Table 2.

Effect of calcium intake on health outcomes

Health outcomes	Outcome	Population group	Research evidence	Effect size
Hypertensive disorders of pregnancy	Preeclampsia	Pregnant women	Meta‐analysis	Calcium supplementation compared to placebo reduced the risk of preeclampsia, RR = 0.45 (95% CI: 0.31–0.65) 101
		Pregnant women with low basal calcium intake	Meta‐analysis	Calcium supplementation compared to placebo reduced the risk of preeclampsia, RR = 0.36 (95% CI: 0.20–0.65) 101
	High blood pressure	Pregnant women	Meta‐analysis	Calcium supplementation compared to placebo reduced the high blood pressure RR to 0.65 (95% CI: 0.530.81) 101
Blood pressure	Blood pressure	Normotensive adults	Meta‐analysis	Calcium supplementation reduced SBP in adults by 1.14 mmHg (95% CI: −2.01 to −0.27) with doses of calcium 1000–1500 mg/day and by 2.79 mmHg (95% CI: −4.71 to −0.86) with doses of calcium equal to or over 1500 mg/day. Calcium supplementation had the greatest effect in young adults of less than 35 years as their SBP was reduced by 2.11 mmHg (95% CI: −3.58 to −0.64) 102
	Blood pressure	Hypertensive adults		Calcium supplementation reduced SBP by −1.86 mmHg (95% CI: −2.91 to −0.81) and DBP by −0.99 mmHg (95% CI: −1.61 to −0.37) 37
	Blood pressure	Hypertensive adults with low basal calcium intake		In people with relatively low calcium intake (≤800 mg/day) calcium supplementation reduced SBP by −2.63 (95% CI: −4.03 to −1.24) and DBP by −1.30 (95% CI: −2.13 to −0.47) 37
	Blood pressure	Hypertensive adults		Calcium supplementation as compared to control induced a statistically significant reduction in SBP (mean difference: −2.5 mmHg, 95% CI: −4.5 to −0.6, I(2)= 42%) but not DBP (mean difference: −0.8 mmHg, 95% CI: −2.1 to 0.4, I(2) = 48%) 103
Progeny blood pressure	High blood pressure	Pregnant women/children	RCT	Calcium supplementation showed that children whose mothers received calcium supplementation had, at 7 years of age, a reduction in the risk of high blood pressure (above the 90th percentile) in comparison with children whose mothers were in the placebo group (RR = 0.59; 95% CI: 0.39–0.90) 36
Cholesterol	LDL and HDL cholesterol	Adults	Meta‐analysis	Calcium supplementation reduced low‐density lipoprotein (LDL) cholesterol (−0.12 mmol/L (95% CI: −0.22 to −0.02)) and increased high‐density lipoprotein (HDL) cholesterol (0.05 mmol/L (95% CI: 0.00–0.10)) 104
Colorectal adenomas	Recurrent colorectal adenomas	Adults with previous adenomas	Meta‐analysis	Calcium supplementation with doses from 1200 to 2000 mg/day and treatment duration from 36 to 60 months reduced the risk of recurrent colorectal adenomas, RR = 0.89 (95%CI: 0.82−0.96) 105
Bone health	Bone mineral density	Children	Meta‐analysis	Calcium supplementation had a small effect on total body bone mineral content (standardized mean difference = 0.14, 95% CI: 0.01–0.27) and upper limb bone mineral density (0.14, 95% CI: 0.04–0.24), and this effect persisted after the end of supplementation only in the upper limb (0.14, 95% CI: 0.01–0.28) 106
Renal stones	Urolithiasis	Individuals with osteoporosis	Meta‐analysis	Calcium supplementation compared to placebo, RR = 0.66 [95% CI 0.19, 2.34]; five studies in postmenopausal or elderly women, including 2038 subjects 107
	Urolithiasis	Pregnant women	Meta‐analysis	Calcium supplementation during pregnancy did not increase the risk of urolithiasis, RR = 1.52 [95% CI: 0.06, 40.67] or renal colic, RR = 1.75 [95% CI; 0.51, 5.99] in two studies with 12,901 women 108

Note: Evidence from randomized controlled trials (RCTs) and systematic reviews of RCTs. Table taken from Ref. 1, with permission of the authors.

CI, confidence interval; DBP, diastolic blood pressure; RR, relative risk; SBP, systolic blood pressure.