Fate of fructose: Interview with Dr. John Sievenpiper

Fructose metabolism. Ref: Tappy & Ka 2010.

Sugar is a hot topic these days. Evidently, it's also a touchy topic. I've been a little amazed at some of the responses (both positive and negative) received since my first rant post about media reporting unfairly that hummingbird fuel was "toxic". There clearly exists a continued need for education about the state of the evidence as it stands now surrounding sugar and its implications on health.

As a follow-up to my report of the "Sugar Showdown" at Experimental Biology -- a debate where scientists voiced clear dissatisfaction with the sensationalism surrounding sugar both in news reports and in the scientific literature -- I decided to seek out greater insight by an expert who was at the event.

John Sievenpiper, M.D., of St. Michael's Hospital, University of Toronto, brings a valuable perspective to our understanding of sugar. He is the lead author of three recent systematic reviews and meta-analyses evaluating fructose's effects on body weight, blood pressure, and glycemic control in humans from randomized controlled feeding trials.

With only very light edits made (for clarity) to my transcribed interview with him by telephone, I give you the take of Dr. Sievenpiper on fructose in his own words:

Confusing messages about sugar are stupid

I'm a bit late in weighing into the "Sugar Makes You Stupid" mess of poor health reporting on a rat study. At the Embargo Watch blog, Ivan Oransky already covered the mishandling of the study's embargo and ripped into the press release for misleading readers into believing that the study had any meaningful conclusions for college students. Then, Deborah Blum at Knight Science Journalism Tracker went further, bringing more reason and logic, by clarifying what the rat study was really about -- the neuroprotective role of omega-3 fatty acids!

Mainly, I hope to bring a little more overall perspective to a study that, while perhaps could be valuable, has brought along with it unnecessary fears that a little hummingbird fuel, aka sugar, will make people walk around aimlessly as brainless as zombies. It's nonsense, of course, that sugar makes you stupid. After all, neurons run on a constant supply of glucose delivered by the bloodstream (as they don't store glucose as glycogen like other cells), a fact that several media reports completely failed to mention.

No, Dr. Gupta, hummingbird fuel is not "toxic"

Sugar is toxic? Not this hummingbird's opinion.

Whenever someone asks me whether or not sugar or high-fructose corn syrup is "toxic," I remind them that every few days I make up a simple solution of four parts boiled water and one part plain white table sugar. This I use to fill the hummingbird feeders in my yard here in Arizona and the little guys never complain about it.

In fact, they lap up the sweet nectar -- as much as they can get with their long tongues -- to fuel their high metabolism. Then, they fly off (or get chased off) to their perches and I make a note that most will return within 30 to 45 minutes for more. Research shows their little bodies will have oxidized all the ingested sucrose by that time (1).