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Calcium supplements increase the risk of heart attack by 24% according to data from 9 studies
Friday, February 03, 2012 11:08 am Email this article
Calcium supplements increase the risk of heart attack by 24% according to a meta-analysis of 8 studies that gave calcium or calcium plus vitamin D, plus data from a ninth study only of the women were were not taking calcium supplements at the start of the study.
However, the total risk of death during the durations of these studies was only 1% greater in those taking a calcium supplements, and this difference was not statistically significant, that is, it could have been due to random chance.
Does the Dose of Calcium Matter?
The dose of calcium did not matter; even small doses (less than 500 mg) were associated with an increase in heart attacks
They did not find any dose-related effect.
That is, even small doses of calcium—less than 500 mg—increase the risk of heart attacks just as much as dose of more than 1000 mg.
“When the personal calcium supplement users were divided into three groups by daily supplement intake (1–499, 500–999, and ≥1000 mg/day), there was no evidence of a relation between the dose of personal calcium supplements and the risk of cardiovascular events,” the paper notes.
They also found no difference in whether people were given calcium alone or calcium plus vitamin D.
“There were no significant three-way interactions between calcium and vitamin D,” the authors wrote.
“We repeated these analyses in the subgroup of women not using personal calcium supplements and found no interactions between calcium and vitamin D… for any cardiovascular end point,” they continued.
Conclusion #1: Calcium with or without Vitamin D increase the risk of heart attacks (and stroke)
“When these results are taken together with the results of other clinical trials of calcium supplements, with or without vitamin D, they strongly suggest that calcium supplements modestly increase the risk of cardiovascular events, particularly myocardial infarction,” the authors concluded.
Conclusion #2: Perhaps older people should NOT take calcium supplements
They went on to question whether or not older people should be taking calcium supplements.
“These data justify a reassessment of the use of calcium supplements in older people.”
Other Evidence Supporting This Idea
Elevated levels of blood calcium are associated with heart attack and and increased risk of death
They also note that other research has found that elevated levels of calcium are associated with an increased risk of heart attack and death.
“If calcium supplements do increase cardiovascular risk it is important to consider the potential underlying mechanisms,” the authors note.
“Calcium supplements acutely increase serum calcium concentration by a modest amount, an effect that is sustained during long term treatment, as evidenced by lower levels of parathyroid hormone.
“Serum calcium concentrations are positively associated with
- carotid artery plaque thickness
- aortic calcification
- incidence of myocardial infarction (heart attack)
- and mortality.
“These findings are consistent with observational data suggesting increased risk of cardiovascular events and death in primary hyperparathyroidism, a condition in which serum calcium concentration is elevated.”
Bolland MJ, Grey A, Avenell A, Gamble G, Reid I. 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. BMJ. 2011, 342:d2040.
AUTHOR’S CONTACT INFORMATION
Department of Medicine, University of Auckland, Private Bag 92 019, Auckland 1142, New Zealand.
Articles on the same subject can be found here:
On Mar 06, 2012 at 12:20 pm Jan wrote:
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I was unable to find anywhere in this article the type of calcium that was used in the studies. From my personal research, I have found that all forms of calcium supplementation do not behave the same way in the body. I believe that calcium CARBONATE is unusable by the body and is deposited in the arteries, organs, and central nervous system because it is difficult to excrete. Carbonate is the calcium form in most multi-vitamin/mineral tablets, and was probably used in these studies.
Calcium CITRATE, on the other hand is well absorbed and easily utilized by the body. However, taking any type of calcium without balancing it with magnesium and other co-factors is probably going to cause problems. All mineral supplements should be taken with food, and to insure best absorption should be powdered, or if tableted, should be chewed into small bits before swallowing.
After the age of 30ish, the endocrine system of glands make and secrete less of the vital building and maintainance hormones necessary for up-keeping the bone structures, connecting tissues, muscles, organs, etc. (with the exception of cortisol, insulin etc.) As the level of these hormones, (testosterone, estrogen, progesterone, dhea, thyroid, etc.) decrease with age, our bodies gradually lose the ability to fully use nutrients to prevent the physical deterioration that is inevitable as we grow older.
There is growing consensus in the developed countries of USA, Europe, Argentina, Brazil, Australia, and others that using supplemental hormones, nutrients, digestive aids, etc. will prevent the age related break down of tissues and bodily systems. I, for one, believe absolutely that supplementing with bio-identical hormones, probiotics, digestive enzymes, and the co-factors that our brains use to create the neurotransmitters, dopamine, serotonin, GABA, and acetylcholine will prevent our bodies aging.
Please excuse the excessive use of "etc."
On Mar 06, 2012 at 3:14 pm Larry Hobbs wrote:
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Thanks for your input.
The paper does not say the form of calcium supplements used in these 9 studies.
For me, I would error on the side of caution.
I have stopped taking a calcium supplment.
Unless there is are at least a couple of studies showing that they are beneficial, I would advise people to avoid calcium supplements.
On Mar 09, 2012 at 10:07 pm Jan wrote:
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the following is an article by Life Extension Foundation that might be of interest:
Dr. Steven Joyal, MD, President of Scientific and Medical Affairs at the Life Extension Foundation, says that the study is completely flawed and misleading, and that calcium is a vital nutrient for preventing heart problems.
In a rebuttal, Dr. Joyal explains why the methodology used in the study was flawed, and why calcium supplementation is actually highly beneficial in preventing heart attacks, especially when used together with vitamin D, vitamin K and magnesium.
According to Dr. Joyal's analysis, study authors excluded participants who took vitamin D and magnesium in conjunction with calcium, which skewed the results. These two nutrients work together with calcium to protect bone health. Most of those included as part of the study, though they were taking some level of calcium, were deficient in vitamin D, and vitamin D deficiency increases cardiovascular risk. None of these factors were made plain in the study paper.
Calcium Supplementation Without Magnesium Can Increase Heart Attack Risk - Atlantic Medicine and Wellness
According to Dr. Carolyn Dean, MD, ND, magnesium expert and Medical Director of the nonprofit Nutritional Magnesium Association (http://www.nutritionalmagnesium.org), approximately 30 to 40 years ago doctors began prescribing calcium on a routine basis to many men and almost all women over the age of 40 to counter the effects of bone loss due to aging. The conventional wisdom was that bone loss is due to calcium deficiency. "After 40 years, it has become clear that taking calcium alone does not stop or even slow bone loss and does not prevent osteoporosis." The new wisdom now emerging is that magnesium is actually the key to the body's proper assimilation and use of calcium as well as vitamin D. Dr. Dean says, "If we consume too much calcium without sufficient magnesium, the excess calcium is not utilized correctly and may actually become toxic, causing painful conditions such as some forms of arthritis, kidney stones, osteoporosis and calcification of the arteries leading to heart attack and cardiovascular disease. "Magnesium keeps calcium dissolved in the blood. Without the proper balance of magnesium to calcium, about a 2:1 ratio, calcium ends up depositing in kidneys and can create kidney stones, in coronary arteries where it can lead to clogged arteries, and in joint cartilage, rather than in bones where we need it most. The more calcium taken without the balancing effect of magnesium, the more symptoms of magnesium deficiency and calcium excess you are liable to experience," Dr. Dean says.
New York Times best-selling author Dr. Joseph Mercola concurs, "If you decide to supplement with magnesium it is important to understand that its complementary partner is calcium. So you should use both. Typically you would use twice as much elemental magnesium relative to the elemental calcium. That ratio works out quite well for most." Dr. Guy Abraham, M.D., a research gynecologist and endocrinologist specializing in premenstrual syndrome and osteoporosis, has found strong evidence to suggest that women with osteoporosis have a deficiency of the hormone calcitonin that is only made when they take twice as much magnesium as calcium. In fact, he has found that when calcium intake is decreased, it is better utilized than when it is high. Dr. Abraham is one of many doctors and biochemists who advocate taking more magnesium to correct calcium-deficiency diseases. Dr. Dean adds, "Adequate levels of magnesium in the body are essential for the absorption and metabolism not only of calcium but of Vitamin D, because magnesium converts Vitamin D into its active form so that it can help calcium absorption. Magnesium also stimulates a particular hormone, calcitonin, which helps to preserve bone structure and draws calcium out of the blood and soft tissues back into the bones, lowering the likelihood of osteoporosis, some forms of arthritis, heart attack and kidney stones."
Calcium without magnesium will induce magnesium deficiency, a mineral that is vital for the heart. A 1-1 ration of calcium to magnesium is probably best. It's always mystified me as to why doctors prescribe calcium only, or calcium with D.
These calcium studies were done on both genders. Men and women have different calcium requirements,and may have different risk for heart attacks and possibly skewed the results of the study. Also, the study ignored the need for other nutrients besides calcium required to maintain a healthy heart. I was somewhat concerned when I read this report,however, after further research, I have decided to continue my calcium supplementation along with D, magnesium and other minerals and vitamins.
On Mar 10, 2012 at 8:31 am Larry Hobbs wrote:
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I have to believe the data.
I will not take a calcium supplement even with magnesium unless studies are done to show it is beneficial.
It is not worth the risk to me.
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