Fructose, friend or foe? It can be so beneficial to endurance athletes but so detrimental to the sedentary person. These findings may alarm you.
Introduction: As stated previously during sugar month, large fructose ingestion is linked with an array of health problems. In this case, researchers link it to the metabolic syndrome, which consists of insulin resistance, dyslipidemia, abdominal obesity, and elevated blood pressure. The metabolic syndrome often precedes the development of Type 2 diabetes. Some of these effects are not found with glucose or diets consisting of starch. Fructose and glucose metabolism differ and one of the consequences is depletion of ATP and production of inflammatory mediators. The breakdown eventually leads to the production of uric acid, which may have a role in insulin resistance. Therefore, the researchers are trying to use a drug, allopurinol, as a way to reduce uric acid and see if this can reverse the symptoms of metabolic syndrome after fructose consumption.
Methods: Participants were 74 males who ingested 200g daily of fructose sipped throughout the day for a total of 2 weeks. One group received the drug allopurinol and the other did not.
Results: The following showed significant differences from baseline in regards to fructose ingestion:
- Increase in ambulatory blood pressure with subtle greater increases in diastolic blood pressure throughout the day (number of participants who fit the criteria of metabolic syndrome for this went from 9 at baseline to 21)
- Mean increase in fasting triglycerides
- Reduction in HDL cholesterol
- Increase in patients with fasting glucose meeting the criteria for metabolic syndrome ( >5.5 mmol/L)
- Increase in fasting plasma insulin
- Worsening of liver function tests
In regards to the group that consumed the drug (allopurinol) to decrease uric acid there were significant changes found to:
- Protect against increases in systolic and diastolic blood pressure as well as mean arterial pressure
- Protect against metabolic syndrome (32% participants had it before and only 34% after as compared to the fructose only group at 19% to 44% after two weeks)
Discussion/My input: The first thing you are probably thinking is, “Nick, who would drink 200g of fructose per day, this study is not practical.” Well, here is an alarming fact; the upper quintile of Americans consume more than 110 g of fructose daily either as additional sugar or as high-fructose corn syrup. That is pretty close and these changes happened in only 2 weeks! As far as the drug, it may be something included in the future to combat the metabolic syndrome; however, these results cannot be related to obese individuals or even women. The researchers state that fructose metabolism can vary between genders. Once again, fructose might not be the sole reason for the obesity epidemic, but it does lend credence to that notion.
Perez-Pozo et al Int J Obes (Lond). 2010 Mar;34(3):454-61