While it is possible to obtain all essential nutrients from a well-planned vegan diet, many people fall short in several key areas—particularly vitamin B12, DHA, zinc, calcium, and vitamin A. Vitamin B12 is naturally found only in animal products, so B12 supplementation is typically recommended for individuals who avoid all animal foods. Although intestinal bacteria can produce some B12, most people do not have gut conditions sufficient to meet their needs.

Research in Clinical Chemistry (2001;47:1094–1101) found that vegans often have lower antioxidant status and higher homocysteine levels compared to non-vegetarians, suggesting increased need for targeted nutrient support.

Nutrient considerations for vegans

  • Vitamin B12: Essential for neurological development and red blood cell formation. Vegan mothers who breastfeed should be especially attentive to B12 intake, as deficiency in infants can contribute to neurological delays, growth issues, and even brain atrophy. This has been documented in European Journal of Pediatrics (1991;150:205–8) and the Journal of Obstetrics, Gynecology and Reproductive Biology (2005;34(6):610–2).

  • DHA (docosahexaenoic acid): A long-chain omega-3 fatty acid concentrated in the brain and retina. It is naturally abundant in fish and other animal products, though vegan-friendly algae-derived DHA supplements are available.

  • Zinc, calcium, vitamin A: These nutrients can be obtained from plant foods, but intake may require careful planning. Preformed vitamin A (retinol) is only found in animal foods; plant carotenoids must be converted, and the conversion rate varies widely between individuals.

Protein quality

Vegan diets can provide adequate protein, but plant proteins often lack one or more essential amino acids. Achieving a complete amino acid profile is entirely possible through variety and combination—such as legumes with grains or nuts/seeds—but requires more intentional planning than diets that include animal protein.