Way back in 1989, the calcium RDA for middle-aged men and women was a modest 800 milligrams (mg) a day.
That’s close to the amount of calcium that Americans actually get from the foods that we eat.
The average for women is 788 mg, and for men, it’s 950 mg.
Then, in 1997, it all changed. Instead of simply preventing nutrition deficiencies, the goal for calcium was changed to preventing a serious chronic condition—osteoporosis.
The calcium recommendation went up. A lot. The new rule was that women aged 19 to 50 and men aged 19 to 70 needed 1,000 mg a day…while women 51 and older and men 71 and older needed 1,200 mg. Those amounts are actually not very easy to get from food, and that convinced millions of Americans to take calcium supplements and consume food that’s been artificially loaded with extra calcium…day after day…year after year. That’s where things stand today.
But what if it was all a big mistake?
What if all that calcium has been harming us?
THE CALCIUM BOOM AND HOW IT HURT US
When the calcium RDA went up, suddenly, it wasn’t so easy to get enough calcium in a well-balanced diet. Sure, you could eat more dairy, something the dairy industry was happy to promote, and consume calcium-fortified cereal and orange juice, something the cereal and beverage manufacturers were happy to provide. But to get to those higher numbers, chances are, you’d need supplements, too.
The American public obliged. By 2006, 51% of men aged 51 to 70, and 67% of women in the same age range, were supplementing their diets with calcium. Only recently have the numbers started to go down a little.
But taking high doses of calcium supplements, we’ve since found out, may do harm to our hearts and kidneys. In a 2010 study, women (mostly over 70 years old) who took calcium supplements of 500 mg or more had a 30% greater risk of having heart attacks.
The heart attack risk, however, showed up only in women when daily calcium intake from all sources exceeded—wait for it—800 mg.
Later studies have confirmed the heart attack risk from taking supplements. Calcium supplements also increase the risk for painful kidney stones.
PREVENTING OSTEOPOROSIS WITH CALCIUM PILLS? NEVER MIND
Now there’s growing evidence that taking all that extra calcium doesn’t prevent osteoporosis either. In September, 2015, an analysis of more than 50 studies published in BMJ found that…
• High dietary intake of calcium doesn’t prevent fractures.
• Eating lots of dairy foods doesn’t prevent fractures.
• The evidence that calcium supplements prevent fractures is “weak and inconsistent.”
Now some experts are calling for the recommended amount of calcium to come back down—perhaps even to levels that one could reasonably expect to eat in a balanced diet. It’s not our place to set nutrition standards, but from a layman’s standpoint, the “old” standard of 800 mg is starting to look pretty attractive.
One thing is clear—the days when we thought we could keep our bones strong simply by starting to take a calcium pill in our 50s or 60s are gone. It’s not that calcium supplements don’t build bone density—some studies do find a modest increase. It’s just not enough to prevent what really matters—fractures.
It may be that large amounts of calcium taken in a pill are absorbed quite differently than eating small amounts of calcium in our daily meals. Even including a small amount of vitamin D, which improves the body’s ability to use calcium, isn’t effective at protecting bones. According to the US Preventive Services Task Force, “In postmenopausal women…daily supplementation with 400 IU of vitamin D3 combined with 1,000 mg of calcium has no effect on the incidence of fractures.”
Meanwhile, while experts argue, it’s up to you and me to figure out how to eat well to prevent osteoporosis and stay healthy. Right now science may not know enough to tell us the optimal diet, let alone supplement plan, to prevent osteoporosis. But we know that we’re supporting our bones when we eat a diet rich not only in calcium but also magnesium, potassium and boron, and not too high in sodium or caffeine. Vitamin D is also important for bone health (and many other things) and particularly difficult to get enough of without supplementation. Weight-bearing exercise remains a cornerstone for osteoporosis prevention, and if you smoke, quitting is one of the best things you can do for your bones. To learn more, see Bottom Line’s Guide to Strong Bones—for Life!