Daily sugary drinks tied to increased visceral fat

Drinking sugar-sweetened beverages like soda daily may lead to more abdominal fat gain over time, according to a new study.

So-called visceral fat in the midsection wraps around internal organs like the liver and pancreas and affects the function of hormones like insulin. Insulin dysfunction, and becoming resistant to insulin, is closely tied to type 2 diabetes and heart disease risk.

“A lot of prior studies have looked at sugar-sweetened beverages and obesity,” said lead author Dr. Caroline S. Fox. “We looked at body fat distribution, in particular change over time.”

Fox, a former investigator with the Framingham Heart Study of the National Heart, Lung, and Blood Institute, is currently a special volunteer with the National Institutes of Health.

She and her colleagues found that all participants tended to gain visceral fat over time, but those who drank sugary beverages daily gained more.

The researchers used data from about 1,000 adult participants in the Framingham Heart Study in Framingham, Massachusetts, who answered food frequency questions about sugar-sweetened beverages and diet soda.

Sugar-sweetened beverages like regular soda and fruit punch have added sucrose or high fructose corn syrup. Most participants said they drank a mixture of sugary beverages and diet soda.

About a third said they never consumed sugar-sweetened beverages, 20 percent did so occasionally, 35 percent drank them frequently and 13 percent drank them daily.

At the study start, they underwent a computed tomography scan to measure quantity and volume of abdominal fat tissue. Six years later, they underwent another scan.

Over that period, visceral fat volume increased by 658 cubic centimeters for non-drinkers, slightly more for occasional and frequent drinkers, and by 852 cubic centimeters for daily drinkers of sugary beverages, as reported in the journal Circulation.

For daily drinkers, that’s in increase of about 0.8 kilograms, or 1.8 pounds, of abdominal fat, Fox told Reuters Health by phone.

“That’s probably a very small difference of actual visceral fat,” but it’s enough to make a difference for metabolic risk, according to other studies, she said.

Diet soda wasn’t linked to an increase in visceral fat.

It’s not clear from this study whether decreasing sugary beverage intake would decrease the gain in visceral fat over time, Fox said.

The American Heart Association recommends a limit of 100 calories per day of added sugars, such as those found in sweetened beverages, for most women, and 150 calories per day for most men.

“Drinking one 12-ounce soft drink a day would exceed that amount—and while they are a major source, sugar-sweetened beverages contribute only about half of the added sugar consumed by Americans,” said Jean Welsh of Emory University in Atlanta, who was not part of the new study.

“Water and milk are the healthiest beverage choices,” Welsh told Reuters Health by email. “Sugary beverage consumers who are looking to reduce their sugar and calorie consumption may find that diet soda consumption helps—but only as long as they are careful to not eat more of something else.” — Reuters

High-fat diets linked to some types of breast cancer

NEW YORK - Women who eat a lot of fat, particularly saturated fat, may be at higher risk of certain types of breast cancer, new research suggests.

Past studies have come to differing conclusions on a possible association between dietary fat and breast cancer. Whether the two are even linked at all remains controversial.

The new report, a second analysis of a large, long-term study, suggests that fat may play a role in the development of certain forms of the disease but not others, the authors said.

Still, it cannot prove that a high-fat diet is the reason any of the women got cancer.

"In our study we confirm that saturated fat intake was positively associated with breast cancer risk," lead author Sabina Sieri, from the Fondazione IRCCS National Cancer Institute in Milan, Italy, told Reuters Health in an email.

"Saturated fatty acids intake should be as low as possible within the context of a nutritionally adequate diet."

Saturated fat in the diet most often comes from meat and other animal products like butter and cheese.

The research team's findings are based on a study of about 337,000 women from 10 European countries. They filled out questionnaires about their diet and lifestyle and were followed for an average of 11 to 12 years.

During that time, about 10,000 of the women were diagnosed with breast cancer.

The original study found that women who ate the most saturated fat were more likely to develop breast cancer than those who ate the least.

For the new analysis, the researchers used patient medical records to classify breast cancers into specific subtypes, for instance based on whether the tumor may respond to the hormones estrogen and progesterone.

They found that women with diets high in saturated fat were 28 percent more likely to develop tumors that had receptors for estrogen and progesterone than women with the lowest saturated fat in their diets. The pattern was similar for total fat intake.

However, the chance of developing breast tumors without receptors for those hormones was not linked to dietary fat, according to the findings published in the Journal of the National Cancer Institute.

The researchers said it's possible dietary fat increases the level of sex hormones in the body. That could explain why high-fat diets are tied to a greater risk of tumors whose growth is related to estrogen and progesterone, known as hormone-receptor-positive cancers. Those cancers make up the majority of breast cancer diagnoses.

Sieri and colleagues found that high levels of saturated fat were also linked to a greater risk of HER2 negative breast cancer, but not HER2 positive disease. HER2 stands for human epidermal growth factor receptor 2 and is one factor used to determine how fast a cancer is growing.

Dr. Clifford A. Hudis, chief of Memorial Sloan Kettering Cancer Center's Breast Cancer Medicine Service in New York, said the extra risk of hormone-receptor-positive cancer linked to saturated fat was "relatively modest."

What's more, he added, "These patients were not randomly assigned to follow one diet or another."

That means other differences between women who ate high- and low-fat diets may have factored into their cancer risk.

Still, Hudis said, the findings are consistent with recent research looking at specific types of breast cancer and make sense based on what is known about the biological effects of dietary fat.

Dr. Michelle Holmes, who has studied diet and breast cancer at Harvard Medical School and the Harvard School of Public Health in Boston, said that in the grand scheme of things, any possible link between fat and breast cancer still seems to be small.

"In my opinion, the bottom line is that if the association with fat and breast cancer exists, it's fairly small (and) it's probably limited to certain subtypes," Holmes told Reuters Health.

Even though the new study included a "huge" number of women, she said, "the answer doesn't leap out at you."

Hudis and Holmes, who were not involved in the new research, agreed there's no reason women shouldn't still cut back on saturated fat.

"Saturated fat is bad for heart disease anyway," Holmes said.

"The associations with dietary fat are much stronger for heart disease, which still kills more women than breast cancer in the United States." —Reuters

source: gmanetwork.com