Eating a hearty variety of vegetables, fats, and legumes will naturally supply your body with most nutrients. Here are a few exceptions.

Iodine. Omnivores receive most of their iodine, essential for thyroid health, from dairy or fortified salt. (Vegetables contain the micronutrient, too, but in inconsistent levels.) If you’re eating vegan, dash small amounts of iodized sea salt over food or take an iodine supplement of 90–150 mcg two to three times per week, advises Ginny Messina, MPH, RD.

Iron. Although vegans often consume more iron than omnivores, Messina says, plant-food iron isn’t as well absorbed as that in meat sources. A simple solution: With every iron-rich meal, add a bit of vitamin C to aid absorption. For example, mix tomatoes into bean soup or sauté spinach with a splash of orange juice.

Omega-3 fatty acids. Walnuts, hemp seed, and flaxseed contain short-chain versions of this healthy fat, though this form is less bioavailable. You can also supplement with 1,000 mg docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) sourced from microalgae—the same place fish get these essential fats.

Vitamin B12. Plants don’t contain this micronutrient, so vegans (as well as people older than 50) should take a vitamin B12 supplement of at least 25 mcg per day to maintain healthy blood production. B12 supplements are naturally vegan, because B12 is bacteria-produced.