Researchers are taking this basic information and studying the impact of different diets on various mental health issues. They are discovering that diets including whole foods and various nutrients, such as those recommended in the Mediterranean, Japanese and Norwegian diets, can have a positive impact on many pathologies. They also find that high-quality vitamin and mineral supplements, as well as amino acids, herbal formulations and probiotics, can also help. (For recent clinical guidelines on this topic, see Sarris, J., et al., The World Journal of Biological Psychiatry, Flight. 23, no. 6, 2022).
Depression is the most widely studied condition in this research, with studies showing that better nutrition can help people with both non-clinical and clinical levels of the illness. For example, a meta-analysis of 16 randomized controlled trials, primarily in samples of people with nonclinical depression, found that dietary interventions significantly reduced depressive symptoms although they had less effect on anxiety , discovered Joseph Firth, PhD, of the University of Manchester. in the United Kingdom, and his colleagues (Psychosomatic medicine, Flight. 81, no. 3, 2019).
Similarly, a randomized controlled trial led by South Australia-based psychologist Natalie Parletta, PhD, and colleagues revealed the positive effects of a healthy dietary intervention in adults with self-reported depression. Ninety-five participants received either 3 months of bi-weekly cooking classes including a Mediterranean diet and 6 months of fish oil supplements, or 3 months of fun and stimulating bi-weekly social groups plus an additional 3 months of fish oil supplements.
All participants’ moods improved after 6 months, but the diet group did better: Their depression scores dropped by 45%, compared to 26.8% in the social group. Additionally, the reduction in depression in the dieting group was linked to specific types of dietary intake, including eating a diversity of vegetables, eating nuts, and overall adherence to a Mediterranean diet (Nutritional neuroscience, Flight. 22, no. 7, 2019).
According to other studies, a high-quality diet also appears to have a positive effect on people with major depressive disorder. In a randomized controlled trial known as SMILES (Supporting the Modification of Lifestyle in Lowered Emotional States), psychiatric epidemiologist Felice N. Jacka, PhD, director of the Food & Mood Center at the Institute for Mental and Physical Health and clinical translation (IMPACT). at Deakin University in Victoria, Australia, and colleagues tested two interventions on adults with major depressive disorder. Thirty-three participants received seven individual nutritional counseling sessions from a clinical dietitian, and another 34 participants received seven visits from trained staff who “befriended” them, who discussed nutritional topics with them. interest and engaged with them in fun and positive activities. After 12 weeks, 32.3% of people in the diet group reported no symptoms of depression, compared to 8% of those in the social support group (BMC Medicine, Flight. 15, no. 1, 2017). Similar results were found in a randomized controlled trial led by Jessica Bayes, PhD, of the University of Technology Sydney in Australia, and colleagues, who showed that a 12-week Mediterranean diet intervention further improved symptoms of moderate to severe depression in young men than a friendship. intervention (The American Journal of Clinical Nutrition, Flight. 116, No. 2, 2022).
Another condition showing promise with nutritional interventions is ADHD, a major focus of Rucklidge’s work. In 2014, she and colleagues conducted the first blinded randomized controlled trial to examine the effects of a micronutrient supplement on adults with ADHD.
Compared to the 38 participants who took a placebo, 42 participants who took the formula reported having fewer ADHD symptoms, including inattention, hyperactivity and impulsivity, after 8 weeks. Additionally, among participants who had moderate to severe depression at the start of the study, those who took the supplement were significantly more likely to report an improvement in their mood at the end of the study than those who took the placebo. But there were no differences between groups in clinicians’ ratings of ADHD (The British Journal of Psychiatry, Flight. 204, no. 4, 2014).
In a second blinded randomized controlled trial, Rucklidge and colleagues compared how untreated children with an ADHD diagnosis fared over 10 weeks when given a placebo or a broad-spectrum micronutrient formula.
At the end of the study, 32% of children taking the supplement showed clinically significant improvement in inattention symptoms, compared to 9% of children taking the placebo. They also showed greater improvements in emotional regulation, aggression, and general functioning (The Journal of Child Psychology and Psychiatry, Flight. 59, no. 3, 2018).
These findings were replicated in another randomized controlled trial led by psychologist Jeanette M. Johnstone, PhD, of Oregon Health and Science University in Portland. Over an 8-week period, 135 untreated children with ADHD at three sites: Portland, Oregon; Columbus, Ohio; and Alberta, Canada, received either a placebo or a broad-spectrum multinutrient containing all known essential vitamins and minerals.
More than half of those who received the formula (54%) experienced an overall improvement in their symptoms, compared to 18% of controls, based on clinicians’ blinded assessments. The results also suggest another potential benefit: Children receiving the formula grew six millimeters in 8 weeks compared to children taking the placebo when other baseline factors were controlled. This is a potentially important finding because height suppression can be a problem with standard ADHD medications, Johnstone noted (Journal of the American Academy of Child and Adolescent Psychiatry, Flight. 61, no. 5, 2022).
Others are also studying the effects of nutritional interventions on more serious conditions, including bipolar disorder, eating disorders and psychotic disorders, as well as autism. They also study the effects of particular types of diets and foods on some of these disorders. These include the potential impacts of the ketogenic (low-carb, high-fat) diet on bipolar disorder (Campbell, IH and Campbell, H., BJPsych Open, Flight. 5, no. 4, 2019) and Alzheimer’s disease (Phillips, MCL et al., Alzheimer’s disease research and therapy, Flight. 13, no. 51, 2021), and a gluten-free diet as an adjunct treatment for people with schizophrenia (Levinta, A., et al., Advances in nutrition, Flight. 9, no. 6, 2018). While all of these areas show promise, more research is needed to demonstrate their effectiveness, according to these studies.
The researchers conducting this work also say it raises questions about what constitutes good treatment in general, including what kinds of outcomes providers should be looking for.
For example, while Rucklidge’s study of children with ADHD found improvements in symptoms such as inattention, there were no group differences in parent and teacher reports of hyperactivity and impulsivity, some of the main characteristics of the disorder. But parents and teachers have seen an increase in other positive outcomes that aren’t specifically linked to ADHD symptoms, like reduced anger and a greater ability to regulate one’s emotions and cope with stressors.
Additionally, the children in the study did not have to deal with the side effects that can sometimes occur with traditional ADHD medications, such as dizziness, mood swings, loss of appetite and sleep disorders. Instead, by implementing nutritional interventions that do not cause these side effects, some children may improve their functioning and learn better. “So when we think about treatments for these kids, I really encourage a more holistic approach,” Rucklidge said. In fact, she sought and received approval from Pharmac, New Zealand’s equivalent of the Food and Drug Administration, for practitioners to prescribe the micronutrient formula used in her studies as a second-tier treatment. So, if conventional medications haven’t worked or have intolerable side effects, practitioners can try these supplements instead. (There are still many steps to go through before Pharmac actually pays for use of the formula, however, Rucklidge noted.)
