Can Your Diet Make You Happy?

A recent study using data from the UK shows that a healthy serving of fruits
and vegetables everyday can have a positive effect on your mental well-being. 

A recent study from the UK says yes!

by douglas reeser on June 21, 2013
A good friend of mine in Belize recently started working a new job. The job is with a family business, and requires long hours 6 or 7 days per week. I could see the toll the hours were taking, and urged her to be sure to take care of herself, especially by keeping up with a healthy and nutritious diet. I knew that eating well during a time of stress would help her tired body, and I found myself wondering if a healthy diet would also have an effect on her mental health. I know physical health, mental health, and diet are all entangled, but I wondered if diet could directly affect your mental well-being - can your diet make you happy?

After a few days, this question continued to linger in my mind, so I decided to do a little research. My own anthropological research has focused on health and diet, and so I had a few places to look, but I didn't find anything specifically about diet and happiness. I broadened my search and came across an article from 2012 in the journal, Social Indicators Research, a social-science journal that focuses on quality of life measurement. The article I found was titled with the very question I was asking: "Is Psychological Well-Being Linked to the Consumption of Fruit and Vegetables?" It turns out that few studies have actually been done on happiness and health, and perhaps none trying to tease out diet as a factor in our happiness.

The study, done by economists and a public health expert, sought to determine whether consuming fruits and vegetables had an effect on a person's well-being. This is an especially challenging question, considering the many possible factors that could confound such a study, including things like income, where a person lives, their education level, their social networks, the quality of their job, their sexual activity, and so on. Still, the authors were able to control for these factors and provide "evidence of a positive association with psychological well-being, and one that often reaches a peak at or above 5 portions a day or more (in many of our equations, at approximately 7–8 portions of fruit and vegetables per day)" (p3). 

Using samples from a number of health surveys conducted in the UK, the authors were able to analyze data on about 80,000 individuals. In one part of the study, which looked at about 14,000 surveys from Scotland, the authors show that those who eat 8 or more portions of fruits and vegetables per day score higher on a life-satisfaction score than those who are non-smokers or married, and more influential on the score than having a long standing illness or being unemployed. 

A second piece of the data were similarly analyzed, and showed that those who eat 7-8 portions of fruits and vegetables per day scored significantly higher on a scale of well-being than those who ate just a small amount of fruit and vegetables. In this group too, the effects of such a diet had greater influence on well-being than being unemployed or disabled. 

Using yet another subset of the data, the authors were able to control for other aspects of a person's diet, like the consumption of meat or fish that could also affect physical, and thus mental well-being. The apparent impact of fruits and vegetables on well-being is unaffected by meat or fish in the diet, although a no-fish diet was associated with worse mental well-being. Using still more sets of the data, the authors found time and again that  eating a fair amount of fruits and vegetables every day appears to correlate with a person's well-being or happiness. 

They are conservative with their conclusions, and rightfully urge caution when interpreting the study, pointing out that it is "at best only suggestive of any causal relationship." In the end, they call for further study on the topic, and note that their findings need to be replicated outside of the UK. They also point out the importance of their findings for government agencies charged with forming health policy and dietary recommendations. 

So while it's well known that our diet has a direct impact on our physical health, we are finally beginning to uncover what many of us have suspected as well - that our diet can influence our happiness. Just knowing that the science is beginning to support the idea will make all of those fruits and vegetables work that much better! And the urging of my friend to be sure to feed herself especially well during her times of stress may actually do more than keep her physically healthy, it may help to keep her happy.