An essential nutrient that vegans often need to supplement is vitamin B12. This vitamin is primarily found in animal products, and its deficiency can lead to serious health issues such as anemia and neurological problems. Vegans, therefore, are advised to consider fortified foods or supplements to ensure adequate intake of B12. Other nutrients that might require attention in a vegan diet include iron, calcium, and omega-3 fatty acids. A well-planned vegan diet can still provide most essential nutrients with careful consideration.