Dear Doctors: I just moved to a new city for a job. It has been overwhelming, and my diet and workouts went off the rails. Then I got sick and had to take antibiotics. I can tell that my gut microbiome is messed up. What’s the best way to heal it? I’d rather not take probiotics.

Dear Reader: Moving and changing jobs have the dubious distinction of being among the most stressful life events. This grim category also includes major illness, the loss of a loved one and the end of a serious relationship. It’s not surprising that in the course of dealing with two of these stressors at the same time, your diet and exercise routines got thrown off course. You are correct in assuming that these, along with stress itself, can adversely affect the health of the gut microbiome. So can antibiotics. As they kill bacteria that cause infection, antibiotics also eliminate beneficial bacteria. Even narrow-spectrum antibiotics, which are targeted to specific pathogens, can adversely affect the health and diversity of the gut microbiome.

The encouraging news is that our guts are resilient. Research shows that most people see a recovery of their intestinal microflora within a few weeks after antibiotic treatment ends. And with healthful lifestyle choices, you can reverse the damage to the gut that stress in your life may have caused. We tend to think of stress in terms of the emotions that come along with it, such as anxiety, depression, anger, hopelessness and fear. But stress has a physiological component as well. In order to prepare for the perceived battle to come, the body releases hormones such as cortisol and adrenaline. In the short term, these are harmless, but when they persist over time due to chronic stress, they become a risk to general health, and to the health of the gut microbiome.

First, don’t worry about your wish to avoid probiotic supplements. Although they are widely available and the subject of numerous health claims, it remains unclear whether they are helpful. Instead, focus on diet, regular exercise, spending time outdoors, getting enough sleep, getting good-quality sleep and finding a way to relax.

With diet, limit ultra-processed foods and added sugars, which add to low-grade inflammation. Instead, choose fiber-rich foods like vegetables, leafy greens, fruit, beans, nuts, seeds, grains and legumes. The indigestible components, known as prebiotics, reach the colon intact and feed your tiny microbe companions. Fermented foods, such as yogurt, kefir, pickles, kimchi and tempeh -- all natural sources of probiotics -- help bolster gut populations. And remember to drink plenty of water.

Take time out for exercises that help manage stress, such as yoga, tai chi, deep breathing, meditation and stretching. Aerobic and weight-bearing exercises are not only good for the muscles, skeleton, heart and lungs, but they also benefit mental and gut health. Spending regular time outdoors in nature and with other people are beneficial for mental health, and also for adding to the diversity of gut microbiome populations. What’s good for gut health is good for general health. Ease into these lifestyle changes, and your whole body with thank you.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: A good friend has Parkinson’s disease. She’s struggling, so I don’t ask too many questions. She was drinking water, started to choke and her husband mixed something into her glass that helped her swallow. Do you know what that was? Is there something I can do to help?

Dear Reader: When someone you care about is living with a chronic or progressive disease, it can be difficult to figure out the boundaries of what is OK to ask and what topics are off-limits. Adding to the challenge is the fact that, out of necessity, many acts of caregiving take place in public. However, that doesn’t automatically make them open for comment or discussion.

Having one’s health become a focus of attention can be embarrassing, tiring and emotionally isolating. Your decision to not ask questions about the incident you described allowed your friend and her husband to handle an immediate need, and then to move on. You preserved their privacy and spared them the burden of an explanation.

That said, it is also reasonable that you want to understand what you witnessed. In this case, your friend’s husband was helping her manage something known as dysphagia. This is the medical term for difficulty with swallowing. It is common in conditions that affect the nervous system, including Parkinson’s disease. It is also often seen in people living with multiple sclerosis, head and brain injuries, stroke, Alzheimer’s disease and other forms of dementia. Dysphagia also occurs in disorders that affect the esophagus, cancers of the head and neck, and it can begin to affect adults as they age.

Muscle stiffness and slowed movement are two of the primary symptoms of Parkinson’s disease. They are most noticeable in the limbs, but they also affect the coordination and strength of the muscles involved in swallowing. This includes the muscles of the tongue, mouth and throat and the esophagus. The disease can also lead to reduced sensation in the throat, which further interferes with the proper sequence of a successful swallow.

From your description of events, it sounds as though your friend’s husband added a thickener to her glass of water. These are often made up of some sort of starch or gum. They turn a thin liquid, like water, into more of a gellike consistency, like a nectar. A thickened liquid moves more slowly, which allows additional time for the reflexes involved in a swallow to become organized. It also reduces the risk of aspiration, which is when liquid accidentally enters the airways.

While thickeners can be helpful for people dealing with dysphagia, there are some drawbacks. Many people find the texture and taste to be unpleasant. This leads them to drink less, which increases the risk of dehydration. It is also possible for the thickeners themselves to interfere with the bioavailability of some medications. And even with a thickened liquid, aspiration remains a risk. This makes the management of dysphagia an ongoing challenge.

You can help your friends by quietly letting them know you understand the challenges they are facing, and that you are available for support if needed.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctors: I was surprised when a blood test at my annual checkup found I’m low in B vitamins, especially B12. My doctor gave me a shot, and the fatigue that I had been feeling went away. Why is B12 so important? What kinds of foods do you need to be eating to have enough of it?

Dear Reader: Vitamin B12 is what is known as an essential nutrient. That means two things: First, an essential nutrient is a chemical compound that is crucial to the proper functioning of the body, and thus to good health. The other thing that is important to understand about an essential nutrient is that the body either isn’t able to manufacture it or doesn’t produce it in the quantities needed. As a result, essential nutrients must be acquired through diet.

Although B12 is often referred to as a stand-alone vitamin, it is actually one of a group of eight B vitamins. Known as the B complex, these vitamins work individually and also as a group to maintain health and well-being. They help make nutrients available to the body, are important in maintaining brain function and also in the production of energy. B12 plays a crucial role in the manufacture of red blood cells; keeps nerve fibers throughout the body healthy; helps the body convert protein, carbs and fat into energy; and plays a key role the synthesis of DNA.

A B12 deficiency can cause the general fatigue that you were experiencing. It can also lead to certain types of anemia, malfunction or even structural damage of the nerves, muscle weakness and gastrointestinal issues. Additional symptoms can include tingling or numbness in the feet and hands, problems with vision, changes to balance and mobility, pale or jaundiced skin, a sore or swollen tongue, problems with sleep and changes to memory or cognition.

The body can store B12 in the liver. However, the supply is limited and, thus, must be replenished. Red meat, fish, shellfish, eggs, poultry, milk and other dairy products all contain varying amounts of vitamin B12. Prepared products, including breakfast cereals, nondairy milks, nutritional yeast and meat substitutes are fortified with B12. The nutrient is also available in vitamins, nutritional supplements and, as your own doctor delivered it, as an injection. Vegans and vegetarians, who don’t eat animal products, must make a special effort to get adequate B12 in their diets.

A diet rich in B12 is only half of the equation. The body must also be able to properly digest the foods that contain it. As a result, adults over the age of 50, who begin to produce fewer digestive enzymes, people who have undergone weight loss surgery and those living with certain medical conditions, such as Crohn’s disease, can struggle with absorption. The long-term use of heartburn medications, which reduce production of the stomach acid needed to absorb B12, can also contribute to B12 deficiency. If anyone suspects they may have a B12 deficiency, we encourage them to check in with their doctor.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)