Dieting during the flu season a no-no

Dieting during the flu season may impair the body's ability to fight the flu, new research suggests.

Professor Elizabeth Gardner and colleagues at Michigan State University found that mice infected with the influenza A virus were significantly more likely to die, lost more weight, and took longer to recover if they were fed a calorie-controlled diet. Further investigations revealed that even though the mice received adequate amounts of vitamins and minerals their bodies were unable to produce sufficient amounts of immune system cells called natural killer (NK) cells to fight the infection.

The findings led the researchers to advise people to keep dieting on hold until the arrival of spring. “Our research shows that having a body ready to fight a virus will lead to a faster recovery and less-severe effects than if it is calorically restricted,” said Professor Gardner. “Adults can restrict their diet eight months out of the year, but during the four months of the flu season they need to bump it up. You need the reserves so your body is ready for any additional stress, including fighting a virus.”

Ritz BW, Aktan I, Nogusa S, Gardner EM. Energy Restriction Impairs Natural Killer Cell Function and Increases the Severity of Influenza Infection in Young Adult Male C57BL/6 Mice. J Nutr. 2008;138:2269-2275.

Why all new year diets should come with a health warning. Daily Mail. January 2nd 2009.