The facts behind the facts: What the big health headlines are not telling you

For decades there has been a futile narrative that “eating X will cause Y”, with X often being a delicious food (or beverage) and Y being a serious health condition. It can leave many of us feeling either confused, overwhelmed, or completely fed up with the mixed messages. So, why do some foods get such a bad wrap? When a new research study comes out, the results can get cherry-picked, exaggerated, generalised, or simply lost in translation (literally).

Relative risk vs. absolute risk

One of the big culprits of confusion is how disease risk is reported verses how it is interpreted. In the science world there are two types of risk: relative risk and absolute risk. Relative risk is the grab-and-go soundbite statistic that is often a jaw dropping percentage or probability, whereas the absolute risk is the bulky, technical risk that shows how the statistic was determined and is padded with context.

For example, the relative risk of a study could be “Food X is associated with a 50% increase in risk of developing Y disease” which sounds shocking however, when you peel back the layers the absolute risk (and sadly, the less attractive statistic) may be that “The incidence of Y disease increased from 2 people per 100 people to 3 people per 100 for those who eat food X”. Although both statistics are technically true, the relative risk takes the cake when it comes to headlines because it sounds more alarming, whereas the absolute risk provides context and is tangible. What this means however is that suddenly people think food X is the devil in disguise when really it may be a drop in the ocean in terms of absolute risk.

Association vs. causation

When you hear concerning headlines in relation to health, it is important to remember that association does not mean causation. Just because two things have been associated in one study, at a certain time, under certain conditions, with a certain group of people does not mean food X solely causes Y.

For example, a 1991 study found women who didn't wear bras had half the risk of breast cancer than women who did wear bras. But before you rush off and bin your bras, the women in the study who didn't wear a bra were more likely to be thin and have smaller breasts, which the authors concluded might account for their decreased risk of breast cancer, not the absence of a bra.

Summary

To date, no study has shown that a single food alone has been the sole cause of a disease or health condition, and that is because your health status does not ride on whether you sometimes eat or do not eat a certain food. Health is complex, intricate and is determined by a range of things such as genetics, family history, overall diet, lifestyle and environmental factors (e.g. smoking and pollution exposure).

So, it is important to keep your wits about you when you hear new nutrition science or foods getting put down. Food is neither good nor bad, it is how you eat it that matters. If you are eating a varied, balanced diet, regularly exercising and enjoy the delicious food X in moderation you are on the right track. However, if you want further advice, speak to a Registered Nutritionist or Registered Dietitian who can provide guidance on how to navigate the complex world of nutrition science.