Why obese people are more likely to develop cancer

Christiane Fux studied journalism and psychology in Hamburg. The experienced medical editor has been writing magazine articles, news and factual texts on all conceivable health topics since 2001. In addition to her work for, Christiane Fux is also active in prose. Her first crime novel was published in 2012, and she also writes, designs and publishes her own crime plays.

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The phenomenon has been known for a long time: the excess weight increases the risk of cancer. Japanese researchers have now found a hitherto unknown explanation for why this is so: Fatty food could hinder an important self-protection mechanism that would otherwise eliminate sick cells.

Competition of cells

A phenomenon known as “cell competition” plays a central role here. This occurs in the associations of epithelial cells - the flat layers of cells that line the inner walls of many organs. Here, weaker cells are forced out of the association by healthier cells.

Ejected from the cell structure

Yasuyuki Fujita from the University of Hokkaido has discovered that this mechanism also serves to fight cancer. The neighboring cells apparently recognize when a cell mutates into a cancer cell. The healthy cells then break off communication with the diseased cell, they are expelled from the association of epithelial cells and die. The researchers refer to this phenomenon of self-healing as "epithelial defense against cancer" (EDAC).

High-fat diet blocks protective mechanisms

Experiments with mice have shown that a high-fat diet hinders the body's own self-healing powers. The mechanism worked in mice that were fed normal food - degenerate cells could not multiply and no tumors formed. In contrast, in high-fat mice, the cancer defense failed.

The researchers do not yet know exactly how the high-fat diet hinders the protective displacement competition of the epithelial cells. An unfavorable metabolism and inflammatory processes could play a role here.

Other possible cancer drivers in the case of obesity are hormonal changes that result from the additional body fat, increased insulin levels, higher amounts of the growth factor IGF and aggressive oxygen molecules, so-called free radicals, that wreak havoc in the body.

Five percent of cancers are due to obesity

Scientists estimate that around five percent of all cancers are caused by obesity. In some forms of cancer, the influence of body weight is particularly high.

Half of all uterine and kidney tumors, but also adenocarcinomas of the esophagus, are caused by obesity. There is also a connection with colon cancer, breast cancer, liver cancer, pancreatic cancer, ovarian cancer and multiple myeloma: They occur much less often in people of normal weight than in overweight people.

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