This study evaluates the effects of the DASH diet, Mediterranean diet, WCRF/AICR diet, hPDI diet, AHEI-2010, and pro-inflammatory or anti-inflammatory diets on chronic pelvic floor dysfunction diseases (PFD). Two authors conducted literature searches in PubMed, Web of Sciences, and Embase for relevant publications up to August 2024. The systematic search employed both Medical Subject Headings (MeSH) and non-MeSH keywords, including the following terms in titles and abstracts: “DASH” OR “Diet, Sodium-Restricted” OR “Dietary Approaches to Stop Hypertension” OR “Mediterranean diet” OR “Diet, Mediterranean” OR “Healthful Plant-Based Diet Index” OR “Diet, Vegetarian” OR “hPDI” OR “pro-inflammatory diet” OR “Anti-Inflammatory Diet” OR “dietary inflammatory index” AND “pelvic floor dysfunction” OR “pelvic floor disorder” OR “pelvic organ prolapse” OR “urinary incontinence” OR “fecal incontinence” OR “bladder storage” OR “lower urinary tract symptoms” OR “sexual dysfunction” OR “chronic pelvic pain”. The subsequent literature screening process is shown in Figure 1.

Study eligibility was defined according to the Participant, Intervention, Comparator,

Outcome, Study type (PICOS) framework (11). The authors reviewed the titles and abstracts of all identified articles, selecting studies that met the following inclusion criteria: (1) full text available; and (2) studies assessing the relationship between dietary patterns (in cohort studies) or dietary interventions (in trials) and relevant outcomes (e.g., sexual function scores, lower urinary tract symptom scores).

Both cross-sectional and prospective studies were included. As cross-sectional studies provide a broad overview of the population, while prospective studies offer evidence of causality. By combining both study types, this review compensates for the limitations of each individual design, offering more reliable evidence regarding the link between healthy dietary patterns and PFD.

Data extracted from each study included the following: reference (author, year), country, population details (clinical characteristics, sample size, age, and follow-up time), dietary assessment tools and their main relevant features, outcomes, and adjustments for potential confounders. When reporting multivariate models, the model containing the most appropriate set of potential confounders was selected.

For cross-sectional studies, the primary outcome was usually the odds ratio (OR). For prospective studies, the primary outcome was the mean ± standard deviation (SD).

The risk of bias was evaluated using the Newcastle-Ottawa Scale (NOS) for non-randomized controlled trials (non-RCTs) (Table 1), and the Cochrane risk assessment tool was employed for RCTs (12). The NOS uses a scoring system with a maximum score of 9 points, where a score of 7–9 indicates a low risk of bias, and a score of 4–6 indicates a high risk of bias.

Two reviewers independently assessed each study’s quality. Discrepancies were resolved through discussion and major disagreements were brought to a third reviewer to reach a consensus.

Only studies meeting the inclusion criteria were included in the meta-analysis. Statistical analyses were independently performed by two authors using Review Manager version 5.4 (The Cochrane Collaboration, Software Update, Oxford, London). Discrepancies in results were discussed and resolved by a third author. Continuous variables were compared using means and standard deviations, while dichotomous variables were compared using odds ratios (OR). Results are presented as OR or standard mean differences (SMD) with 95% confidence intervals. To standardize the effects of different dietary patterns on urinary incontinence and fecal incontinence, inverse transformation was applied to the pro-inflammatory diet data. The level of significance was set at p < 0.05. Heterogeneity was assessed using the Higgins I² statistic. The results are presented in a forest plot.

Nine studies were included in the analysis of sexual dysfunction, with detailed characteristics shown in Table 2. These studies consisted of 5 cross-sectional studies and 4 prospective studies, focusing on 6 studies related to the Mediterranean diet, 1 study on pro-inflammatory diets, and 2 studies on healthy plant-based diets (hPDI). To standardize the direction of the dietary effects on sexual dysfunction, data from the pro-inflammatory diet studies were reverse-transformed to align with the overall dietary pattern effect. Except for Ruan et al.’s study, all studies assessed dietary intake using food frequency questionnaires (FFQ). For sexual dysfunction assessment, the majority of studies (except 4) used the IIEF-5 and FSFI for male and female sexual function, respectively, where higher scores indicated better sexual function. To ensure consistency across prospective studies, mean results were converted to negative values. All cross-sectional studies utilized multivariable regression analysis to control for potential confounders.

On the Newcastle-Ottawa Scale (NOS) for quality assessment, the average score of the studies was 8.1 points. Two studies achieved the maximum score of 9, eight studies scored 8, and one study scored 7, indicating high methodological quality (Figure 2).

Figure 3 presents the results of five cross-sectional studies. With the exception of the hPDI diet, which did not show a significant improvement in sexual dysfunction, the other four studies demonstrated relatively consistent results (fixed-effect model: OR = 0.69, 95% CI [0.55, 0.85]), with low heterogeneity (I² = 0%) (Supplementary Figure 1). These results indicate that the Mediterranean and pro-inflammatory diets are significantly associated with a lower risk of sexual dysfunction.

Fantus et al. analyzed data from the 2001–2004 National Health and Nutrition Examination Survey (NHANES) in the United States, including men aged 18–85 who completed the prostate and 2-day dietary questionnaires. Among 4,027 participants, 1,085 adhered to the Mediterranean diet, while 2,942 followed a non-restrictive diet. This study found no significant difference in the prevalence of erectile dysfunction between the two groups (OR 0.75, 95% CI 0.36–1.57).

Giugliano et al. conducted a survey in 2010 among men and women with type 2 diabetes in Campania, southern Italy. Participants were divided into three groups based on the Mediterranean diet score by Trichopoulou et al.: low (0–3 points), medium (4–5 points), and high (6–9 points). Men in the highest score group (n = 133) had a lower prevalence of erectile dysfunction than those in the lowest score group (n = 155) (50.3% vs. 62.6%). Similarly, women in the highest score group (n = 149) had a lower prevalence of sexual dysfunction compared to those in the lowest score group (n = 166) (48.9% vs. 57.5%).

Ruan et al. analyzed data from the 2001–2004 NHANES, including 3,693 men. The findings showed that men in the highest DII tertile had a higher risk of erectile dysfunction compared to those in the lowest DII tertile (OR = 1.12, 95% CI 1.04–1.19), suggesting that inflammatory dietary patterns may increase the risk of erectile dysfunction.

Figure 4 displays the combined results of four prospective studies, with an overall standardized mean difference (SMD) of −0.6 (95% CI [−1.02, −0.17]). This indicates greater improvements in sexual function in the intervention groups adhering to healthy dietary patterns compared to the control groups. However, substantial heterogeneity was observed (I² = 87%) due to variations in participant characteristics and study design. Our sensitivity analysis revealed that the two studies by Esposito et al. (24, 25) were the primary contributors to the heterogeneity. When these two studies were removed, the analysis of the remaining studies showed a consistent, positive effect with no heterogeneity (SMD = −0.25, 95% CI [−0.49, −0.01], I² = 0%) (see Supplementary Figure 2).

Esposito et al. conducted a 2-year prospective RCT in 2006 involving 65 men with metabolic syndrome. Participants were divided into a Mediterranean diet intervention group (n = 35) and a control group (n = 30). After 2 years, the Mediterranean diet group showed a significant improvement in the IIEF scores, increasing from 14.4 ± 3.8 to 18.1 ± 4, whereas the control group showed only a minimal increase from 14.9 ± 3.7 to 15.2 ± 3.5. These results suggest that the Mediterranean diet significantly improves erectile function.

In a 2007 RCT, Esposito et al. examined 59 women with metabolic syndrome, allocating 31 to a Mediterranean diet intervention group and 28 to a control group. After 2 years, the Mediterranean diet group demonstrated a significant improvement in FSFI scores, increasing from 19.7 ± 3.1 to 26.1 ± 4.1 (P = 0.01), while the control group showed no significant changes. These findings indicate that the Mediterranean diet significantly enhances sexual function in women with metabolic syndrome.

Loeb et al. conducted a prospective cohort study involving 3,505 participants with non-metastatic prostate cancer. The median time from prostate cancer diagnosis or treatment to the first quality-of-life assessment was 7 years. The study results indicated that a high intake of the hPDI was associated with a lower risk of sexual dysfunction. Participants in the highest hPDI quintile had a mean EPIC sexual function score of 6.11 ± 5.69, compared to 6.73 ± 5.47 in the lowest quintile (higher scores indicate worse sexual function).

Maiorino et al. conducted an 8.1-year RCT involving 215 newly diagnosed type 2 diabetes patients, randomly assigned to a Mediterranean diet group (n = 108) or a low-fat diet group (n = 107). At the end of the trial, declines in IIEF and FSFI scores were significantly smaller in the Mediterranean diet group compared to the low-fat diet group (1.22 vs. 1.18; P = 0.024 and P = 0.019, respectively). These findings indicate that the Mediterranean diet slows the deterioration of sexual function more effectively than a low-fat diet.

A total of six studies on incontinence were included, comprising three cross-sectional studies and three prospective studies. The characteristics of these studies are shown in Table 2. Among these, two studies focused on the DASH diet, three on pro-inflammatory diets, and one on the healthy plant-based diet (hPDI). With the exception of the study by Li et al., all studies used urgency urinary incontinence (UUI) as the primary outcome variable. Multivariable regression analysis was employed in all cross-sectional studies to control for potential confounders and assess the relationship between dietary patterns and urinary or fecal incontinence.

The results of the three cross-sectional studies are presented in Figure 5. Dietary Inflammatory Index (DII) scores were significantly associated with urinary and fecal incontinence, suggesting that reducing pro-inflammatory components in the diet may help lower the prevalence of these conditions (fixed-effect model: OR = 0.77, 95% CI [0.68, 0.87], I² = 0%).

Li et al. analyzed data from 11,747 participants in the 2005–2010 NHANES database, dividing participants into quartiles based on DII scores (Q1 < 0.47; Q4 > 2.71). Participants in the highest quartile (Q4) had a significantly increased risk of fecal incontinence (FI) compared to those in the lowest quartile (Q1) (OR = 1.49, 95% CI [1.04–2.14]).

Similarly, Zhang et al. analyzed data from 3,230 women under the age of 65 in the 1999-2016 NHANES and found that women in the highest DII quartile had a significantly higher risk of UUI compared to those in the lowest quartile (OR = 1.24, 95% CI [1.07–1.44]).

Liao et al. analyzed data from 2,993 men in the NHANES dataset and found that the highest DII quintile was associated with a significantly increased risk of lower urinary tract symptoms compared to the lowest quintile (OR = 1.43, 95% CI [1.01–2.03]).

Figure 6 displays the combined results of three prospective studies, showing an overall standardized mean difference (SMD) of −0.17 (95% CI [−0.38, 0.04]) for participants adhering to healthy dietary patterns. While there was a trend toward improvement in urinary incontinence with healthy diets, the results were not statistically significant, and substantial heterogeneity was observed among the studies (I² = 60%). This moderate heterogeneity likely stems from the stark differences in the study populations and dietary interventions assessed.

Loeb et al. conducted a prospective cohort study and found no significant association between hPDI intake and urinary incontinence, with urinary incontinence scores on the Expanded Prostate Cancer Index Composite being 1.96 ± 4.33 and 2.16 ± 4.38 for the highest and lowest quintile groups, respectively (P = 0.14).

In contrast, two prospective studies by Matsuo et al. investigated the effect of reducing salt intake on urinary symptoms in patients with baseline high salt intake. While focusing on a single nutrient, these studies were included because sodium restriction is the cornerstone of the DASH diet, one of our target dietary patterns. Thus, these studies provide direct evidence on a key active component of this pattern. The study included patients who urinated at least once per night and had excessive salt intake (≥8 g/day for men, ≥7 g/day for women). Of the participants, 223 successfully reduced salt intake (S group), while 98 failed to reduce intake (F group). The urgency urinary incontinence score in the S group improved from 0.7 ± 0.9 to 0.6 ± 0.9 (P = 0.001), whereas the score in the F group worsened from 0.6 ± 0.9 to 0.9 ± 0.9. These findings indicate that reducing salt intake can improve urinary incontinence.

In a 2021 study, Matsuo et al. conducted another 12-week trial focusing on patients with overactive bladder (OAB) and excessive salt intake (≥8 g/day for men, ≥7 g/day for women). Among 98 participants, 71 successfully reduced salt intake (R group), while 27 did not (N-R group). At the end of the trial, the urgency incontinence score on the OABSS questionnaire decreased from 1.3 ± 1.0 to 1.1 ± 1.0 in the R group, with no significant changes observed in the N-R group. These findings suggest that reducing salt intake alleviates urgency urinary incontinence in patients with OAB.