Which is a better choice for protein– meat or legumes?

DEAR DOCTOR K: I know we need protein in our diets and that beans are a good source. But I've read that meat is a great source of protein and iron. Which is a better choice?

DEAR READER: Meat is an excellent source of protein and iron, but unfortunately, red meat is also full of saturated fat -- one of the "bad" fats.

Leaner cuts contain less saturated fat, but eating lean red meat still causes you to consume lots of saturated fat. The saturated fat is not always visible: In addition to the layer of fat that may cover a cut of red meat, and any visible fat "marbled" inside the meat, there is plenty of invisible saturated fat. Just because you can't see it doesn't mean it's not there.

I want to start exercising regularly– Should I join a gym?

DEAR DOCTOR K: I want to start exercising regularly. Should I join a gym?

DEAR READER: You don't need a gym in order to exercise regularly. Your body offers the cheapest equipment available. And the money you save by not paying for a gym membership might be put to good use elsewhere, whether that means monthly bills or tennis lessons. But joining a gym has its benefits, too.

What are the different pills for Type 2 diabetes?

DEAR DOCTOR K: I have Type 2 diabetes and my doctor wants to prescribe medication. Fortunately, he says I don't need shots, just pills. What are the different pills for Type 2 diabetes?

DEAR READER: No one likes needles, but the needles used to give yourself insulin are very small, and the shots are very easy to administer. But for Type 2 diabetes, it is true that pills are often all that are needed. In Type 2 diabetes, like the less common Type 1, blood glucose (sugar) levels are too high.

Do the germs that live on or in us affect our health?

DEAR DOCTOR K: Do the germs that live on or in us affect our health?

DEAR READER: Trillions of germs live in and on us, all of our lives. They live on our skin, in our mouth, in our digestive tract and elsewhere. In yesterday's column, I mentioned that amazing recent discoveries have greatly expanded our understanding of these germs and the effect they may have on our health.

Are all germs dangerous to our health?

DEAR DOCTOR K: Are all germs dangerous to our health?

DEAR READER: Not all microorganisms (also called germs or microbes) are bad for our health -- far from it. Our knowledge of the impact of germs on our health has expanded greatly in just the past five years. I think of germs in two categories. First, there are the germs that enter our bodies from the outside world and are usually with us only temporarily.

Why do I have trouble remembering certain types of information but not others?

DEAR DOCTOR K: As I get older, I've noticed that I have more trouble remembering certain types of information. But other types of memory are as strong as ever. Is this true, or just wishful thinking on my part?

DEAR READER: You've made an interesting observation -- and an accurate one. As we age, some information does become harder to recall, and new memories may be harder to lay down in the brain. But other memories remain as accessible as ever.

Does “mindfulness meditation” really help relieve stress and anxiety?

DEAR DOCTOR K: I've heard a lot about "mindfulness meditation." Does it really help relieve stress and anxiety?

DEAR READER: Mindfulness meditation has become quite popular in recent years. The practice involves bringing your mind's attention to the present without drifting into concerns about the past or future. Many people practice it hoping to stave off stress and stress-related health problems.

What does positive reading on a Mantoux test mean?

DEAR DOCTOR K: My 6-year-old just had a positive reading on her Mantoux test. What does this mean?

DEAR READER: Doctors perform a Mantoux test to see if someone may have been exposed to bacteria that cause tuberculosis (TB). TB is a bacterial infection that typically infects the lungs. Fortunately, in most people exposed to the bacteria, TB never develops.

Which type of tea has the most health benefits?

DEAR DOCTOR K: Is drinking tea good for my health? Which type has the most health benefits?

DEAR READER: Several studies have touted the health benefits of tea, but the benefits of particular foods or drinks are hard to prove. The most persuasive type of study to prove that any practice has health benefits is a randomized trial. When I say "practice," I mean a medicine, a surgical procedure, a particular food or exercise routine -- any practice designed in part to improve your health.

Are there risks of taking a daily aspirin to reduce the risk of a heart attack or stroke?

DEAR DOCTOR K: What are the risks of taking a daily aspirin to reduce the risk of a heart attack or stroke?

DEAR READER: I didn't have to do much homework on this one, because I take a daily aspirin and already know the answer. It was front-page news in 1988 when colleagues of mine at Harvard Medical School reported the results of a randomized trial that found that a daily aspirin protected against heart disease. A simple, cheap, over-the-counter pill could protect against the No. 1 cause of premature death: heart disease (specifically, atherosclerosis of the arteries of the heart)? It seemed too good to be true.