The Nutrients Vegans Need to Watch Closely

Vitamin B12 is the single most important nutrient on this list, because it is the one plants genuinely cannot supply reliably. B12 is made by bacteria, and in a modern hygienic food chain there is no dependable plant source of it. A review of the research found that vegans have consistently higher rates of B12 depletion and deficiency than vegetarians or meat-eaters, across every age group studied. This is not a maybe. It is the reason every credible vegan guideline says the same thing.

B12 matters because a long-term shortfall can cause nerve damage and a type of anaemia, and some of the nerve damage can become permanent. The good news is that fixing it is cheap and simple. A regular B12 supplement, or reliably fortified foods eaten every day, fully covers the need. This is the one nutrient where you should not rely on your diet doing it by accident.

Plants contain plenty of iron and zinc. The catch is that the plant form of iron, called non-heme iron, is absorbed less efficiently than the iron in meat, and compounds in whole plant foods called phytates can bind both minerals and reduce how much you take up. Estimates suggest overall iron absorption from a vegetarian diet may be roughly half that of a mixed diet, which is why guidelines suggest vegans aim for more iron, not less.

The workaround is straightforward. Eat iron-rich plants such as lentils, beans, tofu, wholegrains, and dark leafy greens, and pair them with a source of vitamin C in the same meal, which sharply increases how much non-heme iron you absorb. Squeeze lemon on your lentils, add peppers or tomatoes to a bean stew, or have fruit with an iron-rich meal. For zinc, the same whole foods help, and soaking, sprouting, or fermenting pulses and grains lowers their phytate and frees up more of the mineral.

There are two things people call omega-3. One is the short-chain form, ALA, found in flax, chia, walnuts, and rapeseed oil. The other is the long-chain forms, EPA and DHA, which are the ones linked to heart and brain benefits and which normally come from oily fish. Your body can convert ALA into EPA and DHA, but the conversion is limited, especially the step to DHA, which is often very low.

So while you should still eat ALA-rich plants daily, relying on conversion alone is a weak plan for the long-chain forms. The clean solution for vegans is an algae oil supplement, which supplies EPA and DHA directly, the same fats the fish get from algae in the first place. A daily flax or chia habit plus a small algae oil supplement covers both bases without any fish.

These four are easy to overlook precisely because they rarely get talked about, yet each is simple to cover once it is on your radar.

Calcium

Without dairy, calcium needs a plan. Fortified plant milks and yoghurts, calcium-set tofu, tahini, almonds, and green vegetables such as kale and bok choy all contribute. Fortified plant drinks are the easiest lever, since a glass can carry as much calcium as cow's milk.

Vitamin D

Vitamin D is a concern for almost everyone in low-sunlight climates, vegan or not. Vegans should use fortified foods and a supplement, and can choose a vegan D3 made from lichen if they prefer D3 over D2. This is worth actively topping up in autumn and winter.

Iodine and selenium

Iodine is often missed on a vegan diet because dairy and fish are common sources. A modest supplement or a measured use of iodised salt covers it, while very high-iodine seaweeds are best avoided in large amounts because they can overshoot. Selenium is easy to top up with just one or two Brazil nuts a day, which are unusually rich in it.

This list looks long written out, but the daily reality is small. Most well-planned vegan diets cover everything with a handful of deliberate habits.

1. Take B12 without fail. A daily or weekly supplement, or reliably fortified foods every day. This is the non-negotiable one.
2. Use fortified plant milks and yoghurts. These quietly cover calcium, vitamin D, and often B12 in one move.
3. Pair iron-rich plants with vitamin C. Lemon on lentils, peppers in the stew, fruit with the meal. It changes how much iron you keep.
4. Add a daily ALA source and an algae oil. A spoon of ground flax or chia, plus a small algae oil supplement for EPA and DHA.
5. Cover iodine, selenium, and vitamin D. A modest multivitamin or targeted supplements, plus a couple of Brazil nuts, handles the stragglers.

Finally, get a blood test now and then. A simple panel can check B12, iron stores, and vitamin D, so you are working from facts rather than guesswork. If a level is low, or if you are pregnant, breastfeeding, or feeding a vegan diet to a child, work with a doctor or dietitian to get it right. Handled this way, a vegan diet is not a compromise, it is just a diet you steer on purpose.