Ask 5280's Top Docs

Fifteen of our Top Doctors answer your most pressing health questions.

April 2009

Question: My son's four-year-old friend appears to be obese already. What can I do with my own four-year-old—who right now is of average height and weight—to ensure he doesn't become overweight?

Answer: A child is not going to become obese if he goes to one birthday party at McDonald's. But if your family goes out to fast food three or four times a week, and the house is stocked with junk food, then you put the child at risk. As the parent, it's your job to ensure that the food that's available to him is good, healthy, high-quality food. Plenty of fruits and vegetables, organic if possible.

Four-year-olds should never do the choosing at the grocery store. Things like chips and cookies are appealing, but if you don't want your kids eating that stuff on a regular basis, keep it out of the house. It's also your job to model good eating habits and good exercise habits for your child. Get out and play. Be active. Show him you run and eat broccoli, and he'll learn from you. —Dr. Barbara L. Gablehouse, Pediatrics; Children's Hospital, Lutheran Medical Center

Q: Once and for all: Do childhood vaccines cause autism?

A: In February a special federal court ruled that vaccines—specifically the measles-mumps-rubella vaccine and vaccines that contained mercury—did not cause autism in three children. The nature of science is to ask a question and then to try to seek evidence. Pediatricians have been interested in the question of a potential link between vaccines and autism, and this hypothesis has been tested numerous times. No one knows what causes autism, but the scientific evidence to date is quite clear that vaccines do not cause the disease. —Dr. John Ogle, Pediatric Infectious Disease; Children's Hospital, Denver Health Medical Center

Q: When I run in Denver, I feel completely dehydrated. Is it the altitude?

A: Being at altitude, being closer to the sun, certainly means you need to take a lot of things into consideration to protect yourself from conditions like dehydration. Insensible heat loss (losing moisture from your skin and lungs simply by evaporation) can contribute to dehydration if you exercise routinely. This condition needs to be taken seriously in our climate, especially because we don't have a humid atmosphere layer in Denver that keeps our moisture levels intact.

A really easy way to tell if you're dehydrated is to look at the color of your urine. If it's dark yellow, you're dehydrated. A good rule of thumb is to keep the color of your urine light yellow to clear. Thirst is not a good indicator. By the time you are thirsty, you're already dehydrated.

Some people get excessive in their intake of fluid because they're afraid of getting dehydrated, and they drink too much water. That dilutes the sodium in your body. It's called hyponatremia, or water intoxication (a disturbance in electrolytes or salts in the blood), and that's not good. It can lead to neurological issues, which is a worst-case scenario, but it does happen to marathon runners. Use your urine color as your guide, and don't overdo it. Everything has to be in balance.  —Dr. Deborah Saint-Phard, Sports Medicine; Boulder Community Hospital, University of Colorado Hospital

Q: Seems like everyone has a food allergy these days. What's the deal?

A: Allergic diseases as a whole, including food allergies, are on the rise. Although we aren't sure why, there are several hypotheses. The hygiene hypothesis proposes that our immune systems need the right interactions with bacteria to develop appropriately. Because we now live in such a clean environment, these interactions don't occur, resulting in increased allergies. Another idea suggests decreased levels of vitamin D, which helps regulate the immune system, are partially to blame.

A true allergy is when the immune system is involved in causing a reaction. (For example, lactose intolerance is an example of a metabolic deficiency and has nothing to do with the immune system.) So when someone says, "Oh, I'm allergic to X because that food makes my stomach hurt," it's often misleading because it may be an intolerance rather than an allergy. The most important thing to remember is that if someone is having unexplained symptoms—problems with respiration or the gastrointestinal tract—that aren't going away, it's time to talk to a doctor. —Dr. Dan Atkins, Allergy and Immunology; Children's Hospital, National Jewish Health, University of Colorado Hospital

Q: As American women are trying to have children later in life, what are the risks for mom and baby? Is there an age at which their fertility starts to change?

A: There are additional risks for mother and child when starting a family later. Women's fertility declines beginning at age 30, the rate of decline increases at 35, by 40 it drops even more abruptly, and it's virtually absent by about 45 in the majority of women. Still, women have been delaying childbearing significantly over the past 30 years. In Scandinavian countries, the average age of women at the birth of their first child has gone from 24 to 34 just in the past 30 years. The trend seems even more extreme in the United States, with many women waiting until their late 30s or early 40s to begin a family.

Besides declining fertility, older women have increased risks for pregnancy complications such as high blood pressure, gestational diabetes, fetal growth restriction, and the need for a Cesarean delivery. Additionally, there is an increased risk for chromosomal abnormalities in the baby as women's eggs age. While an amniocentesis can check for these, there is an increased risk for unfavorable results in older moms, along with a higher rate of miscarriage.—Dr. William B. Schoolcraft, Reproductive Endocrinology/Infertility; Avista Adventist Hospital, Rose Medical Center, Sky Ridge Medical Center, Swedish Medical Center