What Supplements Should a Lacto-Ovo-Vegetarian Take?

November 12, 2025 •

3 min read

According to a 2024 review, long-term lacto-ovo-vegetarians may have lower serum vitamin B12 concentrations than those consuming fortified foods. While a lacto-ovo-vegetarian diet is rich in many nutrients, it's crucial to understand which supplements should be considered to fill potential nutritional gaps.

Quick Summary

A well-planned lacto-ovo-vegetarian diet often requires supplementation of key nutrients like B12, vitamin D, and omega-3 fatty acids for optimal health. Pay attention to minerals such as iron, zinc, and iodine, which can be less bioavailable from plant-based sources. Ensure sufficient intake through fortified foods or daily supplements.

Key Points

Vitamin B12 is essential: As B12 is primarily from animal sources and absorption can be low, a reliable supplement is crucial for lacto-ovo-vegetarians.
Consider vitamin D: Due to limited natural food sources and sun exposure, most lacto-ovo-vegetarians will benefit from a vitamin D supplement.
Choose algal oil for omega-3s: Supplementing with algal oil provides direct EPA and DHA, overcoming the body's inefficient conversion of plant-based ALA.
Enhance iron and zinc absorption: Combine iron-rich foods with vitamin C and use food preparation methods like soaking to improve mineral absorption from plant sources.
Assess calcium needs: While dairy provides calcium, ensure intake is sufficient by combining it with fortified foods; supplement only if dietary sources are lacking.
Personalize your plan: Always consult a healthcare professional to create a supplement strategy tailored to your specific dietary needs and health status.

Essential Vitamins for a Lacto-Ovo-Vegetarian Diet

Even with a varied diet that includes dairy and eggs, certain nutrients can be challenging for lacto-ovo-vegetarians to obtain in sufficient, bioavailable quantities. A proactive approach to supplementation ensures optimal health and prevents long-term deficiencies.

Vitamin B12

Vitamin B12 is crucial for neurological function and red blood cell production. It is found primarily in animal products, making it a key concern for all vegetarians, including lacto-ovo-vegetarians. While eggs and dairy contain some B12, the amount and absorption can be inadequate, and fortified foods alone may not be enough. Regular B12 supplementation is the most reliable strategy to ensure sufficient levels.

Vitamin D

Vitamin D is important for bone health, immune function, and mood regulation. While sunlight exposure is a primary source, dietary sources are limited for vegetarians, even with eggs and fortified dairy products. Many people, regardless of diet, are deficient, especially in regions with less sun exposure during certain months. Supplementation is a prudent choice for most lacto-ovo-vegetarians. Vitamin D3 derived from lichen is a vegan-friendly option, while many D3 supplements come from animal sources like lanolin.

Omega-3 Fatty Acids

Long-chain omega-3 fatty acids, specifically EPA and DHA, are vital for brain, eye, and heart health. Plant-based sources provide ALA, which the body can convert to EPA and DHA, but this conversion rate is low. Studies show that vegetarians often have lower levels of EPA and DHA than omnivores. Therefore, an algal oil supplement, which provides direct EPA and DHA, is highly recommended for lacto-ovo-vegetarians.

Minerals and Considerations

Beyond the primary vitamins, lacto-ovo-vegetarians should also pay attention to several key minerals where bioavailability or intake can be compromised.

Iron

Iron is necessary for transporting oxygen throughout the body. While lacto-ovo-vegetarians can get iron from eggs, lentils, leafy greens, and fortified cereals, the non-heme iron from plant sources is less efficiently absorbed than heme iron from meat. Combining iron-rich foods with vitamin C-rich foods (like citrus or peppers) can enhance absorption. Some vegetarians, particularly women, may need to consider supplementation under medical guidance.

Zinc

Zinc plays a critical role in immune function, growth, and wound healing. The phytates in whole grains and legumes, common in vegetarian diets, can inhibit zinc absorption. As a result, vegetarians and vegans may have lower zinc levels. Soaking and fermenting grains and legumes can reduce phytate content and improve absorption, but some may still benefit from a modest zinc supplement.

Calcium

Calcium is a key mineral for bone health. As lacto-ovo-vegetarians consume dairy products, they have a reliable source of calcium. However, it's still important to ensure adequate intake through a combination of dairy and fortified foods, along with plant sources like leafy greens and tofu. Supplemental calcium may be considered if dietary intake is consistently low, but moderation is key.

Comparison of Key Vegetarian Nutrients and Supplements


Nutrient	Primary Food Source	Bioavailability/Concern for LOV	Supplement Recommendation
Vitamin B12	Dairy, eggs, fortified foods	Inadequate intake and poor absorption possible	Highly recommended supplement
Vitamin D	Sunlight, fortified dairy, eggs	Limited natural dietary sources, geographical limitations	Recommended supplement
Omega-3s (DHA/EPA)	Algal oil (ALA in walnuts, flax)	Low conversion rate from plant-based ALA	Algal oil supplement recommended
Iron	Lentils, beans, fortified cereals, eggs	Less bioavailable non-heme iron from plants	May need supplementation, especially for women
Zinc	Legumes, nuts, seeds, dairy, eggs	Phytates in plants inhibit absorption	Consider supplementation; food prep techniques help
Calcium	Dairy, fortified foods	Readily available with adequate planning	Only necessary if dietary intake is insufficient

Conclusion

While a lacto-ovo-vegetarian diet offers many health benefits, strategic supplementation is vital for ensuring long-term nutritional adequacy. Vitamin B12 is an almost universal requirement, while vitamin D, algal oil-based omega-3s, and potentially iron and zinc should be considered based on individual needs and dietary patterns. Consulting a healthcare provider or a registered dietitian is the best course of action to create a personalized plan. As the Academy of Nutrition and Dietetics states, appropriately planned vegetarian diets are healthful and nutritionally adequate across all life stages, and careful monitoring ensures these health benefits are realized.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Please consult a healthcare professional before starting any new supplement regimen.

Frequently Asked Questions

Yes, a B12 supplement is considered necessary. While dairy and eggs contain some B12, the levels are often insufficient and absorption can be unreliable. Supplementation is the most effective way to ensure adequate intake.

Lacto-ovo-vegetarians can obtain the precursor ALA from plant sources like flaxseeds, walnuts, and canola oil. However, because the body's conversion to the more crucial EPA and DHA is inefficient, an algal oil supplement is highly recommended.

In most cases, no. With proper meal planning, protein needs can be easily met through dairy, eggs, and a variety of plant-based sources like legumes, nuts, and seeds. Protein supplements are generally unnecessary unless specific fitness goals or medical conditions require it.

You can improve iron absorption by pairing plant-based iron sources (non-heme iron) with foods rich in vitamin C. For example, add citrus dressing to a lentil salad or have fortified cereal with a glass of orange juice.

Yes, they should be mindful of zinc intake. Phytates in whole grains and legumes can hinder zinc absorption. Soaking beans and grains before cooking can help. A low-dose supplement may be beneficial for those with inadequate intake or absorption issues.

Vitamin D comes in two forms: D2 (plant-derived) and D3. While D3 is often sourced from lanolin, there are vegan D3 supplements available derived from lichen. Both D2 and D3 are effective, but some studies suggest D3 may be slightly more potent.

While a well-planned diet can meet many needs, it is very difficult to obtain sufficient B12 and long-chain omega-3s (DHA/EPA) from food alone. Even with fortified foods, most nutritional experts recommend supplementing these specific nutrients to prevent long-term deficiencies.