Vitamin D needs can be met via the human body's own generation upon sufficient and sensible exposure to ultraviolet (UV) light in sunlight.[102][103] Products including milk, soy milk and cereal grains may be fortified to provide a source of Vitamin D.[104] For those who do not get adequate sun exposure or food sources, Vitamin D supplementation may be necessary.
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.[81] 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.[82] Vegetarian foods rich in iron include black beans, cashews, hempseed, kidney beans, broccoli, lentils, oatmeal, raisins, spinach, cabbage, lettuce, black-eyed peas, soybeans, many breakfast cereals, sunflower seeds, chickpeas, tomato juice, tempeh, molasses, thyme, and whole-wheat bread.[83] The related vegan diets can often be higher in iron than vegetarian diets, because dairy products are low in iron.[68] Iron stores often tend to be lower in vegetarians than non-vegetarians, and a few small studies report very high rates of iron deficiency (up to 40%,[84] and 58%[85] of the respective vegetarian or vegan groups). However, the American Dietetic Association states that iron deficiency is no more common in vegetarians than non-vegetarians (adult males are rarely iron deficient); iron deficiency anaemia is rare no matter the diet.[86]
^ Jump up to: a b Keevican, Michael (November 5, 2003). "What's in Your Cheese?". Vegetarian Resource Group. Archived from the original on March 18, 2018. Retrieved March 18, 2018. Many vegetarians don't consider that some of the cheeses they are eating could actually contain unfamiliar animal ingredients. That's right cheese, a common staple in many vegetarian diets, is often made with rennet or rennin, which is used to coagulate the dairy product.