American women can build stronger bones by eating small meat, chicken and fish portions.
This sounds like heresy after years of weight-loss diets promoting 6- to 8-ounce "meat" portions at both lunch and dinner. But according to Creighton University's Robert Heaney, seven decades of research consistently show that high protein diets reduce calcium absorption.
In November's Journal of the American Dietetic Association, Dr. Heaney says that whether your protein intake is high or low, every time you double your protein, you increase calcium loss by 50 percent. However, if you increase your calcium, you will balance out a high protein diet.
A recent study bears this out. Young women with better FTC calcium-to-protein ratios showed the greatest increases in bone density.
To find out if these women were typical, Dr. Heaney developed an RDA-based reference ratio of 16:1 -- that is, 16 milligrams of calcium to one gram of protein. (The RDA for calcium is 800 milligrams; the RDA for protein is 50 grams.)
In fact, most women eat less calcium and more protein than that. According to the National Health and Nutrition Examination Survey that looks at what people actually eat, the calcium-protein ratio for adult women is about 9:1
Flawed thinking would say, "Pop some calcium pills to even things up." This would improve the ratio, but it would still leave your overall diet unbalanced. Because if you're eating lots of meat, chicken and fish, you're eating too much total food and gaining weight.
In addition, several researchers have begun to link diets high in animal protein to higher cancer rates.
A good way to improve your calcium-protein ratio is to follow the Food Guide Pyramid recommendations for quantity, but choose more carefully from each food group.
Start with a base of grains. Most breads, cereals, pastas and grains contain only small amounts of calcium and protein. Notable exceptions are soy flour and quinoa (pronounced "keen-wa"). Substitute grain-based foods for extra helpings of meat, chicken and fish to help keep energy up and protein closer to ideal. Choose 6-11 servings a day.
A few vegetables are good sources of calcium, while adding only 2 grams of protein per half-cup serving. Good choices include broccoli, Brussels sprouts, bok choy, savoy greens, green peas in edible pods, spinach, and acorn and butternut squash.
Fruits contain very small amounts of calcium. Berries and dried fruits contain the most. Fruits contain no protein, so they improve your calcium protein ratio a little, and help fill in the hungry spots when you decrease animal protein.
Dairy foods have calcium-protein ratio of 92:1 including skim milk, nonfat yogurt and lowfat cheese. Have two servings a day. Cottage cheese contains only small amounts of calcium, but lots of protein. The ratio is 5:1.
Meat, chicken and fish have a ratio of about 0.5 to 1. Limit portions to no more than 5 ounces a day. Better stil, substitute garbanzo beans (5:1), black bean soup (7:1), lentil soup (4:1), tofu (13:1) soybeans (6:1), or black-eyed peas (2:1) several times each week.
Colleen Pierre, a registered dietitian, is the nutrition consultant to the Union Memorial Sports Medicine Center and Vanderhorst & Associates in Baltimore.