A nationwide poll conducted in 2006 determined that 1.4% of the American population is vegan—they eat no meat, fish, dairy, or eggs. Scientists at Andrews University in Michigan reviewed existing studies about veganism to assess the pros and cons of adopting such a diet. Overall, vegans tend to have lower BMI, lower serum cholesterol, and lower blood pressure, decreasing their risk of developing cardiovascular disease. However, because of the elimination of all animal products, vegans are at greater risk of certain nutritional deficiencies such as vitamins B12 and D, calcium, and omega-3 fatty acids. It is suggested that vegans consume foods that are fortified with these nutrients or that they take appropriate supplements to prevent deficiencies.
American Journal of Clinical Nutrition. May 2009; 89:1627s-33s [Craig WJ]