Are heart palpitations dangerous?

DEAR DOCTOR K: I often experience heart palpitations -- almost every time I'm excited, angry or scared. Is this dangerous to my health?

DEAR READER: The word "palpitations" is used differently by different people. To me, palpitations are simply an awareness of your heart beating. People aren't usually aware of their heart beating. But when it beats unusually forcefully, irregularly or rapidly, you notice the heartbeat.

Why does my stomach make growling noises?

DEAR DOCTOR K: As I get older, it seems my stomach is more likely to make growling noises. Why does it do this, and what can I do about it? It's embarrassing.

DEAR READER: Maybe your stomach is trying to talk to my stomach. My stomach is periodically trying to talk to someone, that's for sure.

Am I too old for LASIK surgery?

DEAR DOCTOR K: I would like to have LASIK surgery to treat my nearsightedness. I'm 54 -- is that too old to have this surgery?

DEAR READER: LASIK (laser-assisted in-situ keratomileusis) can correct common eye problems: nearsightedness (myopia), farsightedness (hyperopia) and astigmatism. It can eliminate your need for glasses or contact lenses.

Can exposing babies to common food allergens help prevent food allergies later on?

DEAR DOCTOR K: In a recent column you said that parents should give babies peanut products to help prevent peanut allergies. Does the new advice also apply to other common food allergens, like eggs or cow's milk?

DEAR READER: To answer your question I turned to my colleague Dr. Claire McCarthy, a primary care pediatrician at Boston Children's Hospital. For decades, the standard advice recommended by allergy specialists was to hold off on giving babies foods that commonly cause allergic reactions. Parents were advised not to give egg, dairy, seafood or wheat in their child's first year. And parents were told to wait until two or three years to give peanuts or other nut products. It turns out that was bad advice.

Is addiction a disease or is it caused by a lack of willpower?

DEAR DOCTOR K: My brother has struggled with addiction for years. I've told my husband that addiction is a disease, but he claims my brother is weak and lacks willpower. Is he right?

DEAR READER: There is a lot of stigma and shame associated with addiction. But the truth is, people with substance-use disorders aren't simply weak or immoral. It surely is true that people who try out illegal addictive drugs for recreational purposes are breaking the law. In my opinion, they also are doing something profoundly stupid. But they're often teens, who tend to do a lot of stupid, impulsive things. Moreover, many people who become addicted to legal drugs were started on those drugs by their doctors.

Can you give me some practical solutions to compensate for my minor hearing loss?

DEAR DOCTOR K: I suffer from minor hearing loss, but not bad enough for a hearing aid. My wife complains about the volume on the TV, and I can't always keep up with conversations at a party or restaurant. I'm not looking for a technological fix just yet. Can you give me some practical solutions?

DEAR READER: I'm happy to share some practical tips for dealing with minor hearing loss. Before I do, though, I'd advise you to see a doctor. Hearing loss may be caused by a variety of things, including an underlying health condition.

Does hormone replacement therapy increase heart disease risk or not?

DEAR DOCTOR K: I'm in my third year of menopause, and my doctor won't prescribe hormone therapy. He says it increases the risk of heart disease. I think I recall that you told another reader that this is not true. Is my doctor right, or are you?

DEAR READER: You won't be surprised to learn that I think I'm right. But in the previous column you refer to, I didn't say exactly what you remember. I said that the effect of hormone therapy (HT) on heart disease depends on a woman's age and how recently she entered menopause. In younger women, in their first six to 10 years after menopause, HT protects against heart disease. In contrast, in older women, HT increases the risk of heart disease. It's called the "age effect."

Could my daughter have anorexia?

DEAR DOCTOR K: I'm worried about my 15-year-old daughter. She eats like a bird. She is very thin, but thinks she is fat. I'd like to think this is just a phase some teenagers go through, but could she have anorexia nervosa?

DEAR READER: As with most illnesses, there is not a magic dividing line between having anorexia and not. In fact, there's a big gray zone where people don't meet the criteria for a disease, yet they're not normal, either. An example is "pre-diabetes." Tens of millions of people in the United States have blood sugar levels that are not high enough to be called diabetes, but also aren't normal. It's important to recognize them, because such people have a higher risk for developing diabetes in the future.

What’s considered normal aging when it comes to sex?

DEAR DOCTOR K: My wife and I are in our 70s. Sex is not what it once was. Is there anything "natural" I can do to improve sex? I don't want to take pills. What's normal aging when it comes to sex?

DEAR READER: As a man in the last half of his life, I would like to be able to tell you that nothing changes. However, even in healthy men, sexuality changes over time. It's often a gradual, almost unnoticeable process that usually begins in a man's 40s.

Are there any new treatments on the horizon for Alzheimer’s disease?

DEAR DOCTOR K: Is there anything new on the horizon for treatment of Alzheimer's disease?

DEAR READER: Alzheimer's disease affects more than 5 million people in the United States, alone. And that number is expected to more than double by 2050. I spoke to my colleague Dr. Gad Marshall about advances in Alzheimer's treatment. He is an assistant professor of neurology at Harvard Medical School.