(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: Is it true that HIV can now be considered a chronic disease? Does that mean people are no longer looking for a true cure?

Dear Reader: To answer this, we first have to agree on the meaning of "chronic disease," which, believe it or not, has more than a few definitions. Rather than take a deep dive into those important but perhaps snooze-inducing distinctions, let's go with the most common understanding of the term. That is, a chronic disease is one that cannot be cured, but with ongoing medication and treatment can be managed. And thanks to the stunning success of antiretroviral therapies, infection with HIV now fits that definition of chronic disease.

As most of our readers probably know, HIV is shorthand for the human immunodeficiency virus. The virus undermines the immune system by attacking certain white blood cells that are vital to the ability to fight infection. The loss of these white blood cells leaves HIV-positive individuals vulnerable to disease, infection and complications of illness. AIDS is the stage of HIV infection at which damage to the immune system is profound, and patients are unable to fight off a host of opportunistic infections. For people with AIDS, infections that a healthy immune system would brush off become potentially deadly.

According to one school of thought, the antiretroviral drugs that are now the main treatment regimen for people living with HIV amount to a functional cure. But just because infection with HIV is no longer a near-certain path to developing AIDS, that doesn't mean living with the virus is problem-free. The drugs, which must be taken daily and for the rest of an infected person's life, are extremely powerful. Cumulative toxicity becomes a real concern. And while the antiretrovirals do prevent an HIV infection from progressing to full-blown AIDS, the individual's immune system remains affected by the presence of the virus and, consequently, is less robust. Add in the ability of HIV, like all viruses, to rapidly mutate and become resistant to existing drugs, and infection remains a serious condition.

Compared to the early days of the HIV crisis, when each new development in decoding and understanding the virus was heralded, things may now seem quiet on the news front. But as researchers focus on both prevention and a cure, the science continues to move forward.

For many, the idea of a vaccine is the gold standard. In that regard, there has been encouraging news from researchers at the University of Massachusetts, who recently reported that they are about to enter into a phase 1 trial to assess the safety of a potential HIV vaccine. Other scientists are looking into topical medications that can stop the virus at the site of infection.

And thanks to ongoing advances in the field of immunotherapy, there is renewed hope of finding a cure. Earlier this year, researchers at the University of Maryland reported success in engineering immunotherapeutics that target and neutralize the virus on multiple fronts and across multiple strains. (And yes, that's a greatly simplified explanation.)

An estimated 36 million people worldwide now live with HIV, and while scientific advances don't always make headlines, they do make a difference.

Dear Doctor: I am an 88-year-old man who, until recently, played a decent game of golf twice a week. Then, about 18 months ago, I began to experience weakness throughout my body, especially in my legs. Casual research indicated that Crestor, a statin I have taken for several years, was likely to blame. My doctor took me off Crestor two months ago in hopes that the condition would reverse, but any improvement is insignificant. Why do doctors prescribe debilitating drugs with no regard to side effect warnings?

Dear Reader: Pharmaceuticals are a large part of a doctor's armamentarium in treating and preventing disease. The medication you mentioned, Crestor (rosuvastatin), is one of many statins used to lower cholesterol. These medications are beneficial in decreasing the possibility of heart attacks and strokes in people who are at risk, as data have repeatedly born out.

But statins also can lead to mild or debilitating muscle aches in 1.5 to 5 percent of people taking them. In rare cases, they can cause a severe breakdown of muscle, a condition known as rhabdomyolysis. Theoretically, water-soluble statins such as rosuvastatin, pravastatin and fluvastatin are less likely to cause muscle aches; in fact, I've seen rhabdomyolysis twice with Crestor.

As your doctor knows, when a patient experiences muscle aches while taking a statin, the best course of action is to stop taking the drug. Sometimes the reduction in muscle aches is immediate, sometimes not. The average time that it takes for people to develop muscle aches with a statin is 6.3 months; the average time it takes for the muscle aches to improve after stopping a statin is 2.3 months.

Patients should be warned about statins' potential side effects and be monitored for them. But to come back to your question concerning what a doctor should do about medications with both potential benefits and potential side effects, my answer is don't overprescribe them.

As for statins, many in the medical community advocate their use for a large swath of the general population, often using cardiovascular risk calculators to estimate a person's chances of a heart attack and thus their need for a cholesterol-lowering medication. However, preliminary findings from a 2016 Kaiser study question the efficacy of the calculator, which means many doctors who make statin recommendations may be overestimating the risk of a cardiovascular event.

That said, statins are far from the only commonly prescribed drugs with a substantial risk of side effects.

Anti-hypertensive medications, which effectively lower the risk of heart attacks and strokes, can pose additional problems. Thiazide diuretics can lower sodium levels, sometimes to dangerous levels, leading to hospitalization and even death, while ACE inhibitors and angiotensin-receptor blockers can elevate potassium levels and cause abnormal heart rhythms.

Opiates control pain in the short term but can be abused in the long term. And, of course, chemotherapy, while curative for many cancers, often has severe side effects.

While doctors can't go through every potential side effect of a medication, they do need to take the time to describe the most common risks. And they need to be careful in not overprescribing medication.

(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 know that all sorts of studies show that fiber is good for you, but has anyone figured out the reason why?

Dear Reader: You're right -- the upside of fiber has been with us for quite a while now. Not only has the list of proven health benefits continued to grow, but also the language itself has changed: It used to be referred to as "roughage." But whatever it's being called, fiber is basically the carbohydrates in our food that resist digestion. And though there has been plenty of educated guessing about why we do measurably better over the short and long haul with a regular supply of fiber in our diets, a definitive answer has proven elusive. Now, however, ongoing research into the gut microbiome is offering up some intriguing answers.

First, some of what researchers had already believed about fiber's benefits continue to hold true. Foods that are high in fiber help to slow the absorption of sugars during digestion, which is a boon in regulating blood sugar levels. As a result, fiber in the diet can be a hedge against developing diabetes. Fiber makes you feel full after a meal, helps lower inflammation, and its presence in the intestines aids in elimination. Research shows that a diet high in fiber results in lower rates of heart disease and certain cancers, which may be why eating lots of fiber has been linked to a longer life span in general.

What's really interesting is scientists are now discovering that the fiber we consume feeds the billions of microorganisms each of us hosts in our bodies. Better known as the gut microbiome, it's becoming clear that they play an important role in keeping us healthy. If that number sounds like a lot, you're right. It's now estimated that these tiny hitchhikers make up between 1 and 3 percent of a person's total body weight. That means if your scale says 135 pounds, up to 4 pounds of that weight is beneficial bacteria. And since both quantity and diversity of beneficial bacteria are equally important, making sure they stay fed and happy is key.

Recent studies suggest that the way to cultivate a strong gut microbiome is keeping it supplied with plenty of fiber. When mice were put on a diet loaded with fat and low on fiber, the number and diversity of bacteria in their guts plummeted. At the same time, the mice themselves underwent changes that adversely affected their health. Not only did their intestines shrink, the protective coating of mucus along the intestinal walls became dangerously thin. This woke up the immune system and triggered an inflammation reaction. In time, this chronic inflammation was associated with weight gain and unhealthy blood sugar levels.

Bottom line -- the fiber you consume feeds the beneficial gut bacteria that help to keep us healthy in ways we don't yet fully understand and have yet to discover. So, when you're having that salad of leafy greens, a handful of walnuts, an apple or banana, or a serving of beans, you're not just eating for one -- you're eating for a few billion.

(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.)