You may feel virtuous when you choose diet soda over regular or dump artificial sweetener into your coffee, but you aren't doing your body any favors. Artificial sweeteners rely on chemicals for their sweetness, and though they are calorie-free, they have been linked to weight gain and metabolic syndrome. The sweetness activates certain processes in your body that never get shut off because the sweetener doesn't have calories. In other words, your body thinks you've pulled a fast one. As a result, your body's craving for energy intake remains high, and so can your insulin levels.
Blood Sugar Regulation
When you eat food, your digestive system breaks the various nutrients down into their most basic constituents, which are sugars. The sugars enter your blood stream, and your blood sugar is temporarily high. So your pancreas releases insulin to help the sugar molecules enter your cells, where they become the cell's energy source -- leftovers are stored in the muscles and liver for later use. Your insulin levels remain high until the influx of sugar is dealt with, then both insulin and blood sugar levels taper off.
False Stimulation
The problem with artificial sweeteners is that they activate this process, but they don't provide any sugar molecules for the insulin to escort around. Your blood sugar doesn't rise because there's no sugar -- but there's a load of insulin circulating, waiting for work to do. A 1987 study in the journal "Hormone and Metabolic Research" found that rats injected with the artificial sweetener acesulfame potassium displayed insulin levels similar to those of rats injected with actual glucose, except the acesulfame group did not also display the concurrent high blood sugar. When the insulin has no work to do, it doesn't know when it's OK to go away.
Insulin Resistance
Over time, having prolonged periods of high insulin levels may allow your body to react by building up a tolerance. It's called insulin resistance, and it means that although your body releases more and more insulin when you eat, the insulin doesn't do it's job. You end up with sugar still circulating in your bloodstream, which stimulates your pancreas to release even more insulin. In other words, you have high blood sugar and high insulin levels at the same time, and your body isn't getting enough of its energy source. Before long, your pancreas fails to meet your body's insulin demand, and you end up with type 2 diabetes.
Ongoing Research
The relationship between artificial sweeteners and insulin levels is still being investigated, but preliminary research suggests that different sweeteners have different effects. A 2010 study in the journal "Appetite" found that stevia, a plant extract that is used as a natural sugar substitute, produced lower post-meal blood sugar ratings than regular sugar, but it also produced lower insulin levels and a lower difference between blood sugar and insulin levels than either regular sugar or the common sweetener aspartame. Because artificially sweetened products are commonly used for weight control but have been linked to weight gain, this is an area of study that promises to yield interesting results.
References
- MayoClinic.com; Hypoglycemia; Jan. 12, 2010
- "Diabetes Forecast"; Understanding Insulin Resistance; Erika Gebel; June 2011
- "Scientific American"; Just Desserts: Artificial Sweeteners Linked to Weight Gain; Lisa Stein; Feb. 11, 2008
- "Hormone and Metabolic Research"; The Effect of Artificial Sweetener on Insulin Secretion. 1. The Effect of Acesulfame K on Insulin Secretion in the Rat (Studies In Vivo); Y. Liang, et al.; June 1987
- "Appetite"; Effects of Stevia, Aspartame, and Sucrose on Food Intake, Satiety, and Postprandial Glucose and Insulin Levels; Stephen Danton, et al.; August 2010
