Calcium Intake and Potential Risks of High Calcium Intake

calcium-rich

Have you ever wondered about how much calcium you need and whether it should be as food or supplements? How much is enough and are there are any risks in taking more than the recommended amount?

 

Most of us have heard that it is important to consume enough calcium to keep our bones healthy.  Yes, it’s true; however, as it is with everything it’s important not to overdo it.  As the common expression goes; “everything in excess can be harmful” and when we talk about calcium intake, there is no exception, especially in men.  There are numerous studies that show a relationship between high calcium intake and a higher risk of prostate cancer (more on that below).

What is Calcium and What is it Used for?

Calcium is the most plentiful mineral found in the human body; with teeth and bones containing the most calcium and nerve cells, body tissues, blood and other body fluids containing the remainder. Approximately 99 % of the body’s calcium is stored in the bones and teeth[1] and the other 1% has also important uses like muscle contraction, transmission of nervous signals, blood clotting and regulation of heartbeat. Calcium also plays an important function in building strong bones early in life and keeping them strong and healthy later in life.

Sources of Calcium

Calcium is mainly found in dairy products; milk, yogurt and cheese, but there are many good non-diary sources as well, including fish (especially the bones in canned salmon and sardines) and seaweed, nuts and seeds such as almonds, hazelnuts, sesame, and pistachio, as well as beans, quinoa, kale and broccoli. There are also calcium-fortified products such as juice, milk alternatives (rice, almond, oat beverages) tofu and cereals that are good sources of calcium.

What is the Recommended Amount of Calcium?

How much calcium you need depends on your age and gender and any illnesses you may have.  As well, women who are pregnant or breastfeeding need additional calcium. The Recommended Dietary Allowance (RDA) for vitamins reflects how much of each vitamin most people should get each day.  Below is a table with the RDA for calcium;

Recommended Dietary Allowances (RDAs) for Calcium [1]

Age Male Female Pregnant Lactating
0–6 months* 200 mg 200 mg
7–12 months* 260 mg 260 mg
1–3 years 700 mg 700 mg
4–8 years 1,000 mg 1,000 mg
9–13 years 1,300 mg 1,300 mg
14–18 years 1,300 mg 1,300 mg 1,300 mg 1,300 mg
19–50 years 1,000 mg 1,000 mg 1,000 mg 1,000 mg
51–70 years 1,000 mg 1,200 mg
71+ years 1,200 mg 1,200 mg

* Adequate Intake (AI)

Calcium Supplements

Calcium supplements may be a good option for people that are lactose intolerance,  have a cow’s milk allergy, have certain illness (such as problems with their parathyroid gland) or who have taken the decision to not include dairy in their diet (e.g. those that follow a vegan diet).

There are different forms of calcium supplements; with calcium carbonate and calcium citrate being the most common ones. Calcium carbonate is less expensive and more widely available but depends on the presence of gastric acid for absorption.  As a result, calcium carbonate is better absorbed when taken with meals.  Calcium citrate absorbs the same whether taken with or without food.

It is also important to know that the highest absorption of calcium is when taken in doses of less than or equal to 500 mg, with the excess being excreted.

High Calcium and Dairy Intake and the Increased Risk of Prostate Cancer in Men

Several epidemiological studies have found an association between high intakes of calcium, dairy foods or both and an increased risk of developing prostate cancer (2-5).  The authors of a meta-analysis of several prospective studies concluded that high intakes of dairy products and calcium might slightly increase prostate cancer risk (6). It becomes difficult to separate the effects of dairy and calcium, but overall, results from observational studies suggest that total calcium intakes >1,500 mg/day or >2,000 mg/day may be associated with increased prostate cancer risk (particularly advanced and metastatic cancer) compared with lower amounts of calcium of 500–1,000 mg/day (1).

Getting a Safe Amount of Calcium

Research is still determining the effect of dietary supplements (including calcium) on people’s health.  Meanwhile, a varied and balanced diet is the safest and best way to assure getting the optimum amount of vitamins and minerals, including calcium (7).

How Nutrition to You can help

Nutrition to You Dietitians can help you assess if you are getting enough calcium or other nutrients from your diet and/or supplement sources.  Please click on the “Our Services” tab above to learn more about our Complete Assessment Package.

References

  1. “Dietary Supplement Fact Sheet: Calcium”. Office of Dietary Supplements, NIH. Retrieved 31 March 2011.
  2. Chan JM, Giovannucci EL. Dairy products, calcium, and vitamin D and risk of prostate cancer. Epidemiol Rev 2001;23:87-92. [PubMed abstract]
  3. Rodriguez C, McCullough ML, Mondul AM, Jacobs EJ, Fakhrabadi-Shokoohi D, Giovannucci EL, et al. Calcium, dairy products, and risk of prostate cancer in a prospective cohort of United States men. Cancer Epidemiol Biomarkers Prev 2003;12:597-603. [PubMed abstract]
  4. Kesse E, Bertrais S, Astorg P, Jaouen A, Arnault N, Galan P, et al. Dairy products, calcium and phosphorus intake, and the risk of prostate cancer: results of the French prospective SU.VI.MAX (Supplementation en Vitamines et Mineraux Antioxydants) study. Br J Nutr 2006;95:539-45. [PubMed abstract]
  5. Mitrou PN, Albanes D, Weinstein SJ, Pietinen P, Taylor PR, Virtamo J, et al. A prospective study of dietary calcium, dairy products and prostate cancer risk (Finland). Int J Cancer 2007;120:2466-73. [PubMed abstract]
  6. 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;97:1768-77. [PubMed abstract]
  7. Practice-Based Evidence in Nutrition (PEN): Guidelines after a prostate cancer diagnosis, 2011