Dear Doctor: I'm 12 years old, and I really want to get a dog. Can you help me find some studies to convince my mom and dad about the benefits of having a dog?

Dear Reader: First, we think it's terrific that you're going for a fact-based approach to persuade your parents to get a family pet. The good news is that plenty of scientists share your enthusiasm and, to that end, have amassed quite a body of research about the benefits of having a dog in your life.

We're going to begin by assuming no one in the family has pet allergies. It'll be a game-changer if they do. But if there's no sneezing, coughing, itching, asthma or other adverse reaction among the people in your home, then let's get to what science has to say.

Many studies suggest that dogs help their owners in many realms: emotionally, physically and mentally. That's because pet owners tend to walk more, get emotional support and comfort from their pets, suffer less depression, are more social thanks to regular dog walks, and may even get a protective effect against allergies. This last point is thanks to the constant low-grade exposure to the dander, dirt and pollen that an active indoor-outdoor dog brings into the house.

One study showed that older adults who had dogs and walked them regularly had a lower body mass index, had fewer visits to the doctor, and generally spent more time interacting with people than those without dogs. Other studies have shown that being around a dog can reduce stress, which translates to lower blood pressure and better sleep patterns. Several studies have found a link between having a dog in the home and lower rates of asthma and certain allergies among the young children who grow up with the dog.

A study that your parents might like looked at 240 married couples. The couples with a pet in the home had lower blood pressure and heart rates than those without a pet. This applied to when they were just sitting around, as well as while undergoing the rigors of a stress test. And when something did cause them to feel stress, the pet owners' physical responses were less extreme, and their recoveries were faster.

If a list of the many benefits of dog ownership isn't working, try some amazing facts about dogs themselves, like that dog noses are so sensitive they can sniff out certain types of cancer more accurately than actual lab tests.

To be fair, we have to address some potential drawbacks. One is that dogs tend to get ticks and fleas, each of which is associated with disease. Dogs that are not properly trained (and even some that are) may bite. And pets getting underfoot are responsible for some of the up to 8 million visits to the ER for falls each year.

As pet lovers ourselves, we have heard from our own patients about how much their dogs mean to them. We wish you a happy outcome when you talk to your mom and dad.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: French fries are absolutely one of my favorite foods, but because of their calorie content, I try to limit them to twice a week. Now I just read that eating them even that rarely is linked to a higher risk of death. Just how problematic are a couple of servings of fries each week?

Dear Reader: In my younger days, I also loved french fries. It didn't take me long to figure out that potatoes fried in oil were not the healthiest of foods, so I gave them up. I didn't rely on any studies to make this decision, but the research to which you're referring raises some interesting questions about the potential risks of potatoes, especially fried potatoes.

The study, published recently in the American Journal of Clinical Nutrition, assessed 4,400 people who were at high risk of osteoarthritis of the knees. All participants filled out a food questionnaire; two of the questions were about consumption of fried potatoes and un-fried potatoes. Fried potatoes included french fries, hash browns and tater tots.

Participants were then divided into sub-groups, depending on how often they ate potatoes: less than once a month, two to three times a month, once a week, twice per week or, lastly, three or more times per week. Over the eight years of the study, 236 people died. People who ate fried potatoes twice a week had almost double the risk of death, compared to people who ate fried potatoes less than once a month. Those who ate fried potatoes three or more times per week had more than twice the risk of death, compared to the group who ate the fewest fried potatoes. The authors did not find a correlation between death risk and un-fried potatoes.

Note that there were significant limitations to this study. One is that it was relatively small. Second, the authors did not make mention of other foods that participants ate, such as processed meats, trans fats or sodas. So to take fried potatoes in isolation -- and then draw conclusions -- is difficult. Lastly, the groups who ate the fewest fried potatoes included a greater proportion of women, who have a lower death rate within any given time frame as compared to men.

That said, let's assume the data are reliable. If so, why are fries so risky? A 2016 study combined data from three large trials with a total of 199,181 people. In that analysis, three servings per week of french fries correlated with a 19 percent increased risk of diabetes. This increased rate of diabetes was also seen in two other studies. Further, a 13-year Swedish study found a 22 percent increase in the cardiovascular death rate among people who ate fries -- not other fried potatoes -- three days per week. Something to consider: At the time of these studies, fries may have contained greater amounts of trans fats, which have been associated with increased death rates.

The research correlating fries and death rate is not perfect, but there does appear to be a correlation. I would recommend decreasing your intake. Now I have to convince my kids to do the same.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: We live in Orlando, and last year a teenager here was infected with that brain-eating amoeba. Now we're reading that it's in the drinking water in Louisiana. How common is it? Should we be worried about an epidemic?

Dear Reader: There's nothing quite like the words "brain-eating amoeba" to get the news cycle humming. And the reassurance we're about to give you -- it is extremely, exceedingly rare -- is not necessarily the most attention-grabbing. But that's where we're going to begin.

Between 2007 and 2016, there have been just 40 cases of the so-called brain-eating amoeba reported in all of the United States, according to the Centers for Disease Control and Prevention. To put that into even clearer perspective, that's 40 cases in 10 years among 324 million people.

The microscopic creature that's been making headlines is called Naegleria fowleri. Trace amounts of it were discovered in two community water systems in southern Louisiana during routine testing last June. Customers of the affected water facilities were promptly alerted by the Louisiana Department of Health, and disinfection procedures were implemented.

So what is it?

Naegleria fowleri is a single-celled organism found throughout the world in warm freshwater, like lakes, streams, rivers, ponds and hot springs. It enters the body through the nose, typically when people accidentally inhale water while swimming or diving. The amoeba then travels through the nasal passages and enters the brain via the olfactory nerve. Once there, it begins to destroy brain tissues.

You can't become infected by drinking contaminated water, or by swimming in water that has been adequately chlorinated. There have been no known cases of transmission through water vapor, as during a shower or through a humidifier.

The majority of infections reported since 1962 have been in the southern U.S., with half of those in Florida and Texas. But infections have occurred as far north as Minnesota and as far west as Nevada and California. The specific disease the organism causes is called primary amebic meningoencephalitis, or PAM. It's diagnosed using specific laboratory tests that, because the disease is so rare, are not widely available.

Symptoms begin one to nine days after infection, and are divided into two stages. They're similar to those of bacterial meningitis, which adds a level of difficulty to an accurate diagnosis.

The first stage of the disease is marked by a severe headache in the front of the head, often with fever, nausea and vomiting. This is followed by stiffness in the neck, altered mental state, seizures and coma.

Although in most cases the disease is fatal, the Orlando teenager you're referring to survived. It is believed that a swift diagnosis -- the infection was identified within hours of the onset of symptoms -- was key to his beating the odds. So was aggressive treatment, which included an investigational drug, and cooling his body to well below normal body temperature, a process known as therapeutic hypothermia.

Unlike other survivors, who had permanent neurological damage, the Orlando teen recovered fully and is back in school. The hope is that early diagnosis and novel therapeutics may lead to higher survival rates in the future.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)