Plant-based diet index and erectile dysfunction in the Health Professionals Follow-Up Study

Plant-based diets, animal agriculture, and the connection with urological and planetary health

PURPOSE OF REVIEW

We summarize the latest evidence regarding the impact of plant-based diets on urological and planetary health to facilitate patient counseling and research regarding dietary intervention.

RECENT FINDINGS

Studies have highlighted the association of plant-based diets with a lower risk of multiple urological conditions including prostate cancer, erectile dysfunction, benign prostatic hyperplasia, and nephrolithiasis, as well as benefits for planetary health.

SUMMARY

Plant-based diets are associated with numerous benefits that co-promote urological and planetary health.

Plant-based diet associated with better quality of life in prostate cancer survivors

BACKGROUND

Plant-based diets have many health benefits, including a lower risk of fatal prostate cancer, and greater environmental sustainability. However, less is known regarding the impact of plant-based diets on quality of life among individuals diagnosed with prostate cancer. The authors' objective was to examine the relationship between plant-based diet indices postdiagnosis with quality of life.

METHODS

This prospective cohort study included 3505 participants in the Health Professionals Follow-Up Study (1986-2016) with nonmetastatic prostate cancer. Food-frequency questionnaires were used to calculate overall and healthful plant-based diet indices. Quality-of-life scores were calculated using the Expanded Prostate Cancer Index Composite. Generalized estimating equations were used to examine associations over time between plant-based diet indices and quality-of-life domains (sexual functioning, urinary irritation/obstruction, urinary incontinence, bowel functioning, hormonal/vitality), adjusted for demographics, oncologic history, body mass index, caloric intake, health-related behaviors, and comorbidities.

RESULTS

The median age at prostate cancer diagnosis was 68 years; 48% of patients underwent radical prostatectomy, and 35% received radiation as primary therapy. The median time from diagnosis/treatment to first the quality-of-life questionnaire was 7.0 years. A higher plant-based diet index was associated with better scores for sexual function, urinary irritation/obstruction, urinary incontinence, and hormonal/vitality. Consuming more healthful plant-based foods was also associated with better sexual and bowel function, as well as urinary incontinence and hormonal/vitality scores in the age-adjusted analysis, but not in the multivariable analysis.

CONCLUSIONS

This prospective study provides supportive evidence that greater consumption of healthful plant-based foods is associated with modestly higher scores in quality-of-life domains among patients with prostate cancer.

Scoping review of the association of plant-based diet quality with health outcomes

Introduction

The association of plant-based dietary patterns with health outcomes has traditionally been assessed without considering nutritional value. The plant-based dietary index (PDI), first published in 2016, overcomes this limitation with both a healthful PDI (hPDI) and an unhealthful PDI (uPDI), based on the quality of plant foods consumed plus the frequency of animal foods. We sought to summarize the breadth of research using the hPDI and uPDI to gain insight into how the quality of plant-based dietary patterns might be associated with health outcomes.

Methods

Scoping review of studies that used the PDI, hPDI, or uPDI to report associations with health outcomes. Multiple databases were searched from 2010 through April 2023 with 2 authors independently assessing eligibility and extracting data. In addition to assessing the association of the indices to health outcomes, we determined the frequency of concordant or discordant findings for hPDI versus PDI and for hPDI versus uPDI.

Results

We included 95 articles (54% longitudinal, 37% cross-sectional, and 9% case-control) with a median sample size of 3,646. Higher hPDI levels were associated with favorable health outcomes in 36% of comparisons (most often for obesity, mortality, diabetes, cardiovascular disease, and psychiatric disorders), compared to 25% for the PDI and only 2% for the uPDI. Conversely, higher levels of the uPDI were associated with unfavorable health outcomes in 33% of comparisons, in contrast to under 1% for the hPDI and 2% for the PDI. When the hPDI association to an outcome was discordant with the uPDI or PDI, the significance and directionality always favored the hPDI over the uPDI, and nearly always favored the hPDI over the PDI.

Discussion

Dietary indices that account for the quality of plant foods can show health benefits that might be missed by a generic plant-based index. A greater focus on the quality of plant foods could improve nutrition guidelines, raise awareness about the benefits of adding unrefined plant foods to the diet, and empower consumers to make incremental additions of such foods to displace unhealthy foods. We anticipate increasing use of indices that address food quality in future research.

Should Men Eat More Plants? A Systematic Review of the Literature on the Effect of Plant-Forward Diets on Men's Health

OBJECTIVE

To perform a systematic review of the literature on plant-based and plant-forward diets and the prevention/treatment of the following common men's health conditions: prostate cancer (PCa), erectile dysfunction (ED), and benign prostatic hyperplasia (BPH).

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses system criteria were utilized to search PubMed and Medline databases for the following search terms: "Diet (Mesh)" OR "Diet Therapy (Mesh)" AND "Prostatic Hyperplasia (Mesh)" OR "Prostatic Neoplasm (Mesh)" OR "Erectile Dysfunction (Mesh)." Articles in English published from 1989 to 2022 using human participants were analyzed, data summarized, and assessed for bias.

RESULTS

Studies reporting on plant-based or vegetable-forward diets (Mediterranean) as an intervention were included. Cohort and cross-sectional studies using food frequency questionnaires or diet classification indices to quantify plant-based food intake patterns were included in the study. Ultimately, 12 PCa articles, 4 BPH articles, 6 ED articles, and 2 articles related to both BPH and ED were reviewed. Overall, the literature suggests plant-forward diets confer a protective effect on the men's health conditions reviewed.

CONCLUSIONS

Evaluation of the literature on the impact of plant-forward diets on urologic conditions includes a heterogenous range of dietary patterns and study designs. The greatest amount of research has evaluated the application of plant-forward diets for PCa. While there is currently a lack of high-quality evidence for the use of plant-forward diets as prevention and/or treatment for PCa, ED, or BPH, reported outcomes suggest a consistent small beneficial impact alongside well-established benefits for common chronic conditions.

Association between dietary inflammation and erectile dysfunction among US adults: A cross-sectional analysis of the National Health and Nutrition Examination Survey 2001-2004

BACKGROUND

Although chronic low-grade inflammation has been linked to the development of erectile dysfunction (ED), the association between pro-inflammatory diets and ED is unclear. The dietary inflammation index (DII) is a novel method to quantify the inflammatory potential of a diet.

OBJECTIVE

Our objective was to investigate the association between the DII and ED among US males.

DESIGN

This cross-sectional study included 3,693 males 20-85 year of age from the National Health and Nutrition Examination Survey (NHANES) 2001-2004. Multivariable-adjusted logistic regression models were used to assess the association between the DII and ED. All analyses accounted for the complex sampling design.

RESULTS

The mean ± SE of the DII was 0.8 ± 0.1 and 0.4 ± 0.1 among participants with and without ED, respectively. After adjusting for age, race/ethnicity, education, smoking status, physical activity, drinking status, hypertension, diabetes, cardiovascular disease, hypercholesterolemia, BMI, and eGFR, the DII score was associated with ED (odds ratio 1.12; 95% CI: 1.04-1.19). Moreover, this association was also stable in our subgroup analysis or sensitivity analyses.

CONCLUSION

Dietary inflammatory potential, as estimated by the DII score, is positively associated with ED among US males.