After analyzing 10 years of medical tests on more than 2,700 people in a federally funded heart disease study, researchers at Johns Hopkins Medicine and elsewhere conclude that taking calcium in the form of supplements may raise the risk of plaque buildup in arteries and heart damage, although a diet high in calcium-rich foods appears be protective.
An estimated 43 percent of American adult men and women take a supplement that includes calcium, according the National Institutes of Health.
“Our study adds to the body of evidence that excess calcium in the form of supplements may harm the heart and vascular system.”
The researchers were motivated to look at the effects of calcium on the heart and vascular system because studies already showed that “ingested calcium supplements — particularly in older people — don’t make it to the skeleton or get completely excreted in the urine, so they must be accumulating in the body’s soft tissues,” says nutritionist John Anderson, Ph.D.
Scientists also knew that as a person ages, calcium-based plaque builds up in the body’s main blood vessel, the aorta and other arteries, impeding blood flow and increasing the risk of heart attack.
The investigators looked at detailed information from the Multi-Ethnic Study of Atherosclerosis, which included more than 6,000 people seen at six research universities, including Johns Hopkins. Their study focused on 2,742 of these participants who completed dietary questionnaires and two CT scans spanning 10 years apart.
At the study’s onset in 2000, all participants answered a 120-part questionnaire about their dietary habits to determine how much calcium they took in by eating dairy products; leafy greens; calcium-enriched foods, like cereals; and other calcium-rich foods
Separately, the researchers inventoried what drugs and supplements each participant took on a daily basis.
The investigators used cardiac CT scans to measure participants’ coronary artery calcium scores, a measure of calcification in the heart’s arteries and a marker of heart disease risk when the score is above zero.
Initially, 1,175 participants showed plaque in their heart arteries.
the researchers separated out 20 percent of participants with the highest total calcium intake, which was greater than 1,400 milligrams of calcium a day.
That group was found to be on average 27 percent less likely than the 20 percent of participants with the lowest calcium intake — less than 400 milligrams of daily calcium — to develop heart disease, as indicated by their coronary artery calcium test.
Next, the investigators focused on the differences among those taking in only dietary calcium and those using calcium supplements. Forty-six percent of their study population used calcium supplements.
supplement users showed a 22 percent increased likelihood of having their coronary artery calcium scores rise higher than zero over the decade, indicating development of heart disease.
“There is clearly something different in how the body uses and responds to supplements versus intake through diet that makes it riskier,” says Anderson.
This should be obvious to any scientific person. Tossing down a lump of a mineral (essentially a rock) cannot possibly have the same effect as eating foods containing calcium along with so much else.
“It could be that supplements contain calcium salts, or it could be from taking a large dose all at once that the body is unable to process.”
More than half of women over 60 take calcium supplements — many without the oversight of a physician — because they believe it will reduce their risk of osteoporosis.
That’s because this is what they were told to do by the same “medical experts” now castigating people for doing what they themselves suggested for many years.
It seems medical corrections in such recommendations never admit error, just give new recommendations. How can we trust any more medical recommendations after so many reversals have made it clear they are often ignorant and even wrong.
John J.B. Anderson, Bridget Kruszka, Joseph A.C. Delaney, Ka He, Gregory L. Burke, Alvaro Alonso, Diane E. Bild, Matthew Budoff, Erin D. Michos. Calcium Intake From Diet and Supplements and the Risk of Coronary Artery Calcification and its Progression Among Older Adults: 10‐Year Follow‐up of the Multi‐Ethnic Study of Atherosclerosis (MESA). Journal of the American Heart Association, 2016; 5 (10): e003815 DOI: 10.1161/JAHA.116.003815