When it comes to diet and nutrition, there is no end of advice—often conflicting and confusing. One particularly common area of debate is a vegetarian versus a nonvegetarian diet. Those following a plant-based diet claim benefits ranging from weight loss to cancer prevention, while meat-eaters praise protein for benefits that include increased muscle, strength, and energy.
One way to make sense of the variety of dietary advice is to look at your specific health concerns and what the research suggests are your best choices. One area in which a vegetarian diet may have the upper hand is in colorectal cancer prevention.
A study that included almost 100,000 men and women in North America compared diets with incidence of colorectal cancer. Diets included nonvegetarian and four types of vegetarian: vegan (eggs, dairy, fish, and all other meats less than once per month), lacto-ovo vegetarian (eggs or dairy once or more per month but fish and other meats less than once per month), pesco-vegetarian (fish one or more times per month but all other meats less than once per month), and semivegetarian (meats other than fish one or more times per month but one or less time per week).1
After following study subjects for several years, the researchers found that people who followed any type of vegetarian diet had a lower incidence of colorectal cancer compared with nonvegetarians. Pesco-vegetarians had the lowest risk. Based on these findings, if your goal is to reduce your risk of colorectal cancer, there is evidence in favor of a vegetarian diet.
Even Vegetarian Diets, However, Can Have Risks
The path to health might not be as simple as just giving up meat or animal products. If you are avoiding these food choices, you’ll want to consider nutrients you may be missing and make sure you are taking steps to replace them. A 2014 study, for example, found that vegans had a high risk of vitamin B12 deficiency. Vitamin B12 plays an important role in proper function and development of the brain, nerves, blood cells, and many other parts of the body. According to another 2014 study, although there were significant benefits of a vegetarian diet (including weight control and disease prevention), there were also risks, including protein deficiency, anemia, decreased creatinine content in muscles (an indicator of kidney health), and menstrual disruption in women who are physically active.2,3
- Orlich MJ, Singh PN, Sabaté J, et al. Vegetarian dietary patterns and the risk of colorectal cancers. JAMA Internal Medicine. 2015;175(5):767-76. doi: 10.1001/jamainternmed.2015.59.
- Woo KS, Kwok TCY, Celermajer DS. Vegan diet, subnormal vitamin B-12 status and cardiovascular health. Nutrients. 2014;6(8):3259-73. doi: 10.3390/nu6083259.
- Pilis W, Stec K, Zych M, Pilis A. Health benefits and risk associated with adopting a vegetarian diet. Roczniki Pastwowego Zakładu Higieny. 2014;65(1):9-14.