“Our study found that consuming a high-calcium diet, which is defined as not exceeding 2,000 milligrams of calcium a day, is not a risk factor for heart attacks,” said Connie Weaver, distinguished professor and head of the Department of Nutrition Science. “The recent concern that calcium supplements were a risk factor led people to stop supplementing their diets. This is a great concern because supplementation is essential to fill a void to meet the daily recommended amount of calcium for strong bones.”
“We’re already at epidemic levels for osteoporosis as one in two women older than 50 will get a fracture in her lifetime, and 20 percent of hip fractures occur in men,” said Weaver, who is an expert in mineral bioavailability, calcium metabolism, botanicals and bone health.
The research is published online in the Journal of the American Heart Association. The project was funded by Pharmavite LLC, the Dairy Research Institute, Dairy Australia, Fonterra Cooperative Group Limited, Kraft Foods Inc., Nestle and grants from the National Institutes of Health. Weaver serves on the scientific advisory board for Pharmative LLC. Collaborators included Scott Radcliff, Meryl Wastney, Bill van Alstine and George Jackson from Purdue; Mike Sturek from the Indiana University School of Medicine; and Sean Newcomer from California State University.
“It had been reported that there is a 30 percent higher chance of heart attack from consuming calcium supplements,” Weaver said. “In 2011, 22 percent of the population consumed calcium supplements, and that decreased in 2012 to 17 percent. The research supporting such a risk has been based on self-reports or from correlations or secondary analysis rather than primary causes. And this would be too hard to study in humans in such a way to control their diet and identify concerns prior to having a heart attack.”
In Weaver’s study, three groups of pigs were fed a normal diet, a high-calcium diet from supplements or a high-calcium diet from dairy products over a six-month period. The high-calcium diets were equivalent to 2,000 milligrams of calcium consumed one time each day. Neither high-calcium group had an increase of calcium in the arteries.
“The speculation was that calcium deposited in the soft tissue of the arteries and that a big dose of calcium from a supplement would cause it to precipitate in the blood,” Weaver said.
The researchers determined this by using the calcium 41 technology, an isotope measure to trace calcium deposits through accelerator mass spectrometry in the Purdue Rare Isotope Measurement Laboratory (PRIME Lab). It can measure atomic quantities and determine whether any of the calcium 41 is deposited in the arteries’ soft tissue. The researchers also used CT imaging and ultrasounds, as well as other biological measures.
“There is no cause for concern, and for every serving of low-fat dairy you miss, take 300 milligrams of calcium to get what you need for bone health,” she says.
Weaver is a member of the National Academy of Medicine, formerly the Institute of Medicine, and she is deputy director of the National Institutes of Health-funded Indiana Clinical and Translational Science Institute. She also is director of Purdue’s Women’s Global Health Institute.
In 2011 she was appointed to the Institute of Medicine’s Food and Nutrition Board, and in 2005 she was appointed to the U.S. Dietary Guidelines Advisory Committee. She served on the National Academy of Sciences Food and Nutrition Board Panel to develop new requirement recommendations for calcium and related minerals.
Writer: Amy Patterson Neubert, 765-494-9723, [email protected]
Source: Connie Weaver, [email protected]
Note to Journalists: Journalists interested in a copy of the Journal of the American Heart Association article “Effect of High Calcium Diet on Coronary Artery Disease in Ossabaw Miniature Swine with Metabolic Syndrome” can contact Amy Patterson Neubert, Purdue News Service, at 765-494-9723, [email protected]
Effect of High Calcium Diet on Coronary Artery Disease in Ossabaw Miniature Swine with Metabolic Syndrome
Alyssa K. Eakley, Mikaela L. McKenney, Martin Bahls, Sean C. Newcomer, John S. Racliffe, Meryl E. Wastney, William G. Van Alstine, George Jackson, Mouhamad Alloosh, Berdine Martin, Michael Sturek, Connie M. Weaver
Background: Calcium is a shortfall essential nutrient that has been a mainstay of osteoporosis management. Recent and limited findings have prompted concern over the contribution of calcium supplementation to cardiovascular risk. One proposed mechanism is through the acceleration of coronary artery calcification (CAC). Determining causality between calcium intake and CAC has been hindered by a lack of sensitive methodology to monitor early vascular calcium accumulation. The primary study aim was to assess the impact of high calcium intake on CAC using innovative calcium tracer kinetic modeling in Ossabaw swine with diet-induced metabolic syndrome. Secondary endpoints (in vitro wire myography, histopathology, intravascular ultrasound) assessed coronary disease.
Methods and Results: Pigs (n=24; ~15 months of age) were fed an atherogenic diet with adequate calcium (0.33% by weight) or high calcium (1.90% from calcium carbonate or dairy) for 6 months. Following 5 months of feeding, all pigs were dosed intravenously with 41Ca, a rare isotope that can be measured in serum and tissues at a sensitivity of 10-18 M by accelerator mass spectrometry. Kinetic modeling evaluated early CAC using 41Ca values measured in serial blood samples (collected over 27days) and coronary artery samples obtained at sacrifice. Serum disappearance of 41Ca and total coronary 41Ca accumulation did not differ among groups. Secondary endpoints demonstrated no treatment differences in coronary artery disease or function.
Conclusions: There was no detectable effect of high calcium diets (from dairy or calcium carbonate) on coronary artery calcium deposition in metabolic syndrome swine.