Can dietary modifications improve symptoms of Obsessive-Compulsive Disorder (OCD) and anxiety?

From the Guidelines

Dietary modifications, specifically adopting a Mediterranean diet rich in anti-inflammatory foods and those supporting gut health, can improve symptoms of Obsessive-Compulsive Disorder (OCD) and anxiety. This approach is supported by recent evidence indicating that diet has a critical role in the treatment of depression, with the Mediterranean diet being the most studied and showing significant improvements in symptoms of depression and anxiety 1. The Mediterranean diet, characterized by high intake of vegetables, fruits, legumes, whole grains, nuts, seeds, and olive oil, and low intake of red meat, has been shown to alleviate symptoms of depression and may have a similar effect on OCD and anxiety.

Key components of the diet that may contribute to its beneficial effects on mental health include:

• Omega-3 fatty acids found in fatty fish, flaxseeds, and walnuts, which have anti-inflammatory properties
• Probiotic-rich foods like yogurt, kefir, sauerkraut, and kimchi, which support gut microbiome health
• Complex carbohydrates from whole grains, fruits, and vegetables, which help regulate serotonin levels and affect mood and anxiety
• Magnesium-rich foods such as dark leafy greens, nuts, and seeds, which may help reduce anxiety symptoms

It is also important to reduce consumption of:

• Caffeine
• Alcohol
• Refined sugars
• Highly processed foods, as these can exacerbate anxiety and OCD symptoms

Maintaining stable blood sugar levels by eating regular meals with balanced protein, healthy fats, and complex carbohydrates can prevent mood fluctuations. While diet alone is not typically sufficient to treat clinical OCD or anxiety disorders, these dietary changes can complement traditional treatments like medication and therapy by reducing inflammation, supporting neurotransmitter production, and promoting overall brain health 1.

In contrast to other dietary approaches like the low FODMAP diet, which may have some benefits for gastrointestinal symptoms but limited evidence for psychological symptoms, the Mediterranean diet offers a more balanced and sustainable approach to improving mental health outcomes 1. Therefore, adopting a Mediterranean diet is a recommended dietary modification for improving symptoms of OCD and anxiety, given its strong evidence base and potential for beneficial effects on both mental and physical health.

From the Research

Dietary Modifications and Obsessive-Compulsive Disorder (OCD) and Anxiety

• There is evidence to suggest that dietary modifications can improve symptoms of anxiety, which is often comorbid with Obsessive-Compulsive Disorder (OCD) 2, 3, 4, 5, 6
• A scoping review found an association between less anxiety and more fruits and vegetables, omega-3 fatty acids, "healthy" dietary patterns, caloric restriction, breakfast consumption, ketogenic diet, broad-spectrum micronutrient supplementation, zinc, magnesium and selenium, probiotics, and a range of phytochemicals 2
• A systematic review of observational studies found that high total intake of fruits and vegetables may promote higher levels of optimism and self-efficacy, as well as reduce the level of psychological distress, ambiguity, and cancer fatalism, and protect against depressive symptoms 3
• A systematic review of randomised controlled trials found some evidence for dietary interventions improving depression outcomes, although the evidence for anxiety outcomes was limited 4
• A study found that diet quality was significantly worse among subjects with a current depressive or anxiety disorder than among healthy controls, and that more chronic depression or anxiety disorders and increased severity were associated with poorer diet quality 6
• The Western diet, which is high in processed and refined foods, has been linked to a higher risk of depression and anxiety, while a low-glycemic, modified Mediterranean diet rich in fruits, vegetables, whole grains, and seafood has been recommended for optimizing mental health 5

Key Dietary Components

• Fruits and vegetables: high intake associated with reduced anxiety and depressive symptoms 2, 3
• Omega-3 fatty acids: associated with reduced anxiety symptoms 2
• "Healthy" dietary patterns: associated with reduced anxiety symptoms 2
• Probiotics: associated with reduced anxiety symptoms 2
• Zinc, magnesium, and selenium: associated with reduced anxiety symptoms 2
• Whole grains: recommended as part of a low-glycemic, modified Mediterranean diet for optimizing mental health 5
• Seafood: recommended as part of a low-glycemic, modified Mediterranean diet for optimizing mental health 5

Limitations and Future Directions

• Many of the studies included in the reviews were observational or had methodological limitations, and therefore more high-quality intervention studies are needed to confirm the findings 2, 3, 4
• The evidence for the impact of dietary modifications on OCD symptoms is limited, and more research is needed in this area 2, 3, 4, 5, 6