Science
Recent studies suggest it has some specific benefits. But there are caveats to keep in mind with this kind of research.
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We love to think that our vices are secretly good for us—that chocolate is healthy (even dark chocolate is very sugary), that red wine is something of an elixir (nope), and, most recently, that coffee can keep diseases at bay. Dozens of headlines have been talking about this study, which found an association between moderate coffee intake and a reduced risk of dementia; another study published in September led to articles about how coffee is good for your heart. Another tiny study also made news in August for showing that a higher intake of caffeine was very vaguely associated with a lower risk of Alzheimer’s disease in a cohort of 263 people.
I’ve been writing about this issue—the idea that coffee might have some wonderful health benefits— for nearly a decade now, and more research comes out but the bottom line never really changes. In these studies, the authors have typically taken a large (or not so large) database of people who have been asked a range of questions about what they eat and drink. One or two of those questions usually includes asking how much coffee they have each day. Those people have then been followed up with for years. The researchers look at whether this self-reported coffee intake at the start of the study is associated with the future risk of disease.
The problem is that this sort of study has a lot of weaknesses. People are terrible at reporting how much they eat and drink. Notoriously terrible. There are hundreds of scientific studies showing this. People’s reports vary by season, depend on how much they’ve recently eaten, differ depending on which foods they are asked to talk about. An occasional survey is generally just not a good basis for knowing how much people eat each day. (Can you remember what you ate last week? What about the week before?). Unfortunately, we have no other practical methods for getting this information, so these large studies are forced to accept that, even with complex statistical corrections, they may not be properly measuring how much coffee people drink. Just how much coffee people would estimate they drink.
These studies also give us limited information about cause and effect. We can say with quite a bit of certainty that (self-reported) moderate coffee drinking—usually defined as about two to three cups a day—is associated with better health than drinking no coffee or drinking a very large amount of it. But, even taking the self-reported data at face value, that doesn’t necessarily mean that coffee causes better health. In many of these studies, the design is simply not robust enough to give us useful data on whether coffee is causing benefits or it’s simply that people who drink a moderate amount of coffee are on average a bit healthier in lots of ways than people who drink none or loads.
We do have some interventional studies looking at coffee and a range of health outcomes. These are studies where people are given coffee or a placebo and then followed up after a few weeks to see what’s happened to their health. But large reviews analysing these interventions have failed to find benefits (or harms) for heart health. There is some suggestion of short-term harm for people with diabetes, although this is partially contested by other research.
So: We can say with some certainty that people who drink a few cups of coffee a day are on average quite healthy. What we can’t say with any confidence is whether the coffee is making a difference or if there are other factors involved. When we actually give coffee to people in controlled clinical settings, there’s not much evidence that it has a benefit to their health.
Personally, I find this news relieving. Why? Well, there’s not much data showing that coffee has health benefits, but there’s also no data showing that it has health harms. Indeed, if you look at the entire gamut of scientific investigation into coffee as a whole, what you tend to see is that in moderate quantities, coffee is basically neutral, and for every possible detriment, there is a possible benefit to balance it out.
My opinion, as an expert who drinks a lot of coffee and has a strong vested interest in this question, is that there really doesn’t seem to be any health reasons to either drink or avoid coffee. There’s certainly evidence that a lot of coffee is bad for you, and if you’re breaking eight to 10 cups a day—in this case, a cup is defined as a standard eight ounce serving in most studies—you might want to cut back. At a minimum, that much coffee is likely to affect your sleep.
But if you don’t drink coffee, there’s really no need to start unless you want to. It’s probably not going to affect your health much either way, so don’t worry about it. I’m going to go take my own advice and have a second cup.
Food
Research
Source : Slate News