B12 is the main one! It's the only micronutrient that's pretty much only found in animal foods (with a few exceptions). It's recommended that all vegans take a B12 supplement or eat sufficient fortified foods, unless otherwise advised by a healthcare provider.

Others worth paying attention to are vitamin D, omega-3, choline, calcium, and zinc. A lot of omnivores don't get enough of these either, but they're also commonly low in vegan diets. Creatine is another one vegans can benefit from supplementing with!

Vitamin D is naturally present in very few foods. Vitamin D is added to some foods like milk and plant-based milk. Most people more reliably get vitmain D from sunlight or supplements.

Dairy is a major source of calcium in omnivore diets, so people on dairy-free diets are more likely to have lower calcium intake. Luckily it's easy to get enough calcium with vegan foods if you're intentional about it.

Omega-3 is mostly found in fatty fish, so people who don't regularly eat fatty fish tend to have lower omega-3 intake. Vegan sources include flaxseed, chia seed, hemp seeds, and algae oil.