Recently it has been shown through epidemiological studies that habitual consumption of caffeinated and decaffeinated coffee is significantly associated with a decreased risk of Type II Diabetes. However, short term intervention trials have demonstrated coffee to acutely reduce insulin sensitivity. This may sound like many other nutritional news reports you have read or heard; one day they say something is good for you, and the next they say it’s bad. Who do you believe?
There are a few things to remember when you have been given conclusive statements regarding the toxicity or benefits of different nutrient extracts, whole foods, or beverages. First, if you are reading it in the newspaper and hearing it on the news, remember the only stories that get published in the news are those that draw a reaction out of the public. We see reports of floods, hurricanes, and crimes… not reports of those towns that didn’t get flooded, or reports of people who have managed to follow the law perfectly. It’s not any different in the nutrition world. One study does not represent the entire story. Second, many reporters will take a correlation and make it seem like a cause. The months of June, July, and August are correlated to increased ice cream sales. These months don’t cause the sales to increase, it just so happens the temperatures are higher and most people prefer ice cream when it’s hot. In other regions of the world it could we warm year round, or hot during a different time of year. Which bring me to my next point; understand the context! Due to ethical reasons, many studies are conducted using animal models. They may or may not be representative of human metabolism. It is also very common to increase the doses in order to see results, because interesting results means more publications, which ultimately leads to a larger paycheck. Many of these doses are so high, they are unrealistic to that of human consumption. Remember what the Paracelsus stated in the 1950’s; “Everything is poison. Only the dose makes a thing not a poison.” So before you jump on the bandwagon of the next nutritional claim supported by a study or two, albeit positive of negative, do your research. 1. Does the person reporting the findings stand to benefit from making these proclamations? 2. Have the proper conclusions been drawn, in other words is it causative or correlative? 3. Are the settings and dosages/exposures realistic? You don’t have to acquire your PhD to decide whether a claim is true or not, just use common sense.
Back to the coffee controversy. This is an interesting topic a couple of my friends and I have been tackling for a Nutrition Toxicology class. Yes one side is more correlative and the other is more causative. However, the negative effects caused from coffee seem to only occur acutely, and the amount of caffeine within the coffee also seems to have a significant role as well. Could it be dependent on our P450 genes (a topic discussed previously in this blog)? Could we adapt to the initial negative effects of coffee to the point where other components within the coffee, namely the many different phytochemicals, provide a more positive impact? Due to the lack of fruits and vegetables in the average consumers’ diet, many people receive most of their phytochemicals from coffee, especially when it’s not uncommon to have over 500 mL a day. We know many phytochemicals have antioxidant capacity, and that oxidative stress is also significantly associated with insulin resistance. By no means is this enough information to draw proper conclusions, but it begs for another study to help solve the mystery! I’m not telling you to increase your coffee consumption, nor am I telling to stop drinking it all together. Remember what you consume does impact your health, and balance is the key to a healthy diet.
4th year BSc. Nutrional and Nutraceutical Sciences
University of Guelph