Dear Doctor: I keep reading about something called “resistant starch.” People are saying I should get it into my diet. Why is it so important? How much do I need?

Dear Reader: As with so many areas of diet and medicine these days, the answer leads directly to the gut microbiome. That’s the vast and complex community of bacteria, fungi, yeasts and viruses that live in our intestines. They number in the trillions, can account for 2 to 5 pounds of our weight and, as we’re learning every day, play complex and crucial roles in our physical and even mental health. In fact, because these microscopic creatures are necessary to survival, the gut microbiome is increasingly regarded as an organ in its own right.

One of the keys to a healthy and diverse gut microbiome is keeping our microscopic residents well-fed. This involves prebiotics, a type of dietary fiber that stimulates the growth and activity of the good-guy bacteria in the gut. For fellow science nerds, prebiotic foods contain high levels of a starchy substance known as inulin and certain types of sugars, including fructo-oligosaccharides and galacto-oligosaccharides. Although apples, oats, lentils, leeks, Jerusalem artichokes, garlic, asparagus and bananas are cited as good sources of prebiotics, the fact is that a wide range of fruits, vegetables, grains and legumes contain prebiotics in varying amounts.

Another potential source of prebiotics is the subject of your question -- resistant starch. As the name suggests, these are starches, or carbohydrates, that resist digestion. That means they survive the journey through the digestive tract and make it all the way to the colon, where they become available to gut microbes. Resistant starches fall into four general categories. They may be protected by fibrous cell walls, as with grains, seeds and legumes. They are available in certain raw foods, such as raw potatoes or raw plantains. And they can be manufactured via a chemical process. What’s of particular interest is the final category. This is a range of carbohydrates that, when cooked and then cooled, develop into resistant starch. These include rice, potatoes, yams, pasta and whole grains such as oats and barley.

One benefit is that, instead of being broken down into glucose and raising blood sugar levels, these types of carbohydrates pass into the colon. This improves glycemic control, an important factor in good health. Once in the colon, resistant starches feed the beneficial bacteria that live there. Through the process of fermentation, bacteria turn resistant starch into compounds known as short-chain fatty acids. These include butyrate, which is linked to lower rates of colorectal cancers, and propionate, which has been shown to lower inflammation and improve immune support.

How much resistant starch do we need? There’s no set amount. Instead, think in terms of daily goals for dietary fiber in general. Most Americans get less than half the recommended 25 grams per day for women and 38 grams per day for men. We recommend eating from a diverse range of fresh fruit, vegetables, whole grains, legumes and nuts. If they’re new to your diet, add them slowly to avoid gas and bloating. And with every bite, know you’re making your gut microbiome very happy.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I've had lower back pain for years, and nothing has helped. I’ve tried physical therapy, yoga and chiropractors, and I’ve even contemplated surgery. My sister suggests something called the Alexander technique. What do you think? I'm willing to try anything, but I don't want to chase after treatments that aren’t useful.

Dear Reader: When our ancient ancestors stood up and became bipeds, they gave humans a crucial evolutionary advantage. They also left us with another lasting legacy -- back pain. It’s a near-universal complaint, and it ranks among the largest contributors to disability throughout the world. Yet, because the spine is a complex structure, the specific causes of back pain often remain elusive. This can make finding an effective treatment both difficult and frustrating.

The majority of back pain affects the lower back, which supports much of the weight of the upper body. The most common causes of pain in the region are the mechanics of how we stand and move, injuries to the tissues and structures of the back and spine and, often, a combination of the two. Poor posture, poor alignment and the ergonomics of the tools and objects in our daily lives all play a role. Put too much stress or torque on the spine, and you’re at risk of injuries to the muscles, ligaments, tendons and nerves in the region.

A back injury can make itself known suddenly, as with a muscle spasm or a slipped disc, or may emerge over time. Either way, the pain and disruption can be daunting. Yoga, physical therapy and chiropractic care can indeed lessen lower back pain, and we’re sorry to hear that none of these approaches brought you relief. Massage, acupuncture and mindfulness exercises also can help. Some of our patients living with lower back pain have had success using topical heat, as well as over-the-counter creams, gels and patches.

All of which brings us -- at last! -- to your sister’s suggestion, the Alexander technique. It’s a series of posture lessons that focus on alignment, balance, breathing, coordination, spatial awareness and the release of tension, particularly in the neck, shoulders, spine, back and hips. Developed in the 1890s by Frederick Matthias Alexander, the technique has been used for chronic back pain, arthritis and Parkinson’s disease. In this method, students relearn how to sit, stand, walk, bend, reach and move, all with an awareness of gravity’s downward pull. A single session may focus solely on the proper alignment for rising from a chair, or it may be spent lying on the ground methodically assessing and releasing areas of tension.

Classes typically are one-on-one, carried out by a certified teacher who observes the student and guides them with both verbal explanations and gentle, hands-on adjustments. Several studies have confirmed the benefits of the Alexander technique for back pain, including one published in the journal BMJ. In that study, researchers found that one-on-one lessons with a certified teacher had long-term benefits for patients with chronic back pain. We recommend the Alexander technique to our own patients who are dealing with back pain. If lessons are available in your area, we think this approach to dealing with lower back pain is worth exploring.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I’m worried about my best friend. She seems overwhelmed taking care of her elderly parents as well as her own family, but she won’t admit it. How do I know if she’s in trouble?

Dear Reader: There’s a name for the rapidly increasing number of Americans who find themselves in your friend’s position of caring for older parents while raising a family -- the sandwich generation. They account for a significant chunk of the estimated 43 million adults in the United States who act as unpaid caregivers to aging parents or relatives. And when the scope and stress of the duties they’ve taken on become too great, many put the needs of loved ones ahead of their own well-being. Among cooking, cleaning, shopping, errands, homework help, extracurricular activities for their own families and managing similar tasks, plus medical appointments for an aging or ailing relative, personal welfare often falls by the wayside. This includes no longer spending time with friends and engaging in personal interests, and neglecting their careers, medical care, and mental and spiritual health.

There’s no question that being a caregiver can be rewarding. When you pitch in to help an aging parent, relative or friend, you enhance that person’s quality of life. Often, this unpaid care allows older adults to remain in their own homes. Much of the help involves emotional support, and many caregivers report a deepening of their relationships with the people they’re helping.

But the role of caregiver is often complicated. It can be difficult for both parties to navigate the change of roles when a child becomes a parent’s guardian. An aging parent’s escalating lack of control over his or her own life can be frightening, and the parent can grow demanding and even unreasonable. This becomes even more of a challenge when someone has cognitive problems, as with dementia and Alzheimer’s disease.

You're correct that the demands of caregiving can be overwhelming. They often lead to fatigue, apathy, anger, depression and, eventually, burnout. Signs of this include withdrawal from family, friends and activities, as well as feelings of loss, worthlessness or hopelessness. There may be changes to sleep and mood; changes to weight; abuse of alcohol or drugs, which includes prescription medications; and a lack of interest in self-care.

To prevent burnout, it’s important for caregivers to make time each day for themselves. Even a half-hour for a solo walk, a dive into a magazine or a novel or to chat with a friend can help to ease stress. It’s also important to be willing to ask for help, and to be specific. Make a list of tasks for friends and relatives who want to lend a hand, such as shopping for groceries, handling a doctor’s visit, taking a pet to the vet or doing some housecleaning.

A support group for caregivers is a great place to share experiences, vent, meet new friends and learn about support services. Speaking of which, you’ll find very good suggestions at the AARP website (AARP.org) and the U.S. Department of Health & Human Services website (HHS.gov). Just put the words “caregiver resources” into the search box.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)