Diet Soda and Diabetes

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In reply to my recent blog entry “Stopping Diabetes Medicines,” Patsy wrote: “I have stop[ped] drinking Diet Cokes, or anything with artificial sweeteners. I can’t tell you what a difference that has made! … I am overweight and have lost 14 pounds. My blood sugar has gone down, too.”

How could this be? How could diet sodas, which have essentially no carbohydrates and no calories, raise blood glucose and weight? Or is the whole thing an illusion?

Four studies in the last decade have raised concerns about diet soda. In 2005, University of Texas researchers reported that people who drank diet soda were more likely to gain weight than those drank regular soda. Fewer calories = more weight! Strange…

In 2006, Dartmouth scientists found that people with diabetes who drank one or more cans of diet soda a day raised their A1C levels by an average of 0.7%, compared to those who didn’t.

In 2007, the American Heart Association found that those who drank either regular or diet soda had a higher risk of “metabolic syndrome,” which includes diabetes, high blood pressure, high levels of LDL (“bad”) cholesterol, and obesity, compared to nondrinkers. This is just a correlation; it doesn’t show cause, but it’s still interesting.

In the January 16, 2009 issue of Diabetes Care, a group of analysts reviewing the Multi-Ethnic Study of Atherosclerosis found that “Daily consumption of diet soda was associated with… a 67% greater relative risk of… Type 2 diabetes compared to non-consumption.” They said the increased diabetes was not due to increased weight, although that happened too. “Associations between diet soda consumption and Type 2 diabetes were independent of baseline measures of adiposity or changes in these measures,” they wrote. The data was adjusted for “lifestyle and dietary differences.”

The Internet is full of anecdotal reports saying similar things, that people felt better and had better blood glucose levels when they stopped the artificially sweetened drinks. But what is going on here?

Some skeptics believe that the effect is an illusion. “It may be that many people who drink diet soda, do so because they realize they are becoming fat,” wrote the Web site “However, the basic habits that cause obesity (lack of exercise, over eating) still exist.” I don’t buy this theory.

Another explanation is that artificial sweeteners may confuse the body about how much energy it is consuming. They could make you feel your blood glucose is low when it’s not, so you seek out food and eat more.

It could also be the taste buds that are thrown off. Most artificial sweeteners are even sweeter than sugar. Compared to them, real foods don’t taste very sweet, so we are tempted to sweeten them or eat more of them to meet caloric needs.

Animal studies seem to support this idea. Purdue University researchers have shown that rats eating food sweetened with saccharin took in more calories and gained more weight than rats fed sugar-sweetened food.

I haven’t seen studies on it, but I can imagine that artificial sweeteners might raise blood glucose by confusing the liver into thinking glucose levels are low, causing it to release sugar to keep us from going low.

Certain sweeteners used in diet drinks could also cause other health problems. Diabetes Self-Management has a long article on these sweeteners here.

I’m not suggesting switching from diet sodas to regular ones. Although apparently that would be some improvement, it would seem that lemon water, sparkling water, or fruit juice diluted with water would be better. (I’m feeling really good lately with some unsweetened cranberry juice twice a day. Now that is seriously unsweetened! I mix a couple of ounces of juice in eight ounces of water to make it drinkable. But it seems to be helping my bladder function and energy level.)

I believe our bodies are so complicated, and so poorly understood, that we don’t want to put artificial anything in there unless we have to. The chemists and companies who brought us artificial sweeteners were probably trying to do something good, as well as make money. But perhaps they just didn’t know.

At any rate, I think we might be better off if we do like Patsy and cut the artificial sweeteners out.

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