We like our sweets…If I really wanted to impress you with scientific taste I would phrase that differently and point out that the taste receptor for sweetness, T1R2/RIR3 detects sugar at a concentration of 1 part to 200 and “notifies” the brain about this pleasurable sense. But as great as our fondness for sweet tasting foods, we are much more aware of and put off by bitter substances, which can be detected in the range of a few parts per million! (I will spare you the receptor details.)
When refined and concentrated sugar (usually sucrose and high fructose corn syrup) is consumed in large amounts, it immediately causes a rise in blood glucose. In order to stabilize elevated blood glucose levels the pancreas will, if functioning, produce insulin. Elevated insulin then causes an increase in triglycerides, fat deposition (in unwanted parts of our body), inflammatory factors, and oxidative radicals….all of which are associated with coronary heart disease, diabetes and obesity.
In an effort to please our taste buds without suffering the consequences of too much refined sugar many of us use artificial sweeteners, especially in our drinks. According to an article in the American Journal of Clinical Nutrition, our per capita diet drink intake has increased from less than 1 ounce per day in the 1960′s to about 4 ounces per day in this decade. Moreover, among regular consumers of diet drinks, intake is now greater then three 8-oz servings per day.
I switched from diet colas to water about 2 years ago, but admit I still indulge in ice tea and (when my reflux lets me) coffee, both sweetened with artificial sweetener. After all, there are currently 5 types of synthetic “no-calorie” sweeteners as well as Stevia (a natural extract) that have received FDA approval. They all are more potent than sucrose and elicit a sense of sweetness in very small concentrations. It’s so easy to just tip a pink, yellow or blue packet into a drink. (And the manufacturers of all those diet sodas do it for us.)
A recent commentary in The Journal of the American Medical Association pointed out some disturbing concerns that I thought we should all consider. The author (who is an MD and PhD in the Department of Medicine at Children’s Hospital in Boston) pointed out that calories displaced by artificial sweeteners may be replaced over time with other fattening sources. (I immediately thought of my dinners with friends…we put sweetener in our coffee and then smugly order a calorie intense dessert.) He also stated that “frequent consumption of hyper-intense-sweeteners may cause taste preferences to remain in or revert to, an infantile state”. This can cause individuals to pass up less intensely sweet foods such as fruit and indeed avoid foods that are unsweet. (There go the vegetables and legumes!). An overly stimulated sweet tooth may end up sabotaging the type of healthy diet that prevents weight gain.
The author then went after diet drinks which, as we know, have no calories and no nutrients. If they are consumed instead of other foods, they can produce a disassociation between sweet taste and caloric intake and hence “disrupt the hormonal and neurobehavioral pathways regulating hunger and satiety”. He cited an experiment in which rodents fed saccharine compared with those fed glucose, increased their overall caloric intake and gained weight. Another study compared rodents’ preference to cocaine versus saccharine…and surprisingly, they preferred the latter! This would seem to show that the taste and desire for sweetness (at least among rats) was more addictive than the desire for abused drugs.
Although he admits that there are no long-term prospective studies of diet drink consumption and body weight in humans, he does cite an observational study: The San Antonio Heart Study found a relationship between diet drinks and measures of adiposity over a 7 year period among 5158 adults. Those that consumed more than 21 servings of diet drinks per week (if you haven’t done the math, it’s 3 a day or what the average diet drink consumer now imbibes), had a 2-fold increased risk of becoming overweight or obese. And in another study of 6814 individuals (The Multi-Ethnic Study of Atherosclerosis), daily consumption of diet drinks was associated with a 36% increase risk for metabolic syndrome (high blood pressure, high triglycerides, high blood sugar, excess weight around the waist and ultimately high risk for coronary heart disease) as well as a 67% greater risk for type 2 diabetes when compared to non diet drinkers.
So what are we to take away from all this? I don’t think the current data constitute a mandate against any diet drink consumption. We certainly don’t want our children (or ourselves) ingesting a major portion of their calories from refined sugars and corn syrup. However, if artificially sweetened drinks replace unsweetened drinks or less sweet food, the result may be weight gain as well as the absence of the nutrition needed to maintain good health. So when you reach for that diet drink or sweetener, why not reconsider and try quenching your thirst with water (flat or carbonated), non fat milk or even tea or coffee sweetened with just 2 teaspoons of sugar. Or, if like me you can’t reach for that sugar, use that yellow, pink or blue packet, but as rarely as possible.