Older adults may benefit from a lower CVD risk with a higher calcium intake, but it may not lower the risks for stroke and fractures.
This is the conclusion of a new study recently presented at Endo 2016 - the annual meeting of The Endocrine Society, held in Boston, MA.
Calcium is one of the body's most important minerals. Around 99% of the body's calcium supply aids the structure and functioning of bones and teeth, while the remaining 1% supports various metabolic functions, including cell signaling, blood clotting, muscle contraction, nerve function, heartbeat regulation and hormonal secretion.
Dairy products - such as milk, yogurt and cheese - are rich sources of calcium and make up most of Americans' calcium intake.
Green leafy vegetables, such as kale, broccoli, Chinese cabbage, turnip greens, collards and bok choy, are also good sources of the mineral, as are salmon, sardines - canned with bones - almonds, brazil nuts and sunflower seeds.
Calcium is also available as dietary supplements, primarily in the form of carbonate and citrate.
According to the National Institutes of Health (NIH), men aged 51-70 should aim to have 1,000 mg of calcium daily, increasing to 1,200 mg from the age of 71. Women's recommended daily intake of calcium is 1,200 mg daily from the age of 51.
Previous studies have suggested that higher calcium intake in older age may protect heart health, as well as reduce the risk of fractures.
However, such evidence has been conflicting. Last September, for example, Medical News Today reported on research that claims increasing calcium intake does not improve seniors' bone health.
"Moreover, participants in previous studies were from populations that had calcium-rich diets," notes the lead author of this latest study, Dr. Sung Hye Kong, of the Department of Internal Medicine at Seoul National University Hospital in South Korea.
Significantly lower CVD risk with higher calcium intake
For their study, Dr. Kong and colleagues set out to investigate how high calcium intake affects the risks for cardiovascular disease (CVD), stroke and fractures among older adults from a population with a low calcium intake.
- 8 oz of plain, low-fat yogurt contains 415 mg of calcium
- 1.5 oz of cheddar cheese contains 301 mg
- A 3-oz serving of salmon contains 181 mg.
To do so, the team analyzed data of 2,199 men and 2,704 women aged 50 and older - without a history of CVD or stroke - who were part of Korea's Ansung and Ansan Cohort Study. Beginning in 2001, the study followed participants for an average of 13 years.
The team assessed the dietary calcium intake of participants, determined through a food frequency questionnaire. Every 2 years, participants underwent health examinations and interviews, from which the researchers identified any CVD, stroke or fracture events.
Compared with subjects who had a lower calcium intake, those who had a higher calcium intake had a significantly lower risk of CVD, according to the results. However, no significantly reduced fracture or stroke risks were identified for those with a higher calcium intake.
These findings remained after the team accounted for numerous factors that may influence heart health and fractures, including age, body mass index (BMI), intake of fruits and vegetables, protein and sodium intake, total energy intake and women's menopausal status and use of hormonal therapy.
In October 2014, MNT reported on a study suggesting that a high milk intake may increase the risk of fractures and premature death.