Effects of dietary supplements, foods, and dietary patterns in Parkinson's disease: meta-analysis and systematic review of randomized and crossover studies.

BACKGROUND: Diet significantly impacts Parkinson's disease (PD) with plausible biological hypotheses. Although the thesis has been explored in several human clinical trials, no current meta-analyses or reviews summarize the results. We examined the effect of intervention of dietary supplements, foods, and dietary patterns in treating PD. METHODS: We conducted a meta-analysis and systematic review of randomized and crossover studies published between 1989 and 26 June 2022, searching from PubMed, Embase, Medline, Scopus, Cochrane Library databases, and Chinese databases. Twenty-four studies were included in this review. RESULTS: The meta-analysis results show that dietary supplements intervention significantly increased the quantitative insulin sensitivity check index (QUICKI) [MD = 0.02, 95% CI (0.01, 0.02), p < 0.00001]. Dietary supplement intervention does not significantly affect the total Unified Parkinson Disease Rating Scale (UPDRS) score and six-min walk test (6MWT) distance. We did not find evidence that dietary supplements or food intervention may minimize the UPDRS III score. However, systematic review results indicated that the Mediterranean, low-fat, and ketogenic diets significantly reduced the total UPDRS score; low-protein diets meaningfully mitigated motor symptoms. CONCLUSIONS: This meta-analysis result displays that diet and diet supplements had a very modest but statistically significant impact on QUICKI but no effect on motor and non-motor symptoms in PD. The systematic review concludes that dietary patterns intervention may positively attenuate the overall symptoms of PD, including both motor and non-motor symptoms.

Effect of fruit intake on functional constipation: A systematic review and meta-analysis of randomized and crossover studies.

Functional constipation (FC) is commonly treated with fruits whose efficacy remains unclear. We conducted a meta-analysis of fruit intervention for FC and provided evidence-based recommendations. We searched seven databases from inception to July 2022. All randomized and crossover studies on the effectiveness of fruits on FC were included. We conducted sensitivity and subgroup analysis. A total of 11 studies were included in this review. Four trials showed that kiwifruits have significantly increased stool frequency (MD = 0.26, 95% CI (0.22, 0.30), P < 0.0001, I2 = 0%) than palm date or orange juice in the fixed-effect meta-analysis. Three high-quality studies suggested that kiwifruits have a better effect than ficus carica paste on the symptom of the FC assessed by the Bristol stool scale in the fixed-effect meta-analysis [MD = 0.39, 95% CI (0.11, 0.66), P < 0.05, I 2 = 27%]. Besides, five trials showed that fruits can increase the amount of Lactobacillus acidophilus [MD = 0.82, 95% CI (0.25, 1.39), P < 0.05, I 2 = 52%], analyzed with the random-effect model. Subgroup meta-analysis based on the types of fruits suggested that fruits including pome fruit, citrus fruit, and berries have increased the effect of Bifidobacterium t more than the stone fruits in the random effect meta-analysis [MD = 0.51, 95% CI (0.23, 0.79), P < 0.05, I 2 = 84%]. Totally, fruit intake may have potential symptom alleviation on the FC as evidence shows that they can affect stool consistency, stool frequency, and gut microbiota. Further large-scale studies are needed to gain more confident conclusions concerning the association between fruit intake and FC in the future.