Fresh advice about a misunderstood mineral.
Fresh advice about a misunderstood mineral. An interview with Connie Weaver, Ph.D. Director, National Institutes of Health Botanical Center for Age-RelatedDiseases, Purdue University She is 54 years old, she is one of the world's top experts on calcium, and she rarely takes acalcium supplement. "I don't have to," says Connie Weaver. "I drink plenty of milk." While her three boys were growing up, theworld-renowned researcher had one unwavering mealtime rule: milk for breakfast, lunch and dinner. Call her the dairy queen, butthe old-fashioned dictum was a direct result of evolving research on a mineral that is clouded by confusion and misinformation.Weaver has masterminded studies that helped to form the most compelling advice yet for calcium intake in the world and in thiscountry, where osteoporosis afflicts 25 million people. Much of her research at Indiana's Purdue University has focused onchildren during their peak bone-growing years, between the ages of 12 and 15. The results, however, have implications for menand women of all ages. As the number of bone fractures escalates across the globe, Weaver has found herself invited to advisenations like Malaysia and Thailand, countries that only a few decades past dismissed osteoporosis as a Western disease. "About60 percent of bone strength is determined by genetics," Weaver says. "You can't do anything about choosing your parents, butyou can make a huge amount of difference in the other 40 percent with diet and exercise. My kids were such daredevils, theywere constantly crashing and burning. I think their good bones saved them lots of problems." Q:Is there a role for calcium in the body beyond bone strength? If you don't maintain calcium in your body, you'll die. Calciumis needed in every life process: it's needed for your nerves to act, your muscles to contract, your brain to function, forpractically every activity in the body. Ninety-nine percent of the body's calcium is in the skeleton, and only 1 percent,concentrated in your blood, is used for all of those vital functions I just mentioned. Although it's a small amount, thecalcium in your blood must be maintained. So either you keep the blood replenished from your diet, or your body will take itfrom the big bank it has, the bones, because they are a lower priority. Q: How many of us getenough calcium? Over the age of about 11, people on average get only half of the calcium they need. Q: How does that calcium deficit affect most people? A deficiency in calcium doesn't play out with animmediate consequence: you don't get a canker sore, you don't have a collapse right away. It plays out in later years, andoften in the form of weakened bones. Look at the statistics: hip fractures occur in one out of every four Caucasian women over50 and in one out of ten African-American women (who are the most protected genetically for having strong bones). Twentypercent of hip fractures occur in men, so they're not immune. Twenty percent of people who have a hip fracture die becausetheir lack of mobility harms their lungs and they get pneumonia. Q: Is it true that children arenow suffering more bone problems? Bone fractures in children are tripling. There's a vulnerable period at the start of youradolescent growth when you spurt up before your bones can fill in. Fractures are rising during this lag time when kids haverelatively low bone density. Years ago it was more common to have milk with every meal: there wasn't such a plethora of sodaand other calcium-absent drink choices. Bone strength is also improved with weight-bearing exercise like walking, aerobics,basketball. But today people are much more sedentary, addicted to television and computer games. There's one more factor: withthe increase in childhood obesity, children are falling with greater force because of their weight, so the impact is higher.Q: Bone density is established during adolescence, but we can still influence bone strengthlater in life, right? After adolescence you can't do very much more in building bone, just in preserving it. Hips finishgrowing first, about age 16. By the time you're 17, you have 95 percent of your bone. Your spine is still pliable throughcollege, up until the late twenties, 30. But at Purdue, we're finding that sedentary women students are losing spine bonealready. Others who exercise, drink milk or get other forms of dietary calcium continue to gain spine throughout that period.Q: What kind of exercise do you follow? I practice Aquacize [water aerobics] twice a week,circuit training when I can, and my vacations are active with skiing, hiking, etc. But I also wear a pedometer much of thetime, take the stairs and practice other ways to get my daily 10,000 steps. Q: Can you get adaily dose of calcium from vegetables alone? Although calcium is well-absorbed from vegetables like bok choy, broccoli, kaleand so forth, the amount you would need to eat is immense: the calcium in 21/4 cups of broccoli or nearly 5 cups of red beansrivals that in 1 cup of milk. Q: So how do you explain cultures that rarely eat dairy but havefew problems with osteoporosis and hip fractures? If you have an Asian beside a Caucasian and they have equal bone density, theCaucasian will be more vulnerable on average to getting a fracture because their hip-bone length is longer. Asians' geometry issuch that if they fall, they're much less likely to crack that shorter bone. There is nothing about diet that can change that.It's an advantage that Asians have over Caucasians. Now to say that Asians don't have a problem with osteoporosis isn't myobservation. Even though they're protected by their bone geometry, they do have a problem, an increasing problem. In over adecade of reporting hip fractures in Hong Kong, researcher Edith Lau has seen the incidence triple. She attributes that to poordiet, low calcium and, ironically, to better overall nutrition that is causing the Asian population to get taller-consider theChinese professional basketball players of today. Just like fat children, taller people fall harder on their bones and are morelikely to break them with a harder impact. Q: Why do calcium needs change as we age? In mysixties will I need more calcium for those nerve actions? It's not that the need for the biological activity of calciumchanges, but the ability to utilize calcium for those activities changes. During adolescence, you absorb the most calcium andyou excrete the least. About age 40, your efficiency starts declining so your calcium requirements go up to offset thatdeficiency. Q: Why does menopause make a difference? Estrogen suppresses calcium coming out ofthe bone, or bone resorption, so during menopause, all of a sudden you have an estrogen deficiency and resorption reallyescalates. You're in this really rapid bone-loss period for the first few years after menopause, until your body readjusts, andthen it sort of levels off on average to probably about 0.7 to 1 percent bone loss per year. Q:So someone age 55 is probably losing more than someone 65. Right, but then you go into another vulnerable period above age 80,when calcium efficiency declines again. Q: Do you think that the focus on calcium for women hasshortchanged men? The research is way behind for men. Only recently have there been research trials in men and have we beenable to make clinical guidelines for physicians working with men. But it's still not in the practice of most physicians to eventhink, "Oh we should do a bone scan on an elderly man that comes in." In many areas of the country, a man has to break a bonebefore anything is done. Q: Can we believe advertisements that suggest calcium can help inweight loss? The evidence isn't strong enough to make a conclusion. I think there are good reasons to consume calcium, butresearch has yet to determine whether weight management is an important one. Q: Many peoplebelieve that protein leaches out calcium and thus milk isn't a good source of calcium. It's true that increasing proteinincreases calcium loss in urine, but that loss is offset by increased calcium absorption. So there's no net disadvantage ofextra protein in the diet. Q: If a person is not a fan of dairy, how do you suggest he or sheget enough calcium? We have done a lot of work on different sorts of fortified foods, and many of them are as good as milk.Soymilk fortified with calcium carbonate is as good as milk as long as you shake it up to make sure the calcium gets into yourmouth. Fortified orange juice seems to be quite a good substitute. If you can't get enough of either dairy (which provides apackage of nutrients needed for bone health including calcium, potassium, magnesium and vitamin D) or calcium-fortified foods,use supplements. Q: Can you overdose on calcium? There is an upper level of 2,500 milligrams(mg) per day, a level that is far above what you need. You just need to approach calcium with a little education. Don't drink aquart of milk plus fortified cereal plus fortified juice plus a supplement. Healthy people excrete the extra calcium, but thereare situations in which too much calcium can exacerbate renal problems and other conditions. Q:Do salty meals block calcium absorption? Every ion of sodium that a Caucasian excretes pulls out an ion of calcium with it.That can cause problems for bones. African Americans, on the other hand, retain a lot of sodium, which in adults can lead tohigh blood pressure. It does protect their bones, though, because they retain more calcium. Q:What about caffeine? We don't know whether the calcium is coming from the bones or from the diet, but caffeine can increase theamount of calcium lost through urine. Some reports say that 2 to 4 tablespoons of milk will offset the effects of 5 cups ofcoffee. Lattes, for example, are good. Q: Do you have milk with every meal? My priority is milkwith meals but that can't always be accomplished. I'm 54, I need 1,200 mg calcium a day. I drink about two glasses of milk,giving me 600 mg, and in the rest of my diet-vegetables, cheese, fortified whole-grain cereal-I get another 400 to 600. I don'ttake a supplement or even a multivitamin; I just try to follow the dietary guidelines. You ought to be thinking about a calciumsource, a fruit, a vegetable and a whole grain at just about every meal to meet your dietary guidelines. -Allison J.Cleary