After being injected with an opiate-like chemical produced in the human brain, laboratory rats ate twice the normal amount of sweet fatty food. (Photo: Alexandra Difeliceantonio)

Are you on a diet but  having a hard time resisting that candy bar or cheeseburger?  The problem  might really be in your head.

Researchers have found that an opium-like chemical produced in the brain might explain why some people overeat sweet and fatty foods.

“This means that the brain has more extensive systems to make individuals want to over consume rewards than previously thought,” says Alexandra DiFeliceantonio of the University of Michigan, Ann Arbor, who led the study. “It may be one reason why over-consumption is a problem today.”

The researchers found  a region of the brain called the neostriatum, located near the middle and front of the brain, which is best known for  controlling motor movements. It also produces the opiate-like chemical called enkephalin, which  DiFeliceantonio says sparks and intensifies the urge to consume pleasant rewards.

To make their findings, DiFeliceantonio and her team injected some of the morphine-like drug directly into the neostriatum of their lab rats.  After the injections, the rats were fed candy-coated chocolate. The rodent test subjects ate more than twice the number of chocolates than they would normally have eaten.

The researchers also found the levels of enkephalin – the opium-like chemical manufactured by the neostriatum – surged when the rats began to eat the  candy. And while the enkephalins, or comparable drugs, didn’t actually make the rats enjoy the candy more, they did increase their cravings and compulsion to eat them.

“The same brain area we tested here is active when obese people see foods and when drug addicts see drug scenes,” says DiFeliceantonio. “It seems likely that our enkephalin findings in rats mean that this neurotransmitter may drive some forms of overconsumption and addiction in people.”

DiFeliceantonio says the findings  reveal a lot about our tendency to binge and could eventually lead to the development a drug that  blocks the impulse to overeat.

Washing hands with some antibacterial soap (Photo: Laura Holder via Flickr/Creative Commons)

Scientists in Colorado and California say in a study recently published online by the Proceedings of the National Academy of Sciences that they have found that a chemical used in some antibacterial soaps and similar products can obstruct muscle contractions.

They say that at a cellular level, the chemical can slow a fish’s swimming abilities and it reduces muscular strength in mice.

The chemical, called triclosan is an antimicrobial agent and its uses in the U.S. are regulated by both the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA).  Triclosan can be found in products such as soaps, deodorants, mouthwashes, toothpaste, bedding, clothes, carpets, toys and trash bags.

It should be noted that most hand sanitizers however use alcohol and do not contain triclosan.

According to researchers, a 1998 estimate by the EPA found more than 454 metric tons of triclosan is produced each year in the U.S.  The chemical was found in human urine, blood and breast milk. It was also found in various waterways and marine life including algae, fish and dolphins.

To assess the effects of triclosan on muscle activity, the scientists performed several experiments on mice and fish. They used doses of the chemical similar to what people and animals could be exposed to during everyday life.

“The effects of triclosan on cardiac function were really dramatic,” said study co-author Nipavan Chiamvimonvat, MD. “Although triclosan is not regulated as a drug, this compound acts like a potent cardiac depressant in our models.”

Dr. Chiamvimonvat cautioned that taking the results of their experiments with animal models to humans would be a large step and that further study is needed.  But researchers said the fact that the effects of the chemical were so striking in their experiments, provides strong evidence that triclosan could have effects on animal and human health at current levels of exposure.

Other experts are said to have also expressed concern that the overuse of antibacterial products could lead to the development of resistant bacterial strains.

The U.S. Food and Drug Administration said that although triclosan is not currently known to be hazardous to humans, they’re continuing to review it because of several scientific studies that have come out since the product was last reviewed.

“Triclosan can be useful in some instances,” noted Bruce Hammock, the study’s co-author, “however it has become a ubiquitous ‘value-added’ marketing factor that actually could be more harmful than helpful. At the very least, our findings call for a dramatic reduction in its use.”