Updated: Oct 8, 2020
By Kalindi Bakshi PhD
An article published on BBC earlier this year claimed that a vegan diet could affect your intelligence. I am used to people questioning my protein intake, but this is perhaps the first time my intelligence was being blamed on veganism. The claim made by the article in question: Veganism can cause nutritional deficiencies and, without question, it can affect your intelligence.
And of course, being a Neuroscientist, I wanted to conduct a scientific inquiry.
Let’s dive a bit deeper into the brain to understand the mechanisms. Of all the nutrients in question, a particular one struck me was choline, because it is a building block of the neurotransmitter/neurochemical acetylcholine. Too much or too little of this chemical messenger has been implicated in cognitive decline and neurological disorders, including Alzheimer’s and Parkinson’s Disease. It was not until 2016, FDA included choline as an essential nutrient with an reference daily intake of 425-550 mg. Therefore, getting adequate levels of dietary choline is very essential for brain health. Citing unpublished data, the article in question claims that vegetarians have the lowest level of choline, to the point that it may be concerning, and vegans are entirely at a loss, which could potentially lead to cognitive decline and stunt brain development.
My initial PubMed search did not yield any scientific support to the above claim. So, I posed this question to my scientist colleagues, researchers, and physicians. My neuroscience guru, Dr. Hoau Yan Wang, an expert in Alzheimer’s Disease Research & Medical Professor at City University of New York Medical College explained it very well. According to Dr. Wang, “Choline can be obtained from food as choline or phosphatidylcholine –a component of the cell membrane– although de novo synthesis of choline occurs in the liver, however it’s not enough. As for dietary sources, animal derived like –liver, egg yolk, meats are all very rich in choline. However, plant-derived sources tofu, broccoli, nuts, wheat germ all have decent choline levels. Choline is required for acetylcholine and S-adenosylmethionine -to make homocysteine-an amino acid high levels of which is a risk factor for heart disease. Lacking choline can lead to nonalcoholic fatty liver, muscle damage and contribute to cognitive decline (not prominent, however). Too much leads to diarrhea, sweating, and dead fish smell due to its metabolite, trimethylamine. While a vegan or vegetarian diets has lower choline than meat, I wouldn’t think it is that significantly low to cause muscle damage, or cognitive decline.” The two charts below compiled from the USDA lists vegan & some top animal-derived food sources of choline. Although, the animal-derived sources listed below have much higher choline, they are significant risk factors for coronary artery disease, hypertension, diabetes and cancer, says Dr Shernik Shah an Internal Medicine Specialist. Several research studies show an association between increased choline intake and high risk of lethal prostate cancer.
The Mediterranean Intervention for Neurodegenerative Delay (MIND) diet, which is a combination of two very popular healthy diets is predominantly plant-based zeroes in on brain-healthy foods to lower the risk of progressive mental decline including Alzheimer’s Disease. The MIND diet emphasizes daily consumption of whole grains, greens, and other vegetables, snacking on nuts and berries, and eating a cup of beans. Although these diets do include poultry 2x/week and fish once a week the major emphasis is on plant-based foods. Therefore, the claim that vegan diets lack brain-healthy nutrients does not hold. A balanced vegan diet is rich in antioxidants and phytochemicals, which help the brain repair and fight against the damage caused by oxidative stress. Tryptophan, another amino acid and a precursor to mood-elevating neurochemical serotonin is also found abundantly in plant-based foods including tofu, beans, oats, lentils, walnuts, leafy greens, butternut squash, potatoes, mushrooms, and cauliflower.
The Physicians Committee for Responsible Medicine highly recommends a plant-based diet to fight mood disorders. Data from randomized controlled trials presented at the American Public Health Association’s annual conference show although omega-3 fatty acids obtained from fish are higher compared to a vegetarian diet, there is no difference in the mood scores. Another study showed higher mood scores in the vegetarian diet group compared to their omnivorous counterparts. The review article suggested since a well-planned vegan diet contains alpha-linolenic acid (ALA), which the body can convert into long chain fatty acids -EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)-, so there is no need to consume it from animal sources. ALA can be obtained from foods like walnuts, flax seeds, chia seeds, and leafy green vegetables. All the above are essential fatty acids for heart and brain function.
To conclude, a well-nourished vegan brain does not lack any nutrients in question. A well-rounded plant-based diet can conquer both the brain and heart. It’s a win-win for vegans!
Richman EL, Kenfield SA, Meir J Stampfer MJ, Giovannucci EL, Zeisel SH, Willett WC and Chan JM. Choline intake and risk of lethal prostate cancer: incidence and survival Am J Clin Nutr. 2012 Oct; 96(4): 855–863.
Beezhold BL, Johnston CS, Daigle DR. Vegetarian diets are associated with healthy mood states a cross-sectional study in seventh-day Adventist adults. Nutr J. 2010;9:26.
Beezhold BL, Johnston CS, Daigle DR. Preliminary evidence that vegetarian diet improves mood. Paper presented at: American Public Health Association Annual Meeting; November 7-11, 2009; Philadelphia, PA.