Saturday, September 20, 2014

The Nutrition Debate #246: “Sugar Substance Reduces HDL”


“Sugar Substance Reduces HDL,” the headline in Diabetes in Control, is reporting on an August 2014 paper in Nutrition and Diabetes. Most people know LDL is the “bad” cholesterol and HDL is the “good” cholesterol. That message has been pushed to promote the use of statin drugs, which do lower LDL cholesterol (and thereby Total Cholesterol). But how to raise HDL?

The Diabetes in Control lede: “The substance, methylglyoxal (MG), was found to damage ‘good’ cholesterol, which [HDL] removes excess levels of ‘bad’ cholesterol from the body.” MG is formed during glycolysis, the utilization of glucose to eventually make ATP, the little energy furnaces in our cells. Wikipedia explains that “Why methylglyoxal (MG) is produced remains unknown, but it may be involved in the formation of Advanced Glycation Endproducts (AGEs). ... Due to increased blood glucose levels, methylglyoxal has higher concentrations in diabetics, and has been linked to arterial atherogenesis.”

“Low levels of High Density Lipoprotein (HDL) are closely linked to heart disease [#27: "...the strongest predictor of a heart attack"], with increased levels of MG being common in the elderly and those with diabetes or kidney problems.” “MG destabilizes HDL and causes it to lose the properties which protect against heart disease. HDL damaged by MG is rapidly cleared from the blood, reducing its HDL content, or remains in plasma having lost it beneficial function,” the researchers say. MG damage to HDL is a new and likely important cause of low and dysfunctional HDL…,” they say.

To recap, when you eat carbohydrates, glucose (sugar) becomes energy (ATP) and along the way HG is produced. The HG damages the “good” cholesterol and prevents it from removing LDL, the “bad” cholesterol, from the body. (Sounds a bit like sugar isn’t a very clean “fuel” for your body, doesn’t it?) Well, what can be done about it, the researchers ask? Not surprisingly, they have an answer: “By understanding how MG damages HDL we can now focus on developing drugs that reduce the concentration of MG in the blood, but it won’t only be drugs that can help.” (That’s promising, I’m thinking. Maybe they’ll mention a dietary intervention. Let’s see.)

“We could now develop new food supplements that decrease MG…” “This means that in future we have both new drugs and new foods [somehow a “food supplement” becomes a “food”] that help prevent and correct low HDL, all through the control of MG.” To emphasize just how dangerous MG really is and the importance of their “new” discovery they add:

“A potentially damaging substance, MG is formed from glucose in the body. It is 40,000 times more reactive than glucose and damages arginine residue (amino acid) in HDL at a functionally important site causing the particle to become unstable.”

“Practice Pearls” from Diabetes in Control for the busy physician trying to keep up on the latest research in lipid chemistry:

     Methylglyoxal (MG) was found to damage “good” HDL cholesterol.

     There are currently no drugs that can reverse low levels of HDL.

So what can a type 2 diabetic or elderly person or a person with kidney problems or heart disease do now to raise their HDL? Well, my answer is you don’t have to wait for a drug or a supplement to be developed. You don’t need a drug or a food supplement. You need to simply but substantially reduce the amount of “sugar” (carbohydrates) that you eat.

All carbohydrates, whether simple sugars or “complex” carbohydrates, become glucose in your blood. Carbs will raise your triglycerides, and there’s an inverse relationship between HDL and triglycerides. So, lower carb = lower trig -> increased HDL (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1950669/). The British Heart Foundation, which funded this study, should request a refund. 
My doctor, since deceased, first suggested that I eat very low-carb. It worked. I lost a lot of weight, my health improved and I felt much better. Then, when I started writing about my success, he read my blog regularly. A few years ago he emailed me suggesting I write a column, “Foods that Raise HDL.” So I did (#34)   Nine months later I wrote a sequel, #67, “HDL Cholesterol and the Very Low Carb Diet.” The table in #67 shows how before I changed my diet my average HDL over 10 visits was 39. When I wrote that column the average of my most recent 10 HDLs was 81. Since writing that column, my average of the most recent 7 HDLs is 78; median 77, range 58 to 91. Wanna double your HDL? And reduce your triglycerides by 2/3rds (#68)? You can do it by diet.

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