Editor’s note: This article originally appeared on Kris Gunnars’ site, Authority Nutrition. I agree with what Kris has written, and while I think some people can thrive on a vegetarian or vegan diet, careful supplementation should be included to avoid deficiencies of the nutrients mentioned below.
The human brain is the most complex object in the universe. It is also the organ that consumes by far the most energy, compared to its weight. The brain is only about 2% of our body weight, but uses 20% of the energy. This remarkable organ has evolved over millions of years. During this time, humans were omnivores. We ate both meat and plants.
There are many nutrients in these foods that are absolutely critical for the proper function of this very delicate system. Unless proper care is taken to supplement, going vegan and eschewing animal foods may lead to a deficiency in some of these important substances.
Here are 5 nutrients that are very important for the brain and only found in animal foods:
1. Vitamin B12
Did you know that not a single population in the history of the world has ever willingly adopted a vegan diet? That’s because before the era of supplements, such a dietary shift would have started killing people within a few years. The most well known vitamin that the body can’t produce and can only be gotten from animal foods, is Vitamin B12.
Vitamin B12 is a water-soluble vitamin that is involved in the function of every cell in the body. It is tightly involved in the formation of blood and the function of the brain. Deficiency usually results in anemia, impaired brain function, symptoms of mental disorders and a smaller brain (1, 2, 3). There is also evidence linking B12 deficiency to Alzheimer’s Disease, which is the most common cause of dementia in Western countries (4, 5). The only good food sources of B12 are animal foods like meat, fish and eggs.
A deficiency is widespread among vegans and vegetarians, who avoid these foods. In one study, a whopping 92% of vegans and 47% of lacto-ovo vegetarians were deficient in this critical brain nutrient (6). Being deficient in B12 can cause irreversible damage to the brain. If your levels are just slightly lower than they should be, you may have symptoms like poor memory, depression and fatigue (7). So even if you’re not suffering clinical symptoms of B12 deficiency, you may still be less sharp than you should be. If you choose to avoid animal foods, then make sure to supplement with Vitamin B12 or eat foods that have been fortified with it. Algae are a potential plant source of B12, but whether they can be effective at correcting B12 deficiency in humans is not known at this point (8, 9).
Bottom Line: Vitamin B12 is critical for the health of the brain and nervous system and is primarily found in animal foods. A deficiency can cause all sorts of adverse effects on brain function.
Every athlete, bodybuilder and gym enthusiast knows about creatine. It is the most popular muscle building supplement in the world, for good reason. Scientific studies consistently show that creatine supplementation can increase muscle mass and strength (10).
The way creatine functions is that it forms an energy reserve, where it is able to quickly recycle ATP in our cells. ATP is the “energy currency” of cells, what the energy from our foods and body fat stores ultimately get turned into. During workouts that consume a lot of energy in a short amount of time, creatine gives us more strength and helps us last longer (11).
Creatine is actually not an essential nutrient, because the liver can produce it out of other amino acids. However, this conversion process appears to be inefficient. About 95% of the creatine in the body is stored in skeletal muscle. However, creatine is also concentrated in the brain. The same way that our muscles require energy to do work, our brain needs energy to do various things… like thinking.
Vegetarians who take creatine supplements see improvements in cognitive performance, especially in more complex tasks, while there is no difference in non-vegetarians (12, 13). This implies that vegetarians have a deficiency of creatine that is adversely affecting their brain function. Vegetarians also have a lower amount of creatine in skeletal muscle. Creatine supplements are particularly effective at improving athletic performance in this group (14). If you must avoid meat, consider supplementing with some Creatine Monohydrate. It will definitely make you stronger and may even make you smarter as well.
Bottom Line: Creatine is an important nutrient in muscle and brain that helps to supply energy. Studies show that vegetarians have a deficiency in creatine that leads to adverse effects on muscle and brain function.
3. Vitamin D3
I’m sure you’ve heard of Vitamin D before… it has received massive attention in the past few years. Vitamin D is produced out of cholesterol in the skin when it is exposed to ultraviolet rays from the sun. Today, a large part of the world is deficient in this critical nutrient, which actually functions as a steroid hormone in the body. Many people live where sun is basically absent throughout most of the year. But even in countries where sun is abundant, people tend to stay inside and use sunscreen when they go outside.
There are two main forms of Vitamin D in the diet: Vitamin D2 (ergocalciferol) and D3 (cholecalciferol). D2 comes from plants, D3 from animals. Studies show that D3 is much more effective than the plant form (15, 16). There are few good sources of Vitamin D3 in the diet. Cod fish liver oil is the best source. Fatty fish also contains some D3, but you’d have to eat massive amounts of it to satisfy your body’s need.
A deficiency in Vitamin D is linked to all sorts of diseases, including cardiovascular disease and cancer (17, 18, 19). Low blood levels have also been associated with various disorders of the brain, including the autoimmune disease Multiple Sclerosis, depression and cognitive impairment (20, 21, 22). If getting enough sun is not an option, the only way to get D3 from foods is to take cod fish liver oil or eat lots of fatty fish.
The alternative is to take a D3 supplement, which is highly recommended for people who have a diagnosed deficiency.
Bottom Line: A large part of the world is deficient in Vitamin D3, which is only found in animal foods. A deficiency in this critical nutrient is associated with depression and various diseases.
Carnosine is a very important nutrient that you may never have heard of before. The prefix Carno- is the latin term for meat or flesh, like Carni-vore (meat eater). It is strictly found in animal tissues, meaning that vegans and vegetarians aren’t getting much, if any, from the diet.
Carnosine is created out of two amino acids and is highly concentrated in both muscle tissue and brain. This substance is very protective against various degenerative processes in the body. It is a potent antioxidant, inhibits glycation caused by elevated blood sugars and may prevent cross-linking of proteins (23, 24, 25). For this reason, Carnosine has become very popular as an anti-agin supplement.
Carnosine levels are significantly lower in patients with various brain disorders, including Parkinson’s and Alzheimer’s – the two most common neurodegenerative disorders (26, 27, 28). Many researchers have speculated that animal foods may protect the brain and body against aging due to their large amount of carnosine (29, 30).
Bottom Line: Carnosine is found strictly in animal tissues. This nutrient can reduce damage caused by elevated blood glucose and may have strong anti-aging effects.
5. Docosahexaenoic Acid (DHA)
Everyone concerned with nutrition knows that Omega-3 fatty acids are extremely important. The human body can not make them, therefore we must get them from the diet. This is why Omega-3s (and Omega-6s) are termed “essential” fatty acids – if we don’t eat them, we get sick.
There are two active forms of Omega-3s in the body, EPA and DHA. DHA is the most abundant Omega-3 fatty acid in the brain and it is criticial for normal brain development (31). Low intakes of DHA can adversely affect various aspects of cognitive function and mental health, especially in children (32, 33).
It is also very important for women at a childbearing age, because a woman’s Omega-3 status can have profound effects on the brain of the offspring (34). Many people who avoid animal products supplement with flax seed oil instead, which is a great source of ALA… a plant form of Omega-3. However, ALA needs to be converted to DHA for it to work. Studies show that this conversion process is notoriously ineffective in humans (35). For this reason, vegans and vegetarians are very likely to be deficient in this very important fatty acid (36, 37). The best source of DHA is fatty fish. Other good sources include grass-fed and pastured animal products. There are also some algae that can produce EPA and DHA.
Bottom Line: The Omega-3 fatty acid DHA is critical for proper function of the brain. It is primarily found in animal foods like fatty fish. Studies show that vegans and vegetarians are often deficient in it.
Just Eat Some Animals
Humans evolved eating both animals and plants. However, we can function in some cases without either. The Inuit, for example, survived mostly without plants, but they had to compensate by eating lots of organ meats. In the 21st century, people can survive and function without animal foods if they make sure to supplement with critical nutrients. Before the era of supplementation, completely removing animal foods would have lead to a slow and painful death due to B12 deficiency. But even though functioning without either plants or animals is possible… neither is optimal.
In the same way that a meat-based diet is healthier with a little bit of plants, a plant-based diet is healthier with a little bit of animals. I highly recommend that people who choose to avoid meat for ethical reasons (because there is NO proven healh reason) at least include some eggs and fatty fish. A little bit goes a long way and it is possible to choose natural, humanely raised sources.
But to those who really decide to remove all animal foods from their diet… make sure to be very prudent about your diet and supplement, or you may end up very sick with a poorly functioning brain.