Dispelling nutrition myths, ranting, and occasionally, raving


2 Comments

Cruciferous crusaders or (not so) superfoods? The truth about veggies & cancer

carrot-144965_1280

Did you hear the news? Last week it was announced that there’s no evidence of a link between vegetable and fruit consumption and risk of developing cancer. This proclamation was based on the results of a large-scale analysis of data from cohort studies in Japan.

Before everyone rejoices and throws the contents of their crispers in the compost, opting instead to have ice cream for supper maybe we should take a closer look at the original research.

The first caution I’d make is that this is based on a study of people in Japan. Because the average Japanese diet and lifestyle differs significantly from our North American diet and lifestyle we can’t conclude that results seen in people in Japan will apply to people in Canada or the US, or pretty much any other country.

The second caution, and this is the big one, is that the frequency of consumption of vegetables and fruit used in the study was very different from what’s recommended here. The greatest consumption of veg and fruit recorded in the study was “almost daily”. Compare that to the recommended 8-10 servings per day in Canada’s Food Guide. Stating daily consumption of veg and fruit tells us very little about the true picture of veg and fruit consumption. This categorization allows a person who eats one apple a day (and no other veg or fruit) to be viewed as the same as a person who eats veg and/or fruit at every meal and snack and consumes a wide variety of produce. The method of categorization in this study really only allows us to conclude that at minimal consumption levels, eating vegetables and fruit doesn’t appear to provide protection against cancer when compared to eating vegetables and fruit infrequently (or almost never??). The fact that almost never is even an option makes me wonder about the accuracy of self-reporting and the possibility that people in that group could be more likely to succumb to ailments such as scurvy before cancer would have a chance to get to them.

The third point to mention (although hopefully I don’t need to) is that absence of evidence is not evidence of absence. Just because this study didn’t find a relationship between the consumption of vegetables and fruit and the development (or prevention) of cancer doesn’t mean that there isn’t a connection between the two. It’s possible that using different parameters might show that a greater consumption of vegetables is linked to a decreased risk of certain types of cancer.

The final point that I think is important to make is that we don’t eat food in order to prevent cancer. Even if this study is showing us that eating vegetables and fruit doesn’t confer protection against cancer upon us (and I’m not even remotely convinced that it does) there are plenty of other good reasons to eat vegetables and fruit. Vegetables and fruit provide us with many vitamins and minerals that are vital to the function of our bodies. They provide us with fibre which is essential for gut health. They provide us with water and energy, which are both necessary for our survival. They also add flavour, colour, and variety to our diets making meals and snacks enjoyable. All this to say that while cookies are delicious they still aren’t a balanced nutritious meal. Vegetables and fruit still have important roles to play in keeping us healthy.