Study: High-Carb Consumption Leads To Lower HDL, Higher Triglyceride Levels

Dr. Anwar T. Merchant studied how to raise HDL and lower triglycerides

This Reuters Health column about a new study from Canadian researchers on the ethnic differences in cholesterol levels among various people groups reveals an important fact about livin' la vida low-carb that most people eating this way are already abundantly aware of.

Lead researcher Dr. Anwar T. Merchant, assistant professor in the Department of Clinical Epidemiology & Biostatistics at the Hamilton, ON-based McMaster University and a member of the Population Health Research Institute, and his fellow researchers observed the diet and lipid profile of 619 Canadians of Native American, South Asian, Chinese and European descent to determine if the differences in cholesterol and other blood fat levels could possibly be tied to diet.

However, unlike previous studies that had exclusively look at the role of dietary fat, Dr. Merchant and his colleagues decided to see if carbohydrate consumption had something to do with the disparity among the different ethnic groups. South Asian participants eat more carbohydrates and had the lowest levels of HDL cholesterol in their blood. Conversely, the Chinese participants ate the least amount of carbohydrates and they exhibited the highest levels of HDL cholesterol (something this study showed could happen to HDL levels when a low-carb diet is implemented).

Dr. Merchant noticed that when fat was removed from the diet and replaced with an equal number of carbohydrate calories, both the LDL and HDL cholesterol levels drop while triglycerides go way up.

The following is a list from most to least amount of carb consumption:

1. South Asians
2. Europeans
3. Native Americans
4. Chinese

Even when adjustments are made for age, ethnicity, body mass index and alcohol intake, the carbohydrate connection to lower HDL levels was undeniable. The high-carb group saw an average level of 1.08 mmol/L while the low-carb group experienced an HDL level of 1.21 mmol/L.

The researchers found that for each additional 100 grams of carbohydrates consumed daily led to a 0.15 mmol/L drop in HDL cholesterol and a corresponding rise in triglycerides. The primary culprits named in the study for higher carb intake include sugary soft drinks, fruit juices and junk food snacks with extra sugar and carbohydrates.

"Reducing the frequency of intake of sugar-containing soft drinks, juices and snacks may be beneficial," the researchers conclude.

This study was published in the January 2007 issue of the American Journal of Clinical Nutrition.

Despite the fact that low-fat diet activist Dr. Dean Ornish described HDL cholesterol in his interview with me last year as "garbage trucks" to get rid of the junk (fat) that you put in your body, the fact is that higher HDL cholesterol and lower triglycerides is a VERY GOOD thing. It's also an excellent indicator if you are actually livin' la vida low-carb or not because your HDL will be over 50 and your triglycerides will be below 100.

We have seen from previous research that lower HDL levels put at a greater risk for heart disease; thus, we can infer that higher levels of HDL actually PROTECTS against heart disease. Plus, respected nutrition researcher Dr. Jeff Volek from the University of Connecticut has asserted that examining the triglyceride/HDL ratio is a much better marker than total cholesterol and LDL levels for protecting against heart disease.

I don't know about you, but I trust the findings of a researcher like Dr. Volek who has poured his entire life into this subject over a self-righteous and inaccurate 30-second television ad that blares across my screen 20,000 times a night (by the way, have you seen the new Zetia commercial with that fat lady who has a healthy cooking show calling statins "a good option?" I wanna throw up every time I hear her say that! But isn't it quite ironic that she has to take a medicine to lower her cholesterol when she is supposedly making "healthy" recipes? If they were low-carb she wouldn't need the drugs! But I digress!).

Anyone who is confused about why LDL, HDL, and triglyceride levels are important or simply wants to educate themselves further on the role of cholesterol in the body needs to get a copy of independent researcher Anthony Colpo's magnificent book "The Great Cholesterol Con." He recently expanded and updated it with brand new content, so you will be armed with the facts rather than relying on the pharmaceutical companies to give you the information you need. They're in it to make a buck, so you probably should take EVERYTHING you hear from a cholesterol-lowering medication ad with a grain of salt.

You can e-mail Dr. Anwar T. Merchant about his fantastic study at merchant@ccc.mcmaster.ca.