For decades, physicians have encouraged people to take plenty of calcium, a mineral best known for building healthy bones. About 43% of people in the U.S, including nearly 70% of older women, use supplements that have calcium.
Concern about osteoporosis—the bone-damaging disease that leaves elderly adults prone to fracturing a wrist, hip, or other bone—has triggered this trend.
Calcium also keeps your nerves, muscles, and blood vessels working well, and it’s one of the critical minerals involved in blood pressure control. Concerning cardiac disease, though, there’s one potentially confusing aspect of the calcium story.
Researchers often look for initial signs of a cardiac disease called a CAC (coronary artery calcium) scan. There’s no direct link between the calcium you take and the amount in your arteries. But of late, various studies have observed an association between calcium supplements and a greater risk of cardiovascular disease .
The supplement story
Those trials don’t give the complete picture, though. An extensive analysis that pooled findings from thirty-one individual studies of calcium intake and heart disease, published in the October 2016 issue of Annals of Internal Medicine, observed no cause for concern.
Moreover, the randomized studies of calcium supplements, with or without vitamin D, did not link to cardiac disease .
There is no apparent link between calcium supplements and the risk of stroke or heart attack.
The well-known link between heart health and bone health may explain why supplement users appear to have a greater cardiac disease risk.
Cardiovascular disease and osteoporosis have several shared risk factors, including a lack of physical activity, smoking, and an unhealthy diet. Women who have osteopenia or osteoporosis are typically advised to take calcium supplements. But these women may also be more likely to have a cardiac disease as well.
Your daily dose of calcium
The prescribed daily intake of calcium is 1,000 milligrams (mg) up to age fifty for adults. That amount increases to 1,200 mg each day for women over fifty and men older than seven.
Many individuals can meet that requirement with about 3 daily servings of calcium-dense foods, including yogurt, milk, cheese, canned oily fish with bones, calcium-fortified juice, tofu, and leafy greens.
Receiving your calcium from food has the additional advantage of providing a range of other beneficial nutrients. Also, calcium supplements may cause constipation and increase your risk of kidney stones, a painful disorder.
Still, few people, mainly those sensitive to lactose (a naturally occurring sugar found in milk), may find it tricky to get adequate calcium from food. In that instance, a calcium supplement can make sense.
But most women take 1,000 or even 1,500 mg per day, which is too much for many individuals. A 500 to 700 mg supplement should be more than enough unless your physician particularly tells you to take more.
Seeing calcium specks inside arteries
A CAC (coronary artery calcium) scan uses a particular x-ray machine that takes multiple heart pictures in thin sections. Combined, the scans produce a view that may reveal specks of calcium in the heart’s arteries walls.
These so-called calcifications are an initial sign of atherosclerosis, the fatty buildup on the arteries’ inner walls responsible for many cardiac arrests, and some strokes.
Even though calcium is part of that fatty buildup, we are unsure if excess calcium in the bloodstream makes things worse. In fact, in the research of more than 2,700 adults followed for 10 years, a higher intake of calcium was associated with a lower risk of atherosclerosis, particularly from food sources.
This research observed a slightly greater risk of atherosclerosis in individuals who took calcium supplements. But the connection may not be causal, and any explanation for the finding would be speculative.
What’s more, part of the breakthrough WHI (Women’s Health Initiative) study that helped to lead compared women who took daily 1,000-milligram calcium supplements with those who took a placebo.
After a 7-year follow-up, the coronary artery calcium scores were nearly similar in both groups. This kind of study—a clinical trial—provides more substantial evidence than the aforementioned observational study.
The connection between calcium and heart disease is plausible.
Calcium deposits are part of artery-clogging plaque. They also trigger the stiffening of the arteries and interfere with the heart valves’ action. But whether there is a direct link between the amount of calcium in the bloodstream (calcium supplements spike blood calcium levels) and heart problems aren’t yet known.
An even significant unanswered question is how much calcium the average person needs per day to keep bones healthy and strong. At one end of the spectrum, the WHO (World Health Organization) says 400 to 500 milligrams (mg) of calcium per day are required to prevent osteoporosis.
On the other hand, Americans’ official recommendation is 1,000 mg/day from ages nineteen to fifty and 1,200 mg/day after that.
Given the uncertainty about the risks of calcium supplements and the balance of benefits, it’s probably best to get the calcium you require from dietary sources to prevent bone-thinning osteoporosis and keep your bones healthy.
Don’t just depend on calcium for bone health. You should also include:
Weight-bearing exercise, like running, walking, tennis, and others, is one of the wisest things you can do for your bones. Getting adequate vitamin D from supplements and the sun is also suitable for overall health and bones.
(As with everything, don’t overdo it—800 to 1,000 IU of a vitamin D supplement and not more than 15 to 20 minutes of sunshine without sunscreen.) Vitamin K from green leafy vegetables such as Swiss chard, spinach, and kale is also essential for bone health.