EPIC-Oxford 2007 + BMC Medicine 2020

Vegan vs Vegetarian Calcium: Closing the Fracture Risk Gap

The EPIC-Oxford cohort found that vegans break more bones than vegetarians or meat-eaters. The published difference disappears once vegan calcium intake exceeds about 525 mg per day. This page works through the data, the food sources, and what the published clinical guidance recommends.

The short answer. Get 700 mg calcium per day (UK SACN) or 1,000 to 1,200 mg per day (US IOM) from fortified plant milks, calcium-set tofu, low-oxalate greens (kale, bok choy, collards), almonds and tahini, fortified juice. Vegans who reliably hit this target have no excess fracture risk over meat-eaters. Vitamin D matters too because it controls absorption: see the vitamin D page.

What EPIC-Oxford actually found

EPIC-Oxford is the European Prospective Investigation into Cancer and Nutrition arm based at Oxford, recruiting over 65,000 UK participants from 1993 to 1999 with deliberate over-representation of vegetarians and vegans. The 2007 fracture paper (Appleby P et al., Eur J Clin Nutr 2007; 61: 1400-1406) reported on 1,555 incident fractures across about 5 years of follow-up. Vegans had a 30% higher rate of total fractures than meat-eaters and vegetarians, who were broadly similar to each other. The crucial subgroup analysis found that vegans consuming 525 mg of calcium per day or more had no excess fracture risk.

The 2020 follow-up by Tong and colleagues (BMC Medicine 2020; 18: 353) extended the analysis with longer follow-up and many more events, and confirmed the pattern. Vegans had higher rates of total fractures (around 43% higher), hip fractures (around 130% higher, or 2.3x), and leg fractures than meat-eaters. Lower BMI and lower calcium and protein intakes accounted for much of the excess risk in mediation analysis. After adjusting for BMI, calcium, and protein, the excess hip fracture risk for vegans was reduced but did not disappear entirely.

The honest reading: the fracture excess in vegans is real, but it is modifiable. The cohort included many people who became vegan in the 1980s when fortified plant milks and calcium-set tofu were not widely available. A modern vegan with reliable access to fortified soy milk and calcium-set tofu can clear the 525 mg threshold without effort. The fracture story is not a reason to avoid the diet, but it is a reason to take calcium intake seriously.

Plant calcium sources, ranked by bioavailability

Food	Serving	Calcium (mg)	Bioavailability
Calcium-set tofu (firm)	100 g	350	High (~31%)
Fortified soy milk	250 ml	300	~75% of cow milk
Fortified oat milk	250 ml	300	~75% of cow milk
Fortified almond milk	250 ml	300	~75% of cow milk
Fortified orange juice (US)	250 ml	300	Similar to cow milk
Bok choy (cooked)	1 cup (170 g)	160	High (~54%)
Collard greens (cooked)	1 cup (190 g)	270	High (~52%)
Kale (cooked)	1 cup (130 g)	95	High (~49%)
Watercress	1 cup (35 g)	40	High
Almonds	30 g	75	Moderate (~21%)
Tahini	1 tbsp (15 g)	64	Moderate
Dried figs	50 g	80	Moderate
Spinach (cooked)	1 cup	245	Low (~5%, oxalate)
Swiss chard (cooked)	1 cup	100	Low (~5%, oxalate)
Rhubarb (cooked)	1 cup	105	Very low (oxalate)
Cow milk	250 ml	300	Reference (~32%)
Cheddar cheese	30 g	200	High (~32%)
Plain yogurt	170 g	200	High (~32%)

Bioavailability data from Weaver and Plawecki 1994 (Am J Clin Nutr 59: 1238S) and the Heaney calcium absorption studies. The low-oxalate brassicas (kale, bok choy, collards) absorb at higher efficiency than dairy on a per-mg basis, which is why they punch above their headline calcium number. Spinach is dense with calcium but most of it is not absorbed.

Calcium-set tofu and the label question

Tofu's calcium content depends entirely on the coagulant used. Tofu set with calcium sulfate (gypsum) contains around 350 mg calcium per 100 g. Tofu set with nigari (magnesium chloride) contains around 100 mg per 100 g. Tofu set with glucono-delta-lactone (silken tofu) contains very little calcium. The carton or pack will list the coagulant in the ingredients; look for calcium sulfate or E516.

UK supermarket firm tofu (Cauldron, Tofoo, Clearspring) is typically calcium-set. US supermarket firm tofu varies; Nasoya, House Foods, and Wildwood usually use calcium sulfate for firm and extra-firm grades. If calcium intake is a priority, choose accordingly. A 100 g portion at lunch and dinner from calcium-set tofu delivers 700 mg of calcium alone, which clears the UK SACN target by itself.

Cooking method does not meaningfully affect tofu calcium content. Pressing, baking, frying, and freezing all leave the calcium intact.

The vitamin K2 question, briefly

Vitamin K2 (menaquinone) activates osteocalcin, the protein that incorporates calcium into bone. K2 comes primarily from fermented foods (natto is the densest source, supplying about 1,000 mcg per 100 g) and from some animal products. Vegans on a low-natto diet may run low on K2, and there is published if not yet conclusive evidence (the Geleijnse 2004 Rotterdam Study and the Knapen et al. 2013 trials) that K2 supports bone mineral density and reduces fracture risk.

The Academy of Nutrition and Dietetics 2016 position paper does not yet make a K2 supplementation recommendation for vegans because the evidence base is still developing. The pragmatic position: if you eat sauerkraut, kimchi, miso, tempeh, or natto regularly, you are probably fine. If you do not, a K2 (MK-7) supplement at 90 to 180 mcg per day is low-risk insurance, particularly if your fracture-risk profile is otherwise elevated. Vitamin K1 (phylloquinone, from leafy greens) is also necessary but plays a different role; both forms matter, and most vegan diets are rich in K1.

Salt, caffeine, and the calcium-loss myths

High sodium intake increases urinary calcium loss; this is well established. The effect size in published balance studies is around 60 mg additional calcium lost per gram of sodium ingested above maintenance. A typical Western diet with 8 g of salt is therefore losing several hundred mg more calcium than a 6 g salt diet would. The largest single win for bone calcium retention on a plant-based diet (or any diet) is to keep added salt moderate. SACN recommends adults consume no more than 6 g of salt per day.

Caffeine's effect on calcium loss is real but small (about 4 mg additional calcium loss per 100 mg caffeine). At normal coffee intakes (2 to 3 cups per day, around 200 to 300 mg caffeine) this is not clinically meaningful as long as overall calcium intake is adequate.

The "high protein leaches calcium" claim is largely outdated. Older balance studies suggested high-protein diets increased urinary calcium loss, but subsequent isotope studies (Kerstetter and Insogna et al.) showed the loss was offset by increased intestinal calcium absorption driven by the protein-stimulated rise in IGF-1. Net calcium retention on adequate-protein diets is similar to or better than on low-protein diets. This is reassuring for vegan athletes and older vegans both groups need adequate protein for muscle and bone.

If you are post-menopausal. Bone loss accelerates after menopause regardless of diet, with about 1 to 2% loss per year for the first 5 years. Post-menopausal vegans should aim at the upper end of the calcium RDA (1,200 mg), confirm vitamin D status, ensure adequate protein (around 1.0 to 1.2 g per kg per day), and consider DEXA scanning around age 55 to 60. Weight-bearing exercise is the single most effective non-dietary intervention for bone density. See vegan and vegetarian older adults.

Related nutrient and outcome pages

Keep reading

Frequently asked questions about calcium

Do vegans break more bones than vegetarians or meat-eaters?

The EPIC-Oxford prospective study published by Appleby and colleagues in the European Journal of Clinical Nutrition in 2007 followed 34,696 people for around 5 years and found that vegans had a 30% higher rate of total fracture compared to meat-eaters and vegetarians, who had similar rates to each other. Critically, when the analysis was restricted to vegans consuming at least 525 mg of calcium per day, the excess risk disappeared. The follow-up EPIC-Oxford analysis by Tong and colleagues published in BMC Medicine in 2020 confirmed and refined the finding: vegans had a higher rate of hip fractures (around 2.3x the rate in meat-eaters), driven primarily by lower BMI and lower calcium intake, both modifiable.

How much calcium do vegans and vegetarians need?

The UK SACN reference nutrient intake is 700 mg per day for adults; the US Institute of Medicine RDA is 1,000 mg per day for adults 19 to 50 and 1,200 mg for women over 50 and men over 70. The numbers do not differ by diet, but the EPIC-Oxford fracture data suggest that vegans in particular should comfortably exceed 525 mg per day and ideally hit the full 700 to 1,000 mg target. The Academy of Nutrition and Dietetics position paper repeats the standard RDA for vegans and vegetarians and notes that fortified plant milks make this achievable without difficulty for those who include them daily.

Is the calcium in plant milks the same as in cow milk?

Most fortified plant milks (soy, oat, almond) use calcium carbonate or calcium phosphate added at 120 mg per 100 ml, equivalent to standard cow milk. Bioavailability is similar; the published comparison studies (Heaney 2005 on calcium-fortified soy milk and Zhao 2005 on calcium absorption from various foods) show fortified soy milk calcium is absorbed at around 75% to 90% of the efficiency of cow milk calcium. Almond and oat milks fortify to the same level but typically deliver less protein, so the total package is not identical even though the calcium contribution is. Shake the carton before pouring; calcium settles.

What plant foods are highest in calcium?

By bioavailable calcium per serving: calcium-set tofu (around 350 mg per 100 g if made with calcium sulfate), fortified plant milks (300 mg per 250 ml glass), almonds (75 mg per 30 g), kale and collard greens (90 to 140 mg per cup cooked, low-oxalate so well absorbed), bok choy (75 mg per cup, well absorbed), sesame seeds and tahini (88 mg per tablespoon), figs (60 mg per 50 g dried), and fortified orange juice in the US. Spinach contains a lot of calcium on paper (about 250 mg per cup cooked) but its high oxalate locks most of it up; absorption is around 5% versus 50% for kale.

Does dairy actually prevent fractures?

The evidence is mixed and depends on the population. The Bischoff-Ferrari 2011 meta-analysis in the Journal of Bone and Mineral Research found that higher dairy intake was not associated with reduced hip fracture risk in adults. The 2014 Michaelsson study in the BMJ found higher milk intake associated with higher fracture risk in Swedish women, possibly due to oxidative stress from D-galactose. The countervailing evidence from short-term bone mineral density trials shows calcium plus vitamin D does increase bone mineral density. The reasonable conclusion is that calcium and vitamin D matter, that dairy is one effective vehicle for both, and that fortified plant milks are an equally effective vehicle, with the choice driven by other dietary considerations.

Do I need a calcium supplement on a vegan diet?

Not if you reliably eat calcium-set tofu, drink fortified plant milks daily, and include leafy greens. A vegan with a glass of fortified soy milk on cereal (300 mg), a tofu lunch (175 mg from 50 g calcium-set tofu), kale or bok choy at dinner (90 mg), and a tahini-based dressing (88 mg per tbsp) clears 650 mg before snacks. If your eating pattern misses one of those reliably, a 500 mg calcium carbonate supplement is cheap insurance. Avoid taking calcium supplements with iron supplements (calcium inhibits non-heme iron absorption) and avoid doses above 600 mg in a single intake (above which absorption efficiency drops sharply).

Sources cited. Appleby P et al. Comparative fracture risk in vegetarians and nonvegetarians in EPIC-Oxford, Eur J Clin Nutr 2007; 61: 1400-1406; Tong TYN et al. Vegetarian and vegan diets and risks of total and site-specific fractures: results from the prospective EPIC-Oxford study, BMC Med 2020; 18: 353; NIH ODS Calcium fact sheet; BDA Calcium food fact sheet; Weaver CM, Plawecki KL. Dietary calcium: adequacy of a vegetarian diet, Am J Clin Nutr 1994; 59: 1238S-1241S; Heaney RP. Calcium intake and disease prevention, Arq Bras Endocrinol Metab 2006; 50: 685-693; Knapen MH et al. Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women, Osteoporos Int 2013; 24: 2499-2507. All values as of May 2026.