I use Nalgene bottles for about 75 percent of the water I drink each day. Therefore, I was startled to find out that there is some possibility that these bottles leach chemicals into the water. I've found conflicting opinions about the veracity of these claims on the Internet. What's the truth? Should I dump my Nalgene for glass? You have an earlier post about bottled water, but it doesn't seem to address this issue specifically, and you recommend purchasing reusable bottles like the ones that might be poisoning me. The bottles I use have #7 on the bottom in the recycle symbol.

1) Which is better for you, tap or bottled water?

2) How bad is the water here in New York City? Do you recommend drinking filtered water, or does it really make a difference?

Why is your favorite food very tasteless when you have a cold?

1) This is in reference to your Missed periods Q&A. Another cause of missed or late periods is PCOS (polycystic ovary syndrome). A lot of health care providers don't seem to be aware of this syndrome. In this syndrome, missed or irregular periods are caused by unusual hormone levels, sometimes in combination with insulin intolerance. Because missed and irregular periods cause scar tissue build-up in the uterus (which may cause endometrial cancer) and may cause infertility, it is important that your readers know to ask their health care provider about this syndrome. There are obviously other symptoms and complications, but I just thought that I might mention it to you so that you might read up on it for your readers. Thank you.

2) I was recently diagnosed with polycystic ovary syndrome (PCOS). I'm only 17 and am afraid that this will affect my chance of having children. Should I worry? Also, I know birth control pills will help me regulate my period, but if I take them, will it stop the effects PCOS has on me? Like me gaining rapid weight, missed periods, and losing my hair? This is really worrying me. Can you inform me on this syndrome?