The link between obesity and cancer is well documented, but its impact on the immune system has been a bit of a mystery.
A new study published in the journal Nature Immunology shed light on the problem.
Researchers at Dublin's Trinity College found that excess fat essentially "clogs" natural killer cells, the fast acting immune cells that fight viruses and cancer cells in the body.
When the natural killer cells are clogged, they stop functioning and are unable to wage war against harmful cells. Researchers saw this happen in experiments with mice.
They also discovered that although immune cells were unable to destroy the cancer cells, they did find and attach to them.
Through additional experiments researchers also found they could jolt the natural killer cells back into action, restoring their ability to fight cancer.
Researchers hope this greater understanding of how obesity causes cancer will lead to better prevention and therapies for both conditions.