Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis

Why would calcium supplements increase myocardial infarcts?

26 July 2011

Magnesium and calcium compete for absorption, and high doses of calcium possibly tip some of the 50% of people who have marginal magnesium intake (1), into deficiency. Magnesium, as well as being important for parathyroid hormone and therefore, bone density, is also nature's calcium channel blocker. Low magnesium levels increase dangerous arrthymias (2) increase hypertension (3), myocardial infarction and other adverse cardiac effects (4).

For these reasons nutritional doctors use calcium and magnesium in a 2:1 ratio and we suspect that this prevents many problems. Evidence for this is lacking and definitely needed. Comments to

1. Sebastian RS, Cleveland LE, Goldman JD, Moshfegh AJ. Older adults who use vitamin/mineral supplements differ from nonusers in nutrient intake adequacy and dietary attitudes. J Am Diet Assoc. 2007 Aug;107(8):1322-32

2. Nielsen FH, Milne DB, Klevay LM, Gallagher S, Johnson L. Dietary magnesium deficiency induces heart rhythm changes, impairs glucose tolerance, and decreases serum cholesterol in post menopausal women. J Am Coll Nutr. 2007 Apr;26(2):121-32.

3. Yogi A, Callera GE, Antunes TT, Tostes RC, Touyz RM. Vascular biology of magnesium and its transporters in hypertension. Magnes Res. 2010 Dec;23(4):S207-15

4. Shechter M. [Body magnesium--the spark of life].[Article in Hebrew] Harefuah. 2011 Jan;150(1):41-5, 67.

Competing interests: None declared

Margaret E Taylor, Nutritional GP

Adelaide, Australia

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