The Evidence
The Evidence
Vegan nutrition, answered from the primary sources: government fact sheets, professional-body position papers, and peer-reviewed studies, every one linked. A summary of the cited evidence, not medical advice.
This is a summary of the cited evidence, not medical advice. Evidence last reviewed July 18, 2026.
The nutrients
- 01 Start here
Vitamin B12 on a vegan diet
B12 is the one nutrient where both cited sources speak bluntly about what plant foods do not supply.
On the record The NIH Office of Dietary Supplements and the Academy of Nutrition and Dietetics say vegans need a B12 supplement or fortified foods.
- 02
Protein on a vegan diet
The 'where do you get your protein' question, answered from a dietitians' position paper.
On the record The Academy of Nutrition and Dietetics says varied plant foods eaten across a day supply enough essential amino acids, and calls the terms complete and incomplete misleading.
- 03
Iron on a vegan diet: what the NIH fact sheet says
Plants have iron, just the kind your body absorbs less easily. The government fact sheet quantifies exactly how much less, and what raises the odds in your favor.
On the record The NIH Office of Dietary Supplements says the iron requirement is 1.8 times higher for vegetarians, and that vitamin C enhances absorption of nonheme iron.
- 04
Omega-3s on a vegan diet
Flax and walnuts give you the parent omega-3. Turning it into the ones your brain and heart use is inefficient, which is where algae oil comes in.
On the record The NIH Office of Dietary Supplements puts ALA-to-EPA/DHA conversion below 15%, and the Academy of Nutrition and Dietetics says EPA and DHA intakes are typically absent in vegans.
- 05
Calcium and bone health on a vegan diet
Where calcium intake and fracture risk meet, in NIH data and one large cohort.
On the record The NIH Office of Dietary Supplements says vegans have a higher risk of inadequate calcium intake; EPIC-Oxford found higher fracture risk in vegans, still significant after calcium adjustment.
- 06
Vitamin D on a vegan diet
Vitamin D is the one almost everyone runs low on in winter, vegan or not. The plant-friendly fix is D2 or lichen D3, plus fortified foods and sensible sun.
On the record The NIH Office of Dietary Supplements says vitamin D deficiency is more common among people who follow an ovo-vegetarian or vegan diet.
- 07
Iodine on a vegan diet
Iodine is the quiet one: no drama, easy to miss, easy to fix. Iodized salt or a measured amount of seaweed does it, and kelp can overshoot hard.
On the record The NIH Office of Dietary Supplements says vegans who consume no or minimal iodine-rich foods might not get enough iodine, and names seaweed as one of the best food sources.
- 08
Zinc on a vegan diet
Plants have zinc; phytates make you absorb less of it. The fix is more intake plus a few kitchen tricks that free the zinc up.
On the record The NIH Office of Dietary Supplements says zinc from beans, nuts and whole grains is less bioavailable than from animal foods, and absorption ranges from 5% to over 50% with dietary phytate.
- 21
Creatine on a vegan diet
Your body makes some creatine, and the only foods that carry the rest are meat and fish. That leaves vegans with lower stores, which may be exactly why they respond so well to the supplement.
On the record The NIH Office of Dietary Supplements says the liver and kidneys make about 1 g of creatine a day, and that vegetarians, with lower muscle creatine, might respond more to supplementation.
- 22
Choline on a vegan diet
Choline is the nutrient nobody talks about until pregnancy, and the richest sources are animal foods. The plant list is real but shorter, and most people of any diet already fall short.
On the record The NIH Office of Dietary Supplements lists animal foods as the main US sources of choline, names cruciferous vegetables and certain beans too, and says most people in the US consume less than the AI.
- 23
Selenium on a vegan diet
Selenium is the mineral your food inherits from the dirt it grew in. That makes plant levels a lottery of geography, and it is why vegan intakes can run low, and why two Brazil nuts can flip the whole thing.
On the record The NIH Office of Dietary Supplements says plant selenium varies with soil, that vegetarians and vegans may have lower intakes, and that Brazil nuts contain particularly high amounts.
- 24
Vitamin A on a vegan diet
Vegans get vitamin A the long way round: plants supply beta-carotene, and the body turns it into the active vitamin. The conversion is real but not identical in everyone, which is why the orange and dark-green vegetables earn their place.
On the record The NIH Office of Dietary Supplements says preformed vitamin A comes from animal foods, plants supply provitamin A carotenoids such as beta-carotene, and conversion rates may vary genetically.
- 25
Riboflavin (B2) on a vegan diet
Riboflavin is a quiet one: no dramatic deficiency story, just the fact that dairy and eggs carry a lot of it. Take those away and the NIH puts vegans on the watch list, which fortified foods and a few staples handle.
On the record The NIH Office of Dietary Supplements lists eggs, organ meats, lean meats and milk as rich riboflavin sources, and says vegans are at risk of riboflavin inadequacy.
- 26
Vitamin K and K2 on a vegan diet
Vitamin K1 is one of the easiest nutrients to get on a plant diet: it is what makes leafy greens green. K2 is the one people worry about, and the honest answer involves natto, gut bacteria, and your own biology.
On the record The NIH Office of Dietary Supplements says phylloquinone (K1) is found mainly in green leafy vegetables, and that natto, a fermented soybean food, has high amounts of menaquinones (K2).
- 27
Protein combining at every meal
The old rule was that vegans had to pair rice with beans at every meal to make a complete protein. Here is what the Academy of Nutrition and Dietetics says about it.
On the record The Academy of Nutrition and Dietetics says varied plant foods eaten across a day supply enough essential amino acids when calories are met, and calls complete and incomplete misleading.
- 32
Magnesium on a vegan diet
Magnesium is one of the easier minerals to get on a plant diet, because its best sources are exactly the foods a good vegan diet is built on.
On the record The NIH Office of Dietary Supplements lists green leafy vegetables, legumes, nuts, seeds and whole grains as good sources of magnesium.
- 33
Potassium on a vegan diet
Potassium is the mineral the modern diet is short on, and plant-based eating is where it is easiest to get. Fruit, vegetables, beans and potatoes are all loaded with it.
On the record The NIH Office of Dietary Supplements says many fruits and vegetables are excellent potassium sources, as are some legumes (e.g., soybeans) and potatoes.
- 34
Folate on a vegan diet
Folate is the one B vitamin plant eaters rarely have to think about. The name comes from foliage, and the diet is built on exactly that.
On the record The NIH Office of Dietary Supplements says folate is found in many foods, especially dark green leafy vegetables, and also in fruits, nuts, beans, peas, seafood, eggs, dairy and meat.
- 35
Copper on a vegan diet
Copper is a trace mineral few people think about, and plant eaters have little reason to worry. Nuts, seeds and whole grains carry it well.
On the record The NIH Office of Dietary Supplements lists shellfish, seeds and nuts, organ meats, wheat-bran cereals, whole-grain products and chocolate among the richest dietary copper sources.
- 36
Vitamin B6 on a vegan diet
Vitamin B6 turns up in chickpeas, potatoes and bananas in amounts that rival or beat meat, and the federal government's own list of at-risk groups never once mentions diet type.
On the record The NIH Office of Dietary Supplements says isolated B6 deficiency is uncommon and usually accompanies low levels of other B vitamins; its food table lists canned chickpeas at 65% of the Daily Value.
- 37
Thiamine (B1) on a vegan diet
Thiamine hides in whole grains, legumes and fortified cereal at levels that meet the RDA with room to spare, and the deficiency risk list runs through alcohol use disorder and bariatric surgery, not what's on the plate.
On the record The NIH Office of Dietary Supplements lists whole grains, meat and fish as thiamin sources and says alcohol use disorders appear to be the most common cause of deficiency in industrialized countries.
- 38
Niacin (B3) on a vegan diet
Niacin comes from brown rice, peanuts and fortified grains directly, and the body has a second route: it converts spare tryptophan from any protein, plant or animal, into niacin on its own.
On the record The NIH Office of Dietary Supplements says nuts, legumes and grains provide about 2 to 5 mg niacin per serving, and that severe niacin deficiency leads to pellagra.
- 39
Pantothenic acid (B5) on a vegan diet
Pantothenic acid is in almost everything on a plate, plant or animal, and the deficiency record is so thin that the only confirmed human cases came from deliberate starvation experiments.
On the record The NIH Office of Dietary Supplements says many plant and animal foods contain pantothenic acid, and that deficiency is rare except in people with severe malnutrition.
- 40
Vitamin C on a vegan diet
Vitamin C comes almost entirely from fruits and vegetables, not meat or dairy, so a vegan plate typically carries more of it than a standard one. The federal fact sheet ties deficiency to limited food variety, not diet type.
On the record The NIH Office of Dietary Supplements names fruits and vegetables as the best sources of vitamin C, and says deficiency is uncommon in developed countries but can occur with limited food variety.
- 41
Vitamin E on a vegan diet
Vitamin E's best sources, nuts, seeds and vegetable oils, are plant foods to begin with. NIH ties genuine deficiency to fat-malabsorption disorders, not to what's on the plate, though many Americans of any diet fall short of the RDA.
On the record The NIH Office of Dietary Supplements lists nuts, seeds and vegetable oils among the best sources of vitamin E, and says most Americans' diets provide less than the RDA.
- 42
Phosphorus on a vegan diet
Phosphorus is abundant in legumes, nuts, grains and vegetables, and most people already eat more of it than the RDA calls for. What differs is absorption: plant phosphorus is less efficiently absorbed than the kind in meat and dairy.
On the record The NIH Office of Dietary Supplements says most Americans consume more phosphorus than recommended, and that phosphorus from animal sources has a higher absorption rate than from plants.
- 43
Manganese on a vegan diet
NIH's own food table draws a clean line: whole grains, nuts, legumes and tea carry manganese, while ordinary servings of chicken, beef, eggs and milk register at zero, and no group is named as being at risk of falling short.
On the record The NIH Office of Dietary Supplements lists grain products, tea and vegetables as top US sources of manganese, and says no known groups of people are likely to have inadequate intakes.
- 44
Chromium on a vegan diet
No chromium deficiency has ever been documented in a healthy population, and research doubts whether chromium is even essential. The picolinate sold for weight loss carries an FDA disclaimer calling its own claim highly uncertain.
On the record The NIH Office of Dietary Supplements says chromium deficiency is unreported in healthy populations, and cites the European Food Safety Authority finding no convincing evidence it is essential.
- 45
Molybdenum on a vegan diet
Legumes are NIH's own top food source for molybdenum, ahead of every other food group, and the deficiency record is close to nonexistent: exactly one acquired case has ever been reported, from intravenous feeding with none in the formula.
On the record The NIH Office of Dietary Supplements says legumes are the richest sources of molybdenum and that no known groups of people are likely to have inadequate intakes.
- 46
Carnitine on a vegan diet
A vegan diet supplies about 1.2 mg of carnitine a day against 24 to 145 mg for omnivores, but the liver and kidneys make their own supply, and the same red-meat pathway behind the deficiency worry, TMAO, runs lower in vegans, not higher.
On the record The NIH Office of Dietary Supplements says a vegan diet provides about 1.2 mg of carnitine against 24 to 145 mg for omnivores, and that the body's own synthesis meets the needs of healthy people.
- 47
Taurine on a vegan diet
A 1988 study found vegan men had lower plasma taurine and much lower urinary taurine than omnivores, and the enzyme humans use to build it from scratch runs weak, but decades on there is still no documented taurine-deficiency state in healthy adult vegans.
On the record Laidlaw and colleagues measured lower plasma taurine in vegan men than in omnivores; Ripps and Shen describe taurine as nonessential or conditionally essential.
- 49
What are phytates? How they affect iron and zinc absorption
Phytates, phosphorus's storage form in beans and grains, chelate iron, zinc and calcium and measurably cut how much a vegetarian diet absorbs, but soaking, sprouting and fermenting the same foods strip out most of it, and clinical trials also credit phytate with cutting kidney stones and slowing bone loss.
On the record The NIH Office of Dietary Supplements says phytates bind minerals such as zinc; Pires and colleagues report phytate intake reduced hip and major osteoporotic fracture risk in postmenopausal women.
Health outcomes
- 09
Plant-based diets and heart disease
Two large cohort studies, including one finding on stroke that cuts the other way.
On the record EPIC-Oxford found lower ischaemic heart disease but higher total stroke rates in vegetarians; Adventist Health Study 2 associated vegetarian patterns with lower all-cause mortality.
- 10
Does soy mess with your hormones?
The soy-and-hormones worry, read against a peer-reviewed review.
On the record Mark Messina's Nutrients review says neither soy intake nor isoflavone exposure affects testosterone in men, and describes isoflavones as phytoestrogens and selective estrogen receptor modulators.
- 11
Processed meat and cancer: what IARC actually found
Group 1 carcinogen sounds like bacon equals cigarettes. Here is what the WHO says the category means.
On the record The WHO says IARC classes processed meat as Group 1, carcinogenic to humans, and estimates each 50 g eaten daily raises colorectal cancer risk by about 18%.
- 12
Vegan diets in pregnancy and childhood
This is the page to get right, so it is the page with the most hedging.
On the record The Academy of Nutrition and Dietetics says appropriately planned vegan diets are nutritionally adequate; the NIH says untreated B12 deficiency in infants can cause neurological damage.
- 13
Plant-based diets and type 2 diabetes
Vegetarians and vegans get type 2 diabetes far less often, and a vegan diet helps manage it, though the trial effect on blood sugar is real and modest, not a cure.
On the record Adventist Health Study-2 reports type 2 diabetes in 2.9% of vegans and 7.6% of nonvegetarians; a 74-week trial found HbA1c changes of -0.34 vs -0.14 on vegan vs conventional diets (P = 0.43).
- 14
Plant-based diets and blood pressure
Plant-based eating lowers blood pressure by a few millimetres of mercury, small for one person but the kind of shift that moves population risk.
On the record A JAMA Internal Medicine meta-analysis found vegetarian diets lowered systolic blood pressure by 4.8 mm Hg in 7 controlled trials and 6.9 mm Hg in 32 observational studies.
- 15
Plant-based diets and longevity
Two big cohorts, two different answers on whether plant-based eaters live longer.
On the record Adventist Health Study-2 found a hazard ratio of 0.88 for all-cause mortality in vegetarians; a large UK cohort found no significant difference between diet groups.
- 16
Plant-based diets and cancer risk
What a dietitians' position paper and the WHO report on plant-based eating and cancer.
On the record The Academy of Nutrition and Dietetics cites 18% lower overall cancer incidence in vegetarians; the WHO estimates 50 g of processed meat daily raises colorectal cancer risk by about 18%.
- 17
Plant-based diets, gout and kidney stones
For gout and kidney stones, cutting meat is one of the cleaner wins in nutrition. Vegetarians formed about a third fewer stones, and plant purines never earned their bad reputation.
On the record Choi and colleagues link meat and seafood, not purine-rich vegetables, to higher gout risk; Turney and colleagues report lower kidney-stone risk in vegetarians than in high meat-eaters.
- 18
Plant-based diets, bone health and fracture risk
An unflattering finding, published here anyway: in the largest cohort to look, vegans broke more bones.
On the record EPIC-Oxford (Tong and colleagues) reports a hip-fracture hazard ratio of 2.31 for vegans versus meat eaters, and says bone health in vegans requires further research.
- 28
Vegan diets and athletic performance
A growing list of pro athletes eat plant-based, and the science is not the obstacle it was once assumed to be. The position papers put vegan diets squarely inside the range that works for sport.
On the record The Academy of Nutrition and Dietetics says vegetarian and vegan diets suit athletes and protein needs are well achieved; the NIH says vegetarians might respond more to creatine.
- 29
Plant-based diets and weight
Across tens of thousands of people, the pattern is consistent: the more plant-based the diet, the lower the average body weight.
On the record Tonstad and colleagues report a mean BMI of 23.6 in vegans, the lowest of any diet group; Barnard and colleagues found weight loss did not differ significantly between vegan and conventional diets.
- 30
Plant-based diets and cholesterol
If a diet has one signature effect on the blood, for plant-based eating it is cholesterol. Low saturated fat plus high fibre pushes LDL down, and the trials back it up.
On the record The Academy of Nutrition and Dietetics describes low saturated fat and high fibre in vegan diets; Barnard and colleagues found LDL fell 13.5 mg/dL on a vegan diet versus 3.4 on a conventional one.
- 31
Fibre on a vegan diet
Fibre is the nutrient almost everyone under-eats, and it is the one plant-based diets deliver in abundance. Vegans eat the most of anyone, and the payoff shows up across the body.
On the record The Academy of Nutrition and Dietetics says people eating a vegan diet ate the most fibre and had the healthiest body weights and cholesterol levels compared with omnivores and other vegetarians.
- 48
Oxalates in plant foods
Spinach can carry more than a thousand milligrams of oxalate per 100 grams, and the compound does bind calcium and iron and feed kidney stones in people prone to them, but boiling leaches much of it out and cutting dietary calcium to fight stones backfires.
On the record Salgado and colleagues put normal absorption at 5 to 10% of ingested oxalate; the NIDDK says calcium, in the right amounts, can block substances that may cause kidney stones.
The industry record
- 19
Cultivated meat approval timeline
Not opinion, a ledger. Every US cultivated-meat milestone below is a public government document with a date and a link. Here is what has actually cleared regulators, and when.
On the record The FDA says it has no questions about the safety conclusions of UPSIDE Foods, GOOD Meat, Mission Barns and Wildtype; the Good Food Institute reports USDA inspection grants for UPSIDE and GOOD Meat.
- 20
The climate case for eating plants
Food accounts for roughly a quarter of global greenhouse gas emissions, according to Our World in Data.
On the record Our World in Data's Hannah Ritchie says food is responsible for around one-quarter of the world's greenhouse gas emissions, and points to what you eat not whether your food is local.
How these pages are built
Nutrition is the one topic where a confident tone and a wrong fact do real harm, so on these pages the sources do the talking. Every quote is a word-for-word copy from a named primary source: NIH Office of Dietary Supplements fact sheets, which are US government public-domain documents, the Academy of Nutrition and Dietetics position paper, the EPIC-Oxford and Adventist Health Study 2 cohorts, and the FDA and USDA records behind cultivated meat. Every quotation is checked against the archived source text before the page can publish, so what you read is exactly what the source wrote.
Each page carries an "On the record" line: what the named bodies and studies in that page's own sources say, attributed to them. We describe what the sources say and do not grade the claim. Where a finding cuts against the flattering story, like the higher fracture and stroke findings, we quote that too.
Wondering whether a specific ingredient makes the cut, from carmine to bone-char sugar? That is the job of our companion shelf, Is it vegan?, where each additive gets a plain verdict and the primary source behind it.
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Free, every morning. No guilt. No preaching.