Salt, sugar, frying in oil bad; Ketogenic diet good - health news


Mice fed a very high-salt diet showed accumulation of a protein in the brain linked with Alzheimer’s disease and other dementias

Ketogenic diet helps tame flu virus 



A high-fat, low-carbohydrate diet like the Keto regimen has its fans, but influenza apparently isn't one of them.
Mice fed a ketogenic diet were better able to combat the flu virus than mice fed food high in carbohydrates, according to a new Yale University study published Nov. 15 in the journal Science Immunology.
The ketogenic diet -- which for people includes meat, fish, poultry, and non-starchy vegetables -- activates a subset of T cells in the lungs not previously associated with the immune system's response to influenza, enhancing mucus production from airway cells that can effectively trap the virus, the researchers report.
"This was a totally unexpected finding," said co-senior author Akiko Iwasaki, the Waldemar Von Zedtwitz Professor of Immunobiology and Molecular, Cellular and Developmental Biology, and an investigator of the Howard Hughes Medical Institute.
The research project was the brainchild of two trainees -- one working in Iwasaki's lab and the other with co-senior author Visha Deep Dixit, the Waldemar Von Zedtwitz Professor of Comparative Medicine and of Immunobiology. Ryan Molony worked in Iwasaki's lab, which had found that immune system activators called inflammasomes can cause harmful immune system responses in their host. Emily Goldberg worked in Dixit's lab, which had shown that the ketogenic diet blocked formation of inflammasomes.
The two wondered if diet could affect immune system response to pathogens such as the flu virus.
They showed that mice fed a ketogenic diet and infected with the influenza virus had a higher survival rate than mice on a high-carb normal diet. Specifically, the researchers found that the ketogenic diet triggered the release of gamma delta T cells, immune system cells that produce mucus in the cell linings of the lung -- while the high-carbohydrate diet did not.
When mice were bred without the gene that codes for gamma delta T cells, the ketogenic diet provided no protection against the influenza virus.
"This study shows that the way the body burns fat to produce ketone bodies from the food we eat can fuel the immune system to fight flu infection," Dixit said.

Frying oil consumption worsened colon cancer and colitis in mice


Foods fried in vegetable oil are popular worldwide, but research about the health effects of this cooking technique has been largely inconclusive and focused on healthy people. For the first time, UMass Amherst food scientists set out to examine the impact of frying oil consumption on inflammatory bowel disease (IBD) and colon cancer, using animal models.
In their paper published Aug. 23 in Cancer Prevention Research, lead author and Ph.D. student Jianan Zhang, associate professor Guodong Zhang, and professor and department head Eric Decker showed that feeding frying oil to mice exaggerated colonic inflammation, enhanced tumor growth and worsened gut leakage, spreading bacteria or toxic bacterial products into the bloodstream.
"People with colonic inflammation or colon cancer should be aware of this research," says Jianan Zhang.
Guodong Zhang, whose food science lab focuses on the discovery of new cellular targets in the treatment of colon cancer and how to reduce the risks of IBD, stresses that "it's not our message that frying oil can cause cancer."
Rather, the new research suggests that eating fried foods may exacerbate and advance conditions of the colon. "In the United States, many people have these diseases, but many of them may still eat fast food and fried food," says Guodong Zhang. "If somebody has IBD or colon cancer and they eat this kind of food, there is a chance it will make the diseases more aggressive."
For their experiments, the researchers used a real-world sample of canola oil, in which falafel had been cooked at 325 F in a standard commercial fryer at an eatery in Amherst, Massachusetts. "Canola oil is used widely in America for frying," Jianan Zhang says.
Decker, an expert in lipid chemistry performed the analysis of the oil, which undergoes an array of chemical reactions during the frying process. He characterized the fatty acid profiles, the level of free fatty acids and the status of oxidation.
A combination of the frying oil and fresh oil was added to the powder diet of one group of mice. The control group was fed the powder diet with only fresh oil mixed in. "We tried to mimic the human being's diet," Guodong Zhang says.
Supported by grants from the U.S. Department of Agriculture, the researchers looked at the effects of the diets on colonic inflammation, colon tumor growth and gut leakage, finding that the frying oil diet worsened all the conditions. "The tumors doubled in size from the control group to the study group," Guodong Zhang says.
To test their hypothesis that the oxidation of polyunsaturated fatty acids, which occurs when the oil is heated, is instrumental in the inflammatory effects, the researchers isolated polar compounds from the frying oil and fed them to the mice. The results were "very similar" to those from the experiment in which the mice were fed frying oil, suggesting that the polar compounds mediated the inflammatory effects.
While more research is needed, the researchers hope a better understanding of the health impacts of frying oil will lead to dietary guidelines and public health policies.
"For individuals with or prone to inflammatory bowel disease," Guodong Zhang says, "it's probably a good idea to eat less fried food."


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