Bruno Bizzozero-Peroni

ISNPR member Bruno Bizzozero-Peroni won the ISNPR Outstanding Publication award for round 2 2025 for their study ‘Plant-Based Diets and Mental and Neurocognitive Health Outcomes: A Systematic Review With Meta-Analysis’, published in Nutrition Reviews

Bruno shares some details about their study.

Plant-based eating has become increasingly popular around the world. Many people choose it for health, environmental, or ethical reasons-but what does it mean for our mental and cognitive well-being? Surprisingly, although plant-based diets are often discussed in the context of heart health or chronic disease, their potential impact on mental health has remained unclear. Our new publication set out to change that.

In this study, we conducted the largest and most comprehensive review to date on how different types of plant-based diets relate to mental and neurocognitive health in adults. Rather than treating all plant-based diets as equal, we made a key distinction: healthy plant-based diets rich in vegetables, fruits, whole grains, legumes, nuts, and minimally processed plant foods-and unhealthy plant-based diets, which contain more refined grains, added sugars, and ultra-processed plant products.

We analyzed findings from 23 observational studies, including more than 700,000 adults from diverse populations. What we found was striking. People who adhered most closely to healthy plant-based diets were less likely to experience anxiety, depression, and psychological distress. Over longer periods (7 to 20 years of follow-up), they also had a lower risk of cognitive decline and dementia. In contrast, diets high in unhealthy plant-based foods were linked with a higher likelihood of depression and anxiety.

Why might diet quality matter so much? Healthy plant-based foods are rich in fiber, antioxidants, vitamins, healthy fats, and phytochemicals that may reduce inflammation, support vascular and metabolic health, nourish the gut microbiome, and ultimately influence brain function. Unhealthy plant-based diets, on the other hand, may contribute to blood sugar instability, inflammation, and exposure to additives that could negatively affect mental well-being.

While our findings are promising, we also emphasize caution. The overall certainty of the evidence was low to very low, mainly because many studies relied on self-reported diet and mental health measures, and only a few used clinical assessments. More high-quality, long-term studies are essential.

Still, the takeaway is clear: not all plant-based diets are created equal. Choosing nutrient-dense, minimally processed plant foods may support both mental and cognitive health-and represent an accessible, complementary approach to prevention.