Rerun: To let low-carb right, you must check POSTPRANDIAL blood sugars

2. April 2010 William Davis (12)

Checking postprandial (after-eating) blood sugars yields extraordinary advantage in creating better diets for many people.

This idea has proven so powerful that I am running a previous Heart Scan Blog post on this practice to bring any newcomers up-to-date on this powerful way to improve diet, lose weight, reduce small LDL, reduce triglycerides, and reduce blood pressure.

To get low-carb right, you need to check blood sugars

Reducing your carbohydrate exposure, particularly to wheat, cornstarch, and sucrose (table sugar), helps with weight loss; reduction of triglycerides, small LDL, and c-reactive protein; increases HDL; reduces blood pressure. There should be no remaining doubt on these effects.

However, I am going to propose that you cannot truly get your low-carb diet right without checking blood sugars. Let me explain.

Carbohydrates are the dominant driver of blood sugar (glucose) after eating. But it's clear that we also obtain some wonderfully healthy nutrients from carbohydrate sources: Think anthocyanins from blueberries and pomegranates, vitamin C from citrus, and soluble fiber from beans. There are many good things in carbohydrate foods.

How do we weigh the need to reduce carbohydrates with their benefits?

Blood sugar after eating ("postprandial") is the best index of carbohydrate metabolism we have (not fasting blood sugar). It also provides an indirect gauge of small LDL. Checking your blood sugar (glucose) has become an easy and relatively inexpensive tool that just about anybody can incorporate into health habits. More often than not, it can also provide you with some unexpected insights about your response to diet.

If you’re not a diabetic, why bother checking blood sugar? New studies have documented the increased likelihood of cardiovascular events with increased postprandial blood sugars well below the ranges regarded as diabetic. A blood sugar level of 140 mg/dl after a meal carries 30-60% increased (relative) risk for heart attack and other events. The increase in risk begins at even lower levels, perhaps 110 mg/dl or lower after-eating.

We use a one-hour after eating blood sugar to gauge the effects of a meal. If, for instance, your dinner of baked chicken, asparagus brushed with olive oil, sauteed mushrooms, mashed potatoes, and a piece of Italian bread yields a one-hour blood sugar of 155 mg/dl, you know that something is wrong. (This is far more common than most people think.)

Doing this myself, I have been shocked at the times I've had an unexpectedly high blood sugar from seemingly "safe' foods, or when a store- or restaurant-bought meal had some concealed source of sugar or carbohydrate. (I recently had a restaurant meal of a turkey burger with cheese, mixed salad with balsamic vinegar dressing, along with a few bites of my wife's veggie omelet. Blood sugar one hour later: 127 mg/dl. I believe sugar added to the salad dressing was the culprit.)

You can now purchase your own blood glucose monitor at stores like Walmart and Walgreens for $10-20. You will also need to purchase the fingerstick lancets and test strips; the test strips are the most costly part of the picture, usually running $0.50 to $1.00 per test strip. But since people without diabetes check their blood sugar only occasionally, the cost of the test strips is, over time, modest. I've had several devices over the years, but my current favorite for ease-of-use is the LifeScan OneTouch UltraMini that cost me $18.99 at Walgreens.

Checking after-meal blood sugars is, in my view, a powerful means of managing diet when reducing carbohydrate exposure is your goal. It provides immediate feedback on the carbohydrate aspect of your diet, allowing you to adjust and tweak carbohydrate intake to your individual metabolism.

LDL glycation

1. April 2010 William Davis (11)

The proteins of the body are subject to the process of glycation, modification of protein structures by glucose (blood sugar). In the last Heart Scan Blog post, I discussed how glycated hemoglobin, available as a common test called HbA1c, can serve as a reflection of protein glycation (though it does not indicate actual Advanced Glycation End-products, or AGEs, just a surrogate indicator).

There is one very important protein that is subject to glycation: Apoprotein B.

Apoprotein B, or Apo B, is the principal protein of VLDL and LDL particles. Because there is one Apo B molecule per VLDL or LDL particle, Apo B can serve as a virtual VLDL/LDL particle count. The higher the Apo B, the greater the number of VLDL and LDL particles.

Because Apo B is a protein, it too is subject to the process of glycation. The interesting thing about the glycation of Apo B is that its "glycatability" depends on LDL particle size: The smaller the LDL particle, the more glycation-prone the Apo B contained within.

Younis et al have documented an extraordinary variation in glycatability between large and small LDL, with small LDL showing an 8-fold increased potential.

Think about it: Carbohydrates in the diet, such as wheat products and sugars, trigger formation of small LDL particles. Small LDL particles are then more glycation-prone by up to a factor of 8. Interestingly, HbA1c is tightly correlated with glycation of Apo B. Diabetics with high HbA1c, in particular, have the greatest quantity of glycated Apo B. They are also the group most likely to develop coronary atherosclerosis, as well as other consequences of excessive AGEs.

No matter how you spin it, the story of carbohydrates is getting uglier and uglier. Carbohydrates, such as those in your whole grain bagel, drive small LDL up, while making them prone to a glycating process that makes them more likely to contribute to formation of coronary atherosclerotic plaque.

High HbA1c: You're getting older . . . faster

28. March 2010 William Davis (16)

Over the years, we all accumulate Advanced Glycation End-products, or AGEs.

AGEs are part of aging; they are part of human disease. AGEs are the result of modification of proteins by glucose. AGEs form the basis for many disease conditions.

Accumulated AGEs have been associated with aging, dementia, cataracts, osteoporosis, deafness, cancer, and atherosclerosis. Most of the complications of diabetes have been attributable to AGEs.

There's one readily available method to assess your recent AGE status: HbA1c.

Hemoglobin is the oxygen-carrying protein of red blood cells. Like other proteins, hemoglobin becomes glycated in the presence of glucose. Hemoglobin glycation increases linearly with glucose: The higher the serum or tissue glucose level, the more glycation of hemoglobin develops. Glycated hemoglobin is available as the common test, HbA1c.

Ideal HbA1c is 4.5% or less, i.e., 4.5% of hemoglobin molecules are glycated. Diabetics typically have HbA1c 7.0% or greater, not uncommonly greater than 10%.

In other words, repetitive and sustained high blood glucose leads to greater hemoglobin glycation, higher HbA1c, and indicates greater glycation of proteins in nerve cells, the lens of your eye, proteins lining arteries, and apoprotein B in LDL cholesterol particles.

If AGEs accumulate as a sign of aging, and high blood sugars lead to greater degrees of glycation, it only follows that higher HbA1c marks a tendency for accelerated aging and disease.

Indeed, that is what plays out in real life. People with diabetes, for instance, have kidney failure, heart disease, stroke, cataracts, etc. at a much higher rate than people without diabetes. People with pre-diabetes likewise.

The higher your HbA1c, the greater the degree of glycation of other proteins beyond hemoglobin, the faster you are aging and subject to all the phenomena that accompany aging. So that blood glucose of 175 mg/dl you experience after oatmeal is not a good idea.

The lesson: Keep HbA1c really low. First, slash carbohydrates, the only foods that substantially increase blood glucose. Second, maintain ideal weight, since normal insulin responsiveness requires normal body weight. Third, stay physically active, since exercise and physical activity exerts a powerful glucose-reducing effect. Fourth, consider use of glucose-reducing supplements, an issue for another day.

While HbA1c cannot indicate cumulative AGE status, it can reflect your recent (preceding 60 to 90 days) exposure to this age-accelerating thing called glucose.

If your doctor refuses to accommodate your request for a HbA1c test, you can perform your own fingerstick test.

Slash carbs . . . What happens?

26. March 2010 William Davis (20)

Cut the carbohydrates in your diet and what sorts of results can you expect?

Carbohydrate reduction results in:

Reduced small LDL--This effect is profound. Carbohydrates increase small LDL; reduction of carbohydrates reduce small LDL. People are often confused by this because the effect will not be evident in the crude, calculated (Friedewald) LDL that your doctor provides.

Increased HDL--The HDL-increasing effect of carbohydrate reduction may require 1-2 years. In fact, in the first 2 months, HDL will drop, only to be followed by a slow, gradual increase. This is the reason why, in a number of low-carb diet studies, HDL was shown to be reduced.--Had the timeline been longer, HDL would show a significant increase.

Decreased triglycerides--Like reduction of small LDL, the effect is substantial. Triglyceride reductions of several hundred milligrams are not at all uncommon. In people with familial hypertriglyceridemia with triglyceride levels in the thousands of milligrams per deciliter, triglyceride levels will plummet with carbohydrate restriction. (Ironically, conventional treatment for familial hypertriglyceridemia is fat restriction, a practice that can reduce triglycerides modestly in these people, but not anywhere near as effectively as carbohydrate restriction.) Triglyceride reduction is crucial, because triglycerides are required by the process to make small LDL--less triglycerides, less small LDL.

Decreased inflammation--This will be reflected in the crude surface marker, c-reactive protein--Yes, the test that the drug industry has tried to convince you to take statins drugs to reduce. In my view, it is an absurd notion that you need to take a drug like Crestor to reduce risk associated with increased CRP. If you want to reduce CRP to the floor, eliminate wheat and other junk carbohydrates. (You should also add vitamin D, another potent CRP-reducing strategy.)

Reduced blood pressure--Like HDL, blood pressure will respond over an extended period of months to years, not days or weeks. The blood pressure reduction will be proportion to the amount of reduction in your "wheat belly."

Reduced blood sugar--Whether you watch fasting blood sugar, postprandial (after-meal) blood sugars, or HbA1c, you will witness dramatic reductions by eliminating or reducing the foods that generate the high blood sugar responses in the first place. Diabetics, in particular, will see the biggest reductions, despite the fact that the American Diabetes Association persists in advising diabetics to eat all the carbohydrates they want. Reductions in postprandial (after-eating) blood sugars, in particular, will reduce the process of LDL glycation, the modification of LDL particles by glucose that makes them more plaque-causing.

You may notice that the above list corresponds to the list of common plagues targeted by the pharmaceutical industry: blood pressure, diabetes (diabetes being the growth industry of the 21st century), high cholesterol. In other words, high-carbohydrate, low-fat foods from the food industry create the list of problems; the pharmaceutical industry steps in to treat the consequences.

In the Track Your Plaque approach, we focus specifically on elimination of wheat, cornstarch, and sugars, the most offensive among the carbohydrates. The need to avoid other carbohydrates, e.g., barley, oats, quinoa, spelt, etc., depends on individual carbohydrate sensitivty, though I tend to suggest minimal exposure.

Normal fasting glucose with high HbA1c

23. March 2010 William Davis (24)

Jonathan's fasting glucose: 85 mg/dl

His HbA1c: 6.7%

Jonathan's high HbA1c reflects blood glucose fluctuations over the preceding 60-90 days and can be used to calculate an estimated average glucose (eAG) with the following equation:

eAG = 28.7 X A1c – 46.7

(For glucose in mmol/L, the equation is eAG = 1.59 × A1C - 2.59)

All posts by william-davis

Wheat-free and still fat

15. February 2008 William Davis (14)

Readers of The Heart Scan Blog know that I preach a diet that contains foods with low glycemic index to control weight, raise HDL, and reduce triglycerides, blood sugar, and small LDL.

A crucial aspect of a low glycemic index approach is to sharply reduce, preferably eliminate, wheat products.

I pick on wheat specifically because it has come to dominate the American diet. Look at the shelves in the supermarket: aisle after aisle of processed wheat products. The bread shelves alone in some of the grocery stores in my neighborhood are 40 feet long, six shelves high. There's also breakfast cereals, granola products, cookies, cakes, baking products, pretzels, crackers, pasta, and on and on.

Wheat products like these are tasty and they're addicting--literally. Test animals given processed wheat will eat more and gain more weight. Wheat fails to trigger satiety. So laboratory mice--and you and I--eat and eat, because eating wheat stimulates appetite, creates a hunger for more wheat, and a vicious cycle ensues. Eliminating wheat, on the other hand, results in dramatic drop in appetite, substantial weight loss, followed by correction of the metabolic disruptions it created.

A quick Google search for "gluten-free" turns up a startling array of wheat-free, gluten-free, yet high glycemic index products. The breakfast cereal pictured, for instance, can do as much damage as most wheat containing products--though it won't cause gluten enteropathy (also known as "celiac disease").

The product shown contains:

Brown rice flakes, rice bran, evaporated cane juice, brown rice syrup, raisins, cinnamon, gum arabic, vanilla, molasses, ground flaxseed, rosemary extract.

A 1/2-cup serving contains:
Total Carbohydrate 31g
Dietary Fiber 5g
Sugars 8g

An