Illustration of a bowl of kale with seared tofu cubes and sesame seeds, a glass of oat milk, a dish of sesame seeds and dried figs.

Do vegans get enough calcium? Often not without fortified food, and spinach barely counts

Gregory Knox
November 3, 2026
8 mins

A vegan diet can supply enough calcium, but NIH says people who avoid dairy, vegans included, typically need calcium-fortified foods or supplements to reach the recommended amounts. For most adults that’s 1,000 mg a day. Calcium-set tofu and fortified plant milk do most of the work, low-oxalate greens such as kale help, and spinach mostly doesn’t.

A cup of cooked spinach carries about 245 mg of calcium by USDA’s figures, and a cup of cooked kale about 177 mg (our arithmetic). On paper the spinach wins. Then absorption gets a vote. In a 1988 trial in 13 adults, people absorbed 5.1% of the calcium in spinach, against 27.6% from milk; the authors found slightly more oxalate than calcium in their test spinach and judged it likely that all of its calcium was bound. In a 1990 trial two of the same researchers found 40.9% absorbed from kale, more than the 32.1% from milk in the same women. Apply those rates to the cups and the spinach delivers about 12 mg, the kale about 72 mg, roughly six times as much (our arithmetic, using fractions measured on single test meals, at different doses, in separate trials). If your calcium plan is a big bowl of spinach, it’s mostly a bowl of spinach. The bone side of the story, including the fracture numbers, is in our piece on whether vegans are healthier than meat eaters.

How much calcium do you need?

The RDAs come from the National Academies’ Food and Nutrition Board, NIH lists them, and there’s no separate figure for vegans:

Group	RDA per day
Teens 14 to 18	1,300 mg
Adults 19 to 50	1,000 mg
Men 51 to 70	1,000 mg
Women 51 to 70	1,200 mg
Everyone over 70	1,200 mg

There’s a ceiling too. The tolerable upper intake level NIH lists for adults runs from 2,000 to 2,500 mg a day, depending on age. In our reading, that matters mostly to people stacking a supplement on top of fortified everything.

Whether falling short shows up in bones is the real question, and one of the largest studies to compare diet groups directly is EPIC-Oxford, a British cohort. Its 2007 fracture paper followed 7,947 men and 26,749 women, 1,126 of them vegans, for an average of 5.2 years, with fractures self-reported. The vegans had a 30% higher rate of fractures than meat eaters after adjustment for sex, age and non-dietary factors (incidence rate ratio 1.30, 95% interval 1.02 to 1.66), and 1.15 (0.89 to 1.49) once calcium and energy intake were also taken into account. Among people who ate at least 525 mg of calcium a day, the vegans’ fracture rate did not differ from the meat eaters’ (incidence rate ratio 1.00, with a wide 0.69 to 1.44 interval). The authors’ reading: the vegans’ higher risk “appeared to be a consequence of their considerably lower mean calcium intake”. That’s an observational study, so it shows an association, not a dose that protects you. The authors’ own takeaway was that an adequate calcium intake is essential for bone health, irrespective of dietary preferences.

Which plant foods actually deliver it

NIH’s summary of the absorption research is short. Oxalic and phytic acid in plants can reduce calcium absorption; foods high in oxalate include collard greens, sweet potatoes, rhubarb and beans. Broccoli, kale and cabbage, which lack those compounds, give up their calcium about as well as milk does, though there’s much less of it per serving. That lower amount is the catch. A 1999 review by two of the same researchers concluded that the quantity of vegetables needed makes an exclusively plant-based approach impractical for most people unless fortified foods or supplements are included.

Here’s what a serving holds, by USDA’s figures and, for Silk, its label (our arithmetic for the serving sizes):

Food	Serving	Calcium
Firm tofu made with calcium sulfate	½ cup, 126 g	about 861 mg
Silk Original Soymilk	1 cup	470 mg
Spinach, cooked	1 cup, 180 g	about 245 mg, poorly absorbed
Kale, cooked	1 cup, 118 g	about 177 mg
Bok choy, raw, shredded	1 cup, 70 g	about 74 mg
Almonds	1 oz, 28.35 g	about 76 mg
Tahini, roasted kernels	1 tbsp, 15 g	about 64 mg

Check the coagulant printed on the tofu package: our guide to nigari and gypsum in tofu sets USDA’s calcium figures by coagulant next to the brands that use each. The almonds and tahini are fine foods and poor calcium plans. You would need about 370 g of almonds a day, around 13 oz, to reach 1,000 mg (our arithmetic), and at that point calcium is not your biggest dietary problem.

Fortified plant milk: read the calcium on the carton

Not all fortified calcium behaves the same. In a 2000 trial in 16 men, calcium from a fortified soy milk was absorbed at only 75% the efficiency of calcium from cow’s milk. A 2005 trial in 20 young women then compared two soymilks: absorption from the one fortified with calcium carbonate did not differ from cow’s milk (fractional absorption 0.211 against 0.217), while the one fortified with tricalcium phosphate came in lower, at 0.181. Both were small, single-meal studies of the fortificant, not necessarily of a product sold today.

What you can do with that is read the vitamin and mineral blend. Silk Original Soymilk, for example, lists calcium phosphate and calcium carbonate, and its panel gives 470 mg of calcium per cup, 35% of the Daily Value. Neither trial tested that mix, so the panel tells you what is in the cup, not how much of it you absorb. The same blend lists vitamin D2, which matters for the next section.

Supplements, if food doesn’t get you there

NIH’s practical points are the ones worth keeping. Calcium carbonate is 40% calcium by weight and calcium citrate 21%. Citrate depends less on stomach acid than carbonate, so it can be taken without food, and NIH says supplements in general are absorbed better with food. Absorption from supplements is highest at doses of 500 mg or less, which in our reading argues for splitting a larger dose. Vitamin D is required for calcium to be absorbed in the gut by active transport, and NIH notes that low vitamin D status further reduces how much dietary calcium you absorb.

A calcium tablet that adds vitamin D can stop being vegan right there. NIH says vitamin D3 is typically made from lanolin from sheep’s wool, while D2 comes from yeast and an animal-free D3 from lichen also exists. Our page on whether vitamin D3 is vegan shows how to tell them apart on a label. How much to take, and whether you need a supplement at all, is a question for your doctor or a registered dietitian, ideally with a look at what you already eat.

Where the evidence stops

The 2007 EPIC-Oxford result is the hopeful one: at 525 mg a day or more, the vegans’ fracture rate did not differ from the meat eaters’, with that wide interval. The same cohort’s 2020 analysis, built on hospital records over a longer follow-up, is less tidy. Vegans had a hip fracture risk 2.31 times that of meat eaters (95% interval 1.66 to 3.22) after adjusting for socio-economic factors, lifestyle and body mass index; the authors describe the associations as slightly attenuated but still significant when they also adjusted for calcium and protein intake, and the vegan hip figure fell to 1.94 with both. They note the 2007 analysis had under 2,000 self-reported fractures and may have lacked the power to detect a difference once it was split by calcium intake. Their conclusion was that the findings suggest bone health in vegans requires further research.

So calcium is the part we can fix and measure, and it may not be the whole story. That’s the piece of this I’m least sure about: whether a vegan who hits 1,000 mg a day from tofu and fortified milk is as protected as the 2007 paper suggests, or still carries some of the 2020 risk for reasons that paper doesn’t settle. If the food side looks thin for you, our guide to being vegan without supplements puts calcium in the food-first group, alongside iron and zinc.

Sources

Gregory Knox

Gregory has been vegan since 2012 and came to it as a sceptic. He believed a balanced diet needed meat and dairy, so he read the studies and the books until he was sure it didn't. He still reads them, and turns what he finds into plain answers on food, ingredients, supplements and health questions. He also runs the technical side of Vegan Pots. Not a doctor, just very thorough.