You probably already know that getting plenty of calcium in your diet is good for your bones, but it turns out that the mineral potassium might be just as important. Here’s why: A normal drop in hormone levels as you age often causes bone loss, and the acid levels in blood can leach calcium from your skeleton, possibly weakening bones and boosting your risk of osteoporosis—even if you get plenty of calcium and vitamin D. In a decade, that means you could lose 15 percent of your bone density as a result. But potassium—which is probably best known for helping to regulate blood pressure and for preventing muscle cramps—reduces the acidity in your blood. As a result, it locks more calcium in your bones, recent research has found.

But you might not be getting sufficient potassium. Most women get just half of the 4,700 milligrams of potassium per day that is recommended by the Institute of Medicine. So how can you boost your intake? Make sure that you eat more potassium-rich produce, says bone researcher Katherine L. Tucker, Ph.D., professor of nutritional epidemiology at the University of Massachusetts at Lowell. The phytochemicals, antioxidants, and potassium that are in produce play a role in protecting bones, she explains; vitamin K and magnesium help, too.

Smart Ways to Get More Potassium

Here are some smart strategies for ensuring that you get your fill of potassium:

  • Aim for five to nine servings per day of fruits and veggies, says study author Helen Lambert, Ph.D., of the University of Surrey in the U.K. (People with kidney disease should eat less potassium, though.)
  • Potassium-rich foods include spinach (with 840 milligrams in 1 cup, cooked), a baked potato with skin (800 milligrams), yogurt (490 milligrams per cup), sweet potatoes (448 mg per cup), strawberries (460 milligrams per cup), and broccoli (460 milligrams per cup).
  • Add other deep orange, yellow, and green produce rich in the antioxidants known as carotenoids to your diet as well; people who ate the most had higher bone mineral density at the hip and spine in another study by Tucker.