A new study says that artificial sweeteners don’t work. T.V. Jayan reports
In the battle against the bulge, low or no-calorie artificial sweeteners may not have much of a role to play, contrary to what conventional wisdom says. In fact, they might even be counter productive, as the latest research shows.
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Scientists seem to have got the first glimpse of what artificial sweeteners could do to a living organism’s metabolism when they tried out saccharin-laden yogurt on laboratory rats. The researchers Susan Swithers and Terry Davidson, both psychologists at Purdue University in the US found that replacing sugar with saccharin in the animals diet did reduce a few calories (equivalent of that contained in sugar), but the rats ended up hogging more, gained more weight and put on more body fat. More importantly, the animals failed to cut back on subsequent meals accordingly, the researchers say in a paper thatâ€™s appearing today in the journal Behavioral Neuroscience.
Swithers and Davidson found that as compared to rats that ate yogurt sweetened with glucose (a sugar with 15 calories per teaspoon the same as in table sugar), those given yogurt sweetened with zero-calorie saccharin consumed relatively more calories. The rats in all groups were fed yogurt six days a week for five weeks.
In nature, sweetness is normally linked to food that is rich in calories. This association is ingrained in most animals very early in life, the first such experience being that of breast milk. With the growing use of non-calorific sweeteners, millions of people are being exposed to sweet tastes that are not associated with calorific or nutritive values. The scientists suspect this type of exposure may be partly impairing our body’s energy regulation.
By breaking the connection between a sweet sensation and high-calorie food, the use of saccharin changes the body’s ability to regulate intake, the scientists argue. This breakdown of self-regulation may partly be responsible for the ballooning obesity levels, which has coincided with the use of artificial sweeteners.
Sweet tasting substances are known to be strong elicitors of a number of reactions involving the hormones, body temperature and metabolic activity. The moment one pops a chocolate into the mouth or takes the first sip of a sugar-laden drink, a series of reactions sets in motion inside the body. The first one is what scientists call the cephalic-phase reflex. It ensures that gastric acids (that will eventually digest the incoming food) are released the very moment one begins to chew the food. Cephalic-phase reflexes make the system anticipate and prepare for the arrival of nutrients in the gastrointestinal tract so that it can increase the efficiency of nutrient utilisation and minimise the damage that could be caused to the internal environment by the onrush of high-calorie food. Ingestive and digestive reflexes gear up for that intake but when false sweetness isnâ€™t followed by lots of calories, the system gets confused. This may make people eat more and expend less energy than they would otherwise.
The Purdue University researchers designed three different experiments to check whether saccharin changed the animals ability to regulate their intake. They used different assessments calorific intake, weight gain and the animals ability to cut the flab later. The experiments also measured changes in the core body temperature. Normally when we prepare to eat, the metabolic engine revs up. However, the rats that had been trained to respond using saccharin (which broke the link between sweetness and calories) showed a smaller rise in the core temperature than those eating a sweet-tasting, high-calorie meal. The authors of the study think that this blunted response both led to over-eating and made it harder for the animals to burn off sweet-tasting calories.
The data clearly indicate that consuming food sweetened with no-calorie saccharin can lead to greater weight gain and adiposity than consuming the same food sweetened with a higher-calorie sugar, they claim.
The study looks very sound, says Anoop Misra, an internal medicine specialist at Fortis Flt Lt. Rajan Dhall Hospital in New Delhi. It certainly goes against the tide.
But Misra thinks there are several caveats here. One, the study was conducted in rats and the response of human beings may be different. Besides, lab animals are not bothered about obesity or the richness of the food they eat, while a human being â€” in fear of becoming overweight â€” would probably be conscious of the calories consumed. Thus, automatically, there would be a check on the quality and quality of the food eaten. Three, for someone who is determined to shed those extra pounds, artificial sweeteners are not the only way out. Such individuals may also go for walks or hit the gym, he suggests.
Swithers, too, agrees. certainly wouldn’t say that artificial sweeteners are completely bad. From our perspective though, such products might actually contribute to weight gain because they interfere with an automatic process, she told KnowHow. They may be useful for weight loss only if people use more conscious, cognitive methods like calorie counting, she says.
At this point, our data are derived only from animals, so it is difficult to predict how changes in their consumption would affect human obesity, she adds.
…Spare the sugar, fuel the fat: Psychologists Susan Swithers and Terry Davidson
Moreover, as Misra points out, the study was conducted using saccharin, an artificial sweetener that is rarely in use today. Swithers, however, does not think the results with other artificial sweeteners such as aspartame, sucralose and acesulfame K would be dramatically different. The good news, she says, is that people can still count the calories to regulate intake and body weight.
But most dieters lament that counting calories requires a more conscious effort than consuming low-calorie foods. Swithers couldn’t agree more.
Click to read->Artificial sweeteners can be fattening
Sources: The Telegraph (Kolkata, India)