I am the first to admit that I have a sweet tooth. I do not understand people who say that something is “too sweet.” That concept completely eludes me (with the exception of anything with artificial sweeteners or high fructose corn syrup, which I carefully avoid). So I read with interest about a recent study by Henderson, Nalloor, Vazdarjanova, & Parent (2015) in the journal Hippocampus. These researchers found that consuming sweets (sucrose or saccharin) led to increased synaptic plasticity in the dorsal hippocampus of rats. (Note that I’m pretty sure that rats are the only species that finds saccharin tasty–yuck!) The saccharin is interesting, though, because although sweet, it has zero nutritive value. So the effect appears to be from sweetness itself, not the consumption of a dense calorie source.
Remembering what we just ate appears to be important to the timing and size of our next meal. When the dorsal hippocampus is temporarily inactivated, the rats eat earlier and more. People with amnesia will eat a second meal right after finishing a first (reports suggest this was a problem for Henry Molaison, the famous amnesic patient H.M.). Even distractions, like watching television, can apparently disrupt memory formation, leading to eating more food than usual at the next meal.
Although the focus of the research is on the effects of the findings on obesity, I’m left wondering what other memories besides “I really did just eat that whole dessert” might be enhanced by a sweetened meal. Are any ongoing memories associated with eating something sweet enhanced? If I eat a lifesaver while studying new neuroscience papers, would I remember them better? Would that be some good news about sugar?
We surely have plenty of bad news about the stuff. The average American consumes about 20 tsp per day in spite of recommendations by the American Heart Association to limit intake to 6 tsp for women and 9 tsp for men. The World Health Organization (WHO) recommends that no more than 10% (and preferably less than 5%) of daily calories should come from added sugars or natural sugars in foods like fruit juice. A single 12-oz regular soda doubles most people’s “healthy” daily sugar allowance.
There is also compelling research suggesting that the brain processes sugar similarly to addictive drugs (Volkow & Li, 2004). After also reading that one of my other major food groups, cheese, is similarly addictive, I’m starting to see some disturbing patterns in my behavior!
I’m not ready to give up sweets entirely, but obviously moderation is in order here, as it is in most things, I’ve noticed. What I’ve tried to do is to make my sweets “count” by having something truly wonderful in a small quantity. I’d rather have a single, small piece of marvelous candy than a large, waxy commercial candy bar.