The vegan and vegetarian blind spots

Let's be clear up front, because this topic attracts more heat than light: a well-constructed plant-based diet can be genuinely healthy, and there are people thriving on one. This isn't an argument against plants. It's an argument against pretending the gaps don't exist, because the gaps are real, predictable, and documented, and the people most harmed are the ones who were told there's nothing to plan around.

The non-negotiable: vitamin B12

B12 is the clearest issue in all of nutrition. It's synthesized by microorganisms and accumulates only in animal and fermented foods, unfortified plant foods contain essentially none.^[1] A literature review found B12 deficiency in a substantial share of vegetarians and an even higher share of vegans, exceeding half of adults in some unsupplemented groups.^[1] This is not a "eat more spinach" problem; it's an absence. And because B12 deficiency can cause irreversible neurological damage, supplementing it on a vegan diet is mandatory. Evidence: A

The one most people miss: DHA and EPA

Even conscientious vegans usually nail B12 and then miss the omega-3s. The long-chain omega-3s EPA and especially DHA, critical for the brain, eyes, and (in pregnancy) fetal development, are scarce in plant foods. Plants supply ALA, which the body converts to DHA at a famously poor rate, so vegan diets reliably run low in DHA.^[2] An algae-based DHA/EPA supplement closes this gap directly, and it matters most for pregnant and breastfeeding women, whose milk DHA tracks their intake.^[2] Evidence: B

The bioavailability gaps: iron, zinc, protein

This is where the bioavailability thesis applies directly. Plant iron (non-heme) and plant zinc are both real but poorly absorbed, phytate and the lack of heme iron mean the listed milligrams overstate what you actually get.^[3] And plant protein is lower in quality per gram: less digestible, shorter on key amino acids, and thinner on leucine, so it stimulates muscle protein synthesis less effectively unless eaten in larger or blended amounts.^[4] None of this is disqualifying, it just means a plant-based eater has to be deliberate about iron pairing, zinc, and protein quantity in a way an omnivore doesn't. Evidence: A

The overlooked one: creatine

Creatine is found almost entirely in animal flesh, so vegetarians and vegans carry lower muscle and (some evidence suggests) brain creatine stores. It's not an essential nutrient, the body makes some, but lower status may matter for power output and cognition, and vegetarians often respond more strongly to supplementation precisely because they start lower.^[5] A few grams a day of creatine monohydrate is cheap, safe, and an easy win on a plant-based diet. Evidence: B

The outcome that should change the conversation: fractures

Here's the finding that rarely makes it into the plant-based marketing. In the large prospective EPIC-Oxford cohort (~55,000 people), vegans had roughly 2.3 times the risk of hip fracture compared with meat eaters, about 15 extra cases per 1,000 people over 10 years, and elevated risk at several other sites.^[6] The likely drivers were lower body weight, and lower calcium and protein intake. Evidence: B

The honest counterpoint

Plant-based diets also have real upsides, they're consistently associated with lower LDL/ApoB, lower blood pressure, and (in many cohorts) lower rates of certain chronic diseases, partly from displacing ultra-processed food and partly from the fiber and phytochemicals. This article isn't a verdict against them. It's a correction to the marketing that says no planning is required. The data say the opposite: plant-based done well is healthy; plant-based done naively produces exactly the deficiencies above.

Do this instead (if you eat plant-based)

1. Supplement B12, always. Non-negotiable, for life.^[1]
2. Add algae-based DHA/EPA, especially in pregnancy and breastfeeding.^[2]
3. Hit protein hard, higher total intake, blended sources, ~1.6 g/kg/day, distributed across meals to clear the leucine threshold.^[4]
4. Engineer iron and zinc, pair with vitamin C, reduce phytate by soaking/sprouting/fermenting, and check ferritin.^[3]
5. Take creatine (5 g/day), cheap, safe, and you likely start lower.^[5]
6. Protect your bones, adequate calcium, protein, vitamin D, body weight, and resistance training directly counter the fracture signal.^[6]

FAQ

Are vegan/vegetarian diets unhealthy? No, healthy if planned around B12, DHA, iron, zinc, creatine, protein quality, and bone health. The failure mode is ignoring those gaps.

Most important vegan supplement? B12, mandatory. Then algae DHA/EPA.

Do vegans break more bones? EPIC-Oxford found ~2.3× the hip-fracture risk, largely from low protein, calcium, and body weight, addressable, not inevitable.

References

1. 1.Pawlak R, et al. (2014). The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature. European Journal of Clinical Nutrition 68(5):541–548. PMID: 24667752. Link
2. 2.National Institutes of Health, Office of Dietary Supplements (2026). Omega-3 Fatty Acids, Health Professional Fact Sheet (ALA-to-DHA conversion; vegetarian sources). NIH ODS. Link
3. 3.Hurrell R, Egli I (2010). Iron bioavailability and dietary reference values. American Journal of Clinical Nutrition 91(5):1461S–1467S. PMID: 20200263. Link
4. 4.van Vliet S, Burd NA, van Loon LJ (2015). The skeletal muscle anabolic response to plant- versus animal-based protein consumption. Journal of Nutrition 145(9):1981–1991. PMID: 26224750. Link
5. 5.Kreider RB, et al. (2017). International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation (vegetarian responsiveness). Journal of the International Society of Sports Nutrition 14:18. PMC5469049. Link
6. 6.Tong TYN, et al. (2020). Vegetarian and vegan diets and risks of total and site-specific fractures: results from the prospective EPIC-Oxford study. BMC Medicine 18:353. PMC7682057. Link