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 main articles: vegetarian nutrition and vegan 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 cereals, sunflower seeds, chickpeas, tomato juice, tempeh, molasses, thyme, and whole-wheat bread. the related vegan diets can often be higher in iron than vegetarian diets, because dairy products are low in iron. 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%, and 58% 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. vitamin b12 vitamin b12 is not generally present in plants but is naturally found in foods of animal origin. lacto-ovo vegetarians can obtain b12 from dairy products and eggs, and vegans can obtain it from manufactured fortified foods (including plant-based products and breakfast cereals) and dietary supplements. a strict vegan diet avoiding consumption of all animal products risks vitamin b12 deficiency, which can lead to hyperhomocysteinemia, a risk factor for several health disorders, including anemia, neurological deficits, gastrointestinal problems, platelet disorders, and increased risk for cardiovascular diseases. the recommended daily dietary intake of b12 in the united states and canada is 0.4 mcg (ages 0–6 months), rising to 1.8 mcg (9–13 years), 2.4 mcg (14+ years), and 2.8 mcg (lactating female). while the body's daily requirement for vitamin b12 is in microgram amounts, deficiency of the vitamin through strict practice of a vegetarian diet without supplementation can increase the risk of several chronic diseases. fatty acids plant-based, or vegetarian, sources of omega 3 fatty acids include soy, walnuts, pumpkin seeds, canola oil, kiwifruit, hempseed, algae, chia seed, flaxseed, echium seed and leafy vegetables such as lettuce, spinach, cabbage and purslane. purslane contains more omega 3 than any other known leafy green. olives (and olive oil) are another important plant source of unsaturated fatty acids. plant foods can provide alpha-linolenic acid which the human body uses to synthesize the long-chain n-3 fatty acids epa and dha. epa and dha can be obtained directly in high amounts from oily fish or fish oils. vegetarians, and particularly vegans, have lower levels of epa and dha than meat-eaters. while the health effects of low levels of epa and dha are unknown, it is unlikely that supplementation with alpha-linolenic acid will significantly increase levels. recently, some companies have begun to market vegetarian dha supplements containing seaweed extracts. whole seaweeds are not suitable for supplementation because their high iodine content limits the amount that may be safely consumed. however, certain algae such as spirulina are good sources of gamma-linolenic acid (gla), alpha-linolenic acid (ala), linoleic acid (la), stearidonic acid (sda), eicosapentaenoic acid (epa), docosahexaenoic acid (dha), and arachidonic acid (aa). calcium calcium intake in vegetarians and vegans can be similar to non-vegetarians, as long as the diet is properly planned. lacto-ovo vegetarians that include dairy products can still obtain calcium from dairy sources like milk, yogurt, and cheese. non-dairy milks that are fortified with calcium, such as soymilk and almond milk can also contribute a significant amount of calcium in the diet. broccoli, bok choy, and kale have also been found to have calcium that is well absorbed in the body. though the calcium content per serving is lower in these vegetables than a glass of milk, the absorption of the calcium into the body is higher. other foods that contain calcium include calcium-set tofu, blackstrap molasses, turnip greens, mustard greens, soybeans, tempeh, almonds, okra, dried figs, and tahini. though calcium can be found in spinach, swiss chard, beans and beet greens, they are generally not considered to be a good source since the calcium binds to oxalic acid and is poorly absorbed into the body. phytic acid found in nuts, seeds, and beans may also impact calcium absorption rates. see the national institutes of health office of dietary supplements for calcium needs for various ages, the vegetarian resource group and the vegetarian nutrition calcium fact sheet from the academy of nutrition and dietetics for more specifics on how to obtain adequate calcium intake on a vegetarian or vegan diet. vitamin d further information: vitamin d vitamin d needs can be met via the human body's own generation upon sufficient and sensible exposure to ultraviolet (uv) light in sunlight. products including milk, soy milk and cereal grains may be fortified to provide a source of vitamin d. for those who do not get adequate sun exposure or food sources, vitamin d supplementation may be necessary. vitamin d2 plants alfalfa (medicago sativa subsp. sativa), shoot: 4.8 μg (192 iu) vitamin d2, 0.1 μg (4 iu) vitamin d3 fungus, from usda nutrient database, per 100 g: mushrooms, portabella, exposed to ultraviolet light, raw: vitamin d2: 11.2 μg (446 iu) mushrooms, portabella, exposed to ultraviolet light, grilled: vitamin d2: 13.1 μg (524 iu) mushrooms, shiitake, dried: vitamin d2: 3.9 μg (154 iu) mushrooms, shiitake, raw: vitamin d2: 0.4 μg (18 iu) mushrooms, portabella, raw: vitamin d2: 0.3 μg (10 iu) mushroom powder, any species, illuminated with sunlight or artificial ultraviolet light sources vitamin d2, or ergocalciferol is found in fungus (except alfalfa which is a plantae) and created from viosterol, which in turn is created when ultraviolet light activates ergosterol (which is found in fungi and named as a sterol from ergot). any uv-irradiated fungus including yeast form vitamin d2. human bioavailability of vitamin d2 from vitamin d2-enhanced button mushrooms via uv-b irradiation is effective in improving vitamin d status and not different from a vitamin d2 supplement according to study. for example, vitamin d2 from uv-irradiated yeast baked into bread is bioavailable. by visual assessment or using a chromometer, no significant discoloration of irradiated mushrooms, as measured by the degree of "whiteness", was observed making it hard to discover if they have been treated without labeling. claims have been made that a normal serving (approx. 3 oz or 1/2 cup, or 60 grams) of mushrooms treated with ultraviolet light increase their vitamin d content to levels up to 80 micrograms, or 2700 iu if exposed to just 5 minutes of uv light after being harvested. choline main article: choline choline is a nutrient that helps transfer signals between nerve cells and is involved in liver function. it is highest in dairy foods and meat but it is possible to be obtained through a vegan diet. ethics and diet general with regard to the ethics of eating meat, scholars consider vegetarianism an ideology and a social movement. ethical reasons for choosing vegetarianism vary and are usually predicated on the interests of non-human animals. in many societies, controversy and debate have arisen over the ethics of eating animals. some people, while not vegetarians, refuse to eat the flesh of certain animals due to cultural taboo, such as cats, dogs, horses or rabbits. others support meat eating for scientific, nutritional and cultural reasons, including religious ones. some meat eaters abstain from the meat of animals reared in particular ways, such as factory farms, or avoid certain meats, such as veal or foie gras. some people follow vegetarian or vegan diets not because of moral concerns involving the raising or consumption of animals in general, but because of concerns about the specific treatment and practices involved in the processing of animals for food. others still avoid meat out of concern that meat production places a greater burden on the environment than production of an equivalent amount of plant protein. ethical objections based on consideration for animals are generally divided into opposition to the act of killing in general, and opposition to certain agricultural practices surrounding the production of meat. ethics of killing for food main article: bioethics ethical vegetarians believe that killing an animal, like killing a human, especially one who has equal or lesser cognitive abilities than the animals in question, can only be justified in extreme circumstances and that consuming a living creature for its enjoyable taste, convenience, or nutrition value is not a sufficient cause. another common view is that humans are morally conscious of their behavior in a way other animals are not, and therefore subject to higher standards. jeff mcmahan proposes that denying the right to life and humane treatment to animals with equal or greater cognitive abilities than mentally disabled humans is an arbitrary and discriminatory practice based on habit instead of logic. opponents of ethical vegetarianism argue that animals are not moral equals to humans and so consider the comparison of eating livestock with killing people to be fallacious. this view does not excuse cruelty, but maintains that animals do not possess the rights a human has. dairy and eggs one of the main differences between a vegan and a lacto-ovo vegetarian diet is the avoidance of both eggs and dairy products such as milk, cheese, butter and yogurt. ethical vegans do not consume dairy or eggs because they state that their production causes the animal suffering or a premature death. to produce milk from dairy cattle, farmers separate calves from their mothers soon after birth to retain cow milk for human consumption. treatment of animals ethical vegetarianism has become popular in developed countries particularly because of the spread of factory farming, faster communications, and environmental consciousness. some believe that the current mass-demand for meat cannot be satisfied without a mass-production system that disregards the welfare of animals, while others believe that practices like well-managed free-range farming or the consumption of game (particularly from species whose natural predators have been significantly eliminated) could substantially alleviate consumer demand for mass-produced meat. religion and diet jainism teaches vegetarianism as moral conduct, as do some sects of hinduism. buddhism in general does not prohibit meat eating, but mahayana buddhism encourages vegetarianism as beneficial for developing compassion. other denominations that advocate a vegetarian diet include the seventh-day adventists, the rastafari movement, the ananda marga movement and the hare krishnas. sikhism does not equate spirituality with diet and does not specify a vegetarian or meat diet. baháʼí faith while there are no dietary restrictions in the baháʼí faith, `abdu'l-bahá, the son of the religion's founder, noted that a vegetarian diet consisting of fruits and grains was desirable, except for people with a weak constitution or those that are sick. he stated that there are no requirements that baháʼís become vegetarian, but that a future society should gradually become vegetarian. `abdu'l-bahá also stated that killing animals was contrary to compassion. while