Osteoporosis, or low bone density, is a growing problem. The CDC estimates that by 2020, more than 20 million Americans over the age of 50 will suffer from osteoporosis. Bone density peaks at age 25 to 30, after which, calcium is slowly leached from bone, weakening its structure. If you’re over 30, however, don’t fret; you can still maintain or even improve your bone health with nutrition and exercise. This is because your bones are made of living tissue that is constantly broken down and re-mineralized through an intricate remodeling process involving the nutrients mentioned above and other regulatory hormones.If you’re interested in health, you probably already know that calcium is essential for strong bones, but did you also know that vitamin D, phosphorus, magnesium, and vitamin K may be just as important to the long term health of your bones?
- Calcium: Meeting your daily calcium needs can help bones hold on to calcium they already have. Adults need 1000mg of calcium daily (1200 mg if you’re over age 50). One cup of cow’s milk (or fortified rice or soy milk) contains 300mg of calcium, which is the equivalent of 6oz of yogurt, 1/2 cup of tofu, 6 oz canned salmon with bones, 1/2 cup Chinese cabbage, 1 cup bok choy, 1 1/2 cups kale, mustard greens or turnip greens, or 2 cups broccoli. If you choose to supplement with calcium to fill in the gaps, take no more than 500mg at a time for optimal absorption, take it with vitamin D, and take separate from iron rich foods or iron supplements. Calcium supplements in the form of calcium carbonate should be taken with food to optimize absorption; calcium citrate can be taken on its own or with food.
- Vitamin D is responsible for maintaining optimal levels of calcium and phosphorus in the blood. Taking 2000IU/day is seen as safe for most adults, but check with your doctor before beginning a regimen. You can read more about vitamin D here.
- Phosphorus and calcium bind together as the structural component of bone, and a balance between these nutrients is essential for proper bone mineralization. The recommended intake of phosphorus for healthy adults is 700mg. One cup of milk, 5 oz. yogurt, 3 oz .lean or fatty fish, 2 oz. hard cheese, or 1/3 cup lentils provide about a third of your daily needs (~230mg), while 3 oz. of chicken or beef, 1 egg, and 1 oz (22-25 nuts) almonds all contribute over 100mg per serving. Most normal diets contain more than adequate dietary phosphorous, however, since its found in so many foods.
- Inadequate intake of magnesium intake can contribute to calcium deficiency and resistance to the effects of bone building hormones and vitamin D. Men and women require 400 mg and 310 mg, respectively, up to age 30; and 420mg and 320mg, respectively, thereafter. Whole grains, nuts, seeds, beans, fish, leafy greens and cocoa powder are among the best dietary sources; one quarter cup of pumpkin seeds provide a whopping 300mg! One half cup 100% bran cereal or firm tofu packs about 130mg, while ½ cup of legumes contains ~45-65mg. But, be careful not to overshoot magnesium recommendations in supplement form, as it can have an unpleasant laxative effect. The maximum dose of magnesium you should take is 350 mg from supplements, but there is no limit to how much you can safely consume from foods.
- Vitamin K is involved in maintaining adequate blood calcium levels by limiting the excretion of calcium and other bone precursors in the urine and by acting in support of bone building proteins. Vitamin K is found in leafy greens like kale, collards and spinach, green veggies like broccoli, green beans and Brussels sprouts, in cranberry juice, avocado, green tea, and cheese, but it is also produced naturally in your colon by the resident friendly bacteria. If you’re not taking antibiotics, blood-thinning medication, or megadoses of vitamins A or E, then you’re likely meeting your needs from diet alone (90 mg/day for women, 120 mg/day for men).
- Exercise: Since bones are living tissue, they need regular exercise for strength — just like muscles. Try to get 30 to 40 minutes of weight-bearing exercise at least 4 days a week. Now is the time to start that yoga class you’ve been pondering or recall your favorite childhood pastime of jumping rope. Carrying groceries, doing house-work, and walking your dog count too; just get moving!
- Beware of bone-thiefs: Eating too much fiber (more than ~35g/day) can impair proper mineral absorption, and a high sodium diet (more than 2,300 g/day) and drinking more than the occasional soda (especially dark sodas which contain phosphoric acid) can cause increased losses of calcium, magnesium, and phosphorus. All three dietary habits may increase the risk of osteoporosis.