- Disrupting bacterial makeup of gastrointestinal tract could affect body's metabolism, study says
- Scientists also linked obesity to 10 common types of cancer
- If you're a heart attack survivor, more exercise isn't always better, study finds
- Inner-city children have more food allergies than their peers, research says
Here's a roundup of five medical studies published this week that might give you new insights into your health, mind and body. Remember, correlation is not causation -- so if a study finds a connection between two things, it doesn't mean that one causes the other.
Antibiotics could screw up infants' metabolism
If young mice are given antibiotics early in life, they have a greater chance of becoming obese, a new study out of NYU Langone Medical Center found. Researchers discovered that when they gave mice antibiotics during a critical part of early development, the bacteria or microbes in the mice's guts were reprogrammed.
Scientists say disrupting the bacterial makeup of the gastrointestinal tract could affect the way the body's metabolism works. A slow metabolic rate could lead to obesity, because the body doesn't burn calories as quickly.
"We found that when you perturb gut microbes early in life among mice and then stop the antibiotics, the microbes normalize but the effects on host metabolism are permanent," says senior author, Dr. Martin Blaser, director of the NYU Human Microbiome Program, and professor of microbiology at NYU School of Medicine. "This supports the idea of a developmental window in which microbes participate. It's a novel concept, and we're providing direct evidence for it."
The study authors stress that more evidence is needed to determine whether antibiotics could lead to obesity in humans, and that the study results should not keep doctors from prescribing antibiotics to small children when necessary.
Obesity may increase your risk for multiple cancers
Journal: The Lancet
In one of the largest studies to date on the connection between cancer and obesity, researchers have found a link between a higher body mass index and 10 common types of cancer.
The study authors analyzed data from more than 5 million people over the age of 16 who were originally cancer-free and then followed for an average of 7.5 years. Every 11-pound increase in weight was roughly associated with a higher risk of uterine cancer, gallbladder, kidney, cervix and thyroid cancers, and leukemia. BMI was also positively associated with liver, colon, ovarian and postmenopausal breast cancers, according to the study.
"The number of people who are overweight or obese is rapidly increasing both in the UK and worldwide," said study author Dr. Krishnan Bhaskaran from the London School of Hygiene & Tropical Medicine. "It is well-recognized that this is likely to cause more diabetes and cardiovascular disease. Our results show that if these trends continue, we can also expect to see substantially more cancers as a result."
More exercise isn't always better
Journal: Mayo Clinic Proceedings
After a heart attack, doctors generally encourage patients to get fit in hopes of reversing the damage caused by cardiovascular disease. But some survivors may overdo it in trying to prevent a relapse.
Researchers at Mayo Clinic followed more than 2,300 heart attack survivors for an average of 10 years. Survivors who did the exercise equivalent of 1 kilometer (.62 mile) of walking or running a day reduced their risk of dying from cardiovascular disease by 21%, compared with the group that exercised the least. Survivors who did the equivalent of 5 to 7 kilometers (3.1 to 4.3 miles) a day reduced their risk by 63%. But survivors who did more than 7.2 kilometers (4.5 miles) a day only reduced their risk by 12%.
The results suggest that running or walking more than around 30 miles a week doesn't have an added benefit, the study authors say.
Dr. Carl Lavie, a cardiologist at the John Ochsner Heart and Vascular Institute in New Orleans, came to this conclusion: "As Hippocrates said more than 2,000 years ago, 'If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health.' "
Americans aren't the only ones eating too much salt
Journal: The New England Journal of Medicine
After analyzing survey and study data from 187 countries around the world, researchers know one thing for sure: Sodium overconsumption is a global problem.
About 1.65 million cardiovascular deaths in 2010 were caused by consuming too much sodium, the authors of a study published Thursday conclude. That's nearly 10% of all the deaths linked to cardiovascular disease.
In fact, researchers say an estimated 99.2% adults have an average daily sodium intake that exceeds the World Health Organization's recommendation of 2 grams per day. Globally the average daily consumption is 3.95 grams per day -- close to double what's recommended.
Too much salt can increase your blood pressure, leading to an increased risk of heart and stroke. For tips on reducing your sodium intake, check out the Centers for Disease Control and Prevention's website.
More food allergies found in inner-city children
Journal: Journal of Allergy and Clinical Immunology
Scientists know that young children from urban areas are more at risk for asthma and environmental allergies. But a new study from Johns Hopkins Children's Center suggests they're also more at risk for food allergies than their peers.
Researchers followed more than 500 inner-city kids living in Baltimore, Boston, New York and St. Louis, from birth through age 5. They found one in 10 of the children were allergic to peanuts, eggs and/or milk. That's 10% -- whereas scientists believe about 6% of children overall in the United States have a food allergy.
The children with food allergies were also more likely to have another type of allergy.
"Our findings are a wake-up call, signaling an urgent need to unravel the causes, contributors and mechanisms that drive the high prevalence of food allergies among an already vulnerable group," says senior author Dr. Robert Wood, director of pediatric allergy and immunology at Johns Hopkins.