Ask the Expert: Calcium

The Physicians Committee

Ask the Expert: Calcium

Q: How much calcium is absorbed from plant foods?

A: Here is a table that gives the absorption percentages for calcium-rich plant foods. For comparison, 32% of the calcium from dairy products is absorbed. Calcium-rich plant foods also contain many cancer-fighting nutrients that are not present in dairy foods.

Food Sources

Calcium Absorption % Rate

Beans, white

17.0 %


52.6 %

Brussels sprouts

63.8 %


58.8 %

Mustard greens

57.8 %

Orange juice, calcium-fortified

37.0 %

Soymilk, calcium-fortified

24.0 %

Tofu, calcium-set

31.0 %

Turnip greens

51.6 %

Q: How much calcium do you recommend per day?

A: Calcium requirements depend on the person and situation. For those eating a plant-based diet, we base our recommendations on the World Health Organization data that advises adults to consume 500 mg of calcium a day along with plenty of exercise and about 15 minutes sunlight exposure. It is important to note, that epidemiologic studies have linked high calcium from dairy sources to an increased prostate cancer risk by lowering vitamin D concentrations in the body.  The Cancer Project experts recommend avoiding calcium depleters--smoking, animal protein, excess sodium, and excess caffeine—if you are concerned with bone health. Good calcium sources include beans, figs, sweet potatoes, and especially dark green leafy vegetables like collard greens, kale, broccoli, mustard greens, and Swiss chard. Fortified soymilk and rice milk and calcium-fortified juices provide a great deal of calcium as well. In addition, eating lots of fruits and vegetables, excluding animal proteins, and limiting salt intake all help the body retain calcium.

For more information, see our fact sheet Milk Consumption and Prostate Cancer.

Qin LQ, Xu JY, Wang PY, Kaneko T, Hoshi K, Sato A. Milk consumption is a risk factor for prostate cancer: meta-analysis of case-control studies. Nutr Cancer. 2004;48(1):22-27.

Gao X, LaValley MP, Tucker KL. Prospective studies of dairy product and calcium intakes and prostate cancer risk: a meta-analysis. J Natl Cancer Inst. 2005;97(23):1768-1777.

Chan JM, Stampfer MJ, MA J, et Al. Dairy products,calcium,and prostate cancer risk in the Physicians’ Health Study. Am J Clin Nutr. 2001;74(4):549-554.

Giovannucci E, Rimm EB, Wolk A, et al. Calcium and fructose intake in relation to risk of prostate cancer. Cancer Res. 1998;58:442-447.

Cohen P. Serum insulin-like growth factor-I levels and prostate cancer risk—interpreting the evidence. J Natl Cancer Inst. 1998;90:876-879.