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Key points
- Brain disorders are the leading cause of illness and disability, affecting a third of the world’s population.
- The world’s consumption of animal products significantly contributes to pollution and global climate change.
- Healthy dietary choices and less animal consumption can improve brain health while slowing climate change.
Brain disorders are now the leading cause of illness and disability, affecting over one-third of the world’s population. As the population continues to grow and age, this burden is expected to further increase in the coming decades. Therefore, brain health has become a global priority. Healthy dietary change is now recognized as a key strategy to improve population health since poor diet is a major contributor to the global burden of disease
Healthy dietary choices, especially eating much less animal products, would also contribute greatly to environmental sustainability and climate change mitigation. The world’s consumption of animal products significantly contributes to environmental pollution through methane emissions, water contamination, and land degradation, making cattle farming a major ecological concern. Cows are major producers of methane, a potent greenhouse gas approximately 23 to 28 times more effective than carbon dioxide at trapping heat over a century. Globally, given that there are over 1.5 billion cows, 1.3 billion sheep, 14 billion chickens, and 1 billion pigs worldwide, livestock accounts for about 20 percent of greenhouse gas emissions, with cattle contributing the majority. Their manure contaminates rivers and streams with pathogens and organic matter, leading to algal blooms, oxygen depletion, and the death of aquatic life. Cattle farming also drives deforestation, particularly in regions like the Amazon, to create pastureland or grow feed crops such as soybeans.
Therefore, one potential path to reduce the impact of global climate change involves a significant change in the human diet. In 2019, the EAT–Lancet Commission (a collaboration between a science-based global platform for food system transformation and The Lancet, a leading medical journal) proposed the Planetary Health Diet to promote both human and environmental health (Willett and team, 2019). This diet mainly consists of plant-rich foods, such as whole grains, fruits, and vegetables, and only small amounts of animal-based foods.
Previous studies have shown that adherence to the Planetary Health Diet resulted in a decreased risk of cardiovascular disease, hypertension, asthma, and mortality. A recent study investigated whether the Planetary Health Diet also benefits brain health. The authors (Li and team, 2026) examined a large dataset from the UK Biobank (Sudlow and team, 2015) to determine the relationship between the Planetary Health Diet and brain disorder risk
They reported that the highest adherence to the Planetary Health Diet was associated with a 12%, 13 %, 13 %, and 19 % lower risk of stroke, depression, anxiety, and multimorbidity, respectively, and had a significant role in decelerating biological aging. Their analyses discovered an inverse relationship between the Planetary Health Diet and these common brain disorders. The link between the Planetary Health Diet and brain disorder risk was more pronounced in adult males under 65 years of age. The mechanistic reasons why compliance with the Planetary Health Diet lowers brain disorder risk are not fully understood; however, this diet shares many features of the Mediterranean diet that are also associated with prevention of cardiovascular disease and cognitive aging. The dietary components of both diets are rich in antioxidants and polyphenols that have the potential to inhibit neuroinflammation in relation to brain disorders and attenuate neuroinflammation via indirect immune pathways from the gut microbiome and systemic circulation [to read more about this topic, see: Your Brain on Food].
There are, however, some important caveats that should be considered. The authors estimate that over one billion people worldwide may not be able to afford the EAT–Lancet diet (Springmann and team,2021), and iron and zinc inadequacies and deficiencies are common among individuals with high consumption of plant-rich foods (Beal and team, 2023). However, these findings provide convincing evidence that it is possible to reduce brain disorder risk, slow down age-related decline, and advance food system sustainability to reduce global climate change.
- What are healthy approaches to dieting?
- Take our Healthy Lifestyle Test
- Find a health professional
Li X, et al., (2026) Planetary health diet benefits brain health by decelerating biological aging. Journal of Affective Disorders 397: 120975. https://doi.org/10.1016/j.jad.2025.120975
Willett W, et al., (2019) Food in the Anthropocene: the EAT–lancet commission on healthy diets from sustainable food systems. Lancet 393 (10170), 447–492
Sudlow C, et al., (2015) UK biobank: an open access rees of middle and old age. PLoS Med. 12 (3), e1001779
Springmann M et al., (2021) The global and regional costs of healthy and sustainable dietary patterns: a modelling study. Lancet Planet Health 5 (11), e797–e807
Beal T, et al., (2023) Estimated micronutrient shortfalls of the EAT-lancet planetary health diet. Lancet Planet Health 7 (3), e233–e237
