What should be a major concern of individuals following a strictly vegan diet?

October 28, 2025 •

3 min read

While vegan diets are lauded for various health and environmental benefits, a systematic review found that vegans often have significantly lower intake of key micronutrients like vitamins B12, D, and calcium. This highlights what should be a major concern of individuals following a strictly vegan diet: a potential for nutritional deficiencies without careful planning.

Quick Summary

The main concern for vegans is the risk of insufficient intake of key nutrients, including vitamin B12, vitamin D, calcium, iron, iodine, and omega-3 fatty acids. Proper dietary planning, including fortified foods and supplements, is essential to mitigate these potential nutrient gaps for optimal health.

Key Points

Vitamin B12 is essential: Vegans must consume fortified foods or supplements, as this nutrient is not reliably found in plant foods and is critical for nerve and blood health.
Strategic Calcium and Vitamin D Intake is Vital: Since dairy is excluded, it's crucial to rely on calcium-set tofu, fortified plant milks, and leafy greens while ensuring adequate sun exposure or supplementation for vitamin D.
Iron and Zinc Absorption Requires Planning: Non-heme iron and zinc from plant sources are less bioavailable due to phytates, so pairing with vitamin C and employing cooking methods like soaking can improve absorption.
Algae Oil Supplements for Omega-3s: While plant sources provide ALA, conversion to the more active EPA and DHA is inefficient, making a microalgae supplement the most reliable source for these essential fatty acids.
Iodine Supplementation is Often Necessary: Relying on fortified sources like iodized salt or supplements is the most reliable way for vegans to get sufficient iodine, as levels in plant foods are inconsistent.
Protein Needs are Easily Met: A varied and sufficient-calorie vegan diet can provide all necessary protein by consuming diverse plant sources, with complete proteins available in options like soy, quinoa, and seitan.

Navigating a Vegan Diet: A Focus on Essential Nutrients

Following a vegan diet, which excludes all animal products, requires a thoughtful and strategic approach to nutrition. While plant-based eating offers many health advantages, several nutrients primarily sourced from animal foods warrant special attention. A poorly planned vegan diet can lead to deficiencies with serious health consequences. Understanding these potential pitfalls and implementing preventative measures is key to thriving on a vegan lifestyle.

The Critical Concern of Vitamin B12

A lack of vitamin B12 is a significant risk for individuals following a strictly vegan diet. This vitamin is crucial for nerve function, red blood cell formation, and DNA synthesis and is not found in unfortified plant foods. Deficiency can cause serious health issues. Vegans must obtain B12 from fortified foods or supplements. Fortified options include plant milks and cereals. Supplementation is the most reliable way to ensure adequate intake.

Addressing Calcium and Vitamin D

Calcium is vital for bones, and vitamin D is needed for its absorption. Vegans must find non-dairy sources.

Calcium Sources: Plant-based options include calcium-set tofu, fortified plant milks, legumes, sesame seeds, and some leafy greens like kale.
Vitamin D Sources: Sunlight is a natural source, but fortified foods and supplements are often necessary, especially in certain seasons or for those with limited sun exposure.

Iron and Zinc Bioavailability Challenges

Iron and zinc are in many plant foods, but compounds called phytates can reduce their absorption.

Enhancing Absorption: Consuming vitamin C with iron sources improves absorption. Soaking and sprouting can also help reduce phytates.
Rich Sources: Good sources of iron include lentils, beans, tofu, and leafy greens. Zinc is found in legumes, nuts, and seeds.

The Omega-3 Fatty Acid Conversion Gap

Omega-3 fatty acids are important for overall health. Plant sources provide ALA, which the body converts to EPA and DHA, but this process is inefficient.

ALA Sources: Include flaxseeds, chia seeds, and walnuts.
EPA and DHA Sources: A microalgae supplement is the most reliable vegan source.

The Iodine Imperative for Thyroid Health

Iodine is needed for thyroid function. Levels in plants vary, and while seaweed is a source, its iodine content can be inconsistent and sometimes excessive.

Reliable Sources: Iodized salt, fortified plant milks, or a daily supplement are the most dependable ways to ensure sufficient iodine intake.

Protein Adequacy from Plant Sources

Getting enough protein on a vegan diet is achievable with sufficient calories and a diverse diet. Combining different plant proteins can ensure intake of all essential amino acids.

Complete Protein Sources: Soy products and quinoa are complete proteins.
Combining Proteins: Pairing legumes with grains, or nuts with seeds, helps create complete protein profiles.

A Quick Comparison: Vegan vs. Omnivore Nutrient Sourcing


Nutrient	Primary Omnivore Sources	Primary Vegan Sources & Consideration
Vitamin B12	Meat, eggs, dairy	Fortified foods (cereals, plant milks, nutritional yeast) & supplements (Essential)
Calcium	Dairy products	Calcium-set tofu, fortified plant milks, leafy greens (kale, bok choy), sesame seeds
Iron	Red meat (heme iron)	Legumes, tofu, whole grains, nuts. Absorption is lower (non-heme iron), enhanced by Vitamin C
Zinc	Meat, dairy	Legumes, nuts, seeds, whole grains. Bioavailability reduced by phytates
Omega-3s (EPA/DHA)	Oily fish, eggs	Flaxseeds, walnuts (ALA). Algae oil supplements for direct EPA/DHA intake
Iodine	Dairy, fish	Iodized salt, fortified plant milks, seaweed (variable amounts), daily supplements

Conclusion

A major concern for individuals on a strictly vegan diet is the potential for deficiencies in nutrients like B12, vitamin D, calcium, iron, omega-3s, and iodine. Careful planning with a varied diet, fortified foods, and supplements, particularly for B12, is crucial for long-term health. Consulting a dietitian is recommended for personalized guidance. For further reading, the Academy of Nutrition and Dietetics provides a position paper on vegetarian and vegan diets.

Academy of Nutrition and Dietetics Position Paper

Frequently Asked Questions

Yes, all individuals following a vegan diet must take a reliable vitamin B12 supplement or regularly consume B12-fortified foods, as this nutrient is not naturally present in plant foods.

Excellent vegan calcium sources include calcium-set tofu, fortified plant milks, sesame seeds, and leafy greens like kale and bok choy.

To improve iron absorption, vegans should pair iron-rich plant foods (e.g., lentils, beans) with a source of vitamin C (e.g., bell peppers, citrus fruits). Soaking and sprouting legumes can also help.

While plant foods provide ALA omega-3, obtaining the more active EPA and DHA is difficult. The most reliable method is to take a microalgae supplement.

Vegans can get iodine from iodized salt, fortified plant-based milk alternatives, or a daily supplement, as levels in plant foods are highly variable.

Yes, vegans can easily meet their protein needs by eating a varied diet that includes protein-rich plant foods such as legumes, soy products, nuts, seeds, and whole grains.

A poorly planned vegan diet can increase the risk of deficiencies in nutrients like vitamins B12 and D, calcium, iron, and iodine, potentially leading to anemia, bone density issues, and neurological problems.