Coffee vs. tea debate highlights how little we know about nutrition

#TeamCoffee forever.


Cynthia McKelvey

Internet Culture

Published Jun 11, 2015   Updated May 28, 2021, 2:52 pm CDT

On ASAPScience’s sister channel, ASAPThought, hosts Gregory Brown and Mitchell Moffit debate the merits of coffee vs. tea in a scientific showdown.

And while the lovable science nerd duo cite many studies and clearly know their stuff, they also highlight how little we really know about nutrition.

“One of the most amazing things about tea is that it has something called antioxidants in it like flavonoids, which have been linked to a slew of awesome health benefits from decreasing your risk of heart disease and even cancer,” Moffit says.

Moffit and Brown continually say that coffee and tea are “linked with” or “associated with” various health risks and benefits for a reason: most of the studies they cite only show a correlation between coffee, tea, and whatever health benefit. But correlation is not causation—a distinction that’s so often the bane of scientific research.

It’s true that there are many studies that find an association between increased flavonoid intake and a lower incidence of diabetes, heart disease, and cancer. The problems with these studies is that they are inconsistent.

Flavonoids are just a category of chemicals, of which there are several classes, and it’s very hard to isolate which of them are the most helpful. Moreover, studies that examine their role in human health have pretty weak data. Whenever researchers study human diet, they are very limited in the amount of variables they can control, so they can only show associations between diet and health effects, rather than a causal effect. On top of that, cancer, type-2 diabetes, heart disease, and dementia develop over a long period of time, during which a person can interact with and consume so many different things in their environment that it’s just about impossible to pinpoint which chemicals are protective or harmful.

When researchers try to pool the data between several studies, they generally find it hard to pull out a true association between flavonoids and health benefits amidst the noise.

Animal studies can be more informative because it’s easier for researchers to tinker with and control the variables of diet, environment, and disease. But then it’s hard to extrapolate out how useful or practical it would be for people to consume enough of one chemical or the other in order to have any tangible health benefits.

And while we’re picking on flavonoids right now, this is true for most dietary compounds and their association with disease. The same is pretty much true for diet and weight loss. This is part of why there’s a seemingly endless stream of “x will make you fat; y will make you skinny.” We don’t know what the optimal diet for weight loss, weight gain, or weight maintenance is because it’s just too hard to control for all the variables of human life to see a really clear trend.

This is not to say that it doesn’t matter what you eat or drink. Obviously the food that goes into your body does something, otherwise you wouldn’t need it to survive. But the concept of food as medicine, prophylactic, or as poison tends to be overblown in the media. And as the Moffit and Brown conclude, there are probably benefits and risks to both coffee and tea consumption—pick your poison.

Screengrab via AsapTHOUGHT/YouTube

Share this article
*First Published: Jun 11, 2015, 4:52 pm CDT