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)

Jonathan's HbA1c therefore equates to an eAG of 145.59 mg/dl--yet his fasting glucose value is 85 mg/dl. 

This is a common situation: Normal fasting glucose, high HbA1c. It comes from high postprandial glucose values, high values after meals. 

It suggests that, despite having normal glucose while fasting, Jonathan experiences high postprandial glucose values after many or most of his meals. After a breakfast of oatmeal, for instance, he likely has a blood glucose of 150 mg/dl or greater. After breakfast cereal, blood glucose likely exceeds 180 mg/dl. With two slices of whole wheat bread, glucose likewise likely runs 150-180 mg/dl. 

The best measure of all is a postprandial glucose one hour after the completion of a meal, a measure you can easily obtain yourself with a home glucose meter. Second best: fasting glucose with HbA1c.

Gain control over this phenomenon and you 1) reduce fasting blood sugar, 2) reduce expression of small LDL particles, and 3) lose weight.  

Can you handle fat?

21. March 2010 William Davis (19)
No question: Low-carbohydrate diets generate improved postprandial lipoprotein responses.

Here's a graph from one of Jeff Volek's great studies:



Participants followed a low-carb diet of less than 50 g per day carbohydrate ("ketogenic") with 61% fat.   The curves were generated by administering a 123 g fat challenge with triglyceride levels assessed postprandially. The solid line represents the postprandial response at the start; dotted line after the 6-week low-carb effort.

Note that:

1) The postprandial triglyceride (area-under-the-curve) response was reduced by 29% in the low-carb diet.  That's a good thing.

2) The large fat challenge generated high triglycerides of greater than 160 mg/dl even in the low-carb group. That's a bad thing. 

In other words, low-carb improves postprandial responses substantially--but postprandial phenomena still occur. Postprandial triglycerides of 88 mg/dl or greater are associated with greater heart attack risk because they signify the presence of greater quantities of atherogenic (plaque-causing) postprandial lipoproteins.

A full discussion of these phenomena can be found in the Track Your Plaque Special Report, Postprandial Responses: The Storm After the Quiet!, part of a 3-part series on postprandial phenomena.

Statin stupid

19. March 2010 William Davis (0)
If we followed the lead of the pharmaceutical industry and my cardiology colleagues, we would all subscribe to the "statins for all" philosophy. There is now $2 billion of clinical "research" to back up this "evidence-based" practice.

I do not endorse this "statins for all" philosophy. I believe it is a product of the raw profiteering of the pharmaceutical industry, who are adept at recruiting physicians to their cause.

But lost in the confusion of tainted studies and over-the-top media saturation is the fact that there are small groups of people who likely do obtain benefit from statin drugs. They would certainly benefit from better informed scrutiny of their lipoprotein and metabolic abnormalities. But treatment may involve statins.

This is entirely distinct from the "statins for all" argument, the simpleminded rule that primary care physicians and cardiologist are told to follow.

Groups who may indeed benefit from statin therapy include:

Homozygous or heterozygous familial hypercholesterolemia--Lacking a receptor for LDL particles, LDL piles up to very high levels in these people. LDLs of 300+ are common and lead to heart disease and stroke at relatively young ages.

Combined mixed hyperlipidemia--Among the one or more genetic defects underlying this condition involves excessive production of apoprotein B and VLDL particles. This leads to high risk for heart disease.

People unable to follow a diet to correct their lipid disorder--I have 80+-year old patients, for instance, who say, "I've eaten this way for 82 years. I'm not going to change now!" In the absence of diet and other efforts (e.g., omega-3 fatty acids from fish oil), drugs may be the answer.

In other words, of the $27 billion annual bill for statin drugs, perhaps a tiny fraction is truly necessary. The majority of people taking statin drugs would not really need them if they had the real answers. But don't let that confuse us: There are some people who do indeed benefit.

Butter and insulin

19. March 2010 William Davis (83)
In a previous post, Atkins Diet: Common Errors, I commented on butter's unusual ability to provoke insulin responses. I offer this as a possible reason why, after a period of effective weight loss on a low-carbohydrate program, inclusion of some foods, such as butter, will trigger weight gain or stall weight loss efforts.

This develops because of butter's insulin-triggering effect, doubling or tripling insulin responses (postprandial area-under-the-curve). If insulin is triggered, fat gain follows.

Here's one such study documenting this effect: Distinctive postprandial modulation of ß cell function and insulin sensitivity by dietary fats: monounsaturated compared with saturated fatty acids

López et al 2008


From Lopez et al 2008. Mean (± SD) plasma glucose, insulin, triglyceride, and free fatty acid (FFA) concentrations during glucose and triglyceride tolerance test meal (GTTTM) with no fat (control), enriched in monounsaturated fatty acids (MUFAs) from refined olive oil (ROO meal), with added butter, with a mixture of vegetable and fish oils (VEFO) or with high-palmitic sunflower oil (HPSO). N = 14.

The postprandial (after-eating) area-under-the-curve is substantially greater when butter is included in the mixed composition meal. This effect is not unique to butter, but is shared by most other dairy products.

Fat, in general, does not make you fat. But butter makes you fat.

Vitamin D as a cardiovascular risk factor gains ground

18. March 2010 William Davis (0)
If you were reading The Heart Scan Blog back in 2007, or read my Life Extension article on vitamin D deficiency as a cardiovascular risk factor, you already knew that vitamin D deficiency is rampant and adds to cardiovascular risk.

Results of a study from the Intermountain Medical Center Heart Institute in Utah bolster the concept that vitamin D deficiency is a cardiovascular risk factor, vitamin D normalization/supplementation reduces cardiovascular risk.

Science Daily reported:

For the first study, researchers followed two groups of patients for an average of one year each. In the first study group, over 9,400 patients, mostly female, reported low initial vitamin D levels, and had at least one follow up exam during that time period. Researchers found that 47 percent of the patients who increased their levels of vitamin D between the two visits showed a reduced risk for cardiovascular disease.


In the second study, researchers placed over 31,000 patients into three categories based on their levels of vitamin D. The patients in each category who increased their vitamin D levels to 43 nanograms per milliliter of blood or higher had lower rates of death, diabetes, cardiovascular disease, myocardial infarction, heart failure, high blood pressure, depression, and kidney failure. Currently, a level of 30 nanograms per milliliter is considered "normal."


Over the past 4 years, people in our program have been enjoying the extravagant benefits of vitamin D restoration. Cardiovascular benefits are becoming better documented and the bone health, cancer-preventing, insulin-normalizing, mood-adjusting, and anti-inflammatory effects likewise.

Atkins Diet: Common errors

18. March 2010 William Davis (74)
No doubt: The diet approach advocated by the late Dr. Robert Atkins was a heck of a lot closer to an ideal diet than the knuckleheaded advice emitting from the USDA, American Heart Association, American Diabetes Association, and the Surgeon General's office.

But having just spent a week with Atkins low-carbers, here are some common errors that I see many make, errors that I believe have long-term health consequences, including impairment of weight loss.

Excessive consumption of animal products--Non-restriction of fat often leads to over-reliance on animal products. Higher intakes of red meats (heme proteins?) have been strongly associated with increased risk for colon and other gastrointestinal tract cancers. It is not a fat issue; it is an animal product issue. We should consume less meat, more vegetables and other plant-sourced foods.

Consumption of cured meats--Cured, processed meats, such as sausage, hot dogs, salami, bologna, and bacon, have a color fixative called sodium nitrite, an additive that has been confidently linked to gastrointestinal cancers. Risk is likely dose-dependent: The more you ingest, the greater the long-term risk.

Overconsumption of dairy products--Dairy products, especially milk, yogurt, cottage cheese, and butter, are potent insulinotropic foods, i.e., foods that trigger insulin release. There can be up to a tripling of insulin (area-under-the-curve) levels. This is not good in a world populated with tired, overworked pancreases, exhausted from a lifetime of high-carbohydrate eating.

Too many calories--While I agree that "a calorie is a calorie" and "calories in, calories out" are faulty concepts, I have anecdotally observed that long-time low-carbers often trend towards unlimited consumption of food, a phenomenon that seems to result in weight gain, especially in the sedentary. I wonder if this is a reflection of the insulinotropic action of dairy products and other proteins, compounded by the poor insulin responsiveness that develops with lack of physical activity. Factor into this conversation that lower calorie intake extends life, probably substantially (Sirt-2 activation and related phenomena, a la resveratrol). If lower calorie intake extends life, unlimited calorie intake likely shortens life.

Please don't hear this as low-carb bashing--it is not. It is a call to improve diets and not stumble into common traps that can impair heart health, weight loss, and longevity.
Is an increase in heart scan score GOOD?

Is an increase in heart scan score GOOD?

20. November 2007 William Davis (30)
In response to an earlier Heart Scan Blog post, I don't care about hard plaque!, reader Dave responded:

Hello Dr Davis,

Interesting post about hard and soft plaque. I recently had a discussion with my GP regarding my serious increase in scan score (Jan 2006 = 235, Nov 2007 = 419).

After the first scan we started aggressively going after my LDL, HDL and Trig...196,59,221

And have them down to 103, 65, 92 - we still have a way to go to 60/60/60 [The Track Your Plaque target values]-

So the increase is a surprise, but my doctor said that the increase could in part be cause some of the soft plaque had been converted to hard plaque and the scan would show that conversion.


Dave's doctor then responded to him with this comment:

"Remember that although your coronary calcium score has gone up, this does not mean that you are at greater risk than you were a year ago. Remember that the most dangerous plaque is the not-yet calcified soft plaque, which will not show up on an EBT [i.e., calcium score]. It is only the safe, calcified plaque that can be measured with the EBT. [Emphasis mine.] For your score to go up like it did, while your lipids came down so much, what had to happen was that lots of dangerous unstable plaque was converted to stable, calcified plaque. There are no accepted guidelines for interpreting changes in calcium scores over time, because the scores tend to go up as treatment converts dangerous plaque to safer plaque. We do know that aggressively lowering LDL reduces both unstable and stable plaque, and we know that risk can be further lowered by adjuvant therapy such as I listed above."


Huh?

This bit of conventional "wisdom" is something I've heard repeated many times. Is it true?

It is absolutely NOT true. In fact, the opposite is true: Dave's substantial increase in heart scan score from 235 to 419 over 22 months, representing a 78% increase, or an annualized rate of increase of 37%. This suggests a large increase in his risk for heart attack, not a decrease. Big difference!

Dr. Paulo Raggi's 2004 study, Progression of coronary artery calcium and risk of first myocardial infarction in patients receiving cholesterol-lowering therapy in 495 participants addresses this question especially well. Two heart scans were performed three years apart, with a statin drug initiated after the first scan, regardless of score.

During the period of study, heart attacks occurred in 41 participants. When these participants were analyzed, it was found that the average annual increase in score over the three year period was 42%. The average annual rate of increase in those free of heart attack was 17%. The group with the 42% annual rate of increase--all on statin drugs--the risk of heart attack was 17.2-fold greater, or 1720%.

The report made several other important observations:

--20% of the heart attack-free participants showed reduction of heart scan scores, i.e., reversal. None of the participants experiencing heart attack had a score reduction.
--Only 2 of the 41 heart attacks occurred in participants with <15% per year annual growth, while the rest (39) showed larger increases.
--The intensity of LDL reduction made no difference in whether heart attacks occurred or not. Those with LDL<100 mg/dl fared no better than those with LDL>100 mg/dl.

Dr. Raggi et al concluded:

"The risk of hard events [heart attack] was significantly higher in the presence of CVS [calcium volume score] progression despite low LDL serum levels, although the interaction of CVS change and LDL level on treatment was highly significant. The latter observation strongly suggests that a combination of serum markers and vascular markers [emphasis mine] may constitute a better way to gauge therapeutic effectiveness than isolated measurement of lipid levels."

This study demonstrates an important principle: Rising heart scan scores signal potential danger, regardless of LDL cholesterol treatment. Yes, LDL reduction does achieve a modest reduction in heart attack, but it does not eliminate them--not even close.

These are among the reasons that, in the Track Your Plaque program, we aim to correct more than LDL cholesterol. We aim to correct ALL causes of coronary plaque, factors that can be responsible for continuing increase in heart scan score despite favorable LDL cholesterol values.

So, Dave, please forgive your doctor his misunderstanding of the increase in your heart scan score. He is not alone in his ignorance of the data and parroting of the mainstream mis-information popular among the statin-is-the-answer-to-everything set.

Just don't let your doctor's ignorance permit the heart attack that is clearly in the stars. Take preventive action now.
Tags :

Comments (30) -

  • Anonymous

    11/20/2007 5:41:00 PM |

    Dr Davis,

    What should Dave do?  He appears to have improved his LDL:HDL ratio as well as his total C to HDL ratio substantially, but his CAC score jumped significantly.  Maybe look at other risk factors?

    The info here gives no indication of median blood pressure for Dave.  LP(a)?  No indication of particle sizes. But, which of these or others would be most likely to be Dave's downfall in attempting to mitigate a future hard endpoint?

    I don't ask this lightly, I myself am trying to follow the TYP program and keep my high-for-my-age 29 CAC score from growning.  But, I'm frankly not looking forward to my rescan in about a year.  I'm a bit worried about the, "What if my scan shows a dramatic increase?  What then?"

    Thank you for the valuable information you provide.

    :LaughingCT

  • Dr. Davis

    11/20/2007 11:17:00 PM |

    I would urge Dave to follow all the principles of the Track Your Plaque program, including:

    1) Fish oil to provide minimum 1200 mg EPA + DHA per day

    2) Correction of all concealed lipoprotein patterns such as IDL and Lp(a)

    3) Vitamin D raised to 50 ng/ml--crucial!

    4) Normalization of blood pressure, including during exericse.

    5) Normal blood sugar (<100 mg/dl).

    Further efforts might be required, depending on the long-term effects on rate of plaque growth.

  • Ross

    11/21/2007 3:41:00 AM |

    My question is: how repeatable do you think the scores are on the CT scan?  Are they bulletproof (+/- 5% no matter where measured), consistent by analyst (+/- 5% with the same doctor analyzing the scan), or...?  

    I am currently visiting my brother in law, who is an FP doctor with a private practice.  One of his professional friends, a cardiologist who seems a cut above (thinks stenting is a cop-out), recently told him that he only trusted two centers in the mid-Ohio region to score a 16-slice CT scan accurately, and that even then, the variability was still too high for his taste.  Two numbers within 20% were within his expected error bars and weren't different enough to indicate any change to him.  Two different scan centers?  He wouldn't even compare the two scan scores.

    In my own job (software), I've had to manage human-measured numbers over and over again.  One observation keeps coming up: a single value doesn't mean much without an understanding of the accuracy of that value.  I really am curious about how you estimate confidence intervals on CT scan scores.

  • Dr. Davis

    11/21/2007 3:55:00 AM |

    Hi, Ross--

    Excellent questions.

    Several thoughts:

    1) 16-slice scanners are, unfortunately, prone to wider error in heart scan scoring, perhaps as much as 20%. The variation in scoring on an EBT or 64-slice device is far less.

    2) Variation from scan to scan, when expressed as percent, depends to a great degree on the score itself. Lumping all scores together, variation should be no more than 8-9%. However,a low score of, say 2, then repeated at 4 means 100% variation. However, the same absolute difference of 2 but with a score of 1002 and repeated at 1004 is <1% variation. Therefore, higher scores assume much less percent variation, usually <5%.

    3) Variation among different reading physicians tends to be a minor issue, since much of the scoring is done by standard criteria determined by software, not the human eye. The only real source of human variation comes from disputable areas, such as the mitral valve (which can sometimes encroach into the coronary area and appear like plaque) and the mouth of arteries, which can be debated as being in the aorta or in the coronary arteries themselves. However, these disputable areas are issues in <5% of scans.

  • Tom

    11/21/2007 4:30:00 AM |

    It's interesting that a 29 year old is able to track his plaque. I'm in my 60's now and recently found your site AFTER bypass surgery and a calcium score >700 via a 64 slice scan.
    In reading past comments, those of us having had the heart procedure are now unable to follow our progress via the cac score. Until this post I had hoped to use your recommended blood tests for indication of progress, but if LDL reduction achieves a modest risk reduction, we are left without a specific guide.
    Question: Was the progress in blood tests in dave's case a result of statins ?

  • Dr. Davis

    11/21/2007 12:46:00 PM |

    That's why lipoproteins are so important--they provide other indicators. In my experience, people who have LDL cholesterol as the sole cause of heart disease are a very small minority. The vast majority of people have multiple causes beyond LDL.

    Also, about 50% of people can still get a heart scan score after bypass surgery if you find a center willing to do a detailed analysis. You will need to ask.

    Also, I don't know what Dave did, since he is a reader and everything he posted is above. Are you there, Dave?

  • Dr. Davis

    11/21/2007 5:41:00 PM |

    Hi, Paul--

    I think your doctor might be confusing heart scans with CT coronary angiograms. She is right in saying that CT angiograms (using X-ray dye) require a lot of radiation; 100 chest x-rays worth with present technology.

    However, a plain heart scan to generate a heart scan score requires 4 chest x-rays worth on an EBT device, 8-10 on an 64-slice multi-detector device.

    See the Track Your Plaque Special Report, Radiation and Heart Scans: The Real Story at http://trackyourplaque.com/library/fl_06-021radiation.asp.

  • Anonymous

    11/21/2007 6:01:00 PM |

    Regarding repeatability, there is a 2005 study by Serukov, Bland, and Kondos that shows that the repeatability is a function of the square root of the calcium score, and that volume score is more repeatable than Agatston score. The reference is

    “Serial Electron Beam CT Measurements of Coronary Artery Calcium: Has Your Patient's Calcium Score Actually Changed?” Alexander B. Sevrukov, J. Martin Bland and George T. Kondos, American Journal of Roentgenology 2005; 185:1546-1553
    http://www.ajronline.org/cgi/content/full/185/6/1546

    In this report, the standard deviation of the difference between two sequential calcium scored is

    SDAG130 = 2.515 *sqrt(avg score)
    SDVol130 = 1.758 *sqrt(avg score)

    This results in the following values, where SDA is the standard deviation for the Agatston score and SDV is the standard deviation for the volume score.

    Score-SDA--%SDA--SDV--%SDV
    5-----5.62---112%---3.93--79%
    10----7.95---79%----5.55--56%
    20----11.2---56%----7.86--39%
    50----17.7---35%----12.4--25%
    100---25.1---25%----17.5--18%
    200---35.5---17%----24.8--12%
    300---43.5---14%----30.4--10%
    400---50.3---12%----35.1---9%
    500---56.2---11%----39.3---8%
    600---61.6---10%----43.0---7%
    700---66.5----9%----46.5---7%
    1000--79.5----7%----55.5---6%

    These values show why many people use 15% as a breakpoint - only if the score has changed by more than 15% can it be said that the change is real. And this is only true for scores above 200 or so.

    Harry

  • Anonymous

    11/21/2007 7:17:00 PM |

    My cardiologist told me that EBT scanning is not recommended for anyone under the age of 30. Is this true? If so, how do I (29 years) reliably know that I am at risk?

    I discovered your blog recently. Since I have a very bad family history of diabetes, high blood pressure, and cholesterol, I decided to visit a cardiologist last month so that I can request for an EBT scan. He said that I'm too young for that, and has instead asked me to take a Carotid IMT and Stress test - are these tests reliable enough to provide insight on my risk? Could these tests return "false positive" values?

    I had found during a blood test I did this July only to find that my triglycerides were at 600!! The other cholesterol values were bad too - totalC-HDL-LDL-Tri (255-31-Not measurable-600)

    Since then I have found your blog, lost around 25 lbs and did a VAP recently (I asked for NMR and all I got from doctors - what? What the heck is that?) So I settled for a VAP, since they knew about it.

    I did a VAP along with a comprehensive blood test and the measures that came up high were.

    LIPID related:
    Total LDL-C Direct:130 (Normal<130)
    Real LDL-C:110 (N<100)
    Sum Total LDL-C: 130 (<130)
    Remnant LIPO (IDL+VLDL3): 30 (<30)
    HDL-2:9 (>10)
    VLDL3: 14 (<10)

    Non-LIPID related high values:
    Uric Acid: 8.3  (4.0-8.0)
    Fasting Glucose: 104 (65-99)
    Creatine Kinase Total: 631 (<=200)


    LP PLA2 is normal: 164 (115-245)
    HBA1C suggests prediabetic: 5.7 (Normal <6%)


    Due to my very high value of CK Total, I researched online and found that this can increase due to high exercise, and I had it repeated after taking rest, and it returned normal results. My doctor was really surprised about this and initially hesitant to fractionise my CK. I feel empowered that I am able to take charge of my health and preventative care with the
    information that is available online (of course, one needs to tread that carefully and make an informed decision due to various conflicting opinions out there).

    Sorry for the long post, Doc. I have a newfound awareness of my health thanks to your blog, and am very much interested in knowing your inputs. I just hope that more physicians in our country follow your noble path and understand the true value and empowerment of preventive care.

    - Philip

  • Dr. Davis

    11/21/2007 8:09:00 PM |

    Hi, Philip--

    In general, 29 is very young, perhaps too young, unless there is an outstanding family history (e.g., father with heart attack at age 37). Although your lipid/lipoproteins are concerning, it would be highly unusual to have anything but a zero heart scan score at your age.

  • Dr. Davis

    11/21/2007 8:14:00 PM |

    Hi, Harry--
    Thanks for the help!

  • Neelesh

    11/22/2007 4:51:00 AM |

    Hi Dr. Davis,
      I've just bought the Track Your Plaque book, waiting for its arrival. I've had a heart attack a year back.I'm 30 years old with no family history, non-alcoholic, non-smoker and vegetarian.
    The event was attributed to ectatic arteries(Type-III) and a very high level of LP(a)- between 120-130. The standard lipid profile was also marginally higher. If I had not insisted for an LP(a) test after reading Dr Agatston's South Beach Heart Program, I would have never found the LP(a) factor.
       I was stented during the hospitalization and now I'm wondering how effective the heart scan will be, given that the accuracy reduces  with stented arteries (http://circ.ahajournals.org/cgi/content/meeting_abstract/114/18_MeetingAbstracts/II_692-a)

    Thanks!
    -Neelesh

  • Dr. Davis

    11/22/2007 2:35:00 PM |

    Hi, Neeleesh--

    I do advocate heart scanning in people with stents, but I generally suggest that only the unstented arteries be scored. It's imperfect, excluding the most diseased artery, but it's proven a useful compromise, leaving you with two "scorable" arteries.

    The study you cite, however, is not about heart scans, it's about CT coronary angiography, a study that yields "percent blockage" sort of information, not an index of plaque.

    Beyond Lp(a), you should strongly consider vitamin D normalization.  By your first name, I take it you are from India/Pakistan or similar background, an ethnic origin that is associated with severe vitamin D deficiency.

  • Neelesh

    11/22/2007 3:00:00 PM |

    Thanks Dr. Davis. And yes, I'm from India.

  • wccaguy

    11/22/2007 3:13:00 PM |

    Dr. Davis,

    I found your answer to Neeleesh to be interesting in the extreme.  I have a  follow up question to it.

    I don't have specific references for the two facts I have heard but couldn't reconcile:

    1   India has high coronary artery disease incidence.

    2   Your answer to Neeleesh states that vitamin d levels are low in India and Pakistan.  And that would help much to explain the high rate of coronary artery disease in these countries.

    3   And yet India is close to the equator and so vitamin d levels should be relatively high because of sun exposure right?

    The question then is this:  What is the cause of the low vitamin d level in those countries?

    Thanks!

  • Dr. Davis

    11/22/2007 4:00:00 PM |

    It is interesting, isn't it?

    I believe part of the explanation is that, the darker your skin complexion, the more you are "protected" from intense and prolonged sun exposure. But, activation of 7-hydrocholesterol to 25-OH-vitamin D3 may require many hours more exposure. Thus, a fair skinned person might activate D within minutes, while a dark skinned individual might require hours.

    Another factor that has not been thoroughly explored but has potential for yielding enormous insights: Vit D receptor genotypes. That is, vitamin D deficiency may express itself in different ways in different populations. Some might get colon cancer, others multiple sclerosis, others coronary disease.

    I believe that the dark-skinned phenomenon becomes especially an issue when migrating to sun-deprived climates such as the northern U.S.

  • wccaguy

    11/22/2007 6:12:00 PM |

    Hi Doc,

    Your explanation makes sense.

    I did a quick google search and found experts on the problem in India attributing it to the increasing extent to which Indians were staying indoors and not "being active."

    But the vitamin D issue throws the whole question of "activity" into question doesn't it?  It might not be the activity per se but instead the amount of sunlight reduction.

    And if, per your explanation, darker skinned people need more time in the sun than lighter skinned people for Vitamin D3 to be "activated" then than a decrease in sunlight would have more effect on darker skinned people than lighter skinned people.

    Very interesting...  And perhaps INCREDIBLY good news!!!

    Because it means that there might be a cheap effective treatment for the coronary disease epidemic in India.

    Does all that make sense?

  • wccaguy

    11/22/2007 6:19:00 PM |

    Just to follow up one more point on this D3 question...

    I guess what we need to do is find a study which shows a correlation between degree of skin pigmentation and Vitamin D3 activation?

    (I'm not sure if the word "degree" is the right word, but perhaps the question is understood anyway?)

    Answering that question would certainly set up the basis for a scientific study right?

  • Dr. Davis

    11/23/2007 12:56:00 AM |

    Yes, it does. It could serve as the basis for a tremendously interesting study.

  • Dr. Davis

    11/23/2007 1:09:00 AM |

    There are indeed a few studies that document this effect, e.g., Factors that influence the cutaneous synthesis and dietary sources of vitamin D (abstract viewable at Arch Biochem Biophys. 2007 Apr 15;460(2):213-7.)

    However, I am not aware of any study that examines the effect of vitamin D supplementation specifically in this population that tracks coronary atherosclerosis. One British study  in Bangladeshi adults did demonstrate dramatic reduction in inflammatory markers with vit D replacement (Circulating MMP9, vitamin D and variation in the TIMP-1 response with VDR genotype: mechanisms for inflammatory damage in chronic disorders? at http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=12454321&ordinalpos=22&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum  ).

  • Dave K

    11/24/2007 12:21:00 AM |

    Hi Dr Davis,

    Sorry - I have been offline for a couple of days.  Interesting discussion.  I will try and add some detail lipid info.

    July 2007 Blood work showed

    My Lp(a) is 7
    IDL = 10
    VLDL=11
    HDL-2 = 15
    HDL-3 = 50
    VLDL C = 18
    VLDL1+2 = 7

    Currently taking fishoil 1700 mg of DHA+EHA
    Vitamin D 800mg - just incresed to 2000
    Baby Aspirin
    Multivitamin
    Crestor
    Just started Zetia after getting this last scan result
    Eat basic South Beach phase 3
    BMI - 27
    Glucose is 105
    Exercise 4X week...
    Lp-PLA2=120

    Blood pressure high-normal but I don't know about during exercise.  Cardilogist scheduled me for a stress test after this volume increase.

    I have not has a blood test for Vit D.

    Also - I had an angiograham after the first scan because I was having chests pains .... it turned up that I had no blockages whatsoever.  So we judged the chest pains as non cardiac.

    So I am following your list pretty close.  I guess I just have to wait to see how these changes do.  How long would you wait for another scan?

    Not sure what else to add - your website says to consider L-arginie...


    I do have a specific question.  In the scan report it shows where the calcium was found.  Don't know the software, but there was one spot where it showed in the early report that it didn't show in this report (of course there was several new areas) - could that have actually been a reversal at that spot?

  • Dr. Davis

    11/24/2007 1:25:00 AM |

    Small LDL and a deficiency of large HDL, along with modest excess weight, high blood sugar, high blood pressure all suggest you are (or were) likely over-dependent on processed carbohydrates like wheat products. Your pattern would likely respond vigorously to reduction or elimination of these foods and weight loss. Niacin can help this pattern. In our experience, normalization of vitamin D is crucial.

  • Dave K

    11/26/2007 5:51:00 AM |

    Dr Davis,

    Few more data ....

    Some of the treatments have only been for the last 6 months or so.  The Statin was first (of course) and it took almost a year to get something I could tolerate.  The we talked about Vit D (700) and fish oil (800 Omega 3).  After a full Lipid scan around 9 months ago - we decided to add more fish oil.  So the full dosage I listed is only 6 months old or so.

    Also - I love my red wine and I know the number says two glasses and i rarely do two - so its three or four ... which might be my next step....

    From your last response, I assume the VLDL and IDL levels are the ones you would target hardest at this point.

    Don't do a lot of sugar or wheat... Do eat Oatmeal everyday with rasins or blueberries.

    Oh and my other question was with this kind of increase how long would you wait for the next scan?

  • Dr. Davis

    11/26/2007 12:08:00 PM |

    Dave-

    I generally recommend waiting a year after all identifiable causes have been corrected. However, given your minimal doses of vit D, I usually have my patients wait at least six month after vitamin D blood levels are corrected.

  • Dave

    11/26/2007 8:01:00 PM |

    Dr Davis,

    Thank you ... keep up the great work and I'll keep reading... and tracking.

    Dave

  • G

    11/27/2007 12:39:00 AM |

    Neeleesh and DR. D,

    This Canadian physician appears to have a lot of indepth awareness of the diff phenotypes. He suggests (in the author's response) that D2 may not work as well in East Indians (may worsen glycemic control) versus D3 (the more biologically active vitamin D). Very fascinating!!

    http://www.cfp.ca/cgi/reprint/53/9/1435
    Repletion of vitamin D with vitamin D2 is common
    practice, and vitamin D2 can be used safely when monitored
    to achieve normal levels of 25(OH)D. This might
    take 2 to 3 months, as discussed in your letter and in my
    paper, because the half-life is about 2 weeks. Using vitamin
    D3 (1000 to 5000 IU) daily, depending on the level
    of deficiency, will also achieve this goal. I also agree
    that the goal is to achieve levels of 25(OH)D higher than
    100 nmol/L, preferably 100 to 125 nmol/L.
    My concern regarding vitamin D2 is that it is a synthetic
    analogue and might interact with the vitamin D
    receptor differently in various cell systems. It has been
    reported that vitamin D3 might improve glycemic control.
    7 Vitamin D2 has been reported to cause worsening
    of glycemic control in people of East Indian descent.8
    Is this because of vitamin D receptor polymorphism, or
    because of enhanced 24-hydroxylase enzyme activation,
    or is it due to how vitamin D2 interacts with the receptor?
    Until this has been sorted out, I feel safest using
    vitamin D3. There are about 2000 synthetic analogues
    of vitamin D. The search is on for one that can cross the
    blood-brain barrier to treat certain types of brain cancers
    without causing hypercalcemia.9 But then again,
    what other effects would this compound have? There
    are still so many unknowns.
    The first step is to recognize that most Canadians
    do not get enough vitamin D, especially in the winter
    months, because of where we live. This recognition
    might reduce the need for expensive drugs to treat
    various conditions and might improve the well-being of
    many Canadians.
    An ounce of prevention is worth a pound of cure.
    —Gerry Schwalfenberg MD CCFP
    Edmonton, Alta
    by e-mail

    here's the orig article which is one of the most excellent summaries I've seen so far -- great minds think alike -- they advise > 50ng/ml like DR. Davis as well!
    http://www.cfp.ca/cgi/reprint/53/5/841

  • Neelesh

    11/27/2007 4:05:00 AM |

    D,
    Interesting study indeed. Thanks for the information. I guess I have a lot of things to discuss with my cardiologist next week. Smile
    -Neelesh

  • chickadeenorth

    12/2/2007 11:16:00 PM |

    Hi to Gerry Schwalfenberg MD CCFP, do you know any Dr In Edtmn who practices Track your Plague, if so could you suggest names to help me. I live out by Jasper and need a skilled Dr in this treatment program, I would travel to Edtmn.Many thanks.
    chickadeenorth
    (hope its ok for me to ask this here)

  • cadoce66

    4/5/2008 8:37:00 PM |

    hi my aunts 63 yrs and she underwent an angioplasty with a medicated stent .. Shes on PLAVIX and her artery was 90% blocked and she had an evolving AWMI...
    Please advise what she should taketo prevent another blockage or heart attack!
    Thanks!

  • buy jeans

    11/3/2010 10:34:10 PM |

    So, Dave, please forgive your doctor his misunderstanding of the increase in your heart scan score. He is not alone in his ignorance of the data and parroting of the mainstream mis-information popular among the statin-is-the-answer-to-everything set.

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