If you’re one of the millions of Americans who have switched to a plant-based diet, you may be wondering which nutrients you could be low on after restricting meat and dairy.

Before reaching for a supplement, Lori Bumbaco, Oncology Dietitian at NorthShore, suggests using food first to meet your daily requirements because “it’s nature’s package of guaranteed nutrition.”

Protein is usually the first deficiency people think about when reducing meat, but Bumbaco said it’s fairly easy to find enough of this macronutrient in whole soy foods, nuts, beans, lentils, quinoa, or cheese and milk if you eat dairy.

Here are four essential nutrients vegans and vegetarians should have on their radar:

Vitamin B12

Vitamin B12 is essential for maintaining your nervous system and building red blood cells. “If someone is vegan, they’ll have to try pretty hard to get this vitamin from food because it’s only found in animal products and our bodies don’t make it,” Bumbaco said. Products fortified with B12 include breakfast cereals, non-dairy milk alternatives and soy products. Shellfish, cheese and eggs are good sources as well. “This is an instance where a B12 supplement would be beneficial,” she said.

Vitamin D

Most of us know vitamin D is essential for healthy bones and that those who live in colder climates are probably low in it. That’s because it’s synthesized in the skin when we are exposed to sunlight. It is present in salmon, mackerel, sardines and cod liver oil; fortified foods include milk, breakfast cereals and some juices; and vitamin supplements. “It’s tricky to consume enough vitamin D from food,” Bumbaco said. “Look toward a supplement if your diet is low in vitamin D or if you don’t get sun exposure.” Vegans can search for fortified products or ask a dietitian about a vitamin D2 or D3 supplement.

 Omega-3s

For vegetarians who do not consume fish, they are probably not getting enough omega-3 fatty acids, Bumbaco said. This good fatty acid is associated with cardiovascular health and brain development. You’ll find omega-3 in canola oil, flaxseed, flaxseed oil and soybeans. Eggs can be enriched when flaxseed or canola oil is added to hen feed.

Iron

The body absorbs two to three times more iron from animal sources than plant sources, so vegetarians can have a hard time getting the iron they need. Iron is important for cell growth and transporting oxygen. Iron is present in beans, whole grains, lentils and some seeds. “We often encourage sprouted grains or soaking seeds to lower phytates,”she said. “Phytates can slow the absorption of iron.”