Sweeteners and the Gut–Brain Axis, Part 2
How sweeteners affect your mental state via the gut-brain axis.
A human being has a natural desire to have more of a good thing than he needs. —Mark Twain
Last week, we discussed the downsides of sugar and some sweeteners. Sugar is ridiculously delicious, but it hides a depressing secret. Sugar disturbs the gut microbes that normally protect us against metabolic disorders, a doorway to obesity and diabetes. Lately, we’ve learned that due to the gut-brain connection, sugar intake can also lead to depression. That has convinced many people to skip the sugar and go for a low-calorie substitute. Sadly, as discussed in my last article, new research finds that some artificial sweeteners raise insulin levels and disrupt gut microbes just as much as the sugar they are replacing.
So, for people with metabolic syndrome or insulin resistance, sugar is out, and artificial sweeteners are suspect. What options are left?
Natural Sweeteners
In this article, we’ll look at some alternative sweeteners that are all-natural and, as a bonus, are also healthy for you. First, we need some definitions. There are several categories of natural sweeteners, and we’ll look at each of them.
Natural nonnutritive super sweeteners include thaumatin, stevia, glycyrrhizin, and monk fruit.
Nutritive sweeteners, or sugar alcohols, include erythritol, xylitol, and maltitol.
Oligosaccharides include inulin, fructooligosaccharide (FOS), galactooligosaccharides (GOS), and xylooligosaccharides (XOS).
Super Sweeteners
Natural sugar substitutes, such as stevia and monk fruit, are hundreds of times sweeter than sucrose. That means you only consume a fraction of the amount, making them essentially zero-calorie. Better yet, they may enhance the microbiota—but in such small doses, probably not much.
Monk fruit is generally lightly refined, but stevia requires more processing to differentiate the two active sugars in the plant: stevioside and rebaudioside. The first sugar has bitterness associated with it, and so rebaudioside is the more popular of the two.
The amounts you need to use are silly, though. For a teaspoon of sugar, an equivalent amount of monk fruit would be a tiny teaspoon 200 times smaller. So typically, these super sweeteners are compounded with sugar alcohol to give them the equivalent bulk of sugar.
Sugar Alcohols
Sugar alcohols are natural sweeteners derived from fruits and berries. They include erythritol, xylitol, mannitol, maltitol, and sorbitol. Some, such as maltitol and xylitol, can reach the colon and feed microbes. That makes them prebiotics, supporting such beneficial bacteria as bifidobacteria, which can improve mood and cognition via the gut-brain axis.
Erythritol is quite popular with makers of sugar substitutes. Most of it gets absorbed in the small intestines and then excreted in the urine, so it’s not much of a prebiotic, but it is essentially calorie-free. It is often the major component of stevia and monk fruit sweeteners.
A caveat: although xylitol has a good reputation for killing oral pathogens (thus its ubiquity in chewing gum), it can be dangerous for dogs, so it may be best for dog owners to avoid this one.
Next week, we’ll circle back to some of the best sugars of all, oligosaccharides. These sugars are like manna to your gut microbes, and have been shown to contribute to good health — and a good mood. Don’t miss out of the best part – subscribe now!