If you want to get the most out of your flu shot, you might want to cut out red meat and butter, new research suggests.
A new study showed that feeding obese mice a low-fat meal before vaccinating them made them better at fighting off the flu virus.
A low-fat diet focuses on eating foods in which only 30 percent of the calories come from fat. according to the American Cancer Society. This means including products like skim milk, lean meats like chicken, whole grains, and plenty of fresh fruits and vegetables.
The experts who carried out the research found that a low-fat diet results in significant and sustained weight loss that strengthens the immune system.
Vaccines work by training the body’s defense cells to recognize and fight viral material, which is why they are effective when introduced to a healthy immune system.
Switching to a low-fat diet before the flu vaccine gave the obese mice a better chance of surviving the flu virus.
A low-fat diet contrasts with the Western diet, which is traditionally high in fat and processed foods, according to Dr. Stacey Schultz-Cherry, deputy director of the WHO Collaborating Center for Studies on the Ecology of Influenza in Animals and Birds. who was a co-author of the new study.
Overweight people are twice as likely to get the flu as people of average weight, even when both groups have been vaccinated, according to 2017 research from the Human Vaccine Institute.
About 370,000 Americans were hospitalized with the flu in 2023 and about 24,000 died. According to the Centers for Disease Control and Prevention.
Although the agency did not report details, it estimates that 95 percent of those hospitalized had an underlying condition that worsens the severity of the flu, such as obesity, high blood pressure or heart disease.
The study was carried out in two groups of 20 mice. All of the mice that lost weight before being vaccinated survived a brush with the flu, but those that didn’t diet did not.
Dr. Shultz-Cherry’s research, which took place at St. Jude Children’s Research Hospital, addresses this gap in the flu vaccine for obese people.
She and her colleagues dove into the topic by giving the flu vaccine to 20 obese mice.
Half of those mice were given a low-fat diet before being vaccinated. About a month later, all the mice were exposed to the flu.
All ten mice on the low-fat diet survived. But all ten mice that continued to eat a high-fat diet died.
Interestingly, when the researchers put a different group of mice on a diet after being vaccinated, the results were not as effective.
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Only two of the mice on the diet survived; the remaining 18 mice, both those on a low-fat and high-fat diet, died.
“Weight loss can affect the effectiveness of the vaccine, but the timing of weight loss makes a big difference” Dr. Schultz-Cherry he told New Scientist.
However, there is still a long way to go before we can assume that the same will happen in humans, Dr. Schultz-Cherry said.
Mice and humans have many biological similarities, but human bodies are much more complex, said Dr Ri Scarborough, a veterinarian and cancer researcher at Monash University. wrote for the conversation.
“Due to differences between species, something that is effective and safe in an animal may not be effective and safe in a human,” Dr. Scarborough said.
Mice, for example, only live about two years. That means a month for a mouse would be years for a human, Schultz-Cherry said.
In all, this could be a new avenue to explore in the future to better protect people with obesity.
“We don’t know for sure, but if the result of using GLP-1 drugs is weight loss and better metabolic health, we could assume it will help.”