For Colorectal Cancer It's the Blood Sugar NOT The Insulin Level That Counts

A recently published study based on data from the Womans Health Initiative (WHI) sheds light on a question many of us have wondered about: Is the higher incidence of cancer among people with Type 2 caused by higher insulin levels (or, perhaps injected insulin) or something else?

The study was conducted by a team at The Albert Einstein College of Medicine, which some of you may remember is where Dr. Bernstein earned his M.D.. It has through the years done several low carb studies, too.

The study is summarized here:

Science Daily: High Blood Sugar Levels in Older Women Linked to Colorectal Cancer

The actual abstract is found here:


A longitudinal study of serum insulin and glucose levels in relation to colorectal cancer risk among postmenopausal women. G C Kabat et al. British Journal of Cancer , (29 November 2011) | doi:10.1038/bjc.2011.512

From the abstract we learn that in a group of 4902 middle aged women who were tracked for 12 years, about 1.6 percent developed colorectal cancer. They had had their fasting blood sugar and fasting insulin measured at the beginning of the study and occasionally through the study. This study found that women whose fasting blood sugar was over 99.5 mg/dl (5.53 mmol/L) at the beginning of the study had a greater risk of developing colorectal cancer than those with blood sugars under 89.5 mg/dl (4.98 mmol/L). The relationship held true for subsequent blood tests too.

However--and this is what is interesting about this study--there was no relationship between these women's fasting insulin levels or the calculated HOMA values (which are believed to measure insulin resistance) and their risk of getting this cancer.

So this data would suggest that it is the high blood sugars, not the high insulin which promotes the cancer.

Before you panic because your fasting blood sugar is over 99.5 mg/dl (as is the case with many of us thanks to dawn phenomenon) remind yourself of this: from what we can see in other contexts, it isn't actually mildly elevated fasting blood sugars that damage our bodies. We see the correlation between fasting sugars and complications in studies because in people eating high carbohydrate diets, mildly elevated fasting blood sugars almost always go hand in hand with significantly elevated post meal sugars. Especially in women, who may be diabetic by glucose tolerance test for up to a decade before they would be diagnosed using a fasting glucose test. (You can see the data backing this up HERE.)

So a woman with a fasting sugar of 105 mg/dl, for example, when she eats her morning bagel with jelly, along with a sweetened latte, may easily reach a blood sugar that approaches 200 mg/dl even if it resolves fairly quickly due to a near-healthy second phase insulin release. But if diabetic you should wake up with a blood sugar of 105 mg/dl and eat an egg and bacon for your breakfast with no carbs, you may easily end up with a blood sugar of 95 an hour later, which suggests you would have a similar health outcome to a completely non-diabetic woman with a fasting blood sugar of 89 mg/dl who ends up at 95 mg/dl an hour after eating her breakfast.

It's also worth noting that the statistical measure the study calculated was "risk" not incidence--and that risk is a statistical artifact that magnifies numbers to provide a more dramatic impact. The actual increase in incididence due to elevated blood sugar was likely around 5 cases per thousand or .5%.

But on the positive side, the fact that even after using magifying statistical techniques like "risk" the researchers couldn't find the expected connection between fasting insulin levels, HOMA, and cancer gives us one more, intriguing, piece of data to answer the quesion, "Do people with diabetes get cancer because of high insulin levels (injected or natural) or because of high blood sugars?" Here at least, it looks like the answer is, as is the case with all the other diabetic complications, "It's the blood sugars, stupid!"

This is very good news because our insulin levels are very hard to control and insulin resistance may be genetic and not something we can lower. Even many devout low carbers with Type 2 continue to be insulin resistant no matter what they weigh (based on how much insulin they have to inject to lower their blood sugars.) But insulin resistant or not, we can control our blood sugars--often most effectively with insulin--and if the conclusion of this study is reinforced by findings in other studies, we may be able to relax about the potential impact on cancer of our injecting insulin to control those blood sugars.

One last note: If you have had years of exposure to higher than normal blood sugars, you might be interested in knowing that Metformin has been shown to suppress the growth of existing early colorectal growths in people without diabetes. Read about that HERE.

Though researchers often state that metformin inhibits cancer due to its effect on lowering insulin, this is just a guess. The belief that it is high insulin levels that cause a greater incidence of cancer among people with diabetes is far from proven and that theory is exactly the belief this study debunks.

In fact, there is evidence emerging that metformin's anti-cancer properties are independent of its effect on insulin and have to do with its ability to suppress TORC1, a cell growth factor. (For example, see THIS STUDY.)

NOTE: Since posting this I have reviewed the full text of the study and see nothing to change the conclusions discussed here. It looks very well conducted, involved people from various well-respected public health departments in universities and medical schools, and gives no hint of corporate meddling.

Another Book?

Now that I've discharged my obligations under my contract with the publisher of my novels, I'm considering what to do next. And that is leading me to ask what I could do that would be of use to the people who visit http://Bloodsugar101.com and this blog.

Publishing the book version of the site has taught me that most people still find books a better way to study a complex topic, even when the information in the book is also available on a web site.

This has been a pleasant surprise, as has been the steady stream of fan mail that the book generates. There's no question that people who read the book learn far more than people who visit the site, if for no other reason than that most people who visit the site only read a couple pages before leaving.

So that raises the question: Should I write another book? And if I do, what should be its subject?

I have some ideas of my own, but before I plunge in I'd love to hear some feedback from you about what topics you would like to learn more about. I'd also like to know, iIf you read my book, Blood Sugar 101, if you thought there was something important that was left out.

Keep in mind, of course, that there are many topics I'd love to be able to write about that are too poorly researched to justify a book. For example, I have spent quite a lot of time looking into the physiology of weight loss, but the more research I read, the less conviction I have that any of it can be trusted. The quality is just abysmal and unlike the publications about diabetes, my many hours of study did not turn up any overlooked gems.

On the other hand, very little has come up that is new since I wrote Blood Sugar 101. In fact, it is rather depressing just how little that would be of any use to someone trying to preserve their health.

But though I might feel that way, life has taught me that one problem with making yourself into an "expert" in some topic area is that the things that bore me after a decade of daily attention to the topic may be exciting to people who haven't soaked their head in this stuff for years.

So I welcome your feedback. What kind of book--if any--do you think would be most useful to a reader who has already read Blood Sugar 101? Click on the comment link below and share your thoughts with me. The only thing I will ask is that you keep your comments on the topic I've sketched out here.

If you want to ask questions or debate other diabetes-related issues, there's a nice community growing on the Blood Sugar 101 Facebook page, where you are welcome to post your thoughts on topics other than the subject of this post.

Normal Blood Sugars in Pregnancy

I have until now avoided discussing the issue of what normal blood sugars should be in pregnancy because it looked like gynecologists were being more aggressive with blood sugar control during pregnancy then other doctors.

Blood sugar control is particularly important in pregnancy because a fetus that is exposed to continually high blood sugars will experience significant changes in the way that its genes express which will affect its blood sugar metabolism for the rest of its life.

High blood sugar will also make babies very large, which poses problems when it is time for delivery, some life-threatening.

Blood sugars are lower in pregnant women because there is a higher blood volume during pregnancy, but it is starting to look like the targets gynecologists have been recommending, which would have been excellent for non-diabetic women are considerably higher than normal.

This was made clear by a new meta-study that analyzed a series of studies of the blood sugars of a wide range of normal pregnant women using Continuous Glucose Monitoring, home testing, and hospital lab results. It makes it clear that the current targets for pregnancy are probably too high.

Here is the full text version of the meta-study:

Patterns of Glycemia in Normal Pregnancy: Should the current therapeutic targets be challenged? Teri L. Hernandez, et al. Diabetes Care July 2011 vol. 34 no. 7 1660-1668.

It concludes that the following appear to be truly normal blood sugars for pregnant women:

AVERAGE BLOOD SUGARS IN NORMAL PREGNANT WOMEN
Fasting: 70.9 ± 7.8 mg/dl (3.94 mmol/L ± .43)
One Hour Post Meal: 108.9 ± 12.9 mg/dl (6.05 ± .72 mmol/L)
Two Hours Post Meal: 99.3 ±10.2 mg/dl (5.52 ± .57 mmol/L )

A commentary published in this month's Diabetes Care gives more insight into the importance of this study and why doctors should aggressively lower blood sugars in pregnancy. You can read it HERE. The Full text version is free.

The commentary suggests that pregnant women should strive for blood sugars that don't exceed the first standard deviation of normal (that's the average with the number following the "±" added to it. Doing that gives us targets that should not exceed

RECOMMENDED MAXIMUM BLOOD SUGARS FOR PREGNANT WOMEN WITH DIABETES
Fasting: 79 mg/dl (4.4 mmol/L)
One Hour After Meals: 122 mg/dl (6.8 mmol/L)
Two Hours After Meals: 110 m/gdl (6.1 mmol/L)

The challenge during pregnancy, of course, is to lower blood sugar without going too low because hypos can also cause problems for the fetus. In addition, the solution that works so well for non-pregnant people--cutting way back on carbs--raises issues.

Very low carb diets raise the concentration of ketones in the blood. This isn't a problem when we aren't pregnant--most of our organs can run quite happily burning ketones. But because ketones are usually produced when humans are starving, it is very possible that fetuses produced when the mother is in a ketogenic state may end up with environmentally-produced permanent changes to their genes (epigenetic changes, to use a technical term) that will predispose them to gaining weight once they are born, because ketones may signal the forming baby that they are being born into an environment of scarcity.

The fact that ketogenic diets downregulate T3 and slow the thyroid in non-pregnant people raises the question about whether a ketogenic diet might also have a negative effect on the baby's developing thyroid.

So it's generally considered to be best for pregnant women to lower their blood sugar as much as possible by cutting back on carbohydrates but to keep their carbs over the threshold (anywhere from 60-100 grams a day) where glycogen is depleted and the concentration of ketones in the blood and urine rises.

You can usually detect your own ketogenic threshold easily: it is the carbohydrate intake level at which, after eating at that level for three days, you suddenly lose anywhere from 3 to 8 lbs (depending on your size.) Raising carbs will immediately restore those quickly lost pounds because they are not fat (or growing baby) but the glycogen stored in your liver and muscles which gets burned away when your carbohydrate level is too low to replenish it.

If you eat only enough carbohydrates to keep your glycogen replenished, you won't have to worry that ketones will give your fetus the message that it's being born into an environment where starvation is occurring and shift its genes into a state where they optimize fat storage.

If you can't lower your blood sugar during pregnancy with diet alone, insulin is a safe medication for pregnant women and most doctors provide pregnant women with diabetes much better education in how to use insulin than family doctors do to their non-pregnant peers.

If you are reading this because you are pregnant and have just discovered you have gestational diabetes though you were not diabetic before your pregnancy, here's one last important fact to keep in mind: abnormal blood sugars in pregnancy almost always point to the pre-existence of abnormal sugars in the non-pregnant state that were missed by your doctor because the tests doctors use to screen for diabetes do a woefully bad job of diagnosing it until you have suffered years of high blood sugars that may irreversibly damage your organs.

Once you deliver your baby, don't rely on doctors to tell you if your blood sugar is normal. Test your blood sugar after meals every so often with a meter to make sure that you are not going over the 140 mg/dl (7.7 mmol/L) level at one hour that is truly normal in the non-pregnant state and that you are under 120 mg/dl (ideally far under) at two hours. If you are going over these levels, cut back on your carbohydrates and if that doesn't help, find a doctor willing to work with you to use safe drugs like metformin that can keep your sugars in the normal range for life.

Don't rely on the A1c test, as most doctors now do. It has been shown to be a poor guide to the high post-meal sugars that characterize the very early stages of Type 2 diabetes and which cause heart disease and early diabetic complications.

Flawed Logic: Eating "Eggs" or "Meat" is Associated with but Does Not CAUSE Cancer

Today the morning news carried this headline: Eggs may Increase Risk Of Lethal Prostate Cancer In Healthy Men. The article starts out by saying that "we already know red and processed meat may increase risk of advanced prostate cancer" and then claims that eggs are just as dangerous.

The actual study is found here:

Egg, red meat, and poultry intake and risk of lethal prostate cancer in the prostate specific antigen-era: incidence and survival. Erin Richman et al., Cancer Prev Res. 2011 Sep 19. [Epub ahead of print]doi: 10.1158/1940-6207.CAPR-11-0354

The study draws its conclusions by looking at 27,607 men followed between 1994-2008. Of these 199 died of prostate cancer. So the researchers analyzed their food consumption and concluded that "men who consumed 2.5 or more eggs per week had an 81% increased risk of lethal prostate cancer compared to men who consumed less than 0.5 eggs per week (HR: 1.81; 95% confidence interval (CI): 1.13, 2.89; p-trend: 0.01)."

Now the first question you have to ask is this. With 27,607 men involved, how did they know how many eggs they ate? And the answer of course is the infamous standard nutritional questionnaire, beloved by nutrition researchers, which is nearly useless for understanding what people really eat.

I've discussed what's wrong with this questionnaire HERE and suggest you read the section headed "1.Based on Inaccurate Questionnaire Data." to better understand the problem here.

In brief, this questionnaire determines how many eggs you've eaten by asking multiple choice questions like "How many eggs did you eat during the past month." The answers you can choose from are very broad along the lines of . "Never, 1-5 times, 6-20 times, more than 21 times."

The chances that the average middle aged man can accurately remember how many eggs he ate during the past month are low, and even if he did, there's a big difference between 6 and 20 eggs which the questionnaire makes it impossible to discover.

But the real problem here is that the way the questions are phrased. In these questionnaires, the subject is asked how many time a day they eat potatoes or bread, but the multiple choice answers assume at least 2 servings a day for each so you would have to say you ate potatoes or bread five or six times a day for the questionnaire software to notice anything odd about your potato or bread intake at all.

But what the questionnaire doesn't ask this: "Did you eat your eggs with toast? "Did you eat your eggs with pancakes and syrup?" "Did you eat your eggs with biscuits?" Or even, "Did you eat your eggs with a large latte?" In fact, it probably doesn't ask about large lattes at all--because one problem with the questionnaire is that the foods it asks about are generic.

Add to this the problem that when a nutritionist thinks of a serving of a food like pancakes, they are thinking of nutritional database values, so the questionnaire does not account for the fact that "one serving" of "pancakes" or "potatoes" at most restaurants today are actually the size of four servings as defined in nutritional databases. So the person reporting that they drank a Latte can only report that they drank "Coffee with sugar," which the software treats as having 8 grams of carbohydrate, rather than as the 66 gram montstrosity the subject drank at Starbucks.

So of course, you can now see where this is going. Men who eat eggs are not eating an egg or two in isolation. Come on guys. I've seen you eat breakfast. And what I've seen is that when a man who is not on a strict diet eats breakfast (and that's 98% of most men) They're eating 2 eggs, ham, bacon or sausage, a big serving of home fries and two slices of toast. If they eat their "egg" at McDonalds or some other fast food outlet, they're very likely having it with a large Coke, or a frappaccino with 88 grams of sugar. They may be having it with a 68 gram Bear Claw from Panera Bread. In short, the egg, which the subject remembers ("I had eggs at Macdonalds) is a marker for a bunch of starch and sugar at goes unnoticed.

We KNOW for a fact that tumors feast on glucose and that high blood sugar promotes the growth of cancers. In constrast, we know of no reason why eating an egg should damage health. Eating dggs, contrary to popular belief, makes no significant difference in people's cholesterol level (not that cholesterol causes cancer, either). Eggs are almost all protein and we know of no connection between eating normal dietary levels of protein. So the real conclusion that should sum up this study should have been this:

In the unlikely case that these questionnaires accurately represent what the men who died of prostate cancer ate, and that the memory of consuming eggs actually correlates with an increase in fatal cancers, this association could be explained by the fact that subjects who consumed eggs ate them in meals containing large amounts of dietary carbohydrate and damaged fats, a circumstance our nutritional questionnaire is incapable of detecting. Remember, too, that association is not causation, and ignore this study until someone comes up with one that uses a better study design.

 

The Blood Sugar 101 FaceBook Page is Where You'll Find Tidbits Too Minor for A Blog Post

Yes, I know FB is the greatest time suck ever invented, and that their entire reason for existing is to steal your personal information. But enough of you asked me to set up a page that I did, and it's getting a respectable number of fans.

I'm posting snippets and links there that don't deserve a whole blog post but which are worthy of your attention.

You can post questions there, too, for other fans of the page to comment on.

The FB page is at http://www.facebook.com/pages/Blood-Sugar-101/194439440617073?sk=wall