A study by Stanford University researchers published in a 2017 edition of the journal Nature Medicine addresses the potential protective and anti-inflammatory effects of caffeine in the “inflammosome” — the structure and processes underlying inflammation in the human body.
In a review of the study, however, USA Today may have taken the author’s findings a step too far by choosing the headline, “Caffeine may lead to a longer life, new study finds.”
While the study did demonstrate a correlation in its subjects between caffeine consumption and having at least one relative who lived past the age of 90, it was not designed to test the hypothesis that caffeine increases longevity as suggested in the related headline.
Good science requires evidence
The inflammosome study appears to have more-or-less checked this box indicating a relationship between caffeine and longevity. It is important, however, to clarify both the study design as well as the specific claims the study tested.
It’s rare in the world of medical research to have access to a population to study longitudinally over a significant period of time. This type of research was perhaps best popularized by the Nun Study, in which 678 nuns were studied over a period of multiple decades to better understand the potential causes and risk factors for the development of Alzheimer’s disease.
The Stanford University team behind the inflammosome study took advantage of a similar albeit more limited model, studying blood samples and employing extensive history and physical exam findings from more than 100 subjects over many years.
Based on blood samples, two groups were drawn out: those with high and low expression of genes known to be associated with inflammation and chronic disease.
While this type of study has a greater capacity to answer complex questions about a group of people over a long period of time, its results should be interpreted carefully and with specificity.
Caffeine: Good or bad?
If good science requires evidence, good medicine and population health requires context.
Moderate caffeine intake certainly has some demonstrated and previously studied benefits. Caffeine consumption may have protective properties for the development of dementias. Drinking coffee may even reduce rates of suicide — although it should be added that heavy coffee drinkers may increase their risk.
Ultimately, it’s important to remember what caffeine is and who you are. Caffeine is the mostly widely consumed drug in the world. Its stimulant vasoactive properties have been shown to increase heart rate and blood pressure, among its many other effects. People with high blood pressure, heart rhythm abnormalities or other cardiovascular disease or risk factors should discuss their nutritional and social habits, including caffeine consumption, with their doctor.
Light or moderate caffeine intake is probably good for you, particularly if you enjoy the taste of your beverage of choice. (Mine is a triple non-fat latte at child’s temp.) Before making decisions on the basis of scientific studies, however, it’s important to understand what scientific question is being answered and how.