Hello, dear readers, and welcome to the first letters column of autumn. How quickly the summer flew by. That means it’s time to schedule vaccinations and boosters, and to stock up on COVID tests -- yes, it’s still with us. Speaking of which, the new COVID-19 vaccine addresses the newest crop of variants, so don’t skip that one. And now, your letters.

-- The importance of staying hydrated comes up in a lot of columns. This may be a challenge for older adults, who can experience a decrease in the signals that indicate thirst. A reader with a tip to share also had a question. “I fill a pitcher with five glasses of water, which makes it easy to remember to drink enough each day,” she wrote. “I figure that’s plenty because I’m getting water in my food, and also in my daily cups of coffee. Is that right?” Yes, both the food we eat and the coffee, tea and other beverages we drink contribute to daily water intake. Food typically delivers about 20% of the water we get. This is particularly true of fruits and vegetables, yet another reason to include plenty of produce in the diet.

-- A recent column discussed the challenges some people face in keeping their skin moisturized. Dry skin can be caused by a dry environment, sensitivity to chemicals in soaps and cleaning products, frequent hand-washing, inadequate hydration and as an effect of aging. We heard from a reader with concerns about their solution to dealing with dry skin. “I like to use Vaseline to help me deal with dry skin. It is amazing how well it works, and how quickly it disappears into my skin,” he wrote. “But I also have a problem with weight control. Is it possible that this is contributing to my weight?” Vaseline, also known as petroleum jelly, is safe for most people to use on their skin. The main caveat is it can contribute to acne in people prone to breakouts. Regarding your question about Vaseline being absorbed by the body and contributing to weight gain, the answer is no. Our skin can absorb oils and fatty acids, but it does not metabolize them. They do not contribute to calorie counts or to weight gain.

-- A column about resistant starch, a carbohydrate that resists digestion and thus reaches and helps feed the gut microbiota in the large intestine intact, continues to generate letters. Cooking and then cooling foods like potatoes, pasta, legumes and beans creates resistant starch. A reader wondered how much is lost when cooked carbohydrates are frozen and then reheated. “I can imagine how freezing the pasta or rice might affect the resistant starch,” they wrote. The good news is researchers have found that although further manipulation of food, such as freezing or reheating, does diminish the total amount of resistant starch, that decrease is negligible.

As always, we appreciate your taking the time to write to us. We have recently had some very kind letters -- thank you! -- and we are very glad to know these columns are useful.

(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: My niece and nephew, ages 5 and 9, will be living with my wife and me this year. We have a good pediatrician for their vaccinations and checkups. What other health-related tasks should we be thinking about?

Dear Reader: Finding a good pediatrician for your niece and nephew was an important first step. These are doctors who specialize in the unique medical needs of infants, children and teens. In addition to preventive health care, which includes keeping up with age-appropriate vaccines and diagnosing and treating illnesses, your pediatrician will help track the children’s growth and development milestones. They can also offer guidance regarding nutrition and safety and keep an eye on changes to a child’s mental and emotional well-being.

Taking care of teeth and gums is another important part of health care. It is recommended that a child has their first dental visit when they get their first tooth, or they turn 1 year old, whichever comes first. After that initial visit, appointments should continue every six months. Baby teeth are blueprints for the permanent teeth to come, so tracking their progress and spotting potential problems is important. In order to preserve the children’s good oral health, you will want to establish a regular -- and enjoyable -- tooth-brushing routine. Your pediatric dentist can help you with this.

Another important evaluation that can be easy to forget is a visit to the eye doctor. Problems with vision can affect all aspects of a child’s development. They may even be misdiagnosed as behavioral issues, such as ADHD, or a learning disability, like dyslexia. An annual eye exam is recommended for children between the ages of 6 and 17. Timing this appointment with the start of the school year will ensure that any deficiencies in eyesight will be caught and corrected.

If either your niece or nephew has any allergies, it is important to let the school know about them. This includes the children’s teachers and coaches as well as the school nurse and administration. Some children require medication during the school day. When this is the case, the school will need your consent to provide them. Your pediatrician will be able to help you with the specifics of this authorization. If there are changes or additions to a child’s medication, it is important that the authorization held by the school be updated promptly.

In most states, children who plan to take part in school-sponsored sports are required to undergo a sports physical. This is sometimes referred to as a preparticipation physical evaluation, or PPE. It includes a medical history of the child and their parents, as well as an in-person physical exam. The goal is to identify any injuries or medical conditions that could put the child at risk of injury or illness.

Your niece and nephew are facing enormous change. So are you and your wife. We think it’s a good idea to explore the resources in your community that can support you all as you navigate this new life.

(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 am an adult woman, and I have an umbilical hernia. I want to decrease the amount of belly fat that I have. What kinds of exercises are safe to do when you have an umbilical hernia?

Dear Reader: A hernia is a gap in a muscle wall that allows tissues from one part of the body to push through and enter a space where they do not belong. The most common type of hernia occurs in the abdominal area. However, it is also possible for a hernia to develop in the diaphragm, the groin and in a surgical scar.

When someone has an umbilical hernia, it means the breach in the abdominal muscle has developed near the navel. This allows the fatty tissues within the abdomen, or the bowel itself, to protrude. Depending on its severity, an umbilical hernia may be barely visible, or it may look like a knob or a blob of tissue. It can vanish completely when lying down and can become larger in response to internal pressure, as when laughing, lifting or having a bowel movement.

Although umbilical hernias occur most often in newborns and infants, they are seen in adults as well. In about 10% of adult cases, the umbilical hernia has been present since birth. But the majority are the result of injury. Common causes of umbilical hernia in adults include the increased pressure on the abdominal wall that occurs during pregnancy, labor and delivery, or from physical activity that entails straining or heavy lifting.

It is not clear from your letter if your umbilical hernia is mild or severe, when it developed and if you have been evaluated by a medical professional. If you have not, it is very important to do so. Not all hernias will require an immediate surgical repair. Some, if they are small and do not cause symptoms, can be monitored and temporarily managed with lifestyle changes. However, this is an injury to the abdominal wall that can quickly and easily grow more severe. It is also possible for the tissues of the hernia to become trapped within the abdominal wall. If blood flow gets cut off -- this is called a strangulated hernia -- the trapped tissues can die and cause a life-threatening infection.

In theory, it is possible to exercise safely if you are living with a hernia that is small and does not cause any symptoms. But with each and every movement, you will be taking the risk of making the hernia worse. If your doctor evaluates your hernia and clears you to exercise, you will be instructed not to do anything that involves lifting weights, and not to engage in exercises that require pulling, pushing or any kind of straining. You will also be told to avoid all forms of contact sports. Even cycling, swimming and yoga can put pressure on the abdominal muscles.

Unfortunately, an umbilical hernia in an adult will not heal. It requires either a surgical repair or a lifetime of careful and watchful management.

(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.)