The dreaded sugar crash following your 3.30 sugar pick-me-up, or the post-lunch slump- most of us have faced the effects food can have on our mood and body function. But can what we eat really influence the way we feel? And can choosing poorer quality food and drink encourage poorer mental health?
Dr Rachelle Opie, research fellow at the School of Exercise and Nutrition Sciences and a member of the Institute for Physical Activity and Nutrition (IPAN), said the idea that a highly processed, non-nutritive diet increases depressive symptoms already has some science behind it.
Dr Opie is no stranger to the idea diet can influence mood; specifically, she helped develop the novel Modified Mediterranean Diet (the ModiMed Diet) to test whether people on a diet high in mood-improving good fats, antioxidants and dietary fibre – and with limited ‘discretionary’ items – experienced reduced depressive symptoms.
“At the time of our trial, studies were already showing a link between a healthy diet pattern and reduced risk of depression, but no intervention studies had been conducted with this specific research focus,” said Dr Opie.
Researchers developed the ModiMed Diet using the Greek and Australian national dietary guidelines, elements of nutritional counselling – such as mindfulness and goal setting – and a take-home resource kit specifically developed for people taking part in the study.
Participants were advised to eat a diet rich in vegetables, fruit, wholegrains, oily fish, legumes, raw unsalted nuts and seeds, and extra virgin olive oil. They were also recommended to eat a moderate amount of lean red meat and dairy. Importantly, Dr Opie said participants were told to eat as much as they felt they needed to in order to satisfy their hunger.
“In that sense, it wasn’t a diet as such; we weren’t restricting food intake, we were just changing the way people viewed food, and altering the kinds of foods they were eating.” “We taught people how to enjoy eating delicious and healthful food in a user-friendly way that suited their lifestyles”, she said.
Did the diet really influence depression?
“By the time the study was complete, the group of participants who were on the ModiMed Diet demonstrated a significant improvement in their Montgomery-Asberg Depression Rating Scale (MADRS scores) compared to the group that received only social support,” Dr Opie said. These MADRS scores assessed changes in depressive symptoms at the beginning and at the end of the 12-week study.
The results also show that nearly 1 in 3 participants who were on the diet achieved remission of depression, meaning they were no longer experiencing symptoms according to the MADRS cut-off scores.
Finally, the research showed that despite the recommended increased consumption of fish and other produce, the ModiMed Diet did not cost more than the highly-processed, poor-quality diet many participants were engaging in prior to the study. “Trial participants spent an estimated average of $138 a week on food and beverages before the study, whereas the total food and beverage costs per person per week for the ModiMed Diet was around $112,” said Dr Opie.
How can food impact how we feel?
Dr Opie said it was the ModiMed Diet’s cumulative effect that would have helped improve depressive symptoms.
“We believe it wasn’t just one single nutrient or type of food,” she said. “Like a traditional Mediterranean diet, the ModiMed Diet is comprised of nutrients with known health benefits, such as dietary fibre and antioxidants (from legumes, vegetables and wholegrains), omega-3 polyunsaturated fatty acids (from fish) and mono-unsaturated fatty acids (from extra virgin olive oil).”
Dr Opie said the diet also helped reduce the intake of discretionary foods such as sweets and fast-food, which are typically higher in refined carbohydrates, added sugar, harmful trans-fatty acids and saturated fatty acids.
Continuing research into the diet-depression space will provide vital evidence to help develop mental health treatments “such as smartphone apps, that can reach many people,” Dr Opie said. “We are also hoping to offer formal training to accredited practicing dietitians to deliver the ModiMed Diet to ensure more people living with depression are able to access the dietary advice and support they need in order to improve their mental health.”
How you can use food to improve your mood
Tips for following a healthy ModiMed diet include:
- Select fruits, vegetables and nuts as a snack
Have 3 serves of fruit every day, and include 1.5 tablespoons of raw unsalted nuts daily
- Include vegetables with every meal
Eat leafy greens and tomatoes every day
- Eat legumes 3 to 4 times per week
- Eat oily fish at least 2 times per week
- Use olive oil as the main added fat
Include 3 tablespoons of extra virgin olive oil daily
- Water is the best drink
Avoid sugary drinks such as soft drinks, energy drinks, sports drinks and fruit juice wherever possible