Calcium
What is it? Overview Usage Side Effects and Warnings
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Calcium Side Effects and Warnings

Written by FoundHealth, ColleenO.

Safety Issues

In general, it's safe to take up to 2,500 mg of calcium daily, although this is more than you need. 1 Greatly excessive intake of calcium can cause numerous side effects, including dangerous or painful deposits of calcium within the body.

Note:If you have cancer, hyperparathyroidism, or sarcoidosis, you should take calcium only under a physician's supervision.

Some evidence hints that use of calcium supplements might slightly increase kidney stone risk. 2 However, increased intake of calcium from fooddoes not seem to have this effect and could even help prevent stones. 3 One study found that if calcium supplements are taken with food, there is no increased risk. 4 Calcium citrate supplements may be particularly safe regarding kidney stones because the citrate portion of this supplement is used to treatkidney stones. 5 There is preliminary evidence that calcium supplementation in healthy, post-menopausal women may slightly increase the risk of cardiovascular events, such as myocardial infarction. However, it remains far from clear whether this possible risk outweighs the benefits of calcium supplementation in this population. 6 Large observational studies have found that, in men, higher intakes of calcium are associated with an increased risk of prostate cancer. 7 This seems to be the case whether the calcium comes from milk or from calcium supplements.

Calcium supplements combined with high doses of vitamin D might interfere with some of the effects of drugs in the calcium channel blocker family. 8 It is very important that you consult your physician before trying this combination.

Concerns have been raised that the aluminum in some antacids may not be good for you. 9 There is some evidence that calcium citrate supplements might increase the absorption of aluminum; 10 11 12 13 for this reason, it might not be a good idea to take calcium citrate at the same time of day as aluminum-containing antacids. Another option is to use different forms of calcium, or to avoid antacids containing aluminum.

When taken over the long term, thiazide diuretics tend to increase levels of calcium in the body by decreasing the amount excreted by the body. 14 15 16 It's not likely that this will cause a problem. Nonetheless, if you are using thiazide diuretics, you should consult with your physician on the proper doses of calcium and vitamin D for you.

Finally, calcium may interfere with the absorption of antibiotics in the tetracycline and fluoroquinolone families as well as thyroid hormone. 17 18 19 20 21 22 If you are taking any of these drugs, you should take your calcium supplements at least 2 hours before or after your medication dose.

Interactions You Should Know About

  • You may need more calcium if you are taking:
    • Corticosteroids
    • Heparin
    • Isoniazid
  • If you are taking aluminum hydroxide , you should take calcium citrate at least 2 hours apart to avoid increasing aluminum absorption.
  • You may need more calcium if you are taking the following anticonvulsants:
    • Phenytoin (Dilantin)
    • Carbamazepine
    • Phenobarbital
    • Primidone
    • Note:It may be advisable to take your dose of anticonvulsant and your calcium supplement at least 2 hours apart because each interferes with the other's absorption.
  • If you are taking the following medications, you should take your calcium supplement at least 2 hours before or after your dose of medication because calcium interferes with the absorption (and vice versa):
    • Antibiotics in the tetracycline or fluoroquinolone (Cipro, Floxin, Noroxin) families
    • Thyroid hormone
  • Do not take extra calcium except on the advice of a physician if you are taking Thiazide diuretics.
  • Do not take calcium together with high-dose vitamin D except on the advice of a physician if you are taking calcium channel blockers .
  • You may need extra calcium if you are taking:
    • Iron
    • Manganese
    • Zinc
    • Chromium
    • Ideally, you should take calcium at a different time of day from these other minerals because it may interfere with their absorption.
  • It may be advisable to wait 2 hours after taking calcium supplements to eat soy (or vice versa). A constituent of soy called phytic acid can interfere with the absorption of calcium.
  • Taking supplemental calcium may be helpful if you are taking metformin.

References

  1. . Optimal calcium intake. Sponsored by National Institutes of Health Continuing Medical Education. Nutrition. 11(5):409-17.
  2. Curhan GC, Willett WC, Speizer FE, Spiegelman D, Stampfer MJ. Comparison of dietary calcium with supplemental calcium and other nutrients as factors affecting the risk for kidney stones in women. Ann Intern Med. 126(7):497-504.
  3. Curhan GC, Willett WC, Speizer FE, Spiegelman D, Stampfer MJ. Comparison of dietary calcium with supplemental calcium and other nutrients as factors affecting the risk for kidney stones in women. Ann Intern Med. 126(7):497-504.
  4. Domrongkitchaiporn S, Sopassathit W, Stitchantrakul W, Prapaipanich S, Ingsathit A, Rajatanavin R. Schedule of taking calcium supplement and the risk of nephrolithiasis. Kidney Int. 65(5):1835-41.
  5. Sakhaee K, Poindexter JR, Griffith CS, Pak CY. Stone forming risk of calcium citrate supplementation in healthy postmenopausal women. J Urol. 172(3):958-61.
  6. Bolland MJ, Barber PA, Doughty RN, Mason B, Horne A, Ames R, Gamble GD, Grey A, Reid IR. Vascular events in healthy older women receiving calcium supplementation: randomised controlled trial. BMJ. 336(7638):262-6.
  7. Giovannucci E, Rimm EB, Wolk A, Ascherio A, Stampfer MJ, Colditz GA, Willett WC. Calcium and fructose intake in relation to risk of prostate cancer. Cancer Res. 58(3):442-7.
  8. Bar-Or D, Gasiel Y. Calcium and calciferol antagonise effect of verapamil in atrial fibrillation. Br Med J (Clin Res Ed). 282(6276):1585-6.
  9. Gaby AR. Aluminum: the ubiquitous poison. Nutr Healing. 1997;4:3-4,11.
  10. Walker JA, Sherman RA, Cody RP. The effect of oral bases on enteral aluminum absorption. Arch Intern Med. 150(10):2037-9.
  11. Preliminary findings suggest calcium citrate supplements may raise aluminum levels in blood, urine. Fam Pract News. 1992;22:74-75.
  12. Weberg R, Berstad A. Gastrointestinal absorption of aluminium from single doses of aluminium containing antacids in man. Eur J Clin Invest. 16(5):428-32.
  13. Nolan CR, Califano JR, Butzin CA. Influence of calcium acetate or calcium citrate on intestinal aluminum absorption. Kidney Int. 1990;38:937-941.
  14. Riis B, Christiansen C. Actions of thiazide on vitamin D metabolism: a controlled therapeutic trial in normal women early in the postmenopause. Metabolism. 34(5):421-4.
  15. Lemann J Jr, Gray RW, Maierhofer WJ, Cheung HS. Hydrochlorothiazide inhibits bone resorption in men despite experimentally elevated serum 1,25-dihydroxyvitamin D concentrations. Kidney Int. 28(6):951-8.
  16. Crowe M, Wollner L, Griffiths RA. Hypercalcaemia following vitamin D and thiazide therapy in the elderly. Practitioner. 228(1389):312-3.
  17. Neuvonen PJ, Kivistö KT, Lehto P. Interference of dairy products with the absorption of ciprofloxacin. Clin Pharmacol Ther. 50(5 Pt 1):498-502.
  18. Minami R, Inotsume N, Nakano M, Sudo Y, Higashi A, Matsuda I. Effect of milk on absorption of norfloxacin in healthy volunteers. J Clin Pharmacol. 33(12):1238-40.
  19. Lehto P, Kivistö KT. Different effects of products containing metal ions on the absorption of lomefloxacin. Clin Pharmacol Ther. 56(5):477-82.
  20. Dudley MN, Marchbanks CR, Flor SC, Beals B. The effect of food or milk on the absorption kinetics of ofloxacin. Eur J Clin Pharmacol. 41(6):569-71.
  21. Flor S, Guay DR, Opsahl JA, Tack K, Matzke GR. Effects of magnesium-aluminum hydroxide and calcium carbonate antacids on bioavailability of ofloxacin. Antimicrob Agents Chemother. 34(12):2436-8.
  22. Butner LE, Fulco PP, Feldman G. Calcium carbonate-induced hypothyroidism [letter]. Ann Intern Med. 2000;132:595.
 
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