Nutrients a Person on a Vegetarian Diet Might Have Trouble Eating Enough Of

December 2, 2025 •

3 min read

While a well-planned vegetarian diet can be perfectly healthy, a 2022 review of studies found that vegans and, to a lesser degree, vegetarians are often at risk for certain nutritional deficiencies, particularly vitamin B12. Understanding what nutrients a person on a vegetarian diet might have trouble eating enough of is essential for maintaining optimal health.

Quick Summary

This guide details the specific nutrients vegetarians should monitor, including iron, vitamin B12, calcium, and omega-3s. It provides practical food sources, absorption tips, and supplementation advice to ensure a balanced and healthy vegetarian eating plan.

Key Points

Vitamin B12: A consistent, reliable source is vital, as it is not naturally present in most plant foods; supplementation or fortified products are necessary to avoid deficiency.
Iron: The body absorbs non-heme iron from plants less efficiently than heme iron from meat, so focusing on vitamin C-rich foods to boost absorption is crucial.
Calcium: Vegans need to consume fortified plant milks, calcium-set tofu, and low-oxalate leafy greens to compensate for the absence of dairy products.
Zinc: Phytic acid in grains and legumes inhibits zinc absorption; processing methods like sprouting and soaking, plus a varied diet, can help increase intake.
Omega-3 Fatty Acids: The conversion of plant-based ALA to critical EPA and DHA is inefficient; high-ALA sources like flaxseeds or direct algal oil supplements are recommended.
Strategic Planning: A well-planned vegetarian diet can be nutritionally complete, but mindful food selection, fortification, and supplementation are often required for these specific nutrients.

Vitamin B12: The Most Critical Concern

Vitamin B12 is essential for red blood cell formation and nerve function. It is found almost exclusively in animal products. Vegans have no natural dietary source, and ovo-lacto vegetarians may not get enough from eggs and dairy.

Fortified foods: Look for vitamin B12 in fortified cereals, nutritional yeast, and plant milks.
Supplementation: Supplements are the most reliable way to prevent deficiency for vegans and many vegetarians.

Iron: Navigating Lower Bioavailability

Iron is vital for oxygen transport. Plant foods contain non-heme iron, which is less efficiently absorbed than heme iron from meat. Vegetarians may have lower iron stores.

Enhance absorption: Combine iron-rich foods with vitamin C sources.
Avoid inhibitors: Limit tea and coffee with meals as they can hinder absorption.
Good sources: Include legumes, fortified cereals, dark leafy greens, tofu, and dried fruits.

Calcium and Vitamin D: Essential for Bone Health

Calcium supports bone health, and Vitamin D aids calcium absorption. Vegans, who avoid dairy, need to pay close attention to their intake.

Plant-based sources: Consume calcium-rich plant foods like low-oxalate greens, fortified plant milks and cereals, calcium-set tofu, and sesame seeds.
Fortified products: Many non-dairy alternatives are fortified with calcium and vitamin D.
Supplementation: A vitamin D supplement is often needed, especially with limited sun exposure.

Zinc: A Bioavailability Challenge

Zinc is important for immune function. Plant-based zinc is less bioavailable due to phytic acid. Vegetarians may have lower zinc levels.

Increase intake: Good sources include legumes, nuts, seeds, and whole grains.
Processing methods: Soaking, sprouting, and fermenting can reduce phytates and improve zinc absorption.
Monitor status: A zinc supplement might be beneficial, particularly for vegans.

Omega-3 Fatty Acids: The Conversion Challenge

Omega-3s are crucial for brain and heart health. Plant sources provide ALA, but the conversion to EPA and DHA is inefficient.

ALA sources: Include flaxseeds, chia seeds, hemp seeds, and walnuts.
Algal oil: Algal oil supplements provide a direct source of EPA and DHA for vegans.

Comparison of Key Nutrient Sources


Nutrient	Primary Animal-Based Sources	Key Vegetarian/Vegan Food Sources	Absorption Considerations
Vitamin B12	Meat, eggs, dairy	Fortified foods (plant milks, cereals, nutritional yeast)	Found reliably in fortified foods or supplements.
Iron	Red meat, poultry	Lentils, chickpeas, tofu, dark leafy greens, fortified cereals	Non-heme iron is less absorbed; pair with Vitamin C and limit tea/coffee.
Calcium	Dairy products	Fortified plant milks, calcium-set tofu, kale, bok choy, sesame seeds	Some plants inhibit absorption; fortified sources are more reliable.
Zinc	Meat, dairy	Legumes, nuts, seeds, whole grains	Phytates inhibit absorption; soaking and sprouting can improve bioavailability.
Omega-3s	Fatty fish (EPA/DHA)	Flaxseeds (ALA), chia seeds (ALA), walnuts (ALA), algal oil (DHA/EPA)	Conversion of ALA to EPA/DHA is inefficient; algal oil is best for EPA/DHA.

Conclusion: Strategic Planning is Key

A well-planned vegetarian diet, especially vegan, requires attention to certain nutrients. While protein and fiber are generally abundant, Vitamin B12, iron, calcium, Vitamin D, zinc, and Omega-3 fatty acids may require strategic focus. Utilizing fortified foods, understanding absorption factors, and considering supplements can help prevent deficiencies and support overall health on a meat-free diet.

Visit the Academy of Nutrition and Dietetics for guidance on a healthy vegetarian eating plan.

The Role of Modern Food Processing and Fortification

Modern food processing and fortification are valuable tools for vegetarians to obtain necessary nutrients. Fortifying plant-based products with vitamins like B12 and minerals like calcium and vitamin D helps individuals meet daily requirements. Techniques like fermentation and sprouting also improve the bioavailability of minerals such as iron and zinc by reducing anti-nutrient levels. These advancements make it easier to maintain a balanced vegetarian diet.

Frequently Asked Questions

Yes, vegetarians can get enough iron, but it requires strategic eating due to lower absorption rates of non-heme iron from plant sources. This involves pairing iron-rich foods like lentils and spinach with vitamin C sources to enhance absorption and avoiding tea or coffee with meals.

Yes, it is highly recommended that vegetarians, especially vegans, take a vitamin B12 supplement. As vitamin B12 is not reliably found in plant foods, relying on fortified foods alone can be inconsistent, making a supplement the most dependable way to prevent deficiency.

Top vegetarian and vegan calcium sources include fortified plant milks, calcium-set tofu, low-oxalate leafy greens like kale and bok choy, and sesame seeds. Fortified products are particularly reliable for consistent calcium intake.

To increase zinc absorption, vegetarians can use food preparation methods that reduce phytate levels, such as soaking and sprouting legumes and grains. Including a variety of zinc-rich foods like nuts, seeds, and fermented products is also helpful.

While plant-based diets provide ALA (a type of omega-3), the conversion to the more beneficial EPA and DHA is inefficient. Therefore, vegetarians, especially vegans, should consider a reliable source of EPA and DHA, such as an algal oil supplement.

No, it is generally easy for vegetarians to meet their protein needs, especially with a varied diet. While individual plant foods might not be 'complete' proteins, consuming a variety of legumes, grains, nuts, and seeds throughout the day provides a complete amino acid profile.

Some researchers suggest that having moderately lower iron stores, typical in well-planned vegetarian diets, might reduce the risk of certain chronic diseases. However, this is distinct from iron deficiency anemia, and maintaining proper iron status is still essential.