What vegetarians and vegans actually need to supplement (the evidence-based list)

Plant-based diets are nutritionally adequate for most people — with deliberate planning and a few specific supplements. Skipping the supplements isn't optional for some nutrients.

Here's the evidence-based list.

The non-negotiable: Vitamin B12

Vegans must supplement B12. Vegetarians should monitor and often supplement.

• B12 is produced by bacteria, not plants or animals directly
• Animal products contain B12 because animals consume it (or it's added to their feed)
• Plant foods don't reliably contain B12
• Deficiency causes irreversible neurological damage
• Recommended dose: 25-100 μg/day cyanocobalamin or 1000 μg 2-3x/week

Cost: $5-10 per year.

This is the most important supplement for vegans. Skip everything else but take B12.

The strong recommendation: Vitamin D

Most adults benefit from D supplementation; vegans/vegetarians especially:

• Limited dietary sources (mostly fatty fish in animal kingdom)
• Synthesized from sun exposure, but most modern adults are deficient
• Plant-based D2 is less effective than animal D3, though vegan D3 from lichen exists
• Recommended dose: 1,000-2,000 IU daily (more if deficient)

Cost: $10-15 per year.

Test 25(OH)D blood level annually; supplement based on results.

The athlete's must: Omega-3 (EPA/DHA)

Plant omega-3 (ALA from flax, chia, walnuts) is poorly converted to EPA and DHA:

• Conversion rates are 5-10% for EPA and 1-5% for DHA
• Direct EPA/DHA from algae oil is more efficient
• Important for cardiovascular and brain health
• Recommended: 200-300 mg DHA + EPA daily (algae oil for vegans)

Cost: $50-150 per year for algae oil supplements.

The likely supplement: Iron

Plant iron (non-heme) absorbs less efficiently than animal iron (heme):

• Non-heme absorption: 5-15%
• Heme absorption: 15-35%
• Female vegetarians/vegans have higher deficiency rates
• Test ferritin annually; supplement if low

When supplementation is needed:

• Ferritin below 30 ng/mL
• Symptoms (fatigue, hair loss, exercise intolerance)
• Pregnancy
• Heavy menstrual losses

Take with vitamin C; avoid coffee/tea within 1 hour. Cost: $15-30 per year.

The often-needed supplement: Zinc

Plant zinc absorption is impaired by phytates:

• Vegetarian RDA: 50% higher than omnivores
• Symptoms of deficiency: poor immunity, hair loss, slow wound healing
• Test serum zinc if symptomatic
• Supplement: 15-30 mg/day

Cost: $10-20 per year.

The maybe supplement: Iodine

If you don't use iodized salt:

• Iodized salt is the major source for most people
• Sea vegetables (kelp, nori) contain iodine but with high variability
• Risk: thyroid dysfunction
• Supplement: 150 μg/day if not getting from salt or sea vegetables

Cost: $5-10 per year.

The athletic supplement: Creatine

Vegans and vegetarians have lower baseline muscle creatine:

• Show LARGER performance benefits from supplementation
• 5g daily monohydrate
• For any strength-based athletic pursuit

Cost: $25-50 per year. Worth it for any vegan athlete.

The "if pregnant or planning" supplements

Pregnant vegan/vegetarian women should add:

• Folate (folic acid): 600 μg/day
• Choline: 450 mg/day (often deficient in plant-based diets)
• DHA: algae-based, 200-300 mg/day

A prenatal vitamin specifically formulated for plant-based pregnancy (Ritual, Persona, etc.) covers most of these.

The "if older than 50" supplements

Older adults often need:

• B12 (absorption declines with age regardless of diet; even more critical for vegans)
• Calcium (bone density)
• D3 (skin synthesis declines)

For older vegan/vegetarian adults, periodic blood work is valuable.

What you don't need to supplement

For most healthy plant-based adults:

• Protein: food sources are adequate if you plan
• Most B vitamins: B12 yes, others no
• Calcium: if you eat dairy or fortified plant milks
• Magnesium: plant foods are usually adequate
• Selenium: Brazil nuts cover RDA easily

Don't supplement what you don't need.

The "expensive supplement stacks" trap

Plant-based wellness brands sell elaborate supplement stacks:

• $50-100/month subscription
• 10-20 different ingredients
• Many redundant or unnecessary

The actual evidence-based plant-based supplement stack:

• B12: $5/year
• D3 (algae or lichen vegan): $15/year
• Algae omega-3: $80/year
• Iron (if needed): $20/year
• Zinc (if needed): $15/year
• Creatine (if athletic): $25/year

Total: $50-160/year. Compare to $600-1,200/year for premium subscription stacks.

The blood-test priority

Test these annually for vegans (every 2-3 years for vegetarians):

• B12 (with MMA if normal-low)
• Vitamin D (25-OH)
• Ferritin and iron panel
• Zinc (if symptomatic)
• Lipid panel (general health)

Cost: $200-400 if not covered by insurance; often covered for adults.

These tests guide which supplements you actually need vs. take "just in case."

The food-based optimization

Before supplementing, optimize food sources:

• B12 fortified foods: plant milks, nutritional yeast, fortified cereals (still supplement; food alone often inadequate for vegans)
• D fortified foods: plant milks, mushrooms exposed to UV
• Iron-rich plant foods: lentils, beans, tofu, fortified grains, dark leafy greens
• Zinc-rich plant foods: beans, nuts, seeds, whole grains
• Omega-3 plant sources: flax, chia, walnuts (still supplement EPA/DHA)

Food-first; supplement to fill specific gaps.

The "I'm raw vegan" considerations

Raw vegan diets present additional challenges:

• Lower bioavailability of some nutrients without cooking
• Higher risk of B12 deficiency
• Often calorie-inadequate for active people
• Strongly recommended to work with experienced RD

Most people don't need to be raw vegan to capture plant-based diet benefits.

The ex-vegan transition

If you're transitioning from vegan to vegetarian or omnivore:

• Maintain B12 supplementation initially (absorption depleted)
• Iron stores recover quickly with animal products
• Omega-3 from fish replaces algae oil
• D and other supplements depend on diet still

Don't quit supplements abruptly during transitions.

When to involve a clinician

Consider consulting a plant-based-savvy RD if:

• You're transitioning to vegan and want to do it well
• You have specific deficiency concerns
• You're an athlete pushing performance
• You're pregnant or planning
• Blood work shows specific gaps

Not all RDs are equally plant-based-knowledgeable; seek one with that experience.

The honest summary

Plant-based diets work but require deliberate supplementation:

• B12: non-negotiable for vegans
• D3: most adults benefit
• EPA/DHA: athletes and brain health
• Iron, zinc: often needed
• Creatine: for athletes

Total cost: $100-150/year. Modest investment for the nutrient adequacy.

Test annually; supplement based on actual gaps. Don't fall for the expensive subscription stacks.

The plant-based diet works. The supplementation isn't optional for some nutrients. Take the right ones and skip the rest.