suggest that vegetarians and vegans who are not taking vitamin B12 supplements or food fortified with B12 do not consume sufficient servings of B12 and have abnormally low blood concentrations of vitamin B12. This is because, unless fortified, plant foods do not contain reliable amounts of active vitamin B12. It is essential, therefore, that vegetarians consume adequate amounts of dietary supplements or foods that have been fortified with B12, such as vegetable stock, veggie burger mixes, textured vegetable protein, soy milks, vegetable and sunflower margarines, and breakfast cereals. B12 used in these foods or supplements is typically grown from vegan sources (such as bacteria). Soybeans and barley seeds from plants grown in soils amended either with cow dung (which is rich in B12) or with pure B12 had a higher B12 content than those grown without this supplementation. Omega-3 fatty acids Vegetarian diets can be low in omega-3 fatty acids (O3FAs). Major vegetarian O3FA sources include algae, hempseeds and hempseed oil, walnuts, flaxseeds and flaxseed oil, olive oil, canola oil, avocado, and chia seeds. A potential problem is that vegetarian diets lacking eggs or generous amounts of edible seaweed generally lack a direct source of long-chain O3FAs such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Vegetarian diets may also have a high ratio of omega-6 fatty acids to O3FAs, which inhibits the conversion of short-chain fatty acids such as alpha-Linolenic acid (ALA), which is found in most vegetarian O3FA sources, to EPA and DHA. Short-term supplemental ALA has been shown to increase EPA levels but not DHA levels, suggesting poor conversion of the intermediary EPA to DHA. To remedy this, DHA and EPA supplements derived from microalgae are available. A 2022 review found that microalgal oil supplementation is consistent in increasing DHA and EPA levels, whilst high dose flaxseed or echium seed oil supplements provide no increase despite significant increases in ALA levels. Calcium In general, lacto-ovo-vegetarians have a relatively high intake of calcium that meet or exceed calcium recommendations. A 2022 review found no significant difference in calcium intake between vegetarians and omnivores. Vegetarians can obtain calcium from dairy products, calcium-fortified plant milks, almonds, figs, oranges, calcium-set tofu as well as low-oxalate vegetables such as bok choy, kale and turnip greens. Compared with omnivores, vegetarians tend to have a lower bone mineral density (BMD) but not a higher fracture rate. Iron Vegetarians are more likely to have lower