 | What Your Doctor Is Reading | | |
Update From the Medical Journals: April 2009
April 30, 2009  By Mary Pickett, M.D.
Harvard Medical School What's the latest news in the medical journals this month? Find out what your doctor is reading. Studies Define Healthy Eating What foods make up a healthy diet? Studies in the March 23 and April 13 issues of the Archives of Internal Medicine tried to answer that question by looking at the evidence supporting a connection between nutrition and health. The first study linked eating red meat with how long people lived. More than 500,000 adults between the ages of 50 and 71 were surveyed about their diets. Their health was monitored during 10 years of follow-up. People in this study were divided into five groups based on how much meat they ate per day. People in the lowest group ate on average less than an ounce of red meat a day. People in the highest group ate 4 to 5 ounces of meat (about a small hamburger) a day on average. It's possible that people underreported the amount of meat they ate. But the results are still of interest. Researchers recorded the number of deaths over 10 years. For every 3 people in the lowest meat-eating group who died, 4 people in the highest meat-eating group died. Red meat was also associated with more deaths from cancer and heart disease. Eating white meat (chicken and fish) was not linked with a shorter survival at all; instead, it was slightly protective. The second study was a "systematic review" of 189 previous studies from the last 50 years or so. The researchers combined their data and found strong evidence that vegetables, nuts and monounsaturated fats (such as olive oil) protect against heart disease. The evidence also found that the "Mediterranean" diet, which emphasizes fruits, vegetables, whole grains, legumes (lentils, dried peas and beans), fish, nuts, olive oil and wine in moderation, was beneficial to health. Trans fats — the hydrogenated and partially hydrogenated oils that are found in many processed foods — seemed to increase risk of heart disease. Sweeteners and refined carbohydrates (foods with a high "glycemic index") also appeared to increase the heart disease risk. Back to top Brown Fat Burns Calories and May Be Important Factor in Obesity Researchers looking for a breakthrough to help fight the obesity epidemic have a new focus: brown fat. This fat burns calories in order to help maintain our body heat. Three studies in the April 9 issue of the New England Journal of Medicine explored the activity of brown fat. Researchers were recently surprised to find brown fat in the upper chest and neck of adults. They thought this type of fat gradually disappeared after infancy. Experts can see brown fat with an imaging test called a PET (positron emission tomography) scan. The small quantity of brown fat in the body appears to make a significant difference in our metabolism. In one study of 24 people, brown fat was found in all but one individual. Fourteen of these people were overweight; their scans showed much less activity in the brown fat compared with people of normal weight. When these people were exposed to cooler room temperatures (16°C or 61°F), the brown fat was more active than at a room temperature of 22°C (about 70°F). An animal study showed that mice kept in a cool cage can lose as much as 14% of their body weight in a week compared to mice living in a warmer home. The mice in the cold can eat more food than warm mice before they gain weight. The brown fat in the cold mice was seen to be more active, and it burned a large number of calories in the process of generating heat. Researchers are intrigued with the possibility that turning down the thermostat might help people lose weight, although this strategy has not been tested in people. Additional research on brown fat might provide new treatments that could prevent or treat obesity. Back to top More News in Brief - Most Americans Have Too Little Vitamin D – Public health experts are calling vitamin D deficiency a "growing epidemic." According to a new study in the Archives of Internal Medicine, three out of four Americans have blood levels of vitamin D that fall below what is necessary for good health. Among blacks, only 3% have an adequate blood level of vitamin D; 29% of blacks have a severe deficiency. These data come from the Third National Health and Nutrition Examination Survey (NHANES III). The study includes more than 13,000 Americans who were surveyed from 2001 to 2004. Vitamin D is important for bone strength and muscle health. It also helps to prevent infections and cancer. Based on this information, experts will probably change the recommendations for vitamin D supplementation. Some say that a daily dose of 1,000 international units (IU) of vitamin D will be needed for adult Americans to have enough vitamin D.
- Anti-inflammatory Pain Medicines Don't Prevent Dementia – Past research has hinted that non-steroidal anti-inflammatory pain medicines (NSAIDS), such as ibuprofen (Advil, Motrin) and naproxen (Naprosyn), might prevent Alzheimer's disease. A new study published in the April 22 online issue of Neurology raises doubts about this suggestion. This study looked at an older group of people than earlier studies. The average age of the 2,736 people studied was 75. After 12 years, researchers compared rates of dementia among users and non-users of anti-inflammatory pain medicines. "Heavy users" had a risk for Alzheimers that was about 1½ times the risk of "rare users." Dementia researchers are uncertain now exactly what the link is between NSAID pain medicines and dementia. NSAIDS may delay the start of dementia, which would explain why new cases would cluster in this group of fairly old people who seemed well at the study's start. This study also raises the possibility that in older people, NSAIDS might increase the risk for dementia. Until we have further research, NSAIDs should be used to treat pain when they are recommended, but should not be used as a way to prevent dementia.
- Acid-Reflux Treatment Is Not Helpful For Asthmatics Without Heartburn – Acid reflux (also called gastroesophageal reflux disease or GERD) can trigger airway tightening in the lungs and in some cases appears to contribute to asthma. Several studies and patient reports have suggested that anti-acid medicines improve asthma control when used regularly. For this reason many doctors recommend anti-acid medicines to patients with poorly controlled asthma, even if they do not have heartburn or acid reflux. But a study published in the April 9 issue of the New England Journal of Medicine found that giving anti-acid medicine to people without reflux symptoms did not improve their asthma symptoms. The study treated 402 patients for six months. All of them had asthma but rarely or never had symptoms of GERD. The researchers were not able to show any improvement in asthma symptoms by treating people with the strong anti-acid drug, esomeprazole. They did find a high rate of silent reflux (reflux with no symptoms) — almost half of the patients had reflux that could be detected by a pH monitor in the esophagus, even though they did not have acid symptoms. People with silent reflux failed to show improvement with anti-acid medicine as did the people with no reflux. It is reasonable to treat GERD symptoms in a person who has asthma. It might help the asthma as well as the GERD. But anti-acid treatment does not seem to help asthma among people who don't have symptoms of GERD.
Back to top Mary Pickett, M.D. is an Associate professor at Oregon Health & Science University where she is a primary care doctor for adults. She supervises and educates residents in the field of Internal Medicine, for outpatient and hospital care. She is a Lecturer for Harvard Medical School and a Senior Medical Editor for Harvard Health Publications.
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