Interviews with Alejandro Gugliucci, MD, PhD, W. Timothy Garvey, MD, and Danielle Mein, RD
Reducing fructose in the diets of obese Latino and African-American children improved their lipid profiles quickly,1 according to research presented at the World Congress on Insulin Resistance, Diabetes and Cardiovascular Disease in Universal City, California.
In as little as 10 days, improvements were achieved, said Alejandro Gugliucci, MD, PhD, dean of research at Touro University California in Vallejo.
"One way clinicians may curb the dual epidemics of diabetes and insulin resistance is by focusing on prevention, particularly with regard to diet," Dr. Gugliucci told EndocrineWeb. Of all the possible dietary changes, fructose ought to be a prime target, he said. In the study of 20 obese children, ''we reduced fructose from 14% to 4% [of calories], to great effect," he said.
According to the Centers for Disease Control and Prevention, diabetes risk is highest among Hispanic and African-American children in comparison to Caucasians.2
Fructose is an important lipogenic molecule, Dr. Gugliucci said; in fact, fructose increases both fatty acid synthesis and triose phosphate fluxes, generating methylglyoxal (MG), which is implicated in diabetes pathogenesis.1 MG is detoxified to D-lactate, a surrogate marker of whole body MG production.
The study hypothesis—fructose restriction leads to decreased MG and D-lactate production—and therefore, appears to have a role in lipid formation.
In this study,1 the 20 children who were classified as obese based on a body mass index greater than 30, had all their meals provided with same calorie, carbohydrate, and macronutrient composition as their standard diet, but with a reduction in fructose from 12% to 4% of total calories. The average fructose intake of this cohort had been more than 50 grams a day prior to the study.
The researchers measured D-lactate levels along with insulin, lipids: total cholesterol, triglycerides (TG), low density lipoprotein cholesterol (LDL-C) and glucose.
Among the findings,
The findings provide the first mechanistic evidence for a link between fructose intake, MG fluctuations, and glycation, a key contributor to diabetes complications,1 according to the researchers.
Because total calories remained the consistent during the study as it was prior to the study start, the changes seen in serum lipid levels had to be due to just to the decreased in the sugar content," Dr. Gugliucci told Endocrine Web, ''
Results of this research did demonstrate that reduced dietary fructose led to lower levels of circulating lactate, ''but did not prove whether this was related to methylglyoxal metabolism and glycation," said W. Timothy Garvey, MD, professor and chair of nutrition sciences at the University of Alabama at Birmingham in reviewing the findings for EndocrineWeb.
"A very minor portion of fructose is directly converted to triglycerides, but most gets converted to glucose in the liver, which is then either stored as glycogen or metabolized anaerobically to lactate," Dr. Garvey said, "The reduction in this metabolic flux to lactate as a consequence of reduced dietary fructose probably explains, for the most part, the reduction in blood lactate levels."
Dr. Garvey agreed that reducing fructose is a good suggestion for endocrinologists and pediatricians to discuss with parents of children who are at risk for overweight and/or diabetes, as fructose represents a source of empty calories that in excess may lead to undesirable weight gain in childhood. Clinicians also may discuss the need for at-risk children to seek desserts and beverages, the biggest contributors of fructose, that may be more heart-healthy as a preventive measure.
Pediatric endocrinologists and pediatricians may consider working with families to proactively recommend guidelines for reducing the calories contributed by fructose as a way to promote weight management, said Dr. Gugliucci. One of the best ways to have children reduce their fructose intake is to eliminate juice and soda, as well as other products in which fructose is the first or second ingredient. "A common misconception is that apple juice and orange juice are very healthy," he said.
Danielle Mein, RD, a pediatric dietitian at the University of California at Los Angeles Mattel Children's Hospital, also commented on the findings for EndocrineWeb.
“Fructose is found in foods that may be a surprise to some, including high fructose corn syrup in processed foods, sandwich breads, salad dressings, and candy,” in addition to juices and soda, Ms. Mein said, “Other foods may not contain high fructose corn syrup but can still have a high fructose content, such as some breakfast cereals.”
As important as it may be for children to avoid fructose-containing foods, she said, it is just as necessary to emphasize a change to incorporating more ''fresh (or frozen), whole fruits, and vegetables" as well as whole grains, and limiting the frequency of fast foods in order to prevent excessive weight gain.