Wednesday, April 10, 2013

Chemistry is Complex

One of the main tasks of my job is to understand our wonderfully complex body processes and explain them in such a way that someone without a biology degree can understand them.  (Or as one of my elderly patients said, “I think like a truck driver, not a doctor.  You explain things in ways that I can relate to.”).  It’s fun, and not without its challenges, as sometimes I have greatly overestimated the person’s desire to learn (I’ve had to deal with a lot of “mandatory” patients over the years) or because the analogy simply was not part of that person’s world (getting older and more experienced helps with that).  Since I am constantly working to better convey these concepts of how our bodies work, I have developed a list of pet peeves regarding the use of certain phrases that are used by health care types that I think convey the wrong idea to our not so science literate public.  One of those phrases is that of “complex carbohydrates” usually coupled with “needed for energy.”  I have dealt with this subject before, but as I keep seeing this phrase pop up and it still makes me mad I wanted to complain again in more detail.
A “complex carbohydrate” is merely a chain of three or more single sugar molecules linked together, colloquially known as “starch.”  It’s a description of how molecules are put together, period, end of story.  It says NOTHING about the impact on our blood glucose levels (i.e. how slowly they are digested), the nutritional value of those foods, or the fiber content.  A “simple carbohydrate” on the other hand, is a chemical structure with only two sugar molecules linked.  Once again, it is a description of how the molecules are put together, period, end of story.  Let's think about it this way--the sugar molecules are a bunch of beads, and a complex carbohydrate is a bunch of those beads woven together, like these:
That's a fairly complex pattern( (to me anyway), but what you have is a bunch of beads held together with string.  And now let's think of the simple carbohydrates as a bunch of beads strung together in a very simple bangle, like this one:
 That's a much more simple pattern, but it's still a bunch of beads on a string.  Now, if I dipped the woven bracelet in some type of acid--it would dissolve the string and the beads would scatter.  If I dipped the bangle in the same acid--it would also dissolve the string and the beads would scatter, maybe somewhat faster, but not really.  You're still going to have a bunch of beads (aka sugar molecules) flying around. 

Now, whenever I would teach the diabetes classes and use this metaphor, I would still get a lot of protests (mostly from people who had been taught all the wrong things about carbs before) that went something like "But don't complex carbs digest more slowly?"  So then I would point them to the glycemic index--(non-diabetic) people were fed 50 grams of carbohydrate of various kinds of carbohydrate containing foods, blood sugars were checked at various intervals, and then the foods were assigned a rating from 0-100 (100 being a very sharp increase in blood glucose).   What happened was some of those foods that are labeled as "complex" (like whole wheat bread) actually had a glycemic index above 50!   (Link) The "complex" structure had nothing to do with how it affected the blood glucose.  The next question I would get would usually come from people who had had diabetes for a while (and/or used insulin to control their blood glucose readings) would sound like "But why was I told to use a simple carbohydrate when my blood glucose was low [hypoglycemia]?" or "Why do crackers raise my blood sugar just as well as drinking regular soda?"  I would (and still do) basically make the excuse that "What they really meant was 'eat 15 grams of carbohydrate in a form that you can chew/swallow very quickly.'" And then I would launch into how once their blood glucose was normalized and they were thinking straight, they would actually need to figure out what happened to keep that from happening again. 

Oh yeah, I would also point out that the GI was figured out using non-diabetic subjects.  If you have diabetes, you will probably still have a different reaction to what's "on the list."  You need to test your blood glucose levels when you try new foods or eat different levels of carbohydrate.  There isn't an easy way around it if you want to figure out what's right for you.  It can also give you a little more flexibility in what you eat.  Boyfriend of SkepticRD, for example, normally does very well with limiting his carbohydrate intake, but on a very rare occaision someone will bring in Krispy Kreme donuts, and they call his name, and he is able to compensate with his short acting insulin.  Now, I am NOT advocating this as a daily thing (nor is he, but it's his body), as that can result in some serious weight gain, which means more insulin will have to be taken overall.  And people with Type 2 diabetes who are not treated with insulin would have to have a spike in blood glucose, and have to deal with the weight gain, and have to deal with the complications of chronically spiking blood glucose.  So, if you have diabetes, when it comes to carbohydrate of any type--test, test, test, and control, control, control the amount you eat!

I know some of you are already wondering "well don't complex carbohydrates have more nutritional value?"  Not necessarily.  Remember, white bread, crackers, and pasta are considered "complex" carbohydrates, but the only nutrition they have is some fortified B vitamins and extra calories.  True whole grains and legumes fare much better on the fiber, b-vitamins, and potassium--but they aren't always better for blood glucose control.  Fruits are technically "simple" carbohydrates (as the predominant form of carbohydrate is fructose), but they also have more fiber and higher nutrition density than complex carbohydrates like pasta.   

Next question that I'm sure is popping in your head is "Don't I need "complex" carbohydrates for energy?"  Technically, no, unless you are a hard core athlete who is depleting your reserves.  If you get enough protein, good fat, and vegetables, your body can make glucose (fuel) from those nutrients (and you can also get fuel from ketones if you are not a poorly controlled Type 1 diabetic and have some fat reserves to use up, so to speak).   If you have difficult to control blood glucose and/or need to lose a lot of weight (or have severe GI problems), you might do a lot better if you stick with minimal carbohydrate from vegetables.  Now, we also live in a carbohydrate centric culture, and some of us (me) like to have the variety that whole grains and legumes provide.  As long as you are not having GI issues, as long as you are staying w/in your blood glucose range, and as long as you are meeting your weight goals (or other health goals), there isn't any reason why you can't include these.  If eating a bowl of "whole wheat" pasta just leaves you feeling hungry an hour later or you find yourself wanting to eat the whole pot of organic heirloom rice on a regular basis (not that I know what that is like), then you are probably shooting yourseslf in the foot and need to make some changes.

Take home message--complex and simple are mere descriptions of how molecules are linked together, it doesn't send a message on health.

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