Sugar in diet depletes good cholesterol

8 September 2014

Scientists at the University of Warwick have discovered that the ‘good’ form of cholesterol, HDL, is degraded by a sugar-derived substance in the body.

The substance, methylglyoxal (MG),  is formed from glucose in the body. Supported by funding from the British Heart Foundation (BHF) and published in the journal Nutrition and Diabetes, the researchers discovered that MG causes HDL to lose the properties which protect against heart disease.

 MG damages the arginine (an amino acid) component in HDL at a functionally important site on the molecule, causing it to become unstable. HDL damaged by MG is rapidly cleared from the blood, reducing its HDL content, or remains in plasma having lost its beneficial function. Increased levels of MG are common in the elderly and those with diabetes or kidney problems.

 HDL cholesterol is called good because it removes excess levels of LDL, the bad cholesterol, from the body. Low levels of HDL are closely linked to heart disease. There are currently no drugs that can reverse low levels of HDL, but the Warwick researchers argue that discovering how MG damages HDL has provided new potential strategies for reducing MG levels.

Lead researcher Dr Naila Rabbani, of the Warwick Medical School, said, “MG damage to HDL is a new and likely important cause of low and dysfunctional HDL, and could count for up to a 9% risk of heart disease. By understanding how MG damages HDL we can now focus on developing drugs that reduce the concentration of MG in the blood, but it not only be drugs that can help. We call abnormally high levels of MG ‘dicarbonyl stress’. This occurs in some diseases, particularly diabetes, kidney dialysis, heart disease and obesity. We need sufficient Glo1 to keep MG low and keep us in good health.

“We could now develop new food supplements that decrease MG by increasing the amount of a protein called glyoxalase 1, or Glo 1, which converts MG to harmless substances. This means that in future we have both new drugs and new foods that can help prevent and correct low HDL, all through the control of MG.”


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