Iron
What it does: Your body needs iron to carry oxygen throughout your body in the hemoglobin of your red blood cells—and when you’re not getting enough, you’ll feel super tired (and possibly anemic).
Why vegans need it: Animal protein—especially red meat—is the best source, but it is possible to get iron from plant-based foods including spinach, dried fruits, prune juice, wheat bran, whole-wheat bread, white beans, kidney beans, and tofu. However, the iron in fortified and veggie foods can sometimes be harder for the body to absorb than the iron in meat.
How to get it: You can get around this by pairing your plant-based iron foods with a vitamin C-rich food to boost absorption—like dowsing red sauce on pasta or having an orange with your PB&J. Cooking in a cast-iron pan also helps put more iron into your food, notes Ana Maria Lopez, M.D., president of the American College of Physicians (ACP).
“You should only supplement iron if you have a deficiency, and most people who are vegan use a lot of beans and lentils and should be okay without a safety net,” says Bergquist. And it’s possible to eat too much, adds Lopez, making it hard for your body to absorb calcium and causing side effects like like abdominal pain, constipation, nausea, and vomiting.
So if you’re concerned about your iron levels, your doctor can test your blood for anemia and iron stores and let you know if you should supplement.