A new review published in the British Medical Journal has found a link between the ingestion of calcium supplements and increased risk of heart attack.
Researchers from the University of Auckland in New Zealand pooled data from 11 clinical trials, in which 12,000 people over age 40 were randomly assigned to receive either 500 mg daily (or more) of supplemental calcium or a placebo for an average of 3 ½ years. After adjusting for other risk factors such as age, smoking, and high blood pressure, the researchers found that those taking calcium supplements were 30% more likely to suffer a heart attack than those not taking the supplement.
Quote from the above study:
Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.
As the above quote indicates, the study examined the effects of calcium intake alone – not calcium in conjunction with accessory nutrients such as Vitamin D.
But while Vitamin D may offer some degree of protection against the negative cardiovascular effects of supplemental calcium, the study authors fail to mention magnesium – perhaps the most important accessory nutrient to calcium in protecting against arterial calcification.
Calcium–to–Magnesium Ratio – The Key in Heart Disease
In recent editions of the Integrated Supplements Newsletter, we examined the importance of maintaining a proper intake of both calcium and magnesium for all aspects of health, including, and especially, cardiovascular health.
Article Link – Stress, Anxiety, Depression, And Magnesium – Part 3 – The Calcium to Magnesium Ratio.
The recent review in the British Medical Journal isn’t the first piece of research to suggest that an excessive calcium intake relative to magnesium may be associated with cardiovascular disorders. Population–based studies have hinted at the same correlation for decades. In the 1970’s, when Finland had among the highest dietary calcium–to–magnesium ratio in the world (approximately 4:1 – similar to many people in the U.S. today) studies found that their incidence of coronary heart disease was notably higher than that of other cultures whose calcium–to–magnesium ratio was significantly lower. Japan – whose calcium–to–magnesium ratio at the time was barely above 1:1 – had a particularly low incidence of both cardiovascular disease and osteoporosis:
Study Link – Minerals, Coronary Heart Disease and Sudden Coronary Death.
Quote from the above study:
Under certain circumstances high intakes of calcium may increase rather than decrease the death rate from CHD [Coronary Heart Disease]. There is a highly significant positive correlation between death rates from CHD and estimated calcium to magnesium ratios of the average diets in OECD countries… Since the daily intake of calcium is higher in Finlandthan in most other countries the high death rate from CHD in this country cannot be attributed to a deficiency of calcium.
The graph below, adapted from the above study, seems to provide clear evidence of a direct relationship between heart disease and an excessive calcium–to–magnesium ratio in several countries. In this respect, it seems that a calcium–to–magnesium ratio of slightly above 1:1 (i.e., only slightly more calcium ingested each day relative to magnesium) is ideal.
Of course, population–based studies and literature reviews aren’t sufficient to prove that supplemental calcium increases heart attack risk, but even controlled animal research seems to confirm the harmful effects of an elevated calcium intake – especially when calcium is elevated in the context of a magnesium deficiency. In a particularly enlightening study, Japanese researchers recently investigated the effects of four different diets on 4 different groups of rats:
Group 1 – Fed the standard laboratory rodent diet
Group 2 – Fed the standard diet with the calcium level doubled
Group 3 – Fed the standard diet, but with the magnesium level lowered
Group 4 – Fed the standard diet, but with the magnesium level lowered and calcium doubled
The researchers found that structural and mitochondrial damage occurred in cells of the heart, liver, and kidney in groups 2 through 4.
In groups 3 and 4, magnesium was lower in serum and was lost from bone.
Levels of lipid peroxides were elevated in the livers of groups 3 and 4, and in the heart in group 4. Severe damage to heart cells was found in group 4.
Quote from the above study:
Epidemiologically, it has been suggested that dietary magnesium/calcium imbalance is associated with the risk of heart diseases. In the present study, the effects of magnesium deficiency and/or calcium over intake were investigated in rats…Our results thus suggest that dietary magnesium deficiency gives rise to retrogressive changes in some organs including the heart, and concurrent calcium overintake synergistically enhances the myocardial injury due to magnesium deficiency.
Calcium supplements are widely recommended and widely consumed. By some estimates, 43% of Americans reported the use of calcium supplements:
Study Link – Estimation of Total Usual Calcium and Vitamin D Intake in the United States.
Quote from the above study:
A total of 53% of the U.S.population reported using any dietary supplement (2003–2006), 43% used calcium (2003–2006), and 37% used vitamin D (2005–2006).
And while a large percentage of these people may be consuming Vitamin D along with calcium, it’s safe to assume that the vast majority are still woefully lacking in magnesium. According to USDA data, almost 68% of people don't consume the recommended daily allowance (RDA) for magnesium - even those who take supplements.
The benefits of calcium and Vitamin D are in the news almost daily, yet magnesium very rarely receives its proper recognition as a mineral necessary to enhance the effectiveness of calcium in supporting bone health – while at the same time helping to counter the negative cardiovascular effects of calcium excess.
The above studies, and many others, repeatedly show that ignoring the importance of magnesium may have life–threatening consequences. This is why, at Integrated Supplements, we’re proud to have created what we believe is the highest-quality, most bio–available, stand–alone magnesium supplement available. We strive to educate the world on the value of this too–often–forgotten mineral, and we humbly ask that you help us to spread the word to anyone who could benefit from this information.
For this, we thank you.
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