Calcium Concerns: Boning up Nutrition

author : Nancy Clark

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Maintaining bone health throughout the lifespan should be a priority for all athletes, starting as youngsters and continuing as master's athletes.

The Athlete’s Kitchen
Nancy Clark MS RD CSSD

“I'm 44. Should I start taking calcium pills?”
“A bone density test indicated I have the bones of a 70 year old—and I'm only 34. I guess I should have had more milk and less soda as a kid…?”
“Will drinking more milk help my stress fracture heal faster?”

Questions and confusion abound about the role of calcium in athletes' diets. If you are like most active people, you may think, “Milk is for kids” and quench your thirst at lunch and dinner with (diet) soda or water. As a result, you can easily end up consuming a calcium-deficient diet (that is, unless you consume yogurt and cheese instead of milk).

Weight-conscious women, in particular, are known to have calcium-deficient diets out of (the unjustified) fear that milk's calories will add to undesired weight gain (1). Many men also have calcium-poor diets. If they are not milk drinkers, mens’ main sources of calcium are from the cheese on cheeseburgers and pizza. Not very health enhancing...

Given that the average American lives for 77.7 years, maintaining bone health throughout the lifespan should be a priority for all athletes, starting as youngsters and continuing as master's athletes. A calcium-rich diet, weight-bearing exercise (such as running, as opposed to biking and swimming) and strength-training to have strong muscles tugging on bones are all important factors for optimizing the bone density of both growing children and active adults.

Bones are alive and require a life-long calcium intake. If your family has a history of osteoporosis, your risk for “shrinking” (losing height) as you get older is high and you should pay special attention to maintaining your bone density. Female athletes with a history of amenorrhea also have a high risk for weak bones and should get their bone density tested so they know where they stand and if they need to take extra steps to try to enhance bone density. Here's some information about calcium and bone health to help you enjoy lifelong health, no bones about it.

Q. Can I take a calcium supplement instead of drink milk?
A. While any calcium is better than none, taking a calcium pill does not compensate for a calcium-poor diet. A supplement offers calcium, but it does not offer the high-quality protein found in milk or soy milk, nor the myriad of other health-enhancing nutrients. Little babies thrive on milk, not calcium pills. Do you really think a pill can replace a whole food?

Q. I like to save calories by taking a calcium pill instead of drinking milk. Is that OK?
A. Not really. Although a calcium pill offers a low calorie alternative to consuming the recommended three (8-ounce) glasses of milk or yogurt each day, research indicates milk drinkers tend to be leaner than milk avoiders (1). I encourage my clients to embrace milk as a “liquid food” that is satiating and curbs one appetite. That is, milk can be more filling than the same number of calories from soda or juice.

Most of my active female clients reduce weight on 1,800 calories; men on 2,100+ calories. That breaks down to 500 to 600 calories per meal (breakfast, lunch, dinner) and 300 calories for a snack. Enjoying low-fat (soy) milk on cereal, a mid-morning latte and a yogurt for a snack seems a powerful way to spend 300 of those calories and approach the recommended intake of 1,000 milligrams of calcium per for adults 19-50 years; 1,200 mg for adults older than 50 years, and 1,300 mg for kids 9-18 years. If you are a parent, be a role model and drink milk at dinner to encourage a calcium-rich intake for your kids. Building strong bones during the ages of 10 to 18 is a wise investment for the future.

Q. I’m lactose intolerant. Can I get enough calcium from non-dairy foods like soy milk, spinach, broccoli and almonds?
A. For certain, you can get calcium from non-dairy sources. Soy milk is calcium-fortified and offers ~300 mg calcium in 8 ounces—similar to cows’ milk. Other convenient non-dairy calcium sources include fortified orange juice (350 mg/8 oz.) and fortified breakfast cereal, such as Total Cereal (1,000 mg/0.75 cup).

If you do not consume dairy products or fortified soy products, you will have to work hard to consume adequate calcium. For example, to get the recommended intake from plant sources, you’d need to eat 10 cups of spinach salad, 3.5 cups of broccoli, and 4 ounces almonds (about 88 almonds @ 675 calories). That’s a lot of eating…

What you do NOT get from those plant sources of calcium is Vitamin D. Vitamin D enhances the absorption of calcium and is needed to not only protect bone health but also to reduce the risk of high blood pressure, diabetes, and heart disease; enhance immune function and reduce inflammation. Vitamin D is added to milk and some brands of yogurt, but is hard to find naturally in foods other than oily fish. Hence, non-milk drinkers have a high risk for not only calcium but also vitamin D deficiency.

Q. I live in Boston and spend lots of time outdoors in the sun. Should I take additional D even though I drink milk?
A. Yes, especially between Thanksgiving and Easter. Vitamin D deficiency is surprisingly common in people who live in northern latitudes (north of Atlanta GA), where the sun’s ultraviolet rays do not effectively convert the body's inactive form of D (just under the skin) into an active form. And even Southerners need to be mindful. A study of southern distance runners indicates 40% of them were D-deficient (2). Indoor athletes (dancers, swimmers, hockey players, figure skaters, basketball players, gym rats, etc.) should ask their doctors about getting their blood tested to determine their level of vitamin D, and if it is low, take steps to correct the problem.

Q. Does the fat in milk contribute to heart disease?
A. Controversial. A study that tracked the health and dairy intake of 4,374 children for 56 years (between 1948 and 2006) reports there was no increased risk of heart disease or stroke among the 34% who died during that time—even though, as kids, the subjects in the study drank whole milk. In fact, the children who consumed the most milk and cheese lived longer. (3)

This study conflicts with the prevalent message to reduce the risk of heart disease by limiting the intake of milk’s saturated fat. Until more research clarifies this confusion, I recommend you enjoy low fat dairy/calcium-rich foods to help reduce excessive fat and calorie intake while maintaining a strong calcium intake.

Q. Will drinking extra milk help a broken bone heal faster?
A. Doubtful. Bones need time to heal ... about 6 to 8 weeks. But perhaps you can reduce the risk of breaking a bone by building it stronger in the first place?

Nancy Clark, MS, RD, CSSD (Board Certified Specialist in Sports Dietetics) counsels both casual and competitive athletes in her private practice at Healthworks, the premier fitness center in Chestnut Hill MA (617-383-6100). Her Sports Nutrition Guidebook, and food guides for new runners, marathoners, or cyclists are available via www.nancyclarkrd.com. See also www.sportsnutritionworkshop.com for information about upcoming workshops in Providence, Boston and Toronto.

References

1. Heaney R, Davies K, Barger-Lux M. Calcium and weight: clinical studies. J Amer College Nutrition 2002. 21(2):152S-155S.

2. Willis KS, Peterson NJ, Larson-Meyer DE. Should we be concerned about the vitamin D status of athletes? Int’l J Sports Nutr & Exerc Metab 2008 18:204-235.

3. van der Pols JC, Gunnell D, Williams G, Holly J, Bain C, Martin R. Childhood dairy and calcium intake and cardiovascular mortality in adulthood: 65-year follow-up of the Boyd Orr cohort. Heart. 2009; July 29. (Epub ahead of print)
 

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date: September 12, 2009