DURHAM, N.C. — Splenda may suppress beneficial bacteria in the gut and interfere with the bioavailability of drugs, according to results of a study performed by researchers at the Duke University Medical Center in Durham and funded by The Sugar Association, Inc., Washington.
McNeil Nutritionals, L.L.C., Fort Washington, Pa., makes Splenda sweeteners. The company said it had a panel of independent experts in the areas of toxicology, pathology, endocrinology, nutrition and principles of scientific research review the study. The panel concluded the study had flaws and that data presented in the study failed to support the researchers’ conclusions.
The study, called "Splenda Alters Gut Microflora and Increases Intestinal P-Glycoprotein and Cytochrom P-450 in Male Rats," appears on-line in the Journal of Toxicology and Environmental Health. The study used Splenda no-calorie sweetener, granular from McNeil Nutritionals. Its contents were 1.1% sucralose, 1.08% glucose, 4.23% moisture and 93.59% maltodextrin.
The rats were divided into five groups: a control group, rats fed 100 mg of Splenda daily, rats fed 300 mg of Splenda daily, rats fed 500 mg of Splenda daily and rats fed 1,000 mg of Splenda daily. The intake of Splenda by rats significantly reduced the number of indigenous intestinal bacteria in the gut, with the greatest suppression for the generally beneficial anaerobes such as bifidobacteria and lactobacilli, the researchers said.
The researchers also said Splenda consumption increased the expression of the intestinal chemical transporter P-glycoprotein (P-gp) and two CYP450 isozymes (CYP3A4 and CYP2D1) at levels associated with reduced bioavailability of drugs and chemicals.
The panel put together by McNeil Nutritionals said the study provides no evidence that sucralose has an effect on enzymes known to be involved at times in drug absorption and that there was no test of sucralose on drug or nutrient absorption or bioavailability.
All control and Splenda-treated animals gained weight over 12 weeks. The mean rise in body weight from baseline to 12 weeks was 93.1% for control, 104% for rats eating 100 mg of Splenda daily, 100.7% for rats eating 300 mg of Splenda daily, 101.5% for rats eating 500 mg of Splenda daily and 88.5% for rats eating 1,000 mg of Splenda daily.
The panel put together by McNeil Nutritionals said the study’s investigators failed to measure the rats’ intake of food and water. The panel added the study’s authors ignored studies in rats that show sucralose has no adverse effects at doses equivalent in sweetness to over 40 lbs of sugar per day for an average-weight person.