Artificial Sweeteners
written by Margi Coggins, CNM
Women often ask what foods they should eat and what they should avoid when pregnant. One of the most common concerns revolves around artificial sweeteners. Many women are in the diet soda habit and don’t want to give it up for pregnancy. Health care providers haven’t had data to rely on in making recommendations in this arena. But studies are accumulating which suggest that artificial sweeteners do more harm than good, particularly for pregnant women.
A study in Denmark surveyed more than 59,000 women at 25 weeks gestation and asked about their soft drink habits. The same women were followed until after they gave birth. Women who daily drank more than four artificially sweetened drinks were almost twice as likely as women drinking sugar sweetened beverages to deliver preterm. The effect was seen in both normal and overweight women. Carbonated beverages were a bit worse than noncarbonated. Women who drank just one diet drink per day also had a somewhat increased risk of preterm birth. This study was reported in the September 2010 issue of the American Journal of Clinical Nutrition.
This study does not prove that drinking artificially sweetened beverages causes preterm birth or preterm labor. The study was not designed to prove cause and effect, only to show correlation. Interestingly, about a third of the preterm births were caused by inductions. Women who drank more diet drinks were more likely to smoke and be overweight, both factors known to be associated with preterm birth. But even when controlled for body mass index and smoking, diet drinks were still associated with preterm birth. The authors wondered if the artificial sweeteners caused pregnancy-induced hypertension (PIH), one of the more common reasons for needing to induce labor early. But again, even when women with PIH were removed from the analysis, diet soda drinkers were more likely to deliver early.
One explanation for the findings could lie in how the human body processes these sweeteners. This study cited others which found that that aspartame breaks down in the body into aspartic acid, phenylalanine and methanol. Exposing primates to even low doses of methanol can cause shortened gestation, vaginal bleeding and unproductive labor.
Even when not pregnant, diet soda might be a bad idea. Two studies released in 2008 followed the dietary habits of 1257 Americans, some since 1958. They found that despite eating the same number of calories, those in the group who consumed artificial sweeteners were heavier than those who did not. Artificial sweeteners turn on “sweet taste receptors” which in turn encourage more glucose absorption. Although refuted by the beverage industry, it seems that diet soda can actually lead to obesity and metabolic syndrome.
(Sources: Circulation (2008;117:754-761) and Obesity (2008;16:1894-1900)).