Dear Doctor: Can Type 2 diabetes be reversed? My son was recently diagnosed with it, but I'm not sure he's taking it seriously enough.

Dear Reader: I understand your concern: Clearly, your son -- and everyone with diabetes -- should do whatever they can to combat the disease. Chronically elevated blood sugar leads to atherosclerosis, increasing the risk of heart attacks, strokes and vascular disease in the legs. It also damages the nerves and kidneys, leading to a loss of sensation and kidney failure. Controlling the disease, though difficult, is not impossible and should be paramount.

Even reversing the disease is doable. As proof, consider the effects of bariatric (weight loss) surgery among people with Type 2 diabetes. They quickly go into remission.

If surgery seems too dramatic, consider the non-surgical evidence from a 2015 study in which 29 patients consumed a liquid diet of 624 to 700 calories per day for eight weeks. In the United States, the reported average caloric intake for a man is 2,600 and in women it is about 1,800; for people with Type 2 diabetes, it's often much higher. After eight weeks of calorie restriction, the average study participant lost about 32 pounds.

Among those who had had diabetes for less than four years, 87 percent reversed their fasting blood sugars to non-diabetic levels. Among those who had had diabetes for more than eight years, 50 percent were able to reverse blood sugars to non-diabetic levels. Blood pressure and cholesterol numbers also improved and the participants were able to tolerate the calorie restriction well.

A 2016 study looked at what happened to these patients after they returned to a normal-calorie diet. All participants received dietary counseling and, six months after the initial start of the study, they had regained -- on average -- only 2 pounds of the 32 pounds they lost during fasting. Those who had reversed their diabetes were able to maintain their blood sugar at the same level even after returning to a normal-calorie diet. Even those who were not able to reverse their diabetes had lower blood sugar levels than before the study.

A current study that won't have complete data until 2018 has followed 140 patients who adhered to 12 weeks of an 825-to-853-calorie diet; it will follow them as they then try to maintain a balanced diet for the next 92 weeks. The results are expected to give Type 2 diabetics hope of reversing diabetes with initial calorie restriction, followed by a balanced diet.

These are tightly controlled university studies and may be difficult to replicate outside of a well-conducted clinical trial. However, newly diagnosed Type 2 diabetic patients eventually may be given directions for a low-calorie diet, followed by a diet overseen by a nutritionist.

In the meantime, to reverse his diabetes, your son needs to start by eliminating foods with added sugar. This seems obvious, but it takes self-control. Cookies, candies, cakes, doughnuts, ice cream, sodas and juices should have no place in his diet. He should also stay clear of low-fiber carbohydrates, especially snack foods. If he's diligent with his diet, he can reverse a disease that has become an epidemic within our country.

So the answer is: Yes, Type 2 diabetes can be reversed, as can the obesity that leads to it. But reality itself isn't that simple.

(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: Does drinking coffee really increase the craving for sweets? I tend to drink a lot of coffee throughout the day, and if it's true, it explains a lot about my dietary choices.

Dear Reader: While recent studies have found a connection between caffeine and the urge for something sweet to eat, the cause and effect isn't quite that direct. It's not the coffee itself that somehow makes us long for the doughnut or Danish, but rather how caffeine affects certain chemical processes within our bodies. To get a fuller understanding of what's going on, let's take a closer look at the research -- and at caffeine.

Our daily coffee (or tea or cola or energy drink) habits give us that boost because the caffeine they contain cuts off access to the adenosine receptors in our brain. Adenosine is a chemical that helps to regulate our internal clocks. It gradually builds up throughout the day, and, as it reaches a certain level, we begin to feel sleepy. By blocking those adenosine receptors with caffeine, we get a sense of energy and alertness.

But scientists at Cornell University found that in addition to giving us a jolt, caffeine dulls our ability to perceive sweetness. When the researchers divided the study's participants into two groups, one that drank decaffeinated coffee and the other that drank regular coffee, the members in the caffeinated group were unable to accurately gauge the sweetness of a sugar solution. They rated it as markedly less sweet than the decaf group did.

Not only that, the caffeine drinkers' palates also remained dulled to the taste of sugar for at least 15 minutes after drinking their high-octane coffee. Because many people continue to reach for caffeinated beverages throughout the day, researchers suspect that the ability to taste sweetness remains suppressed.

This new insight dovetails with the group's previous research, which found that limiting a person's ability to taste sweetness actually creates a craving for it. The result is that people actively seek out sweet (and frequently high-calorie) treats.

Put the two together -- caffeine suppresses sweetness and a dulled palate leads to sweet cravings -- and your coffee habit could be laying the physiological groundwork for a serious sweet tooth.

The study also had some surprising news about how we perceive the effects of caffeine. Although neither group knew whether they were the ones drinking the decaf, almost all the study participants thought that they were the ones who got the caffeine. When they were asked to rate how alert they felt after drinking their particular beverage, both groups reported feeling equally energized.

And it turns out caffeine isn't the only thing that can influence taste. Previous studies by these same Cornell researchers found that mood plays a role. Sports fans in the throes of joy after a victory rated ice cream as markedly sweeter than did the followers of the losing team. Meanwhile, the despondent fans were measurably more sensitive to sour and bitter flavors than the happy ones.

Could the happiness boost cancel out the caffeine effect? That would make for an interesting study.

(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: I normally get a flu shot every year, but now I'm pregnant and have read that the vaccine might cause miscarriages. Is this true?

Dear Reader: First, let's explain why this is an issue: Pregnant women who contract influenza are more likely to develop complications from the influenza virus. The most striking example of this occurred during the H1N1 pandemic in 2009, when pregnant women accounted for 5 percent of virus-related deaths, but comprised only 1 percent of the population.

In general, pregnant women with influenza are more likely to require hospitalization and more likely to end up in the intensive care unit. They also have a greater likelihood of giving birth to children with cleft lip, neural tube defects (spina bifida), hydrocephalus (increased fluid within the brain) and heart defects. These complications of influenza led the Centers for Disease Control and Prevention in 2004 to recommend that all pregnant women get the influenza vaccine, regardless of trimester.

Now let's look at the safety of the vaccine itself.

A recent study in the journal Vaccine obtained data from health care organizations in five states about women who were pregnant during the 2010-2011 and 2011-2012 flu seasons. The authors determined which ones had been vaccinated with the standard influenza vaccine and which ones suffered a spontaneous abortion, or miscarriage. They found that 485 women had a miscarriage; they then compared these women to 485 pregnant women who didn't have a miscarriage.

The major difference was seen among women who were vaccinated the year before they were pregnant and then repeated the vaccination when they were pregnant. Of those, 17 women in the miscarriage group had the vaccine within 28 days prior to the miscarriage. Women in the group who didn't have miscarriages were five times less likely to have had the flu vaccine in that preceding 28 days.

It's possible that an inflammatory response could be to blame for the miscarriages. Because the first shot primes the immune system, the second shot gives a greater immune response, leading to inflammation. Excessive inflammation can then lead to a spontaneous abortion.

However, the authors stressed that their study found a correlation, not a causation. Here are some other factors that emphasize the far-from-conclusive nature of the study:

First, the number of women in this part of the study was small: 17 in the miscarriage group and four in a group who didn't have a miscarriage at the same time. Second, women at increased risk of miscarriage may be more likely to seek medical help and thus be more likely to get a flu shot.

Obviously, a larger study is needed to verify -- or repudiate -- the possible connection. But, ethically, this may be difficult. A researcher would have to compare pregnant women who had the flu vaccine the year before, and give one group the flu shot in the first weeks of pregnancy and not the other. Yet the risks of going unvaccinated are simply too great.

Until we have further data, I would recommend flu shots in pregnancy to prevent the risk of maternal death and birth defects.

(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.)