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Wednesday, December 22, 2010

Cholesterol & HbA1c: What They Are and Why They Matter

(Dec 26, 2010 - This is now the second most frequented page on the blog.  I have updated it with some new information from Ned Kock's site, the Health Correlator).

Let's say you go for a blood test and the results come back that your cholesterol is too high.  How can you lower your cholesterol safely?

To begin, let's define a few terms:

  • LDL - Low density lipoprotein.  This is the bad type of cholesterol that clogs arteries.  You don't want this.
  • HDL - High density lipoprotein. This is good cholesterol because high levels of HDL seem to reduce the risk of heart attacks.
  • Triglycerides - this is a type of fat made in the body.  High triglycerides typically mark a diet high in refined carbohydrates.  When triglycerides are high, LDL also tend to be high and HDL tends to be low.

Most informed doctors today no longer worry about any one number in isolation.  What is important is the ratio between HDL and LDL and the amount of trigylcerides.

Stop Eating These Foods
To improve your cholesterol numbers, simply stop eating:

Foods That Are Sweet
Why do those foods cause cholesterol to be high?  They tend to be high on the glycemic index. They are sweet and will cause the body's blood sugar to rise rapidly. It may surprise you to know that whole wheat bread will cause your blood sugar to rise more than a Snickers bar. Having a lot of sugar in the blood leads to glycation. Imagine what happens when you heat sugar in a pan on the stove.  It melts and become sticky right?  The same thing happens inside our bodies when high levels of sugar are present. The test to measure how much sugar is in the blood is a test called the HbA1c (pronounced hemoglobin A-1-c).

HbA1c  Correlates Cardiovascular Disease
Red blood cells have an average lifespan of 120 days.  The HbA1c measures the average blood sugar during the past 120 days expressed as a percentage.  The lower the number, the better. Numbers between 4% to 5.8% are OK.  6% and higher means the risk of cardiovascular disease is greatly increased.  Greatly.

To calculate your average blood glucose level  over the past 3 months using your HbA1c number, apply the following formulas (choose mg/dl or mmom/L.  x is multiply, - is minus).  Take moment to calculate it if you have your HbA1c number.

Average blood glucose (mg/dl) = 28.7 × HbA1c − 46.7
Average blood glucose (mmol/l) = 1.59 × HbA1c − 2.59

Having high blood sugar in the bloodstream causes arteries to harden. We need to understand that  high HbA1c values are a better predictor of cardiovascular disease than cholesterol.    The graph below is charted using raw data from the EPIC-Norfolk Study by Petro Dobromylskyj who publishes a blog called Hyperlipid.

EPIC Norfolk data. IHD = Ischemic Heart Disease. CHD = Coronary Heart Disease.

What trend do you see here?  I think its pretty obvious that once the HbA1c reaches 6% or greater, that the risk of ischemic heart disease rises rapidly. You can read a summary of the conclusion from the Annals of Internal Medicine - one of the most widely cited peer reviewed journals in the world.

Doesn't Cholesterol Cause Atherosclerosis?
Wait a second!  HbA1c measures sugar in the blood.  What about cholesterol?  Isn't cholesterol the cause of heart attacks?  Eating fat, makes us fat and eating fat will clog our arteries?  This is known as the Lipid Hypothesis.   Although Rudolf  Virchow first articulated the theory in 1856, we have to credit Ancel Keys for selling the idea to North America. Have a look at this video:

Decades of Low-Fat, Obesity Still Rising
For years conventional wisdom waged a war against fat.  This gave rise to a food industry that made "low-fat" variations of every food product imaginable.  Despite 30 years of following the "low-fat" mantra, obesity rates have only increased. Why?  There are only 3 main food groups:  protein, fat and carbohydrates (vegetables, grains, fruits).  A low-fat diet inevitably means a high carb diet.  Have a look at cholesterol levels compared with HbA1c plotted against IHD events.

Same data as above. IHD = Ischemic Heart Disease, TC = Total Cholesterol, LDL = Low Density Lipoprotein.

What this graph shows is that Total Cholesterol and LDL could vary between 4.5 mmol per liter to 7.5 mmol per liter and the relative risk would stay stable at 6 and 4 respectively. Relative risk was not able to be lower than 3.9 regardless how low total cholesterol or LDL was measured at. Only larger amounts of sugar in the blood over the last 120 days track with an increase in coronary heart disease events.  Even better news, HbA1c values of 4.5% equate to a relative risk of 1 (a risk reduction of 3.9 times compared to LDL).

Prolonged High Blood Sugars & Coronary Heart Disease
Looking at the graph and assuming your total cholesterol and LDL are within the range shown above, should you worry more about reducing cholesterol or reducing sugar in the blood?  Still not sure?  Have second opinion here or see what this cardiologist has to say.  Or this: Ned Kock, an evidence-based evolutionary biology researcher also comes to the same conclusion using a different data set. We now know that a high carb diet causes blood sugar to rise and consistently elevated post-prandial (after meals) blood sugar levels damage the body. Could it be that high carbs are more damaging to the body than healthy animal fat?

If this is so, why does mainstream media and the average family doctor obsess over cholesterol numbers to the point of prescribing statins to "control cholesterol"?  I suggest that pharmaceutical marketing pressure on physicians and the deliberate skewing of certain studies to frame cholesterol as the culprit in coronary heart disease benefits drug companies.  They want to sell us a pill to lower cholesterol.  They can't make money just telling us to stop eating sugar and wheat.  Too many industries have too much to lose if people reduced sugar and wheat consumption.  If you find this compelling, read more here.

Hearty-Friendly Foods
So what should we eat instead of the list of foods above?

Eat more eggs, meats, bacon, fish, organ meats, seeds, nuts (peanuts are legumes!), butter, lots of fresh vegetables and fruit in moderation.  Bear in the mind the meats should be free from antibiotics and growth hormones. Wherever possible, they should be free range and pastured. Even though humans are at the top of the food chain, we have an ethical duty to the animals we eat to minimize the suffering they experience being raised as food.  Animals raised in factory-farm conditions typically suffer from overcrowding issues such as disease and deformities requiring antibiotics and chemical feed.

The key here is eating food prepared from a raw state.  Simple dishes that are tasty, satisfying and healthy without pesticide exposure or genetic modification.

Get a full blood test done that measures lipid profile, HbA1c and C-Reactive protein.  More on C-Reactive Protein in future blog posts.  In British Columbia, doctor's don't normally request HbA1c unless you are diabetic so make sure you ask for it.  When you go to the lab for the test, sign up to receive a copy of your test results electronically.  This is done via (available only in British Columbia).  If your blood sugars are high, try taking 2 grams of cinnamon a day. It lowers blood sugar and HbA1c.

Now start talking to your doctor and researching what those results mean.  If the answers are not in-depth enough, start looking for answers on your own. Getting fit after 40 means minimizing our risks to diseases that plague our age group by changing what we eat and how we exercise.

Healthfully yours,


  1. Hi! Great article!!!

    Small correction. Cashews are botanically SEEDS, but not legumes.

  2. Thanks for the correction Sondra! I'll fix the post now. :-)


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