Fructose’s many faces

This exercise is a part of Educator Guide: Small Intestine is First Stop for Fructose / View Guide

1. Can you find an article about how satisfied or how hungry people feel after consuming fructose or glucose? Describe the article. 

Possible student response: The Science News article “Diet and nutrition is more complex than a simple sugar,” published 5/26/2015, describes experiments in which 24 volunteers consumed pure water — water with 75 grams of fructose dissolved in it or water with 75 grams of glucose dissolved in it — for breakfast. How hungry or how satisfied the volunteers felt afterward was evaluated by monitoring their brain activity in a magnetic resonance imaging (MRI) scanner and by asking the volunteers how much they would be willing to pay for various snacks. The water and fructose mixture left the volunteers feeling hungrier than they were after consuming the same amount of glucose and water. Those results may suggest that consuming foods or drinks with large amount of fructose could lead people to consume more calories than they otherwise might. But the article points out that much more research is needed. 

2. Search for an article about how fructose could be involved in weight gain in mice. Describe the results of the study. 

Possible student response: The Science News article “Fructose may be key to weight gain,” published 9/9/2013, discusses the weight gain, fatty liver disease and diabetic-like insulin resistance experienced by mice that consumed glucose water for 14 weeks. Mice that lacked the enzyme aldose reductase, which converts glucose to fructose, had less weight gain, fatty liver disease and insulin resistance. Mice that lacked the enzyme fructokinase, which is essential for fructose metabolism, had similar results to the mice that lacked aldose reductase. More research is needed to determine how relevant these results are for humans.

3. Does fructose affect hormones? Find and summarize an article that describes relevant studies. 

Possible student response: The Science News for Students article “Losing control over sugar,” published 3/1/2012, explores possible links between fructose, the pollutant bisphenol A (BPA) and hormones. The pancreas produces the hormone insulin to regulate blood glucose levels. Sugars and another hormone, estrogen, provide cues to the pancreas about how much insulin it should make. One study found that although fructose alone did not prompt the pancreas to produce insulin, fructose plus glucose made the pancreas produce more insulin than glucose alone. Another study found that BPA, a pollutant in certain plastics, could imitate the hormone estrogen and prompt the pancreas to produce insulin. Researchers suggested that excessive production of insulin could cause cells in the body to start ignoring the hormone, which could lead to diabetes.