By Helene Nauwelaers and Dr Wolf Marx

We have previously discussed Polyphenols; a group of micronutrients with a range of healthy properties. In this previous article, Meghan Hockey talked about the potential beneficial effects of polyphenols found in dark chocolate and turmeric including how their prebiotic-like effect can influence the gut microbiome and how this could positively influence our mood – what we at the Food & Mood centre are all about!

In this article, we want to talk a bit more about the potentially beneficial effects of polyphenols and their connection with mental health. We also want to give you some inspiration to spice up your diet by discussing some of the best food sources for polyphenols.

Found in foods such as oranges, berries, and cocoa products, a specific group of polyphenols called “flavonoids” have been associated with a decreased risk of depression. A recent study found that women who consumed diets high in several types of flavonoids had a lower risk of depression. What’s more, adding polyphenols to your diet might not only lift your mood, but could also slow down cognitive decline. A French study showed that people aged 65 and older, who have a high intake of flavonoids through their diet, had better cognitive performance with ageing. This suggests that having a diet rich in flavonoids could preserve your cognitive performance when you are 65 and older. However, it is important to keep in mind that since these studies measured dietary flavonoid intake, not as an added supplement, it is possible that it is not the flavonoid itself but another dietary component of these high-flavonoid food products that are responsible for these positive effects. Therefore, more research is needed to explore this relationship.

All things considered, these polyphenols sound incredible don’t they? Better mood and cognition. But where do you start now? How can you get some more of these polyphenols in your system and enjoy their benefits?

Luckily, a French study from 2010 can help you out with this. They made two lists of food products high in polyphenols. The first list is of the 100 foods and beverages richest in polyphenols, the second list 89 foods and beverages that have the highest polyphenol content per serving. On the top of this first list, we have spices and dried herbs, which by weight were far and above the richest sources of polyphenols with cloves and star anise being the richest spices. Other food groups rich in polyphenols are cocoa products (e.g. cocoa powder), certain berries (e.g. blueberry), certain seeds (e.g. flaxseed), nuts (e.g. hazelnut), and certain vegetables (e.g. black olives and globe artichokes). Interesting to point out is that when you look at the list of food and beverages that have the highest polyphenol content per serving, fruits and vegetables such as blueberries and globe artichoke heads are at the top of the list.

Even though these two lists can be used as a helpful tool, like all good research it comes with limitations. For example, polyphenol content of a particular food can vary based on the type of analysis used as well as the region and season of when the food was grown. What we do know is that a diet rich in fruit and vegetables has beneficial effects on our physical and mental health. Polyphenols might be a piece of the puzzle to a healthy diet, but it is not the complete picture. All vegetables have a wide-range of healthy nutrients including fibre, vitamins, and minerals so keep on adding the fruits, spices, nuts and veggies that you enjoy to your diet. But if you’re interested in getting more polyphenols in your diet, why not add some blueberries and cinnamon with your breakfast or some spinach and extra virgin olive oil in your dinner? It’s also not a bad excuse to eat some dark chocolate too!

Helene Nauwelaers is a visiting researcher at the Food and Mood Centre from Maastricht University, Netherlands. Dr Wolf Marx is an Accredited Practising Dietitian and Alfred Deakin Postdoctoral Research Fellow at the Food and Mood Centre.