Does Decaf Coffee Reduce Stress? New 2026 Gut-Brain Study
Last updated: 4 Sept 2026
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Can Coffee — Even Decaf — Really Improve Mood and Reduce Stress?
Yes. A 2026 study from University College Cork and the University of Parma, published in Nature Communications, found that regularly drinking coffee — whether caffeinated or decaf — reshapes gut bacteria in ways linked to lower stress, depression, and impulsivity. This suggests coffee's mood benefits go beyond caffeine alone.
How Was the Study Conducted?
Researchers from APC Microbiome Ireland at University College Cork, working with the University of Parma, recruited 62 healthy adults aged 30-50 in Ireland: 31 non-coffee drinkers and 31 moderate coffee drinkers who typically consumed 3-5 cups a day.
The coffee-drinking group abstained from coffee, other caffeinated beverages, and dark chocolate for two weeks. They were then randomly assigned, in a double-blind design, to drink either caffeinated or decaffeinated coffee for a further three weeks, while researchers collected blood, stool, and urine samples along with psychological assessments throughout.
How Do Caffeinated and Decaf Coffee Differ in Their Effects?
After coffee was reintroduced, both groups showed reduced stress, depression, and impulsivity scores — but each type of coffee had its own distinct strengths.
Caffeinated coffee reduced anxiety, improved attention and alertness, and significantly lowered salivary cortisol, the body's main stress hormone.
Decaffeinated coffee improved episodic memory and sleep quality — benefits that were not seen in the caffeinated group.
Why Does Coffee Affect Mood Even Without Caffeine?
Regular coffee drinkers showed higher levels of certain gut bacteria, including Eggerthella sp. and Cryptobacterium curtum, which are linked to bile acid processing and may help protect against harmful pathogens.
Researchers propose that non-caffeine compounds in coffee, such as polyphenols, are broken down by gut bacteria and influence neuroactive metabolites that communicate with the brain via the gut-brain axis — a two-way communication pathway between the digestive system and the brain. This helps explain why decaf coffee, despite having no caffeine, still affected participants' mood.
How Should This Research Be Interpreted Responsibly?
This is a small study (62 participants) in a specific population of healthy adults in Ireland. It is not a conclusion that applies universally, and it is not a clinical trial for treating anxiety or depression.
Anyone experiencing anxiety or depression that affects daily life should consult a doctor or mental health professional directly. Coffee is not a substitute for medical treatment.
So Which Type of Coffee Should You Drink for These Benefits?
Based on this research, both caffeinated and decaf coffee have their own advantages. If you want better focus and lower anxiety in the morning, caffeinated coffee may suit you. If you want to enjoy coffee in the afternoon or evening without disrupting sleep, decaf can offer similar mood benefits.
At Preda Roasting House / Goh Café, we roast Thai specialty Arabica coffee in both caffeinated and decaf options, so you can choose what fits your time of day and lifestyle — without having to choose between flavor and wellbeing.
Frequently Asked Questions (FAQ)
Q1. How many cups of coffee per day are needed to see these effects?
Participants in the study were habitual drinkers of 3-5 cups a day, but the research does not establish a specific minimum amount required for the mood-related effects.
Q2. Does decaf coffee actually help, or is it just the caffeine?
It genuinely helps. The study found decaf coffee reduced stress, depression, and impulsivity just as much as caffeinated coffee, and even outperformed it on memory and sleep quality.
Q3. Can coffee treat anxiety or depression?
No. This was a small study (62 people) in healthy adults, not a clinical treatment trial. Anyone with anxiety or depression affecting daily life should consult a doctor directly.
Q4. Why does caffeinated coffee reduce anxiety if caffeine is a stimulant?
Researchers found caffeinated coffee lowered salivary cortisol (the stress hormone) after the intervention and improved attention and alertness, which may help reduce feelings of anxiety in situations requiring focus.
Q5. Does Preda offer decaf coffee?
Yes. If you want to try the memory and sleep benefits highlighted in this research, you can enjoy Preda's decaf in the afternoon or evening alongside regular coffee in the morning.
Yes. A 2026 study from University College Cork and the University of Parma, published in Nature Communications, found that regularly drinking coffee — whether caffeinated or decaf — reshapes gut bacteria in ways linked to lower stress, depression, and impulsivity. This suggests coffee's mood benefits go beyond caffeine alone.
How Was the Study Conducted?
Researchers from APC Microbiome Ireland at University College Cork, working with the University of Parma, recruited 62 healthy adults aged 30-50 in Ireland: 31 non-coffee drinkers and 31 moderate coffee drinkers who typically consumed 3-5 cups a day.
The coffee-drinking group abstained from coffee, other caffeinated beverages, and dark chocolate for two weeks. They were then randomly assigned, in a double-blind design, to drink either caffeinated or decaffeinated coffee for a further three weeks, while researchers collected blood, stool, and urine samples along with psychological assessments throughout.
How Do Caffeinated and Decaf Coffee Differ in Their Effects?
After coffee was reintroduced, both groups showed reduced stress, depression, and impulsivity scores — but each type of coffee had its own distinct strengths.
Caffeinated coffee reduced anxiety, improved attention and alertness, and significantly lowered salivary cortisol, the body's main stress hormone.
Decaffeinated coffee improved episodic memory and sleep quality — benefits that were not seen in the caffeinated group.
Why Does Coffee Affect Mood Even Without Caffeine?
Regular coffee drinkers showed higher levels of certain gut bacteria, including Eggerthella sp. and Cryptobacterium curtum, which are linked to bile acid processing and may help protect against harmful pathogens.
Researchers propose that non-caffeine compounds in coffee, such as polyphenols, are broken down by gut bacteria and influence neuroactive metabolites that communicate with the brain via the gut-brain axis — a two-way communication pathway between the digestive system and the brain. This helps explain why decaf coffee, despite having no caffeine, still affected participants' mood.
How Should This Research Be Interpreted Responsibly?
This is a small study (62 participants) in a specific population of healthy adults in Ireland. It is not a conclusion that applies universally, and it is not a clinical trial for treating anxiety or depression.
Anyone experiencing anxiety or depression that affects daily life should consult a doctor or mental health professional directly. Coffee is not a substitute for medical treatment.
So Which Type of Coffee Should You Drink for These Benefits?
Based on this research, both caffeinated and decaf coffee have their own advantages. If you want better focus and lower anxiety in the morning, caffeinated coffee may suit you. If you want to enjoy coffee in the afternoon or evening without disrupting sleep, decaf can offer similar mood benefits.
At Preda Roasting House / Goh Café, we roast Thai specialty Arabica coffee in both caffeinated and decaf options, so you can choose what fits your time of day and lifestyle — without having to choose between flavor and wellbeing.
Frequently Asked Questions (FAQ)
Q1. How many cups of coffee per day are needed to see these effects?
Participants in the study were habitual drinkers of 3-5 cups a day, but the research does not establish a specific minimum amount required for the mood-related effects.
Q2. Does decaf coffee actually help, or is it just the caffeine?
It genuinely helps. The study found decaf coffee reduced stress, depression, and impulsivity just as much as caffeinated coffee, and even outperformed it on memory and sleep quality.
Q3. Can coffee treat anxiety or depression?
No. This was a small study (62 people) in healthy adults, not a clinical treatment trial. Anyone with anxiety or depression affecting daily life should consult a doctor directly.
Q4. Why does caffeinated coffee reduce anxiety if caffeine is a stimulant?
Researchers found caffeinated coffee lowered salivary cortisol (the stress hormone) after the intervention and improved attention and alertness, which may help reduce feelings of anxiety in situations requiring focus.
Q5. Does Preda offer decaf coffee?
Yes. If you want to try the memory and sleep benefits highlighted in this research, you can enjoy Preda's decaf in the afternoon or evening alongside regular coffee in the morning.
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