Drs. Michael Roizen, M.D., and Mehmet Oz, M.D.

Q: I'm 45 and healthy, but I want to make sure I don't get osteoporosis when I'm older. Should I be taking calcium supplements now, or is that risky? -- Shirley L., Fresno, Calif.

A: Good question! There's been a lot of news about the risks and benefits of calcium supplements for men and women, and that's got some folks wondering whether to continue with the supplements they're already taking. Today, 43 percent of the U.S. population pops a daily pill that contains some calcium.

A consistent level of calcium (and magnesium, plus D-3) is necessary for healthy nerves, muscles and organs, not to mention bone strength. Chances are you need a D-3 supplement: 1,000 IU a day is what we take, and we have an annual blood test to make sure our levels are 50-80. And a supplement of 600 mg of calcium with 300 mg of magnesium daily is safe to take and may provide benefits.

But you can get too much of a good thing from calcium supplements. One study showed men 50-71 who take a 1,000 mg daily calcium supplement increase their risk of dying from heart disease by 20 percent. The reason? Calcium gets into the lining of the blood vessels, making arteries stiffer. However, 1,000 mg calcium a day from food is part of a bone and heart-friendly diet. (Over 70? Go for 1,200 mg a day from food.)

And the U.S. Preventive Services Task Force recently announced calcium supplements may not be the right choice for women who want to protect their bones. There just isn't proof that a daily supplement of 400 IU or less of vitamin D-3 and less than 1,000 mg of calcium prevents bone fractures. Are larger doses of calcium helpful or risky? No one knows yet. So women 19-50 should aim for 1,000 mg of calcium a day from food; women 51 and older, 1,200 mg calcium from food and 1,000 IU D-3 from a supplement.

We suggest: To protect your heart and keep bones strong, start with plenty of weight-bearing exercise in addition to walking 10,000 steps a day, and get calcium from food. Here's what some tasty choices contain: 1 cup plain, nonfat yogurt, 490 mg; 1 cup cooked kale, 180 mg; 1 cup of cooked spinach, 260 mg; 3 ounces canned salmon, almost 200 mg; a 3-ounce serving of sardines, 325 mg; an ounce of sesame seeds, 280 mg; 1 cup soybeans, 261 mg; 1 cup cooked turnip greens, 200 mg.

Q: We're trying to get pregnant. I've heard so much about how chemicals in plastics can harm a fetus -- and cause a child to have learning problems and illnesses. So, I want some advice on how to protect my baby. -- Alice W., Milwaukee

The latest info on these chemicals indicates that exposure to bisphenol A (BPA) and its cousin BPS in the womb or as an infant increases the risk of childhood asthma and learning disorders. It does this by disrupting hormones and changing the function of a gene important to learning in kids (and adults).

Even more unsettling is the fact that small amounts of BPA seem to interfere with brain development by blocking the action of a protein that instructs neurons where to go.

So, what can you do to protect your future child? First, you want to reduce YOUR exposure to BPA.

1. Check the plastic ID code on the bottom of polycarbonate bottles and packages: No. 7 means it could contain BPA.

2. Don't take thermal cash register receipts. Touching the receipt and then your mouth is the No. 1 way to end up with BPA and BPS in your system.

3. Avoid canned foods: They're lined with resin that contains BPA, unless marked BPA-free.

4. Don't microwave polycarbonate plastics (hard, clear, lightweight).  BPA can leach into your food. Avoid putting them in the dishwasher, too.

5. When your child is born, follow the same precautions regarding bottles, food containers and toys. Wash your hands before preparing food or touching your baby -- especially if you have recently handled a receipt.