Fatty acids found in fish oil supplements may block chemotherapy from attacking tumors and patients should stop taking them, said a study by Dutch researchers on Monday.

Fish oil supplements of omega-3 and omega-6 fatty acids are sold worldwide, and are touted by manufacturers as a way to boost heart and brain health.

The cartoon character SpongeBob SquarePants is in hot water from a study suggesting that watching just nine minutes of that program can cause short-term attention and learning problems in 4-year-olds.

The problems were seen in a study of 60 children randomly assigned to either watch "SpongeBob," or the slower-paced PBS cartoon "Caillou" or assigned to draw pictures. Immediately after these nine-minute assignments, the kids took mental function tests; those who had watched "SpongeBob" did measurably worse than the others.

Adults referred to the commercial weight loss program Weight Watchers shed twice as much weight as people who received standard care over a 12-month period, according to a study published Thursday.

In clinical trials, researchers led by Susan Jebb of the UK Medical Research Council assessed 772 overweight and obese adults in Australia, Germany, and Britain.

A number of cholera cases have been detected in Iran, Health Minister Marzieh Vahid Dastjerdi said on Wednesday, blaming "foreigners" and contaminated vegetables for the outbreak.

"In recent days, due to the illegal entry of foreigners in Iran, cholera appeared in parts of the country," Vahid Dastjerdi was quoted as saying by the government information website dolat.ir.

A new study estimates that about 38 percent of Europeans, or 165 million people, have some type of mental illness and that most are going untreated.

Researchers analyzed data from more than 500 million people in 30 countries in the European Union plus Switzerland, Iceland and Norway.

Researchers in the United States said Sunday they had developed a vaccine for tuberculosis that offered unprecedented protection in mice against the deadly disease.

Tuberculosis kills some 1.7 million people each year, with one in three people around the globe infected, according to the World Health Organization (WHO). The only vaccine currently in use is notoriously inconsistent.

Shortages of vital drugs, particularly cancer-fighting medication, have raised concerns in the United States, where regulators often have to race to try to find replacements.

A recent report by the Food and Drug Administration (FDA) found that the number of important treatments that are difficult or impossible to find nearly tripled from 61 to 178 between 2005 and 2010.

Mexico plans to administer the vaccine against human papillomavirus (HPV), which can cause cervical cancer, to all girls beginning next year, the country's health ministry said Tuesday.

Beginning in 2012, the HPV vaccine will be part of the normal course of shots given to all girls at the age of nine, Health Minister Jose Angel Cordova said.

Global death rates among newborns under one month old are dropping, a study by the World Health Organization showed Tuesday.

"Newborn deaths decreased from 4.6 million in 1990 to 3.3 million in 2009," the U.N. health agency said in a statement.

Canada's health agency on Tuesday warned would-be parents not to purchase "fresh" semen online, saying it may be tainted with infectious diseases.

"Health Canada is reminding Canadians of the serious potential health risks of using donor semen for assisted conception obtained through potentially unreliable sources, such as the Internet," the government agency said.