Calcium from Supplements vs. Food: Different Health Impacts
Several studies and medical reviews indicate that calcium has different health impacts based on its source, with supplements potentially posing risks that aren't associated with dietary calcium. Research shows that while calcium remains essential for bone health and other bodily functions, how we consume it matters significantly.
Cardiovascular Risk: A Key Difference Between Sources
The most notable difference between calcium from supplements versus food sources appears in cardiovascular health outcomes. Multiple studies have found a potential link between calcium supplements and increased cardiovascular risk that isn't observed with dietary calcium.
The Mayo Clinic explicitly states that "There is some evidence that calcium supplements can increase the risk of heart attack," while emphasizing that "calcium from food sources isn't a concern" 7. This distinction is supported by research from Johns Hopkins Medicine, which notes that calcium supplements may lead to major health problems, including cardiovascular concerns 13.
A direct relationship between total calcium intake and cardiovascular disease (CVD) remains controversial, but recent evidence from randomized controlled trials has raised concerns about calcium supplement use and increased risk for CVD events 10. One study published in the British Medical Journal found that taking calcium supplements might be harmful because the extra calcium doesn't strengthen bones but instead can build up in the arteries, potentially causing heart disease 14.
Explaining the Paradox
Why would calcium from supplements affect the body differently than calcium from food? Researchers suggest a possible explanation:
"One explanation for this apparent paradox may be that large boluses of calcium intake through supplements may transiently elevate serum calcium concentrations, which, in turn, may lead to vascular calcification and other adverse health effects" 10.
Dr. Erin Michos from Johns Hopkins Medicine explains it simply: "A nutrient in pill form is not processed in the body the same way as it is when ingested from a food source" 13. Dietary calcium appears to be absorbed more gradually and efficiently when consumed with meals 1.
Kidney Stone Risk
While adequate dietary calcium actually helps prevent kidney stones in most people, calcium supplementation may increase the risk in susceptible individuals 3 13. This represents another area where the source of calcium makes a significant difference in health outcomes.
The Harvard Health article notes that calcium supplements can "potentially interfere with absorption of other important micronutrients, such as iron and magnesium" 3, creating additional concerns not typically seen with food sources of calcium.
Gastrointestinal Effects and Other Concerns
Calcium supplements are associated with side effects not typically reported with dietary calcium, including:
- Bloating
- Constipation
- Gastrointestinal discomfort 4
A study published in the journal Neurology also found that women who took calcium supplements were at a higher risk for developing dementia 4, though this finding requires further investigation.
Absorption and Effectiveness Differences
Research from the National Institutes of Health found that "Dietary calcium has been shown to have greater impact in bone building than supplemental calcium. This is likely due to improved absorption with meals and the tendency of people to intake smaller amounts more frequently, which is more ideal for the body's method of absorption" 1.
Current Recommendations
Most medical experts now recommend getting calcium primarily from food sources:
"The safest thing to do is to try to get their calcium through their diet. We think that the body processes calcium very differently when it comes from food sources versus supplements" 4.
Foods high in calcium include dairy products, leafy green vegetables, fish with edible bones, and calcium-fortified foods 6 9. The recommended daily allowance of calcium for most adults is 1,000 milligrams per day, with women over 51 and men over 71 needing 1,200 milligrams 4.
Conflicting Evidence
It's important to note that not all research supports the food versus supplement distinction. Some studies have found "no detrimental effect of calcium from diet or supplements, with or without vitamin D, on cardiovascular disease" 11. Additionally, a study examining different calcium salt forms found that "The bioavailability of the four different calcium salts was found to be almost identical" 2.
Conclusion
The weight of evidence suggests that calcium from supplements may indeed pose health risks that calcium from food sources does not. Most medical professionals now recommend obtaining calcium primarily through diet unless supplements are specifically prescribed for medical reasons. For those who cannot meet their calcium needs through diet alone, discussing appropriate supplementation with a healthcare provider is essential, as individual risks and benefits need to be carefully considered 5.
If you're concerned about your calcium intake, experts recommend focusing on calcium-rich foods first and using supplements only when dietary sources are insufficient and under medical guidance.
Citations:
- https://pubmed.ncbi.nlm.nih.gov/24200763/
- https://www.scirp.org/journal/paperinformation?paperid=3035
- https://www.health.harvard.edu/staying-healthy/is-taking-too-much-calcium-unhealthy
- https://abc7.com/calcium-supplements-research-study/13443273/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6276611/
- https://utswmed.org/medblog/calcium/
- https://www.mayoclinic.org/diseases-conditions/heart-attack/expert-answers/calcium-supplements/faq-20058352
- https://www.todaysdietitian.com/newarchives/070113p50.shtml
- https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/calcium-supplements/art-20047097
- https://pmc.ncbi.nlm.nih.gov/articles/PMC5121484/
- https://www.sciencedirect.com/science/article/pii/S2161831322010705
- https://now.tufts.edu/2019/04/09/nutrients-food-not-supplements-linked-lower-risks-death-cancer
- https://www.hopkinsmedicine.org/health/wellness-and-prevention/calcium-supplements-should-you-take-them
- https://www.nbcnews.com/better/diet-fitness/calcium-supplements-or-dairy-doesnt-strengthen-bones-study-finds-n435726
- https://www.bonehealthandosteoporosis.org/calcium-vitamin-d-supplement-facts/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10050718/
- https://www.nhs.uk/conditions/vitamins-and-minerals/calcium/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6276611/
- https://www.sciencedirect.com/science/article/abs/pii/S0378512215300840
- https://courses.lumenlearning.com/suny-nutrition/chapter/12-22-calcium-bioavailability/
- https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/calcium-intake-and-absorption
- https://www.hopkinsmedicine.org/health/wellness-and-prevention/calcium-supplements-should-you-take-them
- https://www.betterhealth.vic.gov.au/health/healthyliving/calcium
- https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/
- https://www.heart.org/en/news/2024/04/15/cracking-the-calcium-code-to-understand-its-role-in-health
- https://health.clevelandclinic.org/too-much-calcium-supplements
- https://www.nature.com/articles/s41598-019-55507-x
- https://www.mountsinai.org/health-library/nutrition/calcium-in-diet
- https://bastyr.edu/about/news/calcium-controversy-do-you-need-dairy-or-supplements-meet-your-daily-requirements
- https://www.ccjm.org/content/85/7/543
- https://www.sciencedirect.com/science/article/pii/S0002916522025163
- https://pubmed.ncbi.nlm.nih.gov/31625814/
- https://www.e-enm.org/journal/view.php?number=2371
- https://www.kqed.org/science/10438/controversy-over-calcium-tablets
- https://www.vita4you.gr/blog-vita4you/en/item/calcium-its-importance-food-absorption-and-side-effects.html
See also VitaminDWiki
- High Vitamin D is great, provided you take steps to avoid problems of high Calcium
- Less Calcification if less Calcium or more Vitamin K, Magnesium, etc. - many studies
- Calcium hazards and bioavailability
- Hypercalcemia and Vitamin D - many studies
- Calcium supplements are HARMFUL – a reversal of recommendations from 2000 – Nov 2015
- Plant-based Calcium probably better than rock-based
- 10,000 IU of Vitamin D for 7 years with no excessive Calcium in 4,800 patients – Dec 2018
- Drinking 3 glasses of milk daily associated with doubling the death rate – Oct 2014