Calcium and vitamin D get a lot of attention for promoting bone health. But consuming certain foods and nutrients can weaken your bones, increasing your risk for osteoporosis and dangerous fractures.
The facts you need to know…
Salty Foods = Weak Bones
Too much sodium is widely known to increase blood pressure, but, surprisingly, too much sodium can be bad for bone health, too.
Important finding: Research published in the Journal of Human Hypertension has linked higher sodium intake (more than 2,300 milligrams (mgl daily) to low bone mineral density, a key indicator of bone strength.
How does sodium affect bone health? If you ingest too much sodium, the excess is excreted in your urine. But when sodium is excreted, it drags calcium with it, so you are losing calcium, too.
Self-defense: Do not consume more than 2,300 mg of sodium daily (the amount found in about one teaspoon of salt).
Even better: If you can, strive for no more than 1,500 mg per day. This is not easy to do given today's typical diet...it means limiting processed foods and reading food labels closely.
Protein—Good Or Bad?
Some nutritionists have warned that too much protein-particularly from meat, fish and poultry-raises the risk for osteoporosis. The theory is that the more protein you eat, the more calcium you excrete in urine. However, new research shows that it's not that simple.
Important new finding: A study recently published in the American Journal of Clinical Nutrition shows that the loss of calcium caused by increased protein is offset by increased absorption of calcium in the intestine-calcium retention in the body remains unchanged.
Fact: A high-protein diet can be good for bones, as long as you get enough calcium. Specifically, a 12-year study of more than 3,724 adults found that among people who consumed at least 800 mg of calcium daily, the risk for hip fracture was reduced by 85% for those who ate the most protein (about 76 g daily) compared with those who ate least (about 46 g daily).
Only when calcium intake was below 800 mg daily was high protein intake bad for bones-it was linked to nearly three times the risk for hip fracture.
Self-defense: Instead of limiting your protein intake, make doubly sure to get enough calcium. Aim to consume 1,200 mg of calcium daily if you are age 51 or older (1,000 mg if you are age 19 to 50) from dietary sources...and/or a calcium supplement if your diet is lacking.
The Acid Test
Certain foods, including meat, dairy and grain products, make the blood more acidic. Some nutritionists believe that this promotes bone loss. They cite research linking the negative effect that a high-acid diet has on the blood to chemical signs of bone breakdown, which improve when the subjects are given bicarbonate to neutralize the acid.
But evidence that high acid levels actually sap bone strength is thus far weak. One large Canadian study, in fact, found no association between urine acidity (a measure of acid in the diet), bone mineral density and the risk for fracture unless the acid diet was extreme.
Meanwhile, there is good scientific evidence linking the consumption of fruits and vegetables-most of which are alkaline (they neutralize acid)—to stronger bones.
This is most likely due to the fact that fruits and vegetables contain biologically active compounds that appear to promote bone health.
Important finding: A study published in the Journal of Bone Mineral Research linked dietary intake of flavonoids, which are found in fruits and vegetables, to higher bone mineral density.
Watch What You Drink
Caffeine from any source works against strong bones by interfering with calcium absorption. However, you can offset the caffeine in coffee by consuming calcium-rich foods, such as yogurt and low-fat cheese. The caffeine in chocolate is less of a concern—it contains calcium that mitigates the calcium-inhibiting effect of caffeine.
Self-defense: If you drink a lot of caffeinated coffee, for example, try adding some milk from time to time-or be sure to consume other calcium-rich foods, such as yogurt or low-fat cheese.
Soda consumption has been linked to increased risk for osteoporosis. Some nutritionists theorize that phosphoric acid, a major ingredient in soda, disrupts the balance between phosphorus and calcium that is needed to maintain bone health. However, there's not enough data to prove this theory.
Another possibility is that soda drinkers are likely to skimp on calcium-rich beverages, such as milk or calcium-fortified orange juice.
Self-defense: Limit soda intake-or if you do drink soda, be sure to balance it with heavy calcium intake as described earlier.
Vitamin D is needed to promote calcium absorption. The Institute of Medicine recently confirmed that older adults (age 71 and older) need 800 international units (IU) of vitamin D daily and those ages 14 to 70 need 600 IU daily.
Vitamin D should come, ideally, from foods such as egg yolks, fortified milk and salmon (which provide additional nutrients), but most people will need a supplement to reach the desired level.
However, not all vitamins are necessarily good for our bones. In fact, excessive vitamin A may threaten bone health—very high levels have been linked to bone loss.
Recent finding: An American Journal of Clinical Nutrition study of 75,747 women linked high intake of vitamin A to a slightly increased risk for fracture-but only among those whose vitamin D intake was less than 400 IU daily.
Self-defense: Even though the scientific evidence linking high vitamin A levels to bone fracture is not definitive, it's still wise not to exceed the recommended daily intake for this vitamin—3,000 IU for men and 2,333 IU for women.