diets are under preliminary research for their potential to help people with type 2 diabetes. Cardiovascular system Meta-analyses have reported a reduced risk of death from ischemic heart disease and from cerebrovascular disease among vegetarians. Mental health Reviews of vegan and vegetarian diets showed a possible association with depression and anxiety, particularly among people under 26 years old. Another review found no significant associations between a vegetarian diet and depression or anxiety. Eating disorders The American Dietetic Association discussed that vegetarian diets may be more common among adolescents with eating disorders, indicating that vegetarian diets do not cause eating disorders, but rather "vegetarian diets may be selected to camouflage an existing eating disorder". Mortality risk A 2012 study found a reduced risk in all-cause mortality in vegetarians. A 2017 review found a lower mortality (-25%) from ischemic heart disease. Diet composition and nutrition Western vegetarian diets are typically high in carotenoids, but relatively low in omega-3 fatty acids and vitamin B12. Vegans can have particularly low intake of vitamin B and calcium if they do not eat enough items such as collard greens, leafy greens, tempeh and tofu (soy). High levels of dietary fiber, folic acid, vitamins C and E, and magnesium, and low consumption of saturated fat are all considered to be beneficial aspects of a vegetarian diet. A well planned vegetarian diet will provide all nutrients in a meat-eater's diet to the same level for all stages of life. Protein Protein intake in vegetarian diets tends to be lower than in meat diets but can meet the daily requirements for most people. Studies at Harvard University as well as other studies conducted in the United States, United Kingdom, Canada, Australia, New Zealand, and various European countries, confirmed vegetarian diets provide sufficient protein intake as long as a variety of plant sources are available and consumed. Iron Vegetarian diets typically contain similar levels of iron to non-vegetarian diets, but this has lower bioavailability than iron from meat sources, and its absorption can sometimes be inhibited by other dietary constituents. According to the Vegetarian Resource Group, consuming food that contains vitamin C, such as citrus fruit or juices, tomatoes, or broccoli, is a good way to increase the amount of iron absorbed at a meal. Vegetarian foods rich in iron include black beans, cashews, hempseed, kidney beans, broccoli, lentils, oatmeal, raisins, jaggery, spinach, cabbage, lettuce, black-eyed peas, soybeans, many breakfast