Obesity and higher cancer risk

  • by: Fondazione Valter Longo Onlus Editorial Staff
  • February 4th, 2021

New research reveals how obesity can increase the risk of developing cancer. This is explained by researchers from the City of Hope National Medical Center in California, who presented their study at the American Chemical Society’s annual meeting in 2019. They examined how the main factors responsible for this are high blood glucose levels and DNA damage.

 

Adipose tissue produces specific proteins called adipokines, which induce a state of chronic inflammation and are linked to the development of tumors.

 

RISK IS MORE THAN DOUBLED IN DIABETES PATIENTS

Excess fat can also increase the risk of developing type 2 diabetes five times which, in turn, increases the risk of cancer 2.5 times more than in healthy individuals with normal blood glucose values.

 

From previous studies, it was believed that the increase in the incidence of cancer in people with diabetes was due to hormonal imbalances. However, it is the excess insulin characteristic of type 2 diabetes which stimulates cell growth and thus causes the onset of cancer.

 

Scientists have deepened scientific research to better explain these mechanisms. According to the researchers, the association between diabetes and cancer is found in DNA damaged by hyperglycemia. High blood sugar levels cause more DNA damage and make DNA repair more challenging.

 

THE SOLUTION IS TO KEEP BLOOD GLUCOSE LEVELS LOW

The researchers at the City of Hope National Medical Center wanted to investigate the structure of DNA more closely. In particular, they tried to understand if high blood glucose concentrations are capable of damaging DNA strands, a phenomenon at the core of tumor development. To do this, they analyzed cell cultures and observed mice in the laboratory, finding that some portions of DNA (adducts) associated with tumor development are found mostly in tissues and animals with diabetes. Furthermore, observations showed that excess blood glucose interferes with the repair process of damaged DNA fragments. As a result, it was concluded that high blood glucose concentrations cause damage to DNA and, at the same time, inhibit repair, a mechanism that causes instability in the genome and leads to cancer onset.

 

In the second phase of this clinical study, the researchers found high levels of adducts in both the DNA and RNA of individuals with type 2 diabetes. In these subjects, the scientists found low levels of transcription factors mTORC1 and HIF1α: proteins involved in the DNA repair process. mTORC1 stimulates the production of HIF1α, which activates the genes that trigger all mechanisms. The next research step is to verify whether drugs capable of stimulating the synthesis of these two proteins also lead to a lower incidence of tumors. Given that metformin (the main drug used to lower blood sugar) also stimulates DNA repair, researchers are testing the combination with substances that stabilize these two proteins. In any case, experts recommend keeping blood glucose levels low to lower the risk of developing cancer.

SOURCES

Science Daily – “How Diabetes can Increase Cancer Risk: DNA Damaged by High Blood Sugar” – (August 25, 2019)

American Chemical Society – “How Diabetes can Increase Cancer Risk: DNA Damaged by High Blood Sugar”

 

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