The Nutrients Vegetarians and Vegans Are Most Likely to Miss

Vitamin B12 is produced by microorganisms and found naturally in meaningful amounts almost exclusively in animal-derived foods — meat, fish, dairy, and eggs. For vegans especially, and for many vegetarians who consume limited dairy or eggs, regular intake is nearly impossible through whole food alone.

B12 is essential for nerve function, red blood cell formation, and DNA synthesis. A prolonged deficiency can lead to irreversible neurological damage. Fortified foods — such as certain plant milks, nutritional yeast, and breakfast cereals — provide a route for some people, but supplementation is generally recommended for vegans. Speak with a healthcare provider about appropriate testing and supplementation options.

Plant foods contain non-heme iron, which the body absorbs less efficiently than heme iron from meat. Foods such as lentils, tofu, tempeh, pumpkin seeds, and fortified cereals are solid plant-based sources, but absorption rates can be significantly lower than from animal sources.

Certain compounds in plant foods — particularly phytates found in legumes and grains — can inhibit iron absorption further. Consuming vitamin C-rich foods (like bell peppers or citrus) alongside iron-containing plant foods is a well-established strategy to improve uptake. Soaking, sprouting, and fermenting legumes and grains can also reduce phytate levels.

Dairy products are the most concentrated and well-absorbed dietary sources of calcium in the typical Western diet. Vegans who avoid all dairy must rely on alternatives such as fortified plant milks, calcium-set tofu, tempeh, bok choy, kale, almonds, and white beans. The calcium in some plant foods, however, is bound to oxalates (as in spinach), which reduce how much the body can absorb.

Adequate calcium is important throughout life but particularly during adolescence and older adulthood for bone health. Vegetarians who consume dairy regularly are generally less at risk, though vegans without fortified foods in their diet may fall short of recommended intakes.

There are three main omega-3 fatty acids: ALA (alpha-linolenic acid), EPA, and DHA. Plant foods like flaxseeds, chia seeds, hemp seeds, and walnuts provide ALA, but EPA and DHA — the forms most directly used by the body, particularly for brain and cardiovascular health — are found primarily in fatty fish and seafood.

The human body can convert ALA into EPA and DHA, but the conversion rate is generally considered inefficient. Algae-based omega-3 supplements provide a direct, plant-derived source of EPA and DHA and are widely used by vegans. This is an area where discussing options with a dietitian is particularly worthwhile.

Zinc is involved in immune function, wound healing, and protein synthesis. While legumes, nuts, seeds, and whole grains contain zinc, the phytates in these foods can interfere with absorption. As a result, vegetarians and vegans may need somewhat higher dietary zinc intake to absorb comparable amounts to omnivores.

Soaking and sprouting legumes and grains reduces phytate content and improves zinc bioavailability. Pumpkin seeds, hemp seeds, cashews, and chickpeas are among the more zinc-dense plant options. Fermented soy products like tempeh may also offer better zinc absorption than unfermented equivalents.

Vitamin D is synthesized by the skin in response to sunlight, but dietary sources matter — especially in winter months or for people with limited sun exposure. Few foods are naturally rich in vitamin D; the most significant sources are fatty fish, egg yolks, and liver. Most people in the general population get some through fortified foods like milk or orange juice.

Vegans face added limitations because some fortified foods use vitamin D3 derived from lanolin (sheep's wool), making them non-vegan. Vitamin D2, or lichen-derived vitamin D3, are plant-based alternatives. Given how widespread vitamin D insufficiency is across all dietary patterns, testing and supplementing under medical guidance is often advisable.