There are over 1,000 different compounds in a single cup of coffee, but you know as well as I do, there's only one that matters.
Coffee is the world's #1 drug of choice, and if this latest study is any indication, it's also the healthiest.
Caffeine Intake is Associated with Decreased Risk of All-Cause Mortality
Coffee is well known for its stimulatory effects, it's rich polyphenol content, it's effects on mood, neuroprotection and more.
FUN FACT: Coffee is the richest source of polyphenols in the American diet.
But a recent scientific study concluded that people who stick to a moderate caffeine intake -- whether from coffee or other sources -- have a decreased risk of dying.
Is that a crazy statement or what?
Now, there are a few HUGE caveats to this bold conclusion, so keep reading and I'll explain what this really means for you.
This study was published in the Mayo Clinic Proceedings, a top ranking science journal.
And it isn't an individual study, but a Meta-Analysis.
It's a type of review that involves complex statistical analysis that combines the results of multiple scientific studies. Unlike a literature review or narrative review, the meta-analysis has the data-driven heft behind it to help us understand the outcomes, associations, and implications for health.
In this case, the outcome was caffeine intake and all-cause mortality.
What Is All-Cause Mortality?
This term refers to the number of deaths that occur in a population, regardless of the cause.
Did the subjects die from cancer? A freak accident? Old age?
Any and all causes of death are lumped under one big umbrella term: all-cause mortality.
In epidemiological studies, it's used as an indicator of the safety or potential danger of variable (s) being looked at.
This study sourced its data from the largest ongoing health survey in the country -- the NHANES (National Health and Nutrition Examination Survey).
The NHANES is a population-based survey designed to collect information on the health and nutrition of the U.S. household population. Data collected from this program are used to guide policy and health recommendations. This survey is unique in that it combines interviews and physical examinations.
Unlike, say, randomized controlled trials, which look at the results from individual experiments, the NHANES is continuous, which means data is always being collected (even as you're reading this).
The authors analyzed population data from the NHANES between 1999 - 2010 to look at the relationship between caffeine intake and all-cause mortality.
The goal of the NHANES is to retrieve as much nationally-representative data as possible, then look for possible clues linking lifestyle factors to health issues, or in this case, cause of death.
Here are some details of the caffeine study:
- 17,954 total participants
- Participants were between the age of 20 - 79
- 99.8% of the participants completed the study
Before we dive into the juicy results, how much caffeine does the general population consume anyway?
Based on the sample of 17, 954 people...
- 22.4% have a caffeine intake of less than 10 mg per day
- 24.6% consume 10 - 99 mg per day
- 21.3% consume 100 - 199 mg per day
- 31.7% consume more than 200 mg per day <------This is me.
After a battery of statistical analyses, the results revealed that people who consumed between 100 - 199 mg of caffeine per day had the greatest reduction in all-cause mortality, followed by the 200 or more range, with those ingesting between 10 - 99 mg coming in last.
Here's a quote from the authors:
"Compared with those who had a caffeine intake of less than 10 mg per day, the rates of all-cause mortality were significantly lower in participants with a caffeine intake of 10 - 99 mg per day and 200 mg per day or more."
*Hazard ratio refers to the risk of death attributed to caffeine intake.
The Bigger Picture
We know that coffee has some plausible health benefits, and now it looks like caffeine as an isolated substance may as well.
The results of the study show that consumption of a moderate amount of caffeine (between 100 - 199 mg) on a daily basis is associated with a decreased risk of all-cause mortality.
Now before you run off and start downing double espressos or swallowing handfuls of No-Doz, you need to be aware of a few things...
This was an observational study.
Which means we can't establish a cause and effect relationship.
For instance, you cannot say, "caffeine causes us to live longer and healthier while reducing the risk of death."
Instead you'd say, "caffeine and or coffee consumption are strongly associated with reduced all-cause mortality... let's dig a little deeper to understand why that might be."
Caffeine seems to have a protective effect, but what else could be going on?
This one is less important, but caffeine intake was self-reported.
That means we can't truly know the long-term patterns of caffeine intake in the participants in the study.
Ultimately, coffee and caffeine have convincing health benefits (whether taken together or separately) and this is the very first study to show it.
How much coffee do you drink on an average day? What about other forms of caffeine?
Let us know in the comments below!