Gene link between high fat diet and diabetes

US researchers have discovered why a high fat diet could increase the risk of type 2 diabetes. The team, based at the University of California, San Diego (UCSD), has shown that mice missing a gene that makes a crucial pancreas protein have high blood sugar levels, and eventually develop diabetes. The study, published in the journal Cell, also revealed that normal mice fed a high fat diet had lower levels of the protein, suggesting that high levels of dietary fat 'damp down' the activity of the gene - called GnT-4a. If confirmed, the findings could help explain the 'current human epidemic in type 2 diabetes', say the scientists.

People with diabetes cannot regulate their blood sugar levels properly, either because their pancreas is not making enough of hormone insulin, or because the body becomes resistant to its effects. Type 2 diabetes usually affects people over the age of 40. It is more common in overweight, inactive people, and those with a family history of the disease, which suggests that genetic factors are also involved. Previous research has identified several genes involved in the condition.

In the latest study, the UCSD team showed that the GnT-4a gene makes a protein crucial to the ability of the pancreas to release insulin in response to high blood sugar levels. It seems it is responsible for getting 'glucose transporter' proteins into their correct place at the outer surface of pancreas cells. Without a working GnT-4a gene, this process is disrupted, and the pancreas is no longer able to detect blood sugar levels effectively. To their surprise, the researchers also found that feeding mice a high fat diet lowered their GnT-4a gene activity, which in turn increased their blood sugar levels and lead to diabetes.

According to team leader Jamey Marth, it could be possible to tackle type 2 diabetes by developing medicines that boost levels of GnT-4a. A spokesman for the charity Diabetes UK welcomed the research, saying that diet and lack of exercise are the main factors behind type 2 diabetes. 'If we are able to pinpoint what's behind the diet element then this would be a significant breakthrough', he told the Times newspaper.