The Best and Worst Sweeteners for Brain Health
- Austin Perlmutter MD
- Aug 6
- 4 min read
Here's the science you need to know
By Austin Perlmutter, MD
Sugar is among the most popular villains in nutritional health conversations. But depending on the content you consume, you may have heard everything from “it’s harmless in moderation” to a suggestion that it’s comparable to cocaine for addictiveness. When it comes to brain health and the effect of sugar on our cognitive and mental state, we’re learning that there’s nuance to the conversation, and differences between forms of sugar. In this article, we’re taking a deep dive into what the latest research says about sugar and our brains, and the best and worst choices of sweetener.
Why Does Sugar Relate to the Brain at All?
Like it or not, sugar, and in particular glucose is the primary fuel source for your neurons. Unless you’re on a long fast or consuming extra ketone bodies, this fact is inescapable. Yet, while glucose powers our brain function, there are several important steps separating the sugar we consume in our diet to the sugar being used by our brain. Incidentally, there’s no need for us to consume added sugar to power our brains, as our bodies are more than capable of synthesizing glucose or generating it from the breakdown of carbohydrates. The key takeaway here is that added sweeteners, which is found in 70+% of foods and beverages in the US in unnecessary for most people’s brain health. This means that as we approach the conversation around sugar and other sweeteners and our brains, none of the options are needed for health, despite being incredibly desirable for flavor.
Why Sugars and Sweeteners are Concerning for Brain Health
A host of research over the last decades has revealed the pathways connecting added sugars and sweeteners with worse health outcomes, including mental, behavioral and cognitive effects. At the core of this work, sugars and sweeteners appear to lead to metabolic dysfunction, inflammation, oxidative stress and negative alterations in the gut microbiome. These effects appear to be differentially concerning depending on the form of sweetener and low to non-existent for some sweeteners.
Natural Sugars and Sugar-Rich Food Concentrates
The most popular sweeteners continue to be sugar and sugary food concentrates. This group includes cane sugar, molasses, honey, maple sugar, coconut sugar, high-fructose corn syrup agave and more. These sweeteners are characterized by being high in glucose and fructose (two simple sugar molecules) and typically require some degree of concentration process to create a finished product. Generally speaking, consuming these natural products in larger quantities is believed to elevate risk for dementia and mental health issues. For example, one recent study found that depression risk elevated by almost 30% in those consuming over 100 grams of added sugar per day.
There are differences in the exact makeup of the products in this group in terms of the glucose to fructose ratios, but generally speaking, we’re wise to avoid foods and beverages that contain more than a few grams of added sugar (ideally, chose foods and beverages with 0 grams of added sugar!) One caveat to this would be that honey, due to its wide spectrum of other nutrients (especially polyphenols), may be less of an issue, with some research actually suggesting potential for brain benefits.
Sugar Alcohols
Sugar alcohols are a family of sweeteners that include erythritol, xylitol, mannitol and others. They are generally less sweet than typical sugar sweeteners but are lower in calorie content and don’t spike blood sugar levels as significantly. Sugar alcohols have gained popularity in the keto and other low-carb diet movements. At higher levels (e.g., 30-50 grams a day), these molecules can lead to significant GI issues. Recently, pre-clinical research has suggested that excess consumption of sugar alcohols may negatively impact brain blood vessel health, following observational data indicating a risk for stroke in those with higher levels of the sugar alcohol erythritol.
Artificial Sweeteners
As of 2025, the FDA has approved 6 artificial sweeteners. These include saccharin, aspartame, sucralose, acesulfame potassium, neotame, and advantame. Advantages of artificial sweeteners include less effects on blood sugar and incredibly potent sweetness relative to conventional sweeteners. Concerns for artificial sweeteners are primarily based on pre-clinical animal research suggesting potential for cancer and other risks. In humans, the primary outcome of existing research is a suggestion for alterations in the gut microbiome as a function of consuming these molecules. This carries weight especially considering research on the power of the gut-brain connection’s influence on brain conditions. Artificial sweeteners and sugar alcohols are also common components of ultra-processed foods, and therefore their presence may signal that a food may not be healthy.
Natural Low-Calorie Sweeteners
In recent years, low-calorie sweeteners have been produced and approved by the FDA. Three important examples are monk-fruit extract, stevia and allulose. In comparison to other sugar alternatives, these, as of now, have not been linked to consistent negative effects on physiology. Conversely, some research suggests these molecules may in fact have benefit to multiple pathways including the gut-brain axis, and metabolic health. With this said, the research is still relatively new, and further investigation will be needed to better elucidate the directionality and significance of these types of signals.
What Do We Do with This Information?
The bottom line for most people is that they consume too much sweetener. While standard sugar and sweeteners add “empty calories,” contribute to inflammation and promote metabolic dysfunction, even the healthier alternative options keep us craving sweetened foods and beverages. In choosing between existing options, honey may be the best bet for a conventional sweetener, while allulose, monk fruit and stevia may be the best bet for low-calorie sweeteners.
