Skip to content
ZenBodyLove

Calcium

Adults following a vegan diet eat substantially less calcium than other diet groups and, in large observational studies, have lower bone mineral density and higher fracture rates, especially hip fractures. In adults over 50, raising calcium intake from food or supplements produces small, non-progressive gains in bone mineral density; dietary calcium intake is not associated with fracture risk, and trial evidence on fractures is mixed, with combined calcium and vitamin D looking more promising than vitamin D alone. Large trials and meta-analyses link calcium supplements with more kidney stones and possibly more heart attacks.

  • Longevity
  • Strength
  • Vegan

Evidence retrieved up to

What the research shows

In older adults, daily calcium combined with vitamin D, as part of a healthy lifestyle, may help reduce the risk of fractures by a small amount, while trials of vitamin D alone found no reduction; trial results are inconsistent and the trials at lowest risk of bias found no effect.

Low certaintyFurther research is likely to change this.
Take care: see the safety noteUnclear

Who this is about

older adults

Practical note

Graded low: randomised evidence, downgraded for inconsistency (a 2019 pooled analysis of 6 trials found a 6 percent lower risk of any fracture and 16 percent lower hip fracture risk, but the WHI trial and the 2015 lowest-risk-of-bias trials found no significant effect) and for likely publication bias. Combined trials used calcium at 1000-1200 mg a day with vitamin D at 400-800 IU a day.

Safety note

See the claim on kidney stones and heart attack for the risks reported with calcium supplements.

Sources

In adults over 50, higher dietary calcium intake, including from milk and dairy, is not associated with a lower risk of fracture, and there is no trial evidence that raising calcium intake from food lowers fracture risk.

Low certaintyFurther research is likely to change this.
No known concerns at usual amountsNo clear effect

Who this is about

adults over 50

Practical note

Graded low: based on 44 cohort studies in a 2015 systematic review, with only two small randomised trials (262 participants) of dietary calcium sources.

Vegan note

This finding concerns the general population; it does not address the very low intakes reported in some vegan groups.

Sources

In adults over 50, increasing calcium intake from food or from supplements produces small, non-progressive increases in bone mineral density, which on their own are unlikely to make a clinically significant difference to fracture risk.

Moderate certaintyFurther research may change the size of the effect.
No known concerns at usual amountsBenefit

Who this is about

adults over 50

Practical note

Graded moderate: a 2015 meta-analysis of 59 randomised trials found consistent gains of about 0.6-1.8 percent across skeletal sites, similar for food and supplement sources; downgraded one level because many trials were small and at risk of bias, and bone density is a surrogate for fracture. The large WHI trial found hip bone density 1.06 percent higher with calcium plus vitamin D.

Sources

In randomised trials, calcium supplements were linked with a higher rate of kidney stones when taken with vitamin D and, in a meta-analysis of trials without vitamin D, with a modestly higher rate of heart attack.

Low certaintyFurther research is likely to change this.
Take care: see the safety noteRisk

Who this is about

adults over 40 taking calcium supplements

Practical note

Graded low: the kidney stone signal comes from one large trial (WHI, 36,282 women, hazard ratio 1.17, 1.02-1.34) and the heart attack signal from a 2010 meta-analysis of 15 trials (hazard ratio 1.31, 1.02-1.67) in which cardiovascular events were not a primary outcome; downgraded for imprecision and indirectness. Trials in the meta-analysis used at least 500 mg a day of supplemental calcium.

Safety note

Kidney stones increased in a large trial of postmenopausal women taking calcium with vitamin D; a meta-analysis linked calcium supplements without vitamin D to more heart attacks. Decisions about supplements belong with a health professional.

Sources

Adults following a vegan diet eat substantially less calcium than other diet groups and, in observational studies, have lower bone mineral density and higher fracture rates than meat eaters, particularly for hip fractures; lower calcium intake appears to explain only part of the difference.

Low certaintyFurther research is likely to change this.
No known concerns at usual amountsRisk

Who this is about

adults following a vegan diet

Practical note

Graded low: observational evidence (a 2019 meta-analysis of 20 studies and the EPIC-Oxford cohort followed for an average of 17.6 years) with consistent direction; not upgraded because confounding by lower BMI and protein intake is likely. In EPIC-Oxford, vegans reported a mean dietary calcium intake of 591 mg a day against about 1000 mg a day in the other diet groups, and the hip fracture hazard ratio for vegans was 2.31 (1.66-3.22).

Vegan note

Dairy is a major calcium source in Western diets, so vegan diets rely on other calcium-rich and calcium-fortified foods; the EPIC-Oxford authors note that bone health in vegans requires further research.

Sources