Vegan diets have become increasingly popular in recent years as people are choosing to eliminate animal food products for environmental, ethical, and health reasons. Consuming a nutritionally balanced vegan diet may result in numerous positive health effects, including protection against liver disease, obesity, and certain kinds of cancer (5). However, those consuming a strictly vegan diet can be at risk of nutritional deficiencies that have a detrimental effect on overall health.
Plant-based diets, including vegan diets, have repeatedly been linked to favorable blood lipid profiles and a lower risk of cardiovascular disease (1). Meat and animal products are higher in low-density lipoprotein cholesterol and saturated fats, contributing to plaque build-up. On the other hand, plant-based foods that are rich in monounsaturated fats and polyunsaturated fats help regulate blood lipoprotein levels (1).
As a result, consuming more plant-based foods and reducing or eliminating meat and animal products results in lower levels of low-density lipoprotein cholesterol—a type of cholesterol that contributes to plaque build-up in blood vessels. Plaque build-up in arteries reduces the supply of oxygen-rich blood tissue to vital organs, increasing the risk of heart attack or stroke (1).
Another of the positive health effects of a vegan diet is that nutritionally balanced plant-based diets can be rich in phytonutrients, including vitamins, antioxidants, and dietary fiber (4). Soluble fiber from fruits, vegetables, whole grains, and legumes helps facilitate cholesterol being flushed out of the body and reduces the synthesis of liver cholesterol (1). Fiber-rich foods may also help lower inflammation and reduce levels of leptin—a hormone that regulates appetite and body weight—protecting those who consume more plant-based foods against obesity and cardiovascular disease (2).
The health effects of a vegan diet on cognitive function and brain health are less conclusive. Consuming a balanced vegan diet that is abundant in vitamins and antioxidants may help fight cognitive decline as we age (4). However, vegans who are not taking supplements can be deficient in key nutrients like vitamin B12, vitamin D, and DHA—an omega-3 fatty acid that serves as the main structural component of our brains (4). These deficiencies may increase the risk of Alzheimer’s disease and mental illnesses like depression (3).
Those consuming vegan diets are also at risk of being deficient in nutrients that are less bioavailable in plant foods (6). Bioavailability refers to the percentage of a particular nutrient that the body is able to absorb and utilize. For example, although many plant-based foods are plentiful in iron, plants provide the non-heme form of iron, which is less bioavailable than heme-iron from animal products (6). As a result, vegans and vegetarians can have lower levels of ferritin and hemoglobin (6). Similarly, vegans can suffer from zinc deficiency due to low zinc bioavailability in plants, putting them at greater risk of depression, diarrhea, dermatitis, and alopecia (6).
Many of the benefits of consuming a vegan diet also result from following other plant-based diets, including vegetarian and pescatarian diets. Low-fat, reduced animal-product omnivorous diets that are rich in whole grains, legumes, fruits, and vegetables have also been shown to provide many of the same benefits regarding lipoprotein profiles and the risk of cardiovascular disease (7). Plant-based diets that reduce the intake of animal products but do not necessarily completely eliminate them also have a much larger body of scientific literature to support their benefits compared to exclusively vegan diets (4). A non-vegan plant-based diet that incorporates some amount of animal products may be a better fit for some people depending on the desired health effects and the ability to intake essential nutrients.
Ultimately, reducing your consumption of animal-based foods like meat can reduce your risk of developing certain illnesses, including cardiovascular disease. However, consuming a well-rounded diet that prioritizes plant foods and ensures that you absorb the necessary nutrients for proper organ function is key to harnessing the positive health effects of eating plant based, including vegan.
References
- Elliott, Patrick et al. “Plant-Based Diets and Lipid, Lipoprotein and Inflammatory Biomarkers of Cardiovascular Disease: A Review of Observational and Interventional Studies.” Nutrients, vol. 14, no. 24, 17 Dec 2022, doi: 10.3390/nu14245371
- Gogga, Patrycja et al. “Plant-based diets contribute to lower circulating leptin in healthy subjects independently of BMI.” Acta biochimica Polonica, vol. 69, no. 4, 2022, pp. 879-882., doi:10.18388/abp.2020_6388
- Jain, Rishika et al. “Association between vegetarian and vegan diets and depression: A systematic review.” Nutrition Bulletin, vol. 47, no. 1, pp. 27-49, 19 Jan 2022, doi:10.1111/nbu.12540
- Katonova, Alzbeta et al. “Effect of a Vegan Diet on Alzheimer’s Disease.” International journal of molecular sciences, vol. 23, no. 23, pp. 1494,, 29 Nov 2022, doi:10.3390/ijms232314924
- McManus, Katherine D. “With a little planning, vegan diets can be a healthful choice.” Harvard Health Blog, Feb 6 2020, www.health.harvard.edu/blog/with-a-little-planning-vegan-diets-can-be-a-healthful-choice-2020020618766
- O’Keefe, James H et al. “Debunking the vegan myth: The case for a plant-forward omnivorous whole-foods diet.” Progress in Cardiovascular Diseases, vol. 74, pp. 2-8, September-October 2022, doi: 10.1016/j.pcad.2022.08.001
- Turner-McGrievy, Gabrielle M et al. “Effect of a Plant-Based vs Omnivorous Soul Food Diet on Weight and Lipid Levels Among African American Adults: A Randomized Clinical Trial.” JAMA network open, vol. 6, no. 1, 3 Jan 2023, doi:10.1001/jamanetworkopen.2022.50626