Associations Among Plant-Based Dietary Indexes, the Dietary Inflammatory Index, and Inflammatory Potential in Female College Students In Saudi Arabia: A Cross-Sectional Study

Plant-based dietary indices and biomarkers of chronic low-grade inflammation: a cross-sectional analysis of adults in Ireland

PURPOSE

There is increasing interest in the health benefits of plant-based diets (PBDs). Evidence reports favourable associations with inflammatory profiles and reduced cardiovascular disease risk. However, limited studies have examined relationships between PBD indices (PDIs) and inflammatory biomarkers. We explored overall PDI, healthful PDI (hPDI) and unhealthful PDI (uPDI) associations with inflammatory biomarker profiles.

METHODS

This cross-sectional analysis included 1986 middle- to older-aged adults from the Mitchelstown Cohort. PDI scores were calculated using validated food frequency questionnaires. PDI score associations with inflammatory biomarkers were assessed via linear regression analysis, with adjustment for potential confounders.

RESULTS

Comparison of quintiles (Q5 vs Q1) revealed lower concentrations of C-reactive protein (CRP), interleukin 6 (IL-6), white blood cells (WBCs), neutrophils and monocytes, and the leptin-to-adiponectin ratio (PDI and hPDI P < 0.05); lower leptin (PDI, P < 0.05), and complement component 3 (C3), tumour necrosis factor alpha (TNF-α), plasminogen activator inhibitor 1, lymphocytes and eosinophils (hPDI, P < 0.05); and higher concentrations of adiponectin (PDI and hPDI, P < 0.05). Conversely, higher concentrations of C3, CRP, IL-6, TNF-α, resistin, WBCs, neutrophils, lymphocytes, monocytes and eosinophils, and the neutrophil-to-lymphocyte ratio, and lower adiponectin concentrations were observed comparing uPDI quintiles (P < 0.05). In fully adjusted regression models, higher hPDI scores were associated with lower concentrations of C3, TNF-α, WBCs, neutrophils and monocytes (all P < 0.01). Higher uPDI scores were associated with higher C3 and TNF-α concentrations (all P < 0.01).

CONCLUSION

This study provides evidence that a more healthful PBD is associated with a more favourable inflammatory profile and that a more unhealthful PBD is associated with the reverse.

Construct Validation of the Dietary Inflammatory Index (DII) among Young College-Aged Women

The Dietary Inflammatory Index (DII) is designed to assess the inflammatory potential of the diet. While previous research has utilized DII among college-aged women, no study to date has validated it in this population. We conducted a construct validation of DII among 393 healthy women aged 18-31 years against a robust panel of 14 inflammatory biomarkers, including CRP, IL-1β, IL-4, IL-6, IL-10, and TNF-α, which were used in the development of DII. Three linear regression models were constructed: (1) an age-adjusted model, (2) the most parsimonious model based on likelihood ratio tests, and (3) a fully adjusted model for age, race, body mass index, waist circumference, physical activity, smoking status, and nonsteroidal anti-inflammatory drug use. DII was derived from the Harvard food frequency questionnaire and categorized into quartiles. Consistent with our hypothesis, DII was negatively and significantly associated with back-transformed IL-10 levels, confirming that a more pro-inflammatory diet was associated with lower levels of an anti-inflammatory cytokine (Model 3: Q4 vs. Q1 β = 0.62; 95% CI: 0.42, 0.93; p-trend = 0.04). While validated in other populations, DII may not be a suitable tool for assessing the inflammatory potential of the diet among college-aged women.

The association between diet quality, plant-based diets, systemic inflammation, and mortality risk: findings from NHANES

PURPOSE

To our knowledge, no studies have examined the association of diet quality and plant-based diets (PBD) with inflammatory-related mortality in obesity. Therefore, this study aimed to determine the joint associations of Healthy Eating Index-2015 (HEI-2015), plant-based dietary index (PDI), healthy PDI (hPDI), unhealthy PDI (uPDI), pro-vegetarian dietary index (PVD), and systemic inflammation with all-cause, cardiovascular disease (CVD), and cancer mortality risks by obesity status.

METHODS

Participants from NHANES were included in cross-sectional (N = 27,915, cycle 1999-2010, 2015-2018) and longitudinal analysis (N = 11,939, cycle 1999-2008). HEI-2015, PDI, hPDI, uPDI, and PVD were constructed based on the 24-h recall dietary interview. The grade of inflammation (low, moderate, and high) was determined based on C-reactive protein (CRP) values and multivariable ordinal logistic regression was used to determine the association. Cox proportional hazard models were used to determine the joint associations of diet and inflammation with mortality.

RESULTS

In the fully adjusted model, HEI-2015 (ORT3vsT1 = 0.76, 95% CI 0.69-0.84; p-trend =  < 0.001), PDI (ORT3vsT1 = 0.83, 95% CI 0.75-0.91; p trend =  < 0.001), hPDI (ORT3vsT1 = 0.79, 95% CI 0.71-0.88; p trend =  < 0.001), and PVD (ORT3vsT1 = 0.85, 95% CI 0.75-0.97; p trend = 0.02) were associated with lower systemic inflammation. In contrast, uPDI was associated with higher systemic inflammation (ORT3vsT1 = 1.18, 95% CI 1.06-1.31; p-trend = 0.03). Severe inflammation was associated with a 25% increase in all-cause mortality (ORT3vsT1 = 1.25, 95% CI 1.03-1.53, p trend = 0.02). No association was found between PDI, hPDI, uPDI, and PVD with mortality. The joint association, between HEI-2015, levels of systemic inflammation, and all-cause, CVD and cancer mortality, was not significant. However, a greater reduction in mortality risk with an increase in HEI-2015 scores was observed in individuals with low and moderate inflammation, especially those with obesity.

CONCLUSION

Higher scores of HEI-2015 and increased intake of a healthy plant-based diet were associated with lower inflammation, while an unhealthy plant-based diet was associated with higher inflammation. A greater adherence to the 2015 dietary guidelines may reduce the risk of mortality associated with inflammation and may also benefit individuals with obesity who had low and moderate inflammation.

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.

Urinary Antibiotics and Dietary Determinants in Adults in Xinjiang, West China

The Xinjiang autonomous region, located in west China, has a unique ethnic structure and a well-developed livestock industry. People in this region have a high risk of exposure to antibiotics, but the exposure level to antibiotics in relation to dietary determinants is unknown. In this study, 18 antibiotics, including four human antibiotics (HAs), four veterinary antibiotics (VAs), and 10 preferred veterinary antibiotics (PVAs) were detected in the urine of approximately half of the 873 adults in Xinjiang, including Han Chinese (24.6%), Hui (25.1%), Uighur (24.6%), and Kazakh (25.7%). Logistic regression was used to analyze the association between antibiotic exposure levels and adult diet and water intake. The detection percentage of antibiotics in the urine of adults in Xinjiang ranged from 0.1% to 30.1%, with a total detection percentage of all antibiotics of 49.8%. HAs, VAs and PVAs were detected in 12.3%, 10.3%, and 40.5%, respectively. Fluoroquinolones were the antibiotics with the highest detection percentage (30.1%) and tetracyclines were the antibiotics with the highest detected concentration (17 ng/mL). Adults who regularly ate pork, consumed fruit daily, and did not prefer a plant-based diet were associated with thiamphenicol, norfloxacin, and fluoroquinolones, respectively. These results indicated that adults in the Xinjiang autonomous region were extensively exposed to multiple antibiotics, and some types of food were potential sources of exposure. Special attention should be paid to the health effects of antibiotic exposure in humans in the future.