Calcium

Calcium is the most abundant mineral in the human body. About 99% of it is stored in the bones and teeth, where it provides structure. The rest is used for muscle contraction, nerve signalling, blood clotting and hormone release. Because dairy products supply much of the calcium in many Western diets, calcium is an important consideration for people following a vegan diet.

Recommended intakes

Reference values differ between countries:

Needs are higher during adolescence, when bone mass is being built rapidly.

Calcium and vegan bone health

Studies have found that vegans, on average, have lower calcium intakes than people who eat dairy. Research from the EPIC-Oxford cohort reported that vegans had a higher risk of bone fractures than meat eaters. An earlier analysis from the same study found that the higher fracture risk among vegans was not seen in those consuming at least around 525 mg of calcium a day, suggesting that adequate calcium intake is an important factor. A later EPIC-Oxford analysis, published in 2020, also found higher fracture risk in vegans; researchers noted that lower body mass index and lower calcium and protein intakes may partly explain this. See vegan diet and health for more on these findings.

These results do not indicate that dairy is necessary, but they do suggest that vegans should take care to eat enough calcium-rich foods every day.

Vegan sources

Good plant-based sources of calcium include:

• Calcium-set tofu – tofu made with calcium sulfate or calcium chloride as a coagulant can be one of the richest plant sources. The ingredients list shows which coagulant was used (see tofu).
• Fortified plant milks and yoghurts – many brands add calcium at levels similar to cow’s milk, typically around 120 mg per 100 ml. Organic products in some countries are not fortified, so labels should be checked (see plant-based milks).
• Low-oxalate green vegetables – kale, bok choy (pak choi), spring greens, collard greens, broccoli and watercress.
• Nuts and seeds – almonds, sesame seeds and tahini, chia seeds.
• Legumes – white beans, chickpeas and soya beans.
• Dried figs.
• Fortified foods – some breakfast cereals, and in the UK, white and brown flour, which are fortified with calcium by law.
• Calcium-rich mineral water, depending on the source.

Absorption

How much calcium the body absorbs from a food depends on more than its calcium content.

• Oxalates bind calcium and reduce its absorption. Spinach, chard and beet greens are high in calcium but also high in oxalates, so very little of their calcium is absorbed.
• Low-oxalate greens such as kale and bok choy have calcium that is absorbed at least as well as calcium from cow’s milk.
• Phytates in whole grains and legumes reduce absorption to a lesser extent; soaking, sprouting and fermentation reduce phytate levels.
• Vitamin D is required for efficient calcium absorption (see vitamin D).
• Absorption is more efficient when calcium is consumed in smaller amounts spread across the day.

Other factors in bone health

Bone health depends on many nutrients and lifestyle factors in addition to calcium, including:

1. adequate vitamin D;
2. sufficient protein;
3. vitamin K, found in leafy greens;
4. potassium and magnesium from fruit, vegetables and whole grains;
5. regular weight-bearing and resistance exercise;
6. not smoking and limiting alcohol.

Supplements

Supplements may be useful for people who cannot meet their needs through food. Calcium carbonate and calcium citrate are the most common forms; both are generally vegan, though some calcium supplements are derived from oyster shell or bone, and many are combined with vitamin D3 from lanolin (see hidden animal ingredients). Very high supplemental intakes may cause side effects, and the US tolerable upper intake level for adults aged 19–50 is 2,500 mg per day.

This article is for general information. Individuals should consult a doctor or registered dietitian for personal advice, particularly regarding bone health or supplements.

See also

• Vitamin D
• Meal planning
• Plant-Based Milks