to ask ourselves what is it about our diet in the first place that is causing all the oxidative stress? Plant foods do have antioxidants, but some plant foods also cause oxidative stress (e.g., seed oils). If we eliminate these plant foods, our oxidative stress goes down and so our requirement of antioxidants to that degree also lessens. Our body already produces its own antioxidants and, combined with what comes from animal foods, we shouldn’t such excess amounts of antioxidants. Besides, it’s not clear from studies that plant antioxidants are always beneficial to health. It would be better to eliminate the need for them in the first place. Shawn Baker explained this in terms of vitamin C (interview with Shan Hussain, The Carnivore Diet with Dr. Shawn Baker MD):
“The Carnivore diet is deficient in carbohydrates and essential vitamins like Vitamin C, how do we make up for that? When I wanted to do this I was curious about this as well. You will see a number of potential deficiencies around this diet. There is no role of fibre in this diet. With Vitamin C we know there are some transporters across different cell membranes. In a higher glucose environment, Vitamin C is competitively inhibited and therefore we see less absorption of Vitamin C. We also see that interestingly human red blood cells do have the capacity to actually recycle Vitamin C which is something that not many people are aware of. One of the major function of Vitamin C is that it is an antioxidant. In low carbohydrate states our antioxidants systems particularly things like glutathione are regulated. We may obviate some of the need of antioxidants of the Vitamin C by regulating around systems in a low carb diet. Also, Vitamin C is very important in the function of carnitine which is part of the fat cycle. When we are ingesting carnitine we have actual transporters in the gut which can take up full carnosine. It is a misconception that we can only take amino acids, a number of di and tripeptide transporters that are contained within our gut. The other function of Vitamin C is when we don’t have sufficient Vitamin C relative to our needs, we start to develop symptoms of scurvy, bleeding gum problems, teeth falling out, sores and cuts won’t heal. This is all due to the collagen synthesis. If we look at Vitamin C’s role in collagen synthesis, it helps to take proline and lysine, hydroxyproline and hydroxylysine. In meat-based diet, we are getting that in ample amount. Even a steak has 3% of its content as collagen. There are all kinds of compensatory mechanisms.”
I’ll end on an amusing note. Chris Kresser wrote about the carnivore diet (Everything You Need to Know about the Carnivore Diet and How It Can Affect Your Health). Athough an advocate of low-carb diets and nutrient-dense animal foods, he is skeptical that carnivory will be healthy for most humans long-term. One worry is that there might be nutritional deficiencies, but the argument he makes is funny. He basically saying that if all one eats is muscle meat then key nutrients will get missed. Then he goes onto point out that these nutrients can be found in other animal foods, such as liver and dairy. So, his main concern about a carnivore diet is actually that people might not eat enough animal foods or rather not enough of certain animal foods. So, make sure you eat lots of a wide variety of animal foods if going full carnivore and apparently even critics like Kresser agree you’ll be fine, at least nutritionally. The problem isn’t too much animal foods but potentially too little. That made me smile.
Now to the whole point of this post. Below is a list of nutrients that are commonly deficient in those on plant-based diets, especially those on plant-exclusive diets (i.e., vegans). I won’t explain anything about these nutrients, as there is plenty of info online. But you can look to the linked articles below that cover the details.
- Vitamin K2
- Vitamin D3 (Cholecalciferol)
- Vitamin A (Retinol)
- Vitamin B12 (Cobalamin)
- Vitamin B6 (Pyridoxine)
- B3 (Niacin)
- B2 (Riboflavin)
- Heme Iron
- DHA Omega-3 (Docosahexaenoic Acid)
- EPA Omega-3 (Eicosapentaenoic Acid)
- DPA Omega-3 (Docosapentaenoic Acid)
- ARA Omega-6 (Arachidonic Acid)
- SA Saturated Fat (Stearic Acid)
- CLA (Conjugated Linoleic Acid)
- Phytanic Acid
- Phosphatidylserin, Phosphatidylcholine, and Other Phospholipids
- SOD (Superoxide Dismutase)
- CoQ10 (Coenzyme Q10)
- Nucleotides (Nucleoproteins and Nucleic Acids)
- Anserine (Derivative of Carnosine)
- Beta-Alanine (Precursor to Carnosine)
- Complete Proteins
- Other Essential Amino Acids (Creatine, Beta-Alanine, Glycine, Methionine, Tryptophan, Lysine, Leucine, Cysteine, Proline, Tyrosine, Phenylalanine, Serine, Alanine, Threonine, Isoleucine, and Valine)
[Please note in the comments any other essential or semi-essential nutrients not on the above list.]
“This list doesn’t even include things like peptides including BPC-157, Thymosin alpha-1, LEAP-2, spenlopentin, tuftsin, etc. which are known to occur naturally in animal foods and have beneficial effects in humans” (Paul Saladino). Other peptides, mainly found in animal foods, are not just important for optimal health but truly and entirely essential: aremethionine, threonine, tryptophan, isoleucine, leucine, lysine, valine, and phenylalanine.
Just for the sake of balance, I’ll also share a list of plant compounds that are problematic for many people — from Joe Cohen (20 Nutrients that Vegans & Vegetarians are Lacking):
- Trypsin Inhibitors
- Sulfites, Benzoates, and MSG
- Non-protein amino acids
- Alkaloids [includes solanine, chaconine]
- Phytic Acid [Also Called Phytate]
* * *
Are ‘vegetarians’ or ‘carnivores’ healthier?
Gundry’s Plant Paradox and Saladino’s Carnivory
Dr. Saladino on Plant and Animal Foods
True Vitamin A For Health And Happiness
Calcium: Nutrient Combination and Ratios
Vitamin D3 and Autophagy
The Vegetarian Myth: Food, Justice, and Sustainability
by Lierre Keit
Vegan Betrayal: Love, Lies, and Hunger in a Plants-Only World
by Mara J. Kahn
The Meat Fix: How a lifetime of healthy eating nearly killed me!
by John Nicholson
The Fat of the Land/Not By Bread Alone
by Vilhjalmur Stefansson
Sacred Cow: The Case for (Better) Meat: Why Well-Raised Meat Is Good for You and Good for the Planet
by Diana Rodgers and Robb Wolf
The Carnivore Code: Unlocking the Secrets to Optimal Health by Returning to Our Ancestral Diet
by Paul Saladino
Primal Body, Primal Mind: Beyond Paleo for Total Health and a Longer Life
by Nora Gedgauda
by Sarah Ballantyn
The Queen of Fats: Why Omega-3s Were Removed from the Western Diet and What We Can Do to Replace Them
by Susan Allport
The Omega Principle: Seafood and the Quest for a Long Life and a Healthier Planet
by Paul Greenberg
The Omega-3 Effect: Everything You Need to Know About the Super Nutrient for Living Longer, Happier, and Healthier
by William Sears and James Sear
The Missing Wellness Factors: EPA and DHA: The Most Important Nutrients Since Vitamins?
by Jorn Dyerberg and Richard Passwater
Could It Be B12?: An Epidemic of Misdiagnoses
by Sally M. Pacholok and Jeffrey J. Stuar
What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency
by Martyn Hooper
Living with Pernicious Anaemia and Vitamin B12 Deficiency
by Martyn Hoope
Pernicious Anaemia: The Forgotten Disease: The causes and consequences of vitamin B12 deficiency
by Martyn Hooper
Healing With Iodine: Your Missing Link To Better Health
by Mark Sircus
Iodine: Thyroid: The Hidden Chemical at the Center of Your Health and Well-being
by Jennifer Co
The Iodine Crisis: What You Don’t Know About Iodine Can Wreck Your Life
by Lynne Farrow
L-Carnitine and the Heart
by Stephen T. Sinatra and Jan Sinatra
Food Politics: How the Food Industry Influences Nutrition and Health
by Marion Nestle
Unsavory Truth: How Food Companies Skew the Science of What We Eat
by Marion Nestle
Formerly Known As Food: How the Industrial Food System Is Changing Our Minds, Bodies, and Culture
by Kristin Lawless
Death by Food Pyramid: How Shoddy Science, Sketchy Politics and Shady Special Interests Have Ruined Our Health
by Denise Minge
Nutrition in Crisis: Flawed Studies, Misleading Advice, and the Real Science of Human Metabolism
by Richard David Feinman
Nutritionism: The Science and Politics of Dietary Advice
by Gyorgy Scrinis
Measured Meals: Nutrition in America
by Jessica J. Mudry
(Although more about macronutrients, also see the work of Gary Taubes and Nina Teicholz. They add useful historical context about nutrition studies, dietary advice, and public health.)
20 Nutrients that Vegans & Vegetarians are Lacking
by Joe Cohen
8 Nutrients You May Be Missing If You’re Vegetarian or Vegan
by Tina Donvito
7 Nutrients That You Can’t Get from Plants
by Atli Anarson
7 Supplements You Need on a Vegan Diet
by Alina Petre
The Top 5 Nutrient Deficiencies on a Plant Based Diet
by Kate Barrington
5 Brain Nutrients That You Can’t Get From Plants
by Kris Gunnars
Vitamin Supplements for Vegetarians
by Jeff Takacs
Health effects of vegan diets
by Winston J Craig
Nutritional Deficiencies and Essential Considerations for Every Vegan (An Evidence-Based Nutritional Perspective)
from Dai Manuel
Why You Should Think Twice About Vegetarian and Vegan Diets
by Chris Kresser
Three Big Reasons Why You Don’t Want to be a Vegetarian
by Alan Sears
How to Avoid Common Nutrient Deficiencies if You’re a Vegan
by Joseph Mercola
What is Glutathione and How Do I Get More of It?
by Mark Hyman
Could THIS Be the Hidden Factor Behind Obesity, Heart Disease, and Chronic Fatigue?
by Joseph Mercola
Vegetarianism produces subclinical malnutrition, hyperhomocysteinemia and atherogenesis
by Y. Ingenbleek Y and K. S. McCully
Vegan Diet is Sulfur Deficient and Heart Unhealthy
by Larry H. Bern
Heart of the Matter : Sulfur Deficits in Plant-Based Diets
by Kaayla Daniel
Copper-Zinc Imbalance: Unrecognized Consequence of Plant-Based Diets and a Contributor to Chronic Fatigue
by Laurie Warner
Vegan diets ‘risk lowering intake of nutrient critical for unborn babies’ brains’
by Richard Hartley-Parkinson
The Effects of a Mother’s Vegan Diet on Fetal Development
by Marc Choi
Vegan–vegetarian diets in pregnancy: danger orpanacea? A systematic narrative review
by G. B. Piccoli
Is vegetarianism healthy for children?
by Nathan Cofnas
Clinical practice: vegetarian infant and child nutrition
by M. Van Winckel, S. Vande Velde, R. De Bruyne, and S. Van Biervliet
Dietary intake and nutritional status of vegetarian and omnivorous preschool children and their parents in Taiwan
C. E. Yen, C. H. Yen, M. C. Huang, C. H. Cheng, and Y. C. Huang
Persistence of neurological damage induced by dietary vitamin B-12 deficiency in infancy
by Ursula von Schenck, Christine Bender-Götze, and Berthold Koletzko
Severe vitamin B12 deficiency in an exclusively breastfed 5-month-old Italian infant born to a mother receiving multivitamin supplementation during pregnancy
by S. Guez et al
Long-chain n-3 PUFA in vegetarian women: a metabolic perspective
by G. C. Burdge, S. Y. Tan, and C. J. Henry
Signs of impaired cognitive function in adolescents with marginal cobalamin status
by M. W. Louwman et al
Transient neonatal hypothyroidism due to a maternal vegan diet
by M. G. Shaikh, J. M. Anderson, S. K. Hall, M. A. Jackson
Veganism as a cause of iodine deficient hypothyroidism
by O. Yeliosof and L. A. Silverman
Do plant based diets deprive the brain of an essential nutrient?
by Ana Sandoiu
Suggested move to plant-based diets risks worsening brain health nutrient deficiency
Could we be overlooking a potential choline crisis in the United Kingdom?
by Emma Derbyshire
How a vegan diet could affect your intelligence
by Zaria Gorvett
Vitamins and Minerals – Plants vs Animals
by Kevin Stock
Health effects of vegan diets
by Winston J Craig
Comparing Glutathione in the Plasma of Vegetarian and Omnivore Populations
by Rachel Christine Manley
Vegan diets are adding to malnutrition in wealthy countries
by Chris Elliott, Chen Situ, and Claire McEvoy
What beneficial compounds are primarily found in animal products?
by Kamal Patel
The Brain Needs Animal Fat
by Georgia Ede
The Vegan Brain
by Georgia Ede
Meat, Organs, Bones and Skin
by Christopher Masterjohn
Vegetarianism and Nutrient Deficiencies
by Christopher Masterjohn
Adding milk, meat to diet dramatically improves nutrition for poor in Zambia
from Science Daily
Red meat plays vital role in diets, claims expert in fightback against veganism
by James Tapper
Nutritional Composition of Meat
by Rabia Shabir Ahmad, Ali Imran and Muhammad Bilal Hussain
Meat and meat products as functional food
by Maciej Ostaszewski
Meat: It’s More than Protein
from Paleo Leap
Conjugated Linoleic Acid: the Weight Loss Fat?
from Paleo Leap
Nutritional composition of red meat
by P. G. Williams
How Red Meat Can ‘Beef Up’ Your Nutrition
by David Hu
Endogenous antioxidants in fish
by Margrét Bragadóttir
Astaxanthin Benefits Better than Vitamin C?
by Rachael Link
Astaxanthin: The Most Powerful Antioxidant You’ve Never Heard Of
Antioxidants Are Bullshit for the Same Reason Eggs Are Healthy
by Sam Westreich
We absolutely need fruits and vegetables to obtain optimal antioxidant status, right?
by Paul Saladino
Hen Egg as an Antioxidant Food Commodity: A Review
Chamila Nimalaratne and Jianping Wu
Eggs’ antioxidant properties may help prevent heart disease and cancer, study suggests
from Science Daily
The Ultimate Superfood? Milk Offers Up a Glass Full of Antioxidants
by Lauren Milligan Newmark
Antioxidant properties of Milk and dairy products: a comprehensive review of the current knowledge
by Imran Taj Khan et al
Antioxidants in cheese may offset blood vessel damage
from Farm and Dairy
Identification of New Peptides from Fermented Milk Showing Antioxidant Properties: Mechanism of Action
by Federica Tonolo
Bioavailability of iron, zinc, and other trace minerals from vegetarian diets
by Janet R Hunt
Dietary iron intake and iron status of German female vegans: results of the German vegan study.
by A. Waldmann, J. W. Koschizke, C. Leitzmann, and A. Hahn
Mechanisms of heme iron absorption: Current questions and controversies
by Adrian R. West and Phillip S. Oates
Association between Haem and Non-Haem Iron Intake and Serum Ferritin in Healthy Young Women
by Isabel Young et al
Pork meat increases iron absorption from a 5-day fully controlled diet when compared to a vegetarian diet with similar vitamin C and phytic acid content.
by M. Bach Kristensen, O. Hels, C. Morberg, J. Marving, S. Bügel, and I. Tetens
Do you need fiber?
by Kevin Stock