Research Highlights Diet’s Influence on Immune Response to Flu Vaccination

The World Health Organisation (WHO) estimates that immunization efforts have saved 154 million people over the past 50 years. Certain immunizations, such as the flu vaccine, are not always as effective as we’d like them to be due to various factors. A recent study published in Nature Microbiology examines how healthy dietary interventions before vaccination could influence metabolic health and increase flu vaccine effectiveness. The findings show that improved metabolic health led to better immune function, which increased the vaccine response. 

In this study, dietary changes before and after vaccination were tested. They took two groups of mice and fed one group a lean diet and the other a high-fat diet. The mice then received a flu vaccine and some of them who were on a high-fat diet were switched to a control diet. Mice then received a lethal dose of the flu virus, homotypic H1N1, after either 4 weeks or 12 weeks on the control diet. 

Researchers found that switching to a healthy diet post-vaccination does not improve survival despite the weight loss that the previously obese mice experienced. The previously obese mice had only a 24% survival rate after 4 weeks on the control diet and a 28% survival rate after 12 weeks on the control diet. However, the results suggested that dietary changes to lose weight after vaccination may help control viral spread. 

The results were different when dietary changes were made pre-vaccination. To test these researchers had certain obese mice switch to the lean control diet 4 weeks before vaccination. This switch allowed for several systemic measurements of metabolic dysfunction to return to normal and for weight loss to occur. 

Researchers observed an improved immune response in these mice, particularly among their T cells, and decreased morbidity and mortality. After exposure to the flu virus, the formerly obese mice had a 100% survival rate, and the results suggest that specific dietary changes and weight loss might help improve the flu vaccine’s effectiveness.

Research also adds to how obesity might impact immune response which will be an area for further research. Researchers say that it is important to remember that this study was conducted in mice, and of course, mice are not humans, so it is certainly not definitive in terms of proving that people with obesity don’t respond as well to flu vaccines. 

The study’s main limitation is the ability to determine certain factors, as they had a low sample size of mice on the high-fat diet who survived exposure to the flu. They acknowledge the need for a more in-depth investigation of how nutrition affects immune cell function during vaccination and infection. 

Journal Reference – Honce, R., Vazquez-Pagan, A., Livingston, B., Mandarano, A. H., Wilander, B. A., Cherry, S., … Schultz-Cherry, S. (2024). Diet switch pre-vaccination improves immune response and metabolic status in formerly obese mice.

Retrieved from https://www.nature.com/articles/s41564-024-01677-y