A new study led by Yale University has unexpectedly found that a ketogenic diet , or KD , protects mice from flu infections ,media reported . While experts say the study is interesting and meaningful, many warn that the animal results cannot be used in humans and that people are not advised to fight the flu through KD.
KD refers to a high-fat/low-carbohydrate diet that was originally developed in the early 20th century as a way to reduce seizures in people with epilepsy. Recently, this diet has begun to gain popularity in the weight-loss circle, and scientists are slowly discovering the effects of this dietary strategy on a person’s health span and metabolism.
A previous study found that KD is effective in inhibiting the formation of inflammatory small bodies. Researchers want to know whether this dietary strategy protects the body from influenza or makes it more susceptible to the virus.
The researchers then exposed both groups of mice to influenza viruses — one fed KD (90 percent fat, 9 percent protein, 1 percent carbohydrate) seven days before exposure to the flu virus — and the other on standard feed (18 percent fat, 58 percent carbohydrate 58 percent, 24 percent protein 24 percent). The results showed that the KD group had a lower likelihood of infection and a higher survival rate than the control group for a normal diet.
After amplifying the potential protective mechanisms, the researchers found higher levels of gamma delta T cells in the lungs of mice in the KD group. To confirm that this is a protective mechanism, the researchers bred a mouse that did not have the ability to produce this particular T-cell. When these animals were exposed to influenza viruses after receiving a KD diet, they did not exhibit additional viral resistance, which confirmed the hypothesis that these particular immune cells might be the source of protection.
What made the study even more interesting was that the gamma delta T cells in the lungs of mice fed simpler, high-fat foods but no ketogenic ingredients had no subsequent protective effect after infection. This suggests that a wider metabolic process triggered by KD supports enhanced virus protection from the addition of gamma delta T cells in the lungs.
Study co-author Visha Deep Dixit said: “This study shows that the body burns fat and then strengthens the immune system by producing ketones from food to fight influenza infection. “
But many experts believe that while these results are academically interesting, they are not particularly applicable to humans. Michelle Tate, from the Hudson Institute of Medicine, points out that metabolic differences between mice and humans mean that the findings don’t make much sense for those who want to avoid the flu. Nikolai Petrovsky of Flinders University was more frank about the clinical significance of the study. He said the results were too trivial to be practical. He also noted that increasing inflammatory activity found in the lungs involved in KD may also increase the risk of lung problems in susceptible people. Rosemary Stanton, a visiting scholar from the University of New South Wales, said that even if further research revealed what mechanismwas was at work, its ultimate applicability to human health was still minimal.
The study was published in Science Immunology.