Artificial Sweeteners and Your Brain: 6 Linked to Faster Decline

Picture a busy Tuesday afternoon. You pass on the sugary soda and grab a diet cola. You stir a packet of sweetener into your coffee and tuck a “zero sugar” bar into your purse for later. You feel good about it, because you just dodged a lot of sugar.

In my practice I have watched thousands of sincere, health-minded people make these same swaps. They are trying to do the right thing. So when new questions come up about artificial sweeteners brain health, you deserve a clear, calm and honest explanation.

A large study of 12,772 Brazilian adults, published in the journal Neurology, linked higher intake of six common sugar substitutes to faster decline in memory and thinking over about eight years. ScienceDaily ran the story again on October 29, 2026 under the headline “Six popular sugar substitutes linked to faster brain aging.”

This is not a brand-new study. The paper first appeared online in September 2025, and ScienceDaily has covered it more than once. It is still one of the largest looks we have at this question, though, so let’s walk through what it found, what it did not find, and what you can do about it this week.

🔬 What the Study on Artificial Sweeteners and Memory Loss Found

The research comes from ELSA-Brasil, a large ongoing study of civil servants in six Brazilian cities, as Neurology Today describes it. Dr. Natalia Gonçalves and colleagues followed 12,772 adults with an average age of about 52. Of these, 54.8 percent were women and 43.2 percent were Black or mixed race.

This was a prospective cohort study, which means researchers enrolled people, recorded their habits, and then tracked them forward in time. At the start, each person filled out a food-frequency questionnaire (a detailed survey about how often you eat and drink certain foods). From those answers, researchers estimated each person’s intake of seven sweeteners: aspartame, saccharin, acesulfame-K, erythritol, xylitol, sorbitol and tagatose.

Participants took thinking and memory tests three times: at the beginning, in the middle and at the end of roughly eight years. Average sweetener intake across the whole group was 92.1 mg per day.

The Main Results

• Highest vs. lowest intake: The highest group averaged 191 mg per day and the lowest averaged 20 mg per day. ScienceDaily notes that 191 mg is roughly the amount of aspartame in one can of diet soda.
• 62 percent faster decline: The highest-intake group lost overall thinking and memory ability 62 percent faster than the lowest group. That works out to about 1.6 extra years of cognitive aging over the study period.
• Middle group: Moderate users declined 35 percent faster, or about 1.3 extra years of cognitive aging.
• Six of seven sweeteners: Aspartame, saccharin, acesulfame-K, erythritol, sorbitol and xylitol were all linked to faster decline, especially in memory. Tagatose showed no association. The authors were careful to say this does not prove tagatose is safe or protective.
• Sorbitol led the pack: It had the highest average intake of the seven, at 64 mg per day.

Who Showed the Link, and Who Did Not

Here is a detail that matters a great deal to many of my readers. The link showed up in adults under 60, who had faster declines in verbal fluency and overall thinking. According to the journal article, there was no association in participants aged 60 and older.

The connection was stronger in people with diabetes, who showed faster decline in memory and overall thinking. In people without diabetes, it appeared as faster decline in verbal fluency and global cognition.

The Honest Limitations

I always tell my patients that one study is a signal, not the final word. This one has real limits:

• It shows association, not cause. Because it is observational, it cannot prove the sweeteners caused the decline.
• Intake was self-reported. People filled out one questionnaire at the start, and memory of what we eat is rarely perfect.
• Reverse causation is possible. People who already have higher health risks may be more likely to switch to diet products.
• Hidden factors may play a role. Researchers call this residual confounding: other habits or conditions that travel along with sweetener use.
• Test scores, not brain scans. The “years of aging” estimates reflect changes in test results, not directly measured biological brain aging.
• Not every sweetener was studied. Sucralose, stevia and monk fruit were not among the seven.

🧭 Artificial Sweeteners Brain Health: Why Midlife Matters

You may be wondering why the link appeared in younger adults and not in older ones. The honest answer is that we don’t know yet. This study was designed to look for a pattern, not to explain the biology behind it.

The authors suggested that their findings point to possible long-term harm, particularly from artificial sweeteners and sugar alcohols. They did not prove a mechanism, meaning the step-by-step process inside the body. I won’t pretend otherwise, and I’d be cautious of anyone who claims to know exactly why.

Here is how I see it as a physician. Midlife is the season when we lay the foundation for the brain we’ll live with in our 70s and 80s. A pattern that shows up in people in their 40s and 50s is a reason to pay attention early, while daily habits are easiest to shape.

If you are already past 60, please don’t panic. No association showed up in your age group in this study. Every age is still a good time to eat more whole foods and fewer heavily processed ones.

The research team isn’t finished, either. According to Neurology Today, the ELSA-Brasil investigators are running MRI studies, with about 2,000 brain scans expected, to look at actual structural changes in the brain. Those results should tell us much more.

⚖️ Are Sugar Substitutes Bad for You? The Other Side of the Story

A balanced view means looking at the wider evidence, not only one headline. Two other sources help fill out the picture.

First, in May 2023 the World Health Organization advised against using non-sugar sweeteners for weight control or for lowering the risk of noncommunicable diseases. WHO called this a conditional recommendation because the evidence may be confounded. The guideline excludes people with pre-existing diabetes, and it does not cover low-calorie sugars and sugar alcohols. WHO’s broader advice is to reduce the sweetness of the diet overall and to turn to naturally sweet foods like fruit.

Second, there is a counterpoint. The SWITCH trial was a 104-week randomized controlled trial (people were assigned by chance to one group or another) of 493 adults with overweight or obesity. Diet drinks sweetened with aspartame, acesulfame-K and sucralose performed similarly to water for weight loss. The diet drink group lost 4.8 kg and the water group lost 3.7 kg, a difference that was not statistically significant.

Two things are worth knowing about that trial. It was funded by the American Beverage Association. It also measured weight and metabolic markers, not brain function. So it answers a weight question, not a memory question, and it doesn’t settle the debate about diet soda and cognitive decline.

A Word to My Keto Friends: Erythritol and Xylitol Side Effects

Many of you following a keto or Mediterranean keto lifestyle use erythritol, xylitol or sorbitol. These are sugar alcohols, which are sweet compounds found in small amounts in some fruits and also made commercially. This study linked all three to faster decline, so I want to speak to you directly and calmly.

First, a published reader letter in Neurology pointed out that intakes of xylitol (about 3 mg per day) and erythritol (about 0.1 mg per day) in this group were very low. That makes it hard to know what the findings mean for someone who uses these sweeteners regularly in baking or drinks. Second, as noted above, the WHO guideline doesn’t address sugar alcohols at all.

So I’m not telling you to throw out your pantry in fear. What I am suggesting is what I’ve long taught: sweeteners work best as an occasional tool, not a daily crutch. The real goal of a healthy keto lifestyle is a palate that no longer craves intense sweetness at every meal.

🍓 Natural Ways to Tame the Sweet Tooth and Protect Your Brain

The study authors said more research is needed on alternatives such as applesauce, honey, maple syrup and coconut sugar. Those were not tested as safe alternatives, so I won’t promise you that any of them is better. What I can recommend with confidence is less sweetness overall, and sweetness that comes packaged by God in whole foods.

If cravings feel like a battle, you’re not alone. I explain why they happen and how to calm them in my article on carb cravings. If your morning coffee comes with a flavored creamer, you may also find my look at non-dairy creamers eye-opening.

For the bigger picture of eating for a sharp mind, read my overview of the MIND diet and brain health. It shows how leafy greens, berries, nuts, olive oil and fish fit into a brain-friendly plate.

✅ Your 7-Step Action Plan

1. Take an honest inventory. For three days, write down every diet soda, sweetener packet, sugar-free creamer, gum and “zero sugar” product you use. Most people are surprised by the total.
2. Start with your biggest source. For many people, that’s one or two daily diet sodas. Replace one with sparkling water and citrus this week.
3. Taper, don’t white-knuckle. Use half your usual sweetener in coffee or tea for a couple of weeks, then half again. Your taste buds will adjust as you go.
4. Make fruit your dessert. Keep washed berries at eye level in the refrigerator so the natural choice is the easy choice.
5. Keto readers, use sweeteners as a tool. Save erythritol or xylitol treats for occasional use rather than every meal. If you’d like a structured, whole-food reset, my free 21-Day Keto Zone Challenge can walk you through it.
6. Talk with your doctor if you have diabetes. Don’t return to sugar on your own, and never change a medication without medical guidance.
7. Pray over your plate. Thank God for your food and ask Him for self-control. Gratitude has a way of slowing us down and quieting cravings.

❓ Frequently Asked Questions

Do artificial sweeteners cause memory loss?

This study does not show that. It found that higher intake was associated with faster decline in memory and thinking test scores over about eight years. Because it was observational, other factors could explain part or all of the link. Brain imaging studies now underway should help clarify the picture.

I’m over 60. Should I be worried?

In this study, no association was found in participants aged 60 and older. The link appeared in adults under 60. That said, cutting back on intense sweetness and eating more whole foods is a wise step at any age.

Is erythritol safe on keto?

Erythritol was one of the six sweeteners linked to faster decline. However, the erythritol intake in this group was very low, about 0.1 mg per day, so it’s hard to apply the findings to regular keto use. I suggest using sugar alcohols occasionally rather than daily, and focusing on retraining your palate.

What about stevia, monk fruit and sucralose?

None of these three were studied in this research, so it tells us nothing about them either way. I’d encourage the same principle for every sweetener: use less, and let whole foods like fruit carry most of your sweetness.

Are honey, maple syrup or coconut sugar better choices?

The study authors specifically said these alternatives still need research. They were not tested as safe substitutes. For now, the best-supported approach is to lower the overall sweetness of your diet and enjoy whole fruit in modest amounts.

🌅 A Final Word of Hope

I don’t share this research to frighten you or to make you feel guilty about yesterday’s diet soda. I share it because I want you thinking clearly, remembering well and serving God with a sharp mind for many years to come.

Small changes repeated daily become a new way of living. Start with one swap this week. Thank God for the sweetness of real food, and trust that He gives grace for every step of renewal.

Your brain is a gift, fearfully and wonderfully made. Let’s take good care of it together.

Dr. Don Colbert, MD