Dear Doctor: Can you settle an argument in our family? Ever since the Ebola virus hit the news, my aunt has been using antibacterial products for everything. She even had the kitchen walls coated with antibacterial paint! But from what we're learning in biology, that's not going to help against a virus. Who's right?

Dear Reader: It's true that whenever reports of a dangerous outbreak like Ebola, bird flu or the Zika virus hit the news cycle, sales of antibacterial products spike. People are understandably concerned about their health and safety, and are responding to news reports that can be high in drama but low on important details.

What you're learning in biology is correct. Antibacterial products will have no effect on a virus. In fact, there is growing concern that the overuse of antibacterial soaps, lotions, laundry products, cosmetics and even house paint may cause more problems than it is solving. A bit about that in a moment.

But first, what's the difference between a bacterium and a virus?

A virus, which needs a host to survive, is basically a Trojan horse. It's made up of a protein coat that shields a core of genetic material. Once inside the body, the virus enters a cell and hijacks its biological mechanisms. It forces the cell to turn out thousands of new copies of the virus, which causes the cell to die. These newly minted viruses then go on to attack fresh cells.

Although they cause a host of deadly illnesses, viruses are not all bad. Thanks to their vast numbers and remarkable diversity, scientists believe that viruses have beneficial functions that are not yet understood. In fact, some leading-edge research into cancer is exploring how to harness the unique properties of viruses to formulate new medications, as well as find mechanisms to attack disease cells.

Bacteria, by contrast, are tiny one-celled organisms that can reproduce on their own. The vast majority of them are benign and even helpful, as we're learning in our research into the gut biome. Less than 1 percent of bacteria cause illness in humans. Those that do emit toxins that damage tissue, interfere with important biological pathways and make you sick. Illnesses caused by bacteria include food poisoning, Lyme disease, pneumonia, cholera and dysentery, to name just a few.

Like viruses, bacteria reproduce quickly. Unlike viruses, they can proliferate outside of human cells. That means that good hygiene is the best defense against the spread of bacterial infections.

So how can products that target bacteria be bad?

The problem is that antibacterial products aren't 100 percent effective. The bacteria they leave behind can, over time, develop a tolerance to certain antibacterial agents in the products, a trait known as cross-resistance. Scientists are concerned that this can lead to genetic mutations that will make bacteria immune to antibiotics.

But we have good news.

According to the FDA, plain old soap and water is still the best defense against bacterial contamination. Soap lifts dirt from your hands and, with 30 seconds of scrubbing and a thorough rinse, the bacteria are down the drain.

(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: When does a person require parathyroid surgery? I've heard it discussed, but don't know much about it.

Dear Reader: As their name implies, the parathyroid glands are located next to the thyroid gland. You have four of them, two on each side, behind the thyroid gland in the neck. The parathyroid glands help regulate calcium and potassium levels in the bloodstream. They do this through the production of parathyroid hormone, which is produced in varying quantities depending upon the levels of calcium, phosphorus and vitamin D. As the calcium levels increase, the levels of parathyroid hormone decrease and vice versa.

Sometimes, however, the parathyroid glands overproduce parathyroid hormone, causing levels of calcium to increase. Primary hyperparathyroidism is the overproduction of parathyroid hormone due to a defect with the gland. This occurs in three in 1,000 people, and is more prevalent between the ages of 50 and 65; women are three times more likely than men to have the condition.

In 80 to 85 percent of cases, primary hyperparathyroidism is due to a benign tumor on one of the parathyroid glands. About 6 percent of the time, primary hyperparathyroidism is related to enlargement of two or more parathyroid glands. Only rarely, in 1 to 2 percent of cases, parathyroid cancer is the cause of this hormone elevation.

Most hyperparathyroidism symptoms aren't obvious. The condition is generally found incidentally after a blood test shows a high calcium level. In such cases, patients have often complained of fatigue, weakness, decreased appetite and difficulties with mental tasks. The classical symptoms of primary hyperparathyroidism are a depressed mood, nausea, poor appetite, increased thirst, increased urination, kidney stones and, very rarely, bone pain and psychosis. Of note, people with this condition have a two- to threefold increased risk of bone fractures. Further, when primary hyperparathyroidism is severe, the high calcium levels can lead to confusion and even coma.

In such severe cases, surgery is obviously warranted. It is also indicated if calcium blood levels are greater than 1 mg/dl above the upper limit of normal; if a person has osteoporosis, kidney stones or kidney dysfunction; or if the person is younger than 50.

But, if calcium levels are only mildly elevated, it isn't clear that surgery is necessary. That said, people who have had surgery due to mild calcium elevations have noted increases in bone density, decreased incidence of kidney stones and slight improvement of mood.

For a less invasive surgery, it is important to determine which of the glands is overproducing parathyroid hormone. This is normally done with a SPECT scan and an ultrasound. In the hands of an experienced surgeon, this assessment will lead to a smaller incision, less operating time and less damage to surrounding tissues.

However, when high levels are caused by multiple glands overproducing parathyroid hormone (which occurs 15 percent of the time) or if a thyroid abnormality is also found, then a more extensive surgical exploration is needed. A significant drop in blood calcium levels can happen after surgery, so the levels need to be monitored afterward.

Not everyone is a candidate for surgery. If this is the case, medications like Cinacalcet can lower calcium levels, and bisphosphonates, like Fosamax, can improve bone density.

As with every condition, each person's needs are different.

(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 can't seem to lose weight and am wondering if my gut bacteria could be to blame. How can I change it?

Dear Reader: In recent years, it has become increasingly clear that the bacteria that live in our gastrointestinal tract, also known as the gut microbiome, play a significant and far-reaching role in our health. Researchers now believe that these bacteria, which number in the trillions, have an effect on immunity, inflammation, allergies, asthma, diabetes, weight issues, and even depression and anxiety. In fact, the metabolic activity of these microorganisms, also known as probiotics, is so complex that the gut microbiome has been referred to as the "forgotten organ."

So how does the gut microbiome develop?

Just before birth, a baby's intestinal tract is sterile. The first major infusion of bacteria comes from your mother, both in the birth canal and through breastfeeding. Next come microorganisms from the physical world around you. Throughout your life, your gut microbiome will continue to evolve. Research shows that contact with pets, farm animals, soil, dust and the outdoors contribute to its diversity. Exposure to antibiotics, overuse of antibacterial products and excessive use of alcohol have been shown to damage the gut microbiome.

Although studies have linked the presence of certain strains of gut bacteria to a tendency to be lean, and the absence of other types of bacteria to obesity, the science is still in its infancy. At this time, there is no reliable information on how exactly to harness the power of the gut microbiome to address weight issues. However, considering how important a diverse array of bacteria is to good health, making some lifestyle and behavioral changes to bolster the gut microbiome is a good idea.

Eat more fiber: With what we know about the gut microbiome, the fact is you're not just eating for one; you're eating for trillions. According to new research, fiber not only provides nourishment for gut bacteria, it also helps with diversity. So skip the processed foods and snacks. Instead, choose fruit, vegetables and whole grains. New attention is now focused on prebiotics, which are indigestible fiber that are believed to nourish gut bacteria. Natural sources of prebiotics include asparagus, Jerusalem artichokes, leeks, bananas and jicama.

Choose healthy oils: Replace refined omega-6 rich vegetable oils with a good-quality extra-virgin olive oil. Amp up your omega-3 intake with salmon, halibut, sardines, kale, Brussels sprouts, flax seeds and walnuts.

Skip the sweets: According to the USDA, we Americans consume 94 grams of sugar per day, which is about half a cup. But your gut bacteria crave complex carbohydrates, so try reaching for an orange or a handful of walnuts when that afternoon snack attack hits.

Pick probiotic foods: Fermented foods like yogurt, kefir, miso, kimchi, sauerkraut, kombucha, brine-cured olives and tempeh provide a variety of friendly bacteria. No need to go overboard -- using them in moderation is all it takes.

(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.)