Understanding Which Vitamins Do Vegetarians Not Get

October 28, 2025 •

4 min read

While plant-based diets are associated with lower risks for certain chronic diseases, vegetarians must be mindful of specific nutrients not readily available in plants. An estimated 40% of vegetarians can be deficient in vitamin B12, highlighting the importance of understanding which vitamins do vegetarians not get.

Quick Summary

This article details key vitamins and minerals that can be deficient in a vegetarian diet, including B12, iron, calcium, vitamin D, and omega-3s. It explores why these deficiencies occur and provides strategies for obtaining these nutrients through fortified foods or supplements.

Key Points

Vitamin B12 is the primary concern: Found naturally only in animal products, all vegetarians should consume fortified foods or supplements to prevent deficiency.
Iron absorption needs a boost: Plant-based (non-heme) iron is less bioavailable, so combine iron-rich foods with vitamin C to maximize absorption.
DHA and EPA require planning: The body inefficiently converts plant-based omega-3 (ALA) to the beneficial DHA and EPA, making algal oil supplements a wise choice for some.
Calcium intake requires fortified foods: Especially for non-dairy vegetarians, relying on fortified plant milks, calcium-set tofu, and low-oxalate greens is critical.
Vitamin D often requires supplementation: While sun exposure is a source, limited plant food options mean that supplements are frequently necessary, particularly in winter.
Zinc bioavailability is key: Phytates in whole grains and legumes can hinder zinc absorption; sprouting and soaking, plus a varied diet, can help.
Nutrient status varies by diet type: The specific nutrients at risk of deficiency can vary between lacto-ovo vegetarians and strict vegans, with vegans facing greater challenges for B12, calcium, and iodine.

A well-planned vegetarian diet can be a healthy and sustainable choice, but it's crucial to understand where certain nutritional gaps can occur. While a plant-based diet offers numerous health benefits, the exclusion of meat and other animal products means that some vitamins and minerals require careful attention. This article outlines the key nutrients that vegetarians may find challenging to obtain and provides practical solutions to maintain a balanced and healthy diet.

Vitamin B12: The Most Critical Concern

Vitamin B12 is arguably the most important nutrient for vegetarians to monitor, especially for vegans who consume no animal products at all. It is essential for nerve function and the production of red blood cells. The primary natural sources of B12 are animal products, including meat, eggs, and dairy. A deficiency can lead to serious neurological issues and megaloblastic anemia.

Why it's a risk for vegetarians

Because B12 is produced by bacteria and not by plants, unfortified plant foods are not a reliable source. Lacto-ovo vegetarians who consume eggs and dairy may get some B12, but intake can still be lower than in omnivores. For strict vegetarians and vegans, supplementation or consumption of fortified foods is necessary.

Iron: Navigating Bioavailability

Iron is another vital mineral where vegetarians must pay close attention. While many plant foods contain iron, there are two types: heme and non-heme. Heme iron, found in meat, is absorbed much more efficiently by the body than non-heme iron from plants. Plant-based iron sources also contain compounds like phytates and tannins that can inhibit absorption.

Boosting plant-based iron absorption

Fortunately, there are simple strategies to increase the bioavailability of non-heme iron. Pairing iron-rich plant foods with vitamin C-rich foods significantly enhances absorption. For example, a meal of lentils (iron source) with bell peppers (vitamin C source) is an effective combination. Soaking and sprouting grains and legumes can also help reduce phytate content.

Calcium and Vitamin D: The Bone Health Duo

Calcium and vitamin D work together to maintain strong bones and teeth. Calcium is essential for bone density, while vitamin D helps the body absorb calcium. Vegetarians, especially those who exclude dairy, must be proactive in finding alternative sources. Vitamin D is synthesized by the body in response to sunlight, but dietary sources are also important, especially during months with less sun exposure.

Calcium sources for vegetarians

Fortified plant milks: Look for plant-based milks (soy, almond, oat) that have been fortified with calcium.
Calcium-set tofu: Check the ingredients list for calcium sulfate, which is used as a coagulant.
Leafy greens: Kale, bok choy, and broccoli are good sources, but be aware that spinach contains oxalates that inhibit calcium absorption.
Other foods: Beans, almonds, and figs also provide some calcium.

Vitamin D sources for vegetarians

Aside from sun exposure, dietary options for vegetarians include fortified foods such as cereals and plant milks. For many, a vitamin D supplement is necessary to ensure adequate levels.

Omega-3 Fatty Acids: The ALA Conversion Challenge

Omega-3s are crucial for brain and heart health. There are three main types: ALA, EPA, and DHA. Plant-based sources like walnuts, flaxseeds, and chia seeds provide ALA, but the body's conversion of ALA to the more beneficial EPA and DHA is inefficient. This can lead to lower levels of EPA and DHA in vegetarians compared to omnivores.

Bridging the EPA and DHA gap

For those concerned about their EPA and DHA levels, particularly pregnant women and individuals with certain health conditions, an algal oil supplement is the most direct vegetarian source. Algae are the original source of omega-3s that fish consume, making it a reliable plant-based option.

Comparative Look at Nutrient Needs


Nutrient	Why it's a concern for vegetarians	Good plant-based food sources	Supplementation strategy
Vitamin B12	Found almost exclusively in animal products; production by bacteria.	Fortified cereals, nutritional yeast, fortified plant milks.	Necessary for most vegetarians, especially vegans.
Iron	Plant-based (non-heme) iron is less bioavailable than heme iron from meat.	Legumes, dark leafy greens, whole grains, fortified cereals.	Combine with vitamin C for enhanced absorption.
Calcium	Excluding dairy requires finding alternative, often fortified, sources.	Calcium-set tofu, fortified plant milks, kale, almonds.	Consider a supplement if dietary intake is consistently low.
Vitamin D	Limited natural plant-based food sources; relies on sun and fortification.	UV-irradiated mushrooms, fortified foods.	Often recommended, especially in winter or with limited sun exposure.
Omega-3s (DHA/EPA)	Inefficient conversion of plant-based ALA to EPA and DHA.	Walnuts, flaxseeds, chia seeds (ALA sources).	Algal oil supplements are a reliable source of preformed DHA/EPA.
Zinc	Absorption inhibited by phytates in plant foods.	Legumes, nuts, seeds, whole grains.	Soaking grains and legumes improves absorption; some may need supplements.

Zinc: A Bioavailability Battle

Zinc is another mineral where vegetarians and vegans are at a higher risk of deficiency. Although present in many plant foods, absorption can be hampered by phytates. These compounds, found in whole grains, legumes, and nuts, can bind to minerals like zinc, making them harder for the body to absorb. Strategies like soaking and sprouting can help, but ensuring adequate intake requires careful dietary planning.

Conclusion

While a vegetarian diet is healthful, it does require careful attention to certain key nutrients, including vitamins B12, D, and minerals like iron, calcium, and zinc. The lower bioavailability of some plant-based nutrients and the exclusion of animal-based sources make strategic planning essential. Incorporating a variety of fortified foods and, in some cases, supplements can effectively prevent deficiencies. By understanding these potential gaps and implementing practical nutritional strategies, vegetarians can enjoy the full benefits of their diet while ensuring optimal health. For personalized advice, it's always recommended to consult with a healthcare professional or registered dietitian. For more on managing a plant-based diet, see the American College of Cardiology's position.

Frequently Asked Questions

Vitamin B12 is the most common vitamin that vegetarians and vegans need to actively manage. It is produced by microorganisms and found naturally in animal products, making it absent from unfortified plant-based foods.

Vegetarians can get enough iron by eating plant-based sources like legumes, lentils, fortified cereals, and dark leafy greens. To improve absorption, these foods should be eaten with vitamin C-rich foods such as bell peppers or citrus fruits.

Not necessarily. While dairy is a major calcium source, vegetarians can get enough by consuming fortified plant milks, calcium-set tofu, and certain leafy greens like kale and bok choy. For those who don't consume dairy, careful planning is important to avoid deficiency.

Since the body's conversion of plant-based omega-3s (ALA) to the more active forms (EPA and DHA) is inefficient, a high-quality algal oil supplement is recommended for vegetarians and vegans to ensure optimal levels.

Vegetarians can get vitamin D from sun exposure or fortified foods. However, many individuals require a supplement, especially during months with limited sunlight, to maintain adequate levels.

Zinc absorption can be an issue because plant foods like whole grains and legumes contain phytates, which can interfere with the body's ability to absorb the mineral. Soaking and sprouting can help reduce these inhibitors.

Yes, appropriately planned vegetarian diets can be suitable for all life stages, including pregnancy, infancy, childhood, and adolescence. The key is meticulous planning to ensure all nutritional needs, including potentially lacking vitamins, are met.