Feed a cold, starve a fever: keto diet may boost healing from flu © Yui Mok/PA

Feed a cold, starve a fever: keto diet may boost healing from flu

Mice fed the high-fat, low-carbohydrate diet were better able to fight the virus.

A ketogenic diet may help in the fight against flu, new research suggests.

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Scientists found that mice fed the high-fat, low-carbohydrate diet, were better able to combat the virus than those fed food high in carbohydrates.

The Yale University study suggests the ketogenic diet, which includes meat, fish, poultry, and non-starchy vegetables for people, activates a subset of T cells in the lungs not previously associated with the immune system’s response to influenza.

Researchers found that the cells enhanced mucus production from airway cells that can effectively trap the virus.

Read more about the flu:

Co-senior author Akiko Iwasaki, the Waldemar Von Zedtwitz professor of immunobiology and molecular, cellular and developmental biology, said: “This was a totally unexpected finding.”

Mice that had been fed a ketogenic diet for 7 days before infection were protected from body weight loss and had improved survival relative to mice on a normal chow diet.

In addition, they were able to better maintain blood oxygen saturation, suggesting improved gas exchange as compared with chow-fed mice, according to the paper published in Science Immunology.

The animals were randomised to indicated diet groups for 1 week before infection, and were subsequently monitored for clinical signs of disease and euthanised to assess the immune response.

Co-senior author Vishwa Deep Dixit, the Waldemar Von Zedtwitz professor of comparative medicine and of immunobiology, said: “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.”

Reader Q&A: When I’m ill, should I just let my fever burn itself out?

Asked by: Benjamin Matthews, Crewe

Fever is a classic sign of a viral infection like the flu. There’s nothing for it but to rest, drink plenty of water and take paracetamol to deal with the aches and high temperature. At least, that’s the standard advice, but there’s growing evidence that it might actually hinder recovery.

That’s because the fever isn’t caused by the virus itself, but by the body’s own infection-fighting system. First recognised by physicians over 2,000 years ago, the benefits of having a fever (a temperature of at least 38°C) have been confirmed by the latest immune system research. This has shown that viruses struggle to thrive at high temperatures, while our immune system works better.

Read the full answer here

Dr Jenna Macciochi, lecturer in immunology, University of Sussex, said: “Although the authors have made obvious efforts to delineate the mechanistic link, there are some important considerations, namely that mice and humans are different metabolically.

“In addition, humans and mice do not have equivalent populations of gamma deltas T cells which limits the translatability of the findings to humans.

“Though this study further adds to the growing scientific literature that dietary manipulation of the three macronutrients – protein/carbs/fats – represents a novel avenue to treat inflammatory conditions, it’s too early to speculate on what this may look like for humans.

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“Since 2016 it has been known that there may be a thread of scientific truth to the old adage ‘feed a cold, starve a fever’, and this study adds support to this, opening up the possibility of ketogenic diets for treatment not only of flu but other conditions where inflammation can cause us collateral damage.”