14. Are Animal Foods More Nutritious Than Plant Foods? Carnivore Deep Dive Pt. 4/6

TL;DR: Meats are more nutrient dense than plants in essentially every way, including amounts of creatine, choline, carnitine, carnosine, vitamins, and minerals, protein, omega-3, and collagen. This is likely why vegans and vegetarians have higher rates of nutritional deficiencies and elite athletes can never stay vegan or vegetarian for long.

This article is part of our 6 part series on the carnivore diet. For previous sections, see the links below:

Saladino shatters the biggest myths we are told surrounding plant foods being healthy and animal foods being unhealthy.

Meat Is More Nutritious

The nutrients creatine, carnitine, choline, taurine, and carnosine only occur in appreciable amounts in animal foods, and the vitamins and minerals zinc, iron, and selenium are found in much higher amounts and higher bioavailabilities in animal foods vs. plant foods.

Creatine: Brain and Brawn

Creatine increases intelligence, working memory, reaction time, and strength in humans. It can store energy in bonds with another molecule called phosphate and help us make more ATP when needed. This is why it is the number one supplements for athletes. We produce about 1g/day, which isn’t enough for optimal performance. Creatine is not found in plant foods. As a rough guide, 1 lb red meat contains about 5g of creatine – about the amount recommended for supplementing.

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When given to vegetarians:

“Creatine supplementation had a significant positive effect on both working memory (backward digit span) and intelligence, both tasks that require speed of processing. These findings underline a dynamic and significant role of brain energy capacity in influencing brain performance.” [1 Ch.8]

Another vegetarian study [2 Ch.8], showed vegetarian strength gain was higher vs. non-vegetarian when both took creatine supplementation [3 Ch.8]. This indicates getting some amount of creatine from the diet increases strength gains, but there are diminishing returns when there is already some present in the diet through meat.

Choline: Hair, Nails, and Healthy Pregnancies

Choline is used to make acetylcholine, a neurotransmitter, and is needed to make cell membranes. Acetylcholine is an important neurotransmitter. We make a small amount endogenously, but not enough.

Deficiencies are associated with cardiovascular disease, neurodegenerative disease, and fatty liver disease [4 Ch.8]. Choline is particularly important for pregnancies, otherwise defects are common.

When comparing plant sources to animal sources, we can find that 5 egg yolks contain about 600mg, 100g of liver or kidney contains about 350mg, and meat has some as well. By comparison, the richest plant source of choline, broccoli, has about 500mg in a full pound (454g). See above in the isothiocyanate sections for problems with consuming a lot of broccoli.

Carnitine: Mental Health

Carnitine is important for shuttling fatty acids across the mitochondrial membrane to burn for fuel. Using fat for fuel over carbs has benefits like activating the genes sirtuins and FOXO3 [6,7 Ch.8]. We make some carnitine endogenously, but not enough.

Carnitine has powerful effects on depression and energy levels. Depression correlates with low carnitine in the brain and the degree of deficiency predicts the age of onset of major depression and severity [9 Ch.8]. Impressively, Four randomized clinical studies showed carnitine to be better than a placebo at improving depression [11 Ch.8], and 12 randomized control trials show similar effects of carnitine to antidepressants without side-effects [12 Ch.8]. Administering carnitine to old mice makes them act younger, and improves mitochondrial function and metabolism [10 Ch.8]. This research is extremely impressive for carnitine’s role in mental health.

Much less carnitine is found in vegetarian muscle than non-vegetarian muscle in people. Vegetarians also have less ability to transport it into muscles when intravenously administered or taken through diet [8]. This suggests that supplementing has a lower effectiveness than consuming it through food for some reason.

Carnosine: Antioxidant

Carnosine acts as an antioxidant in our body which quells inflammation, controlling the redox balance touched in the last section. We can make some in our bodies, but not enough for optimal health. Carnosine reduces the formation of advanced glycation end-products (AGEs) – formed in the body when proteins bond to sugars and is associated with diabetes, heart disease, and dementia. Higher levels of AGEs are found in vegetarians [15 Ch.8], which would make sense as they also have lower amounts of carnosine [13, 14, 18 Ch.8].

Taurine is also only found in animal foods and reduces AGEs, and functions as an endogenous antioxidant and anti-anxiety neurotransmitter [17 Ch.8].

Is Meat Correlated with Cancer?

We often hear that studies show vegetarians are healthier, like the China study. As we talked about in the last section on correlation vs. causation, these are correlation studies – they don’t account for the healthy user bias. Furthermore, many have refuted the conclusions that the China study show correlation between red meat and shorter life spans, and in addition, the following studies demonstrate the opposite correlation:

Of 9,000 Australian women, vegetarians showed more mental health issues, more iron deficiency, and higher likelihood of taking prescription and non-prescription medication [19 Ch.8]
Another Australian study found higher rates of depression, anxiety, cancer, allergies, more need for health care and lower quality of life in vegetarians vs non vegetarians, adjusted for age and gender [20 Ch.8]
A cross-sectional study in France showed vegetarians, and those avoiding red meat were more likely to experience depression [21 Ch.8]
In Germany, vegetarians exhibit higher rates of mental disorders [22 Ch.8]
In Sweden and Finland, vegetarians were 4 times as likely to be affected by seasonal affective disorder [23 Ch.8]
The above studies include a total of 130,000 participants

Mental Illness

A theme in this book, and in newer findings in medicine in general, is that chronic inflammation from overstimulation of the immune system plays the primary role in most modern diseases.

Recently, depression passed heart disease and cancer for the highest cause of illness worldwide. A theme in this book is that diet is the central factor in inflammation because the gut is the main gateway for inflammation in our bodies. We mentioned earlier how plant defense compounds like lectin can cause chronic inflammation in our gut. We’ll mention again like Hippocrates said: all disease begins in the gut. Even depression is now showing strong evidence of being related to immune system overstimulation. Those with depression and anxiety, and many other health issues show elevated levels of inflammatory cytokines like IL-6 and TNF-alpha [24,25,26 Ch.8]. Cytokines are used to communicate between cells and to activate the immune system.

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The idea here is that depending on where the inflammation is and where the genetic weakness is in the person, symptoms show in different places and at different stages in life. Rheumatoid arthritis is caused by inflammation in the joints, Crohn’s disease by inflammation in joints and gut, and mental illness by inflammation in the brain. Symptoms may show in different places and times in different people, but the root cause is the same: inflammation. Interestingly, many diseases can be predicted years ahead of time. For instance, arthritis can be predicted by looking to see if your body has made antibodies for your joint tissues. For anyone interested, Tom O’Bryans book The Autoimmune Fix has detailed information on this, or you can look up autoimmune markers or the Cyrex blood panels for more information.

Vitamins and Minerals

Meats are much greater sources of Zinc, Iron, and Selenium. Remember from the previous section how these nutrients are essential for proper functioning of our redox system controlling free radicals and aging.

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Let’s get down to brass tacks: Plant based dieting causes deficiencies in most people.

Plant-based dieters show lower levels of minerals like zinc, iron [39,40 Ch.8], copper, selenium and calcium [31,32,33,34,35 Ch.8]. Vegans have a greater risk of B12, iron, calcium, vitamin D, omega-3 fatty acids, and protein deficiency [36 Ch.8], as well as iodine deficiency [37,38 Ch.8].

Kale and blueberries top the list of nutritious plant foods, yet don’t stack up to animal foods [1]

This is due to two factors it seems, 1. Plants have less of these nutrients as you can see above, and 2. compounds in plants like phytic acid, and oxalates discussed earlier, greatly reduce their bioavailability, or ability to be absorbed. For example, when oysters are eaten with beans, which contain phytic acid, the levels of zinc measured in our blood after are shown to be reduced to ⅓ of what it is when oysters are eaten by themselves. When eaten with tortillas, this absorption drops to 0 meaning the zinc in the oysters doesn’t make it into our blood because of the phytic acid. It is a similar story with magnesium and calcium when consumed with high oxalate foods like spinach [29,30 Ch.8]. This is a very important factor in nutritional status on plant based diets.

B Vitamins

B vitamins are essential for cell division and cellular metabolism. B vitamins, especially B12, is a very common deficiency on plant based diets which increases mental illness and cognitive impairment. Plant foods have little B vitamins, especially compared to animal sources.

A compound called homocysteine, which can be measured in our blood, is correlated with deficiency in B12, B6, and folate and is correlated with reduced brain size [44 Ch.8]. Levels of homocysteine on plant based diets are elevated [43 Ch.8]. Even low to normal ranges of B12 in the blood is associated with Alzheimer’s disease, dementia, and Parkinson’s [45].

Bioavailability of B6 from animal foods is often near 100%, but in plants is much lower. Fiber alone reduces B6 bioavailability by 5-10%. A compound called pyridoxine glucoside reduces absorption of B6 by 75-80% by binding to B6. It is found in many plants and is especially high in crucifers like broccoli [47 Ch.8]

When we compare vitamins like B2 in plant vs. animal foods we see it is only feasible to get enough B2 from animal foods. We need 2 – 3 mg per day. In 100 mg of liver or kidney, we find 3 mg of B2, whereas it would take 3 lbs of spinach to reach this level, and spinach is relatively high for plant foods.

Vitamin A

Just as with the other nutrients, animal foods are a much better source of Vitamin A than plant foods, especially liver. Even the best sources of Vitamin A from plants, like sweet potatoes or carrots pale in comparison due to the fact that the form of Vitamin A they contain, carotenoids like beta carotene, alpha carotene etc. convert at a very low efficiency to the animal form of Vitamin A that we used called retinol.

In fact, the most common plant form of Vitamin A, beta carotene, converts at about a 21:1 ratio. This is why the idea of bioavailability is so important. When you look at a nutrition label for a plant food, you need to divide the Vitamin A content there by 21 to be able to compare it to animal foods.

Vitamin K

Vitamin K is not as well known as other vitamins, but is just as important and is used in managing calcium storage in bones, bone density, and arterial health. There are two primary forms, K1 found in plants, and K2. K2 is also found in certain rare fermented plant foods like Natto. If you’ve heard of NK-4, MK-7, or MK-11, these are also forms of K2. K1 has few uses in the body, but K2 has many.

Higher K2 intake correlates with reduced death from cardiovascular disease and reduced death generally as well as severe aortic calcification, but K1 doesn’t show these benefits. In a well known study called the Rotterdam study, 4,807 subjects were followed and their K1 and K2 intake was surveyed by scientists over 10 years [52 Ch.8]. They found that intake of K2 was inversely correlated with coronary heart disease (clogging of arteries), and severe aortic calcification (calcium deposits accumulating in the heart). Vitamin K1 intake did not correlate with any outcomes measured. See the image below for a graph of the results.

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Another study followed 16,000 women for 8 years and showed K2 intake correlated with reduced heart disease, but not K1. For every 10 mcg of K2 consumed, the risk of heart disease decreased by 9% [53 Ch.8]. Saladino notes that on a carnivore diet, you’ll be getting at least 100 mcg of K2 per day.

Unfortunately, the USDA only measured K1, not K2 in foods, so nutrition labels and trackers don’t show the more important animal form of Vitamin K.

Protein

Protein is a well known issue on plant based diets due to bioavailability as well as getting enough of each type of amino acid. The best measure of protein quality is the Digestible Indispensable Amino Acid Score (DIAAS).

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If you want to maintain good muscle mass, you’ll need enough animal protein sources. Vegetarian or vegan bodybuilders have to use plant based protein powders, which do work for getting enough protein, but they have many of the aforementioned plant defense compounds in them.

Omega-3

Everyone knows omega-3 is good for you. Omega-3 is located in every cell in the body, and makes up a very large amount of the brain. Deficiency in omega-3 is associated with depression, reduced memory and attention, fatigue and infertility [54,55,56,57,58,59 Ch.8]

The form of omega-3 found in plant foods is called ALA, but can’t be used in the body. It needs to be converted into the animal forms EPA, DHA, and DPA. DPA makes up 90% of the omega-3 fat in the brain, and up to 22.5% of our brain in total making it extremely essential. Interestingly, 30 grams of flax seeds contains 6 grams of ALA, but shows no increase in blood levels of EPA or DHA. Saladino also takes the opportunity to note that flax seeds have lignans in them that disrupt hormones. As expected, vegetarians and vegans have sub-optimal omega-3 levels [60 Ch.8].

Vegan athletes

Saladino notes a list of athletes who went vegan but had to switch back, or had injuries:

“These include tennis star Novak Djokovic; basketball players Kyrie Irving, Demarcus Cousins, and Lauri Markkannen; football quarterbacks Andrew Luck and Cam Newton; English free runner Tim Shieff; and baseball pitcher CC Sabathia. Tom Brady is often championed as being “plant-based,” but he has clearly stated that he wisely includes meat in his diet.”

A really interesting study Saladino notes is that when vegetarians are asked about how they feel about eating meat, they report that they are not appetized by it, but when measured by something called event related potentials (ERPs), they neurologically show that they like meat as much as those not on a vegetarian diet [62 Ch.8]

Fiber Isn’t Necessary

We’ve all heard you need fiber to poop, and even that fiber is needed to prevent colon cancer and have a healthy gut. Saladino, yet again, says this isn’t true. In many studies and anecdotes, completely eliminating fiber from the diet results in the best poops. Adding fiber consistently does the opposite.

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Constipation

In an interventional study (causation), those with constipation were randomly put on zero, low and high fiber diets to see what happened. The low fiber diet essentially cured constipation. After one and six months, each group was asked about how often they had a bowel movement, how difficult they were to pass, whether they had anal bleeding, abdominal pain, and bloating:

In the zero fiber group, 100% showed improvement in bloating, in the low fiber group, 31.3% showed improvement and in the high fiber group, 0% showed improvement.
Average bowel movement frequency in the zero fiber group went from 3.75 +/- 1.59 days to 1.0 +/- 0.00 days and there was no improvement in high fiber group [4 Ch.9]
On the zero fiber group, everyone stopped having to strain to pass a bowel movement
Abdominal pain only improved in the zero fiber group, the fiber groups showed no improvement
On the zero fiber group, everyone stopped having anal bleeding

The results of this study are so clear cut that it is hard to argue against it. For more information, check out this YouTube video by Dr. Paul Mason, or some of the anecdotes about digestion improvements on the communities listed in the “more resources” section above the references.

SIBO

A condition called small intestinal bacterial overgrowth (SIBO), which is relatively common and often appears as bloating especially after meals, is often cured when fiber is removed from the diet. This is much better than the standard treatment of antibiotics, where SIBO comes back 75% of the time unless the diet is changed. Saladino thinks this is because of nerve damage to the muscles that move food along, called the migrating motor complex (MMC), due to autoimmunity (the immune system attacking the body’s tissues) from plant defense compounds discussed earlier.

Diverticulosis

Another condition that occurs in half of the US and Canadian population by their 60s is diverticulosis, which is where little pockets form in the colon and can cause bleeding or get infected. Nasty. In one study of 3,950 patients in Asia, high fiber diets showed no benefits for reducing diverticulosis [8,9 Ch.9]. In another study of 2,014 patients, increased fiber was correlated with 70% increased diverticulosis. Red meat, fat, physical activity had no correlations [10,11 Ch.9].

Again, Saladino notes diverticulitis may be inflammatory in nature. One study reports that “This hypothesis is strengthened by early reports that anti-inflammatory mucosal agents such as mesalamine and immune process regulators such as probiotics may improve diverticulitis” [12 Ch.9]

Colon Cancer

We often hear a low fat, high fiber diet with a lot of fruits and vegetables is recommended for colon cancer. When studied, these diets do not improve rates of pre-cancerous polyps (precursors to cancer) in the colon in an interventional trial of 1,905 patients [14 Ch.9]. The same results are found in another interventional study trying fiber supplements [15 Ch.9], and a third study following patients for 8 years on a low-fat, high fiber group vs. regular diet [16 Ch.9].

Blood sugar

Sometimes we hear fiber is good to stabilise blood sugar, weight, or appetite, which are all related.

In the well known study The Opti-Fit trial with 180 pre-diabetic and diabetic patients, some were given insoluble fiber and high fiber diet, the other placebo and regular diet and “no evidence for a beneficial effect of insoluble fiber on glucose metabolism.” [18 Ch.9].

In one controlled study (causation), no benefit was found for appetite control and weight loss [30 Ch.9]. In a large review of 49 studies, no benefit was found for using fiber in appetite control [31 Ch.9].

Fiber Can Be Bad For You

Fiber interferes with hormone metabolism (testosterone, estrogen, progesterone, LH, FSH) and nutrient absorption by reducing bioavailability of zinc, calcium, magnesium, selenium, and iron [19 Ch.9]. Saladino notes 6 other studies show that soluble fiber, insoluble fiber and phytic acid (found in plant foods) reduce mineral absorption [20,21,22,23,24,25 Ch.9]. Another study showed that high-fiber diets correlate to lower blood levels of Zinc [26 Ch.9].

One cohort study (correlation) following 250 women for two menstrual cycles showed decreased hormone concentrations and 1.78 times greater risk of missing periods for every 5 grams per day increase in total fiber [27 Ch.9]. This could be related to the fact that estrogen is normally reabsorbed in the gut, and fiber binds to estrogen in the gut so it can’t be reabsorbed [28 Ch.9][29 Ch.9].

Microbial diversity

When people talk about the microbiome, one measure they use to determine the health of it is a measure called microbial diversity – how wide of a variety in microbes there are. Some argue that fiber is needed to maintain a diverse microbiome, but the evidence doesn’t appear to be there.

One thing we do know is that fructose and glucose rich diets show decreased microbial diversity [35 Ch.9]. We also know that the Western diet is low in fiber and also Western populations have low microbial diversity, but we don’t know if the low fiber is causing it, or if there are other factors – another danger of association studies. Many people use this as evidence that low fiber causes low microbial diversity, but it is simply correlation, and again is confounded by the healthy user bias.

As discussed earlier, lectins can cause proliferation of bad bacteria, which would reduce microbial diversity. In fact, there is more evidence that lectins cause the decreased diversity than the lack of fiber in Western diets [52 Ch.9][53 Ch.9].

Interventional trials (causation) with increased fiber do not increase microbial diversity [36] and trials with the zero fiber carnivore diet do not show decreased alpha diversity [37]. In addition, low-fiber keto diets do not show decreased alpha diversity [38 Ch.9]. In a trial following MS patients on a keto diet for 6 months, an increase in alpha diversity was actually found [39 Ch.9]. These studies pretty conclusively show that even on diets with no fiber, there is no problem with microbial diversity and no indication of an unhealthy microbiome.

Do Our Gut Cells Need Fiber?

One last argument fiber-proponents often throw out there is that we need fiber because our gut cells use short chain fatty acids for fuel, and our gut bacteria make this from fiber. This is true, short chain fatty acids are important for the cells that line our large intestine (epithelial cells) [40,41,42 Ch.9].

Short chain fatty acids made from fiber are commonly implied to be the only important short chain fatty acid for our gut cells, but this is not correct. Gut cells are known to use ketones circulating in the blood for fuel, so this makes the short chain fatty acids made from fiber unnecessary. The carnivore diet is a ketogenic diet since it has near zero carbs. Ketogenic diets also show benefits to restoring microbiome imbalance and irritable bowel syndrome [44,45 Ch.9]. A ketogenic diet allows the body to create ketones that flow all throughout the bloodstream and our gut cells can use these ketones. Also, plenty of different short-chain fatty acids can be produced by our gut bacteria when they ferment protein [37 Ch.9]. Essentially, protein does the same thing as fiber by supplying fatty acids to our gut cells and on low carb diets ketones circulate the blood and supply our gut cells with fuel anyway.

What we’ve learned about the microbiome and gut is that it adapts to whatever our diet is. On plant based diets, our gut cells use different fatty acids than on animal based diets.

Short chain fatty acids are also used for gut cell signalling, and protein derived short chain fatty acids appear to do the job better than fiber derived short chain fatty acids by binding to cell surfaces more readily.

Collagen, the animal fiber

It seems that for every argument so far, animal foods find a way to out compete plant foods. Another one to add to the list is that animal foods have their own form of fiber… collagen, found in tendons, ligaments and other connective tissues. As one study states, “animal tissues have potentially similar functions as soluble or insoluble plant fibers.” [48 Ch.9]

Many people actually use the carnivore diet primarily to improve their digestion, reduce bloating, cure constipation and diarrhea, IBS, and autoimmune diseases. Many report miraculous improvements in these symptoms on the carnivore diet, which supports the argument that it improves digestion.