Drinking Coffee Can Reduce Depression Risk by up to One Third

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08 May 2020 | NEW YORK – Drinking coffee can reduce depression risk by up to one third, according to a comprehensive new review conducted by a leading researcher in neurology.
 

Dr. Alan Leviton of Harvard University conducted the review and commented: "Evidence shows that coffee drinkers are significantly less likely to be depressed than people who do not drink coffee.

“Coffee’s positive impact on mental health appears to be related to its anti-inflammatory, anti-oxidative, and microbiome-promoting properties, which are also associated with coffee drinkers’ reduced risk of developing certain cancers and chronic diseases."

Coffee’s positive impact on mental health may be related to its antioxidant and anti-inflammatory properties, as well as to caffeine’s ability to block receptors in people’s brains from binding with a chemical that causes fatigue and depressed mood.

The new research released today (Friday), evaluating data from more than 100 meta-analyses and independent peer-reviewed studies over five years and covering 300,000 individuals across the world, was commissioned by the U.S. National Coffee Association (NCA).

The study comes during National Health Month in the United States, as medical professionals around the world warn the COVID-19 pandemic and associated lockdowns may create a mental health crisis.

Even prior to the pandemic, one in five Americans suffered from mental illness. Calls to the U.S. government’s mental health crisis hotline rocketed up more than 1000% in April alone as the coronavirus claimed tens of thousands of lives and tens of millions of jobs.

The greatest mental health benefits come from drinking at least two cups of coffee per day. Of almost 10,000 adults in the Korean National Health and Nutrition Examination Survey, those who drank at least 2 cups of coffee per day experienced a 32% lower prevalence of self-reported depression than people who did not drink coffee.

In a study of 14,000 university students in Spain who continue to be followed, those who drank at least four cups of coffee per day were more than 20% less likely to be diagnosed clinically-significant depression.

While further research is necessary to determine the exact relationship between mental health and the more than 1,000 natural compounds in coffee, the study identifies key potential pathways for coffee’s impact on mental health, including:

1. Coffee reduces oxidation. Studies included in the review showed people experiencing depression have elevated levels of oxidative-stress indicators in their blood. Women exhibiting depression symptoms tended to have diets lower in antioxidants capacity (attributed, in part, to lower coffee consumption). Coffee is  the leading source of antioxidants in Americans’ diets.
    
2. Coffee fights inflammation. Depressed people tend to have higher blood levels of inflammation-related proteins than people who are not depressed, and suicidal ideation has also been associated with inflammation. Medications that are commonly used to treat depression (selective serotonin reuptake inhibitors or SSRIs) lower the blood concentrations of some inflammation indicators, raising the possibility that the therapeutic effects of these drugs might, in part, reflect their anti-inflammatory properties. Studies reviewed in the meta-analysis show coffee’s anti-inflammatory properties are associated with decreased depression.
    
3. Caffeine blocks mood-depressing chemicals in the brain. Caffeine blocks receptors in the brain from binding with a chemical (adenosine) that causes fatigue and depressed mood. Studies in the review show that people who drink more coffee have higher adenosine concentration in their blood as the chemical has been  blocked from binding with these receptors. Amongst those suffering from bipolar disorder, adenosine binding to neuroreceptors lowers adenosine concentration in the blood and is associated with more severe symptoms. Coffee is the primary source of caffeine in participants’ diets in most large-scale studies.
    
4. Coffee’s impact on gut health promotes mental health. Probiotics are microorganisms that improve gut health and decrease depression in randomized trials. Some components in coffee (“prebiotics”) feed these microorganisms, enhancing the creation of fatty acids and neurotransmitters that confer mental health benefits and are deficient in people who are depressed. Studies reviewed show considerable evidence supports that gut microbiota influence the occurrence of depression.

NCA President & CEO Bill Murray commented: “With the COVID-19 pandemic dramatically increasing stress for many, this new review of coffee’s mental health benefits is welcome news. Evidence across the board points to coffee drinkers living longer, healthier, happier lives.”