Approved Research

Association between consumption of ultra-processed foods and Parkinson's disease

Lay summary

Neurological diseases are now the leading cause of disability in the world. Of these, Parkinson's disease (PD) is the fastest growing, surpassing Alzheimer's disease. Between 1990 and 2015, the prevalence of PD more than doubled, and disability and death attributable to PD have also increased. The Global Burden of Disease Study currently estimates that 6.2 million people currently have PD. Because patients with PD had lower activities of daily living and quality of life, patients will require care as symptoms progress. Because the incidence of PD increases sharply with age and because the world's population is aging, the number of individuals affected and caregivers are exposed for exponential growth which is called "Parkinson pandemic". Thus, there is an urgent need to elucidate the pathogenesis of PD and development treatment methods. However, the pathogenesis of PD remains unclear, but several lines of evidence have indicated the involvement of central and peripheral inflammation in pathological processes. Furthermore, there is the idea, based on Braak hypothesis, that Lewy pathology, the pathological hallmark of PD, begins in enteric nervous system and spreads to brainstem in a retrograde manner, which highlights the importance of the colon as the place of aggregates of Lewy bodies. Inflammatory bowel disease was demonstrated to be a risk factor of PD in a previous meta-analysis and shared genetic effects of LRRK2 between Crohn's disease and PD risk. These findings suggested important relationship of colonic inflammation resulting altered gut microbiota to PD.

Ultra-processed foods (UPF; e.g., soft drinks, flavorful snacks) have received a lot of attention. They are highly palatable, have a long shelf-life and relatively inexpensive, and can be consumed anytime, and anywhere. However, they are not nutritionally superior. The consumption of UPF is high in many high income countries. For example, the percentage of energy intake from UPF is 29.1% in France, 42% in Australia and 57.9% in the USA. High consumption of UPF can change the gut microbiota and lead to inflammation. Based on accumulating evidence suggested the links between colonic inflammation and PD, consumption of UPF may be associated with onset and development of PD. If we understand the link between UPF consumption and PD, dietary interventions may prevent or suppress the onset or development of PD.