A daily handful of walnuts could help people combat stress, a new study reveals. Undergraduates who ate two ounces of walnuts a day for 16 weeks experienced an improvement in their mental health.
They reported feeling less stressed out by their studies, less affected by depression symptoms and saw an improvement in their quality of sleep. The randomised 16-week clinical trial studied 60 randomly selected university students aged 18 to 35.
Half were put in the treatment group and the other were put in the control group. The treatment group ate around 56 grams of walnuts each day, while the control group avoided eating any type of nut or fatty fish.
Each person provided blood and saliva samples and filled out a series of questionnaires about their mental health, mood, general well-being and sleep habits. They did this three times during the study.
A subgroup of participants also provided faecal samples at each clinical visit. The study showed that the group who ate walnuts daily were less affected by academic stress than those who avoided them.
It also showed that eating walnuts can help with sleep. What is more, the researchers found that eating walnuts had the power to lower the severity and frequency of depression symptoms, improve mood in healthy young adults and increase the chances of achieving overall health in older age.
Being a university student is an especially stressful time in life. In fact, 80 per cent of university students report frequent bouts of stress and 61 per cent seek counselling for anxiety, depression or other needs.
Dr Larisa Bobrovskaya, associate professor of clinical and health sciences at the University of South Australia and lead researcher on the study, said: “University students are a unique population of people who transition into their adulthood while completing university degrees which can be challenging and stressful.
“The pressure to complete and find attractive jobs is high and can impact on students’ mental and physical health and overall well-being. Thus, managing academic stress is important and various strategies can be adopted by students to get through their university journeys.
“Dietary intervention is one of such strategies that can boost students’ brain health but is often neglected by students.”
Most nuts are good for general mental and physical health as they are full of important vitamins, minerals, protein, antioxidants and good fats such as omega 3. Nuts can also improve gut health, decrease inflammation, help lower blood pressure and manage type two diabetes.
The researchers found that eating walnuts led to an increase in proteins such as albumin levels. Albumin is protein in blood plasma. Dr Bobrovskaya said: "While more supporting research is needed, evidence is becoming clear that consuming walnuts as a healthy eating pattern may have positive effects on cognition and mental health, potentially owing to their abundance in omega-3 content.
“Furthermore, research has shown that increasing dietary tryptophan, which the brain uses to make serotonin (a natural mood stabiliser), results in reduced symptoms of anxiety and depression. Thus, the presence of tryptophan in walnuts may have also contributed to these findings.”
Yet the researchers stress that the results could have been influenced by the Covid-19 pandemic, as clinical visits were disrupted during this time. Further work is now needed to improve the understanding of the complex pathways through which eating walnuts can influence the brain or affect mental health.
Mauritz Herselman, a PhD student who worked on the study, said: “We’ve always known walnuts to be a health-promoting food, but because of the design and length of this study, the findings really paint a picture of how a simple food like walnuts can help combat stress.”
Adding walnuts to daily eating patterns could be one small, versatile, simple, and accessible dietary change to promote brain health and overall well-being in university-aged students.
The study was published in the journal Nutrients and was co-funded by the University of South Australia and the California Walnut Commission.
