To build strong bones and keep them sturdy, you need a diet that contains a lot of calcium and magnesium. But there's more to it than that -- you also need plenty of protein and vitamins B, D, and K.
Paying attention to bone health when deciding what to eat is more important than you might think. More than 10 million people over age 50 have osteoporosis, while another 34 million have osteopenia, which means they're on their way. Astonishingly, one expert panel says that by 2020, half of all Americans will have brittle bones.
Thanks to your mother's admonitions to drink your milk, you probably know that's one important bone-building food. But there are many other ways to make your diet bone-friendly. Here are ten foods packed with bone-building nutrients.
1. Yogurt and frozen yogurt
Low-fat dairy is one of the best natural sources of calcium, vitamin D, and other nutrients that build strong bone. And nonfat or low-fat yogurt is one of the best nonfat dairy foods because it has other benefits as well. Frozen yogurt, while typically not as healthy because it has more added sugar, still has lots of calcium -- as much as 200 to 300 milligrams per cup, depending on the brand.
How much: Aim for at least one one-cup serving daily for 300 milligram calcium; one and a half cups if it's frozen yogurt.
Tips: Choose a yogurt with live cultures. The lactobacillus, acidophilus, and bifidus will help maintain healthy intestines and digestion while also aiding calcium absorption.
2. Herring, sardines, and other whole canned fish
Vitamin D plays a key role in promoting the turnover of osteoblasts, the bone-building cells. Herring and sardines (often the same thing when sold here in the U.S.) are king when it comes to vitamin D, with more than 1,300 IUs (international units) in one three-ounce serving. A same-size serving of canned salmon has 530 IUs. You can also drink your fish -- cod liver oil is one of the best sources of vitamin D, with 450 IUs in a single teaspoon. Perhaps the Victorians were onto something when they used to make their children drink the icky-tasting stuff.
How much: Tins of sardines typically come in 3.75-ounce and 4.75-ounce sizes; a snack of half of a smaller can gives you more than half your daily vitamin D.
Tip: To cut calories and boost health benefits, choose sardines and other canned fish packed in their own oil, olive oil, or water rather than in soybean or cottonseed oil.
Dark green leafy vegetables like kale, spinach, collard and turnip greens, broccoli, lettuce, beet greens, and bok choy are the top sources of vitamin K, which is actually not a vitamin but an amino acid also called GLA or Î³-carboxyglutamic acid. Nutritionists are only beginning to understand the role of vitamin K, which is important in the formation and proper functioning of a bone protein called osteocalcin. Vitamin K, by way of osteocalcin, aids the binding process of calcium and phosphorous into the bone protein matrix. Greens are a good source of calcium as well, so there's a double-whammy benefit here.
How much: Official serving sizes vary from a half to a full cup of greens; try to work one serving per day into your diet.
Tip: The darker the color of the greens, the more micronutrients they typically have, with spinach, kale, and collard greens among the most nutrient-dense.
4. Beans and legumes
One of the most recent nutritional discoveries related to bone health is the importance of folic acid and other B vitamins. One recent study published in the American Journal of Clinical Nutrition found that the bones of people with low levels of vitamin B6 and folic acid in their blood underwent structural changes, causing them to be weaker and more prone to fracture. Another study linked vitamin B12 to stronger bones. Scientists are still studying the connection but believe that B vitamins stimulate collagen production, which is essential to bone strength.
Foods high in folate and B vitamins include lentils, chickpeas, and all kinds of beans and legumes. There's also liver, of course, but many of us like beans better.
How much: Nutritionists suggest eating beans several times a week. That doesn't mean just burritos and tacos; sprinkling some kidney beans, fresh soybeans, or chickpeas on your salad counts just as much.
Tip: Fresh soybeans, known as edamame, make a healthy, folate-rich snack -- and they don't give you gas, as so many beans do.
5. Soy milk
Here's a secret: Calcium-fortified soy milk actually has more calcium in it than milk -- up to 400 milligrams a cup. And recent studies show that the calcium in soy milk is as easily absorbed as that in regular milk. Tofu is also calcium-rich: One half-cup serving contains 250 milligrams, which is 25 percent of your daily needs.
How much: To get the recommended one cup a day, put half a cup on your morning cereal and another half cup in your coffee or a chai latte.
Tip: For still more calcium, choose tofu that's preserved with calcium sulfate, making it an even better bone builder.
Rich in omega-3 fatty acids and protein, almonds are the superstars of the nut family, although many nuts contribute to bone health. One ounce, or approximately 23 almonds, contains 6 grams of protein and an unusually wide variety of minerals, including potassium, magnesium, manganese, zinc, and copper -- in addition to calcium. Recently nutritionists have begun acknowledging the important role minerals such as copper, potassium, and manganese play in oxygenating blood, which helps it carry nutrients to the bones.
How much: A large handful of 20 to 25 nuts makes a perfect afternoon snack and contains 20 percent of the magnesium your body needs each day.
Tip: If you aren't an almond fan, walnuts are also high in bone-building nutrients. And you can add them to brownies and other baked goods.
The calcium benefits of soy milk are even more concentrated in tofu, which is made from condensed soy bean milk curd and is typically fortified with additional calcium and magnesium during processing. The fermentation process that goes into making tofu also concentrates the amount of protein and vitamin K. Add a small amount of tofu to salads, stir-fries, and omelets and other egg dishes, and you've found a way to sneak calcium, vitamin D, protein, and vitamin K into your diet without changing much about the way you eat.
How much: One half-cup has 253 milligrams of calcium; add it to a stir-fry or grill as an appetizer topped with peanut sauce.
Tip: Choose tofu prepared with calcium sulfate and magnesium chloride (also called nigari) for the highest mineral content.
8. Evaporated milk
This oft-forgotten product, the mainstay of many an old-fashioned dessert, is a surprisingly good source of calcium and protein. The heating process used to make evaporated milk removes 60 percent of the water content but leaves the nutrients intact, essentially doubling the nutrient content. (Condensed milk, made with a similar process, usually has sugar added, but evaporated milk doesn't.) Make pudding or bake with evaporated milk and your nutrients are tucked into a tasty dessert.
How much: One cup of evaporated whole, low-fat, or nonfat milk contains 700 milligrams of calcium and 16 grams of protein, more than twice that in the same size serving of milk.
Tip: Check labels and choose a brand fortified with vitamin D3.
9. Apricots and dried fruit
Susan Brown, a leading osteoporosis nutrition expert, calls potassium "the hidden bone guardian," with good reason. Potassium, she says, creates an alkaline buffering layer around bone that prevents metabolic acids from leaching minerals from bone and breaking it down. She points out that the suggested adequate intake of potassium for adults, 4,700 milligrams, is much higher than that of calcium and can be difficult to meet through a traditional American diet.
Specific fruits, vegetables, and seeds are the best nutritional sources of potassium. Bananas are the potassium boosters most people think of first, but the average banana actually only contains 400 milligrams of potassium, while a single apricot has 1,380 milligrams. Raisins, figs, dried fruit, wheat germ, and bran are all excellent sources of potassium.
How much: Aim for one fresh apricot daily, when they're in season. The rest of the time, meet your potassium needs by topping your cereal with a half cup of dried apricots (895 milligrams) or raisins (545 milligrams), or by snacking on five dried figs (666 milligrams).
Tip: If you're not a dried-fruit lover, try baked potatoes (yep, must be baked, and in the skin) and avocados for surprise sources of potassium.
10. Wheat germ and seeds
One last "secret" nutrient needed for strong bones is phosphorous. And unfortunately, most of us need to make some changes in our diets to get enough phosphorous. Wheat germ and bran are the best sources of phosphorous, with 1,200 milligrams in a single portion, so add them to your cereal in the morning. Foods high in phosphorous include pine nuts, also called pignolas, and sunflower seeds; add them to your salads or cereal, or snack on them solo. That same herring that was high in vitamin D also has lots of phosphorous, so if you're a herring fan, go for it.
How much: Sunflower seeds are so nutritious that you don't need much; a quarter cup sprinkled on a salad or eaten as a snack gives you one quarter to one third of your daily allotment of folate and essential minerals and almost your entire requirement of vitamin E.
Tip: Sprinkle just one tablespoon of ground flaxseed, now available in most health food stores, onto your breakfast cereal or stir it into yogurt -- you've added more than 1,500 milligrams of omega-3, as well as minerals such as phosphorus, manganese, magnesium, and copper.