DIETARY INFLAMMATORY INDEX AND ITS RELATIONSHIP WITH INFLAMMATION, METABOLIC BIOMARKERS AND MORTALITY

Background: Diet and its components are known to play an important factor in the process of inflammation and in turn on the health effects that are related to inflammation like cancer, and cardiovascular diseases. Previous research so far has mainly looked at the effect of specific food or nutrients on inflammation and health outcomes. In this regard a new literature derived and population based dietary index called Dietary Inflammatory Index (DII) was developed after carefully screening around 6000 articles that looked at the association between 45 food parameters and 6 commonly studied inflammatory markers. The list of food parameters includes various nutrients like vitamins, minerals, macronutrients; food items like garlic, onion, ginger; and bioactive compounds flavonoids. The purpose of this research is to explore the following associations: 1. Association between DII and C - reactive protein (CRP) in NHANES 2005-2010; 2. Association between DII and mortality in NHANES III study and 3. Association between DII and inflammatory and metabolic biomarkers in CAN DO intervention study. Methods: First data from NHANES 2005-2010 was used to examine the association between DII and CRP among the United States population by race/ethnicity and diabetes status.CRP was analyzed as both continuous and as categorical variable (based on the cut-off of 3mg/l). As CRP was not normally distributed it was log transformed and analyzed. In the same dataset HEI-2010 was calculated and used to predict CRP and results were compared with those of DII. Multivariate linear and logistic regression was used for the analyses. Next, we examined the ability of a newly developed dietary inflammatory index (DII) to predict mortality in the National Health and Nutrition Examination Survey (NHANES) III cohort study. The DII was computed based on baseline dietary intake assessed 24-h dietary recalls (1988-94). Mortality was determined from the National Death Index records through 2006. Cox proportional hazards regression was used to estimate hazard ratios. During the follow-up period through the end of 2006, 2795 deaths were identified, including 615 cancer, 158 digestive cancer and 1233 cardiovascular (CVD) deaths. Following this for the third aim data was used from the CAN DO study, a dietary intervention study with a sample size of 234 individuals with metabolic syndrome. The two interventions were 1) a high fiber diet and 2) the American Heart Association (AHA) diet. DII was calculated using 24-h dietary recalls at baseline, 6, and 12 months and was tested against metabolic markers (insulin, blood glucose and homeostasis model assessment (HOMA-IR)) and inflammatory markers, namely C-reactive protein (CRP), IL-6 and TNF-α using linear mixed models adjusted for covariates. All the biomarkers were log transformed and the results are back-transformed and expressed as the ratio of the geometric means. Results: Multivariate analysis revealed CRP to be positively associated with DIIQuartile4vs1 (β =0.19, C.I. 0.13, 0.24), and HEI-2010 Quartile1vs4 (β =0.15, C.I. 0.10, 0.20). Similar associations were observed when CRP was categorized (\u3e3 mg/l), DIIQuartile4vs1 (OR= 1.37, C.I. 1.27, 1.71), and with HEI-2010Quartile1vs4 (OR= 1.31, C.I. 1.12, 1.56). Multivariable analysis, adjusting for , race, diabetes status, hypertension, physical activity, BMI, poverty index and smoking, revealed positive associations between higher DII and overall mortality (HR for DII Tertile3vs1=1.34; 95%CI 1.19- 1.51, p-trend-\u3c0.0001), cancer related mortality (HR for DII Tertile3vs1=1.46; 95%CI 1.10- 1.96, p-trend-0.01), digestive cancer mortality (HR for DII Tertile3vs1=2.10; 95%CI 1.15- 3.84, p-trend-0.03) and CVD mortality (HR for DII Tertile3vs1=1.46; 95%CI 1.18- 1.81, p-trend-0.0006). Across time points DII was lower in the ‘high fiber’ group compared to the ‘AHA’ group. For metabolic factors after multivariate analysis compared to tertile 1 participants in tertile 3 had higher insulin level (1.41; 95% CI 1.02, 1.91), glucose level (1.07; 95% CI 1.02, 1.12) and HOMA-IR (1.51; 95% CI 1.07, 2.09) and for inflammatory biomarkers, compared to tertile 1 participants in tertile 3 had higher IL-6 values (1.35; 95% CI 1.05, 1.78). No significant associations were observed with CRP and TNF-α. Conclusion: The results from all the three aims reinforce the fact that diet as a whole plays an important role in modifying inflammation and health outcomes related to inflammation. Results from aim 1show the DII can predict inflammation in general population with different ethnicities and from different regions of US and also comparatively DII has a slightly better predictive ability (6%) compared to HEI-2010. Results from second aim showed that a pro-inflammatory diet, as indicated by higher DII scores, was associated with overall, cancer and CVD mortality and finally results from the intervention study provide further evidence that fiber has a major effect in reducing inflammation and insulin resistance and also reinforce the opinion that DII can be used as a tool to detect the levels of metabolic and inflammatory biomarkers. Finally all the above mentioned results suggest that diet has a major role in controlling inflammation and thereby plays an important role in the development or prevention of various chronic diseases, hence public health steps should be taken to modify individual’s whole diet rather than the intake of specific nutrients

Dietary Inflammatory Index and Biomarkers of Lipoprotein Metabolism, Inflammation and Glucose Homeostasis in Adults

Accumulating evidence identifies diet and inflammation as potential mechanisms contributing to cardiometabolic risk. However, inconsistent reports regarding dietary inflammatory potential, biomarkers of cardiometabolic health and metabolic syndrome (MetS) risk exist. Our objective was to examine the relationships between a food frequency questionnaire (FFQ)-derived dietary inflammatory index (DII®), biomarkers of lipoprotein metabolism, inflammation and glucose homeostasis and MetS risk in a cross-sectional sample of 1992 adults. Energy-adjusted DII (E-DII) scores derived from an FFQ were calculated. Lipoprotein particle size and subclass concentrations were measured using nuclear magnetic resonance (NMR) spectroscopy. Serum acute-phase reactants, adipocytokines, pro-inflammatory cytokines and white blood cell (WBC) counts were determined. Insulin resistance was calculated by homeostasis model assessment (HOMA-IR). Our data indicate that a more pro-inflammatory diet, reflected by higher E-DII scores, was associated with potentially pro-atherogenic lipoprotein profiles characterised by increased numbers of large very low density lipoprotein (VLDL), small dense low density lipoprotein (LDL) and high density lipoprotein (HDL) particles and less large LDL and HDL particles (all p \u3c 0.001). Inflammatory profiling identified a range of adverse phenotypes among those with higher E-DII scores, including higher complement component C3 (C3), C-reactive protein (CRP), (both p \u3c 0.05), interleukin 6 (IL-6) and tumour necrosis factor (TNF)-α concentrations, higher WBC counts and neutrophil to lymphocyte ratio (NLR) and lower adiponectin levels (all p \u3c 0.001). MetS risk was increased among those with higher E-DII scores (OR 1.37, 95% CI (1.01, 1.88), p \u3c 0.05), after adjusting for potential confounders. In conclusion, habitual intake of a more pro-inflammatory diet is associated with unfavourable lipoprotein and inflammatory profiles and increased MetS risk

Lower Dietary Inflammatory Index Scores Are Associated with Lower Glycemic Index Scores among College Students

The association between the Dietary Inflammatory Index (DII®), the glycemic index (GI), and the glycemic load (GL) is not known, although it is known that carbohydrates are pro-inflammatory. We aimed to measure the association between the DII and both GI and GL among college students. In this cross-sectional study, 110 college students completed a 3-day food diary, which was used to calculate the DII, the GI, the GL, and the healthy eating index (HEI)-2010. Least square means and 95% confidence intervals of the GI, the GL, and the HEI-2010 were presented per DII tertile using generalized linear mixed models. Participants in tertile 1 of DII scores had lower GI and GL scores, but higher HEI-2010 scores than those in tertile 3. Pearson correlations showed that DII score was positively correlated with the GI score (r = 0.30, p \u3c 0.01), but negatively correlated with the HEI-2010 (r = −0.56, p \u3c 0.001). DII score was not correlated with GL score. Results from this study suggest that increased inflammatory potential of diet, as represented by higher DII scores, was associated with increased GI scores and lower quality of diet on the HEI-2010. Use of the DII suggests new directions for dietary approaches for preventing chronic diseases that moves beyond convention by decreasing systemic inflammation

Association between Nutritional Awareness and Diet Quality: Evidence from the Observation of Cardiovascular Risk Factors in Luxembourg (ORISCAV-LUX) Study

This study examined the association between nutritional awareness and diet quality, as indicated by energy density, dietary diversity and adequacy to achieve dietary recommendations, while considering the potentially important role of socioeconomic status (SES). Data were derived from 1351 subjects, aged 18–69 years and enrolled in the ORISCAV-LUX study. Energy density score (EDS), dietary diversity score (DDS) and Recommendation Compliance Index (RCI) were calculated based on data derived from a food frequency questionnaire. Nutritional awareness was defined as self-perception of the importance assigned to eating balanced meals, and classified as high, moderate, or of little importance. Initially, a General Linear Model was fit that adjusted for age, sex, country of birth, and body mass index (BMI). Furthermore, simultaneous contributions to diet quality of individual-level socioeconomic factors, education, and household income were examined across levels of nutritional awareness. Attributing high importance was associated inversely with energy density (p = 0.02), positively with both dietary diversity (p \u3c 0.0001), and adequacy to dietary recommendations (p \u3c 0.0001), independent of demographic factors, weight status and SES. Further adjustment for household income in the EDS-related multivariable model, reduced the β coefficient by 47% for the “moderate importance” category and 36% for the “high importance” category. Likewise, the β coefficient decreased by 13.6% and 10.7% in the DDS-related model, and by 12.5%, and 7.1% in the RCI-related model, respectively, across awareness categories. Nutritional awareness has a direct effect on diet quality, with a minor component of variance explained by improved income. The impact of nutritional awareness on diet quality seems to be a promising area for both health promotion and health policy research

Association between inflammatory potential of diet and risk of depression in middle-aged women: the Australian longitudinal study on women's health

Dietary factors and inflammation markers have been shown to play a role in the development of depression. However, there are very few studies that have explored the association between inflammatory potential of diet and risk of depression. In this study, we examined the association between the dietary inflammatory index (DII), which was developed specifically to measure the inflammatory potential of diet, and risk of depression in the middle-aged cohort of the Australian Longitudinal Study on Women's Health. A total of 6438 women with a mean age of 52·0 (sd 1·4) years at baseline were followed-up at five surveys over 12 years (2001-2013). Depression was defined as a score of ≥10 on the Center for Epidemiologic Studies Depression-10 scale. The DII score, a literature-derived, population-based dietary index that has been validated against several inflammatory markers, was computed on the basis of dietary intake assessed using a validated FFQ. Generalised estimating equations were used to estimate relative risk (RR) of depression according to DII score. Models were adjusted for energy intake, highest education completed, marital status, menopause status and symptoms, personal illness or injury, smoking status, physical activity, BMI and depression diagnosis or treatment. In total, 1156 women (18 %) had scores≥10 on the CESD scale over the course of 9 years. Women with the most anti-inflammatory diet had an approximately 20 % lower risk of developing depression compared with women with the most pro-inflammatory diet (RRDII quartile 1 v. 4: 0·81; 95 % CI 0·69, 0·96; P trend=0·03). These results suggest that an anti-inflammatory diet is associated with lower risk of depression in middle-aged Australian women

Association between Inflammatory Potential of Diet and Bone-Mineral Density in Korean Postmenopausal Women: Data from Fourth and Fifth Korea National Health and Nutrition Examination Surveys

Post menopause is considered a critical period for bone-mass loss. Impaired bone metabolism during this phase can increase the risk of fractures in old age. Inflammation is a risk factor for bone health, and diet is a potential source of inflammation. However, few studies have examined the association between the dietary inflammatory index (DII®) and bone-mineral density (BMD) in postmenopausal women in Korea. The objective of this study was to determine, by means of a Korean cross-sectional investigation, whether higher DII scores are associated with decreased BMD in postmenopausal women. To that end, the raw data from the fourth and fifth Korea National Health and Nutrition Examination Surveys (KNHANES, 2009–2011) for 2778 postmenopausal women aged over 50 years were analyzed. The subjects’ BMD were measured by dual-energy x-ray absorptiometry, and their DII® scores were calculated from a single 24-h dietary recall. Further, the participants were classified into three groups according to DII® score. Women with more pro-inflammatory diets (i.e., those in the highest tertile of DII®) had significantly lower BMD in the femoral neck as compared with women in the lowest tertile (p for trend \u3c0.05) after adjustment for age, body-mass index (BMI), household income, education status, smoking habits, physical activity, total calcium intake, female-hormone use, age at menopause, and blood vitamin D levels. Multiple logistic regression analyses revealed that the odds ratio (OR) of total femur osteopenia/osteoporosis was higher in women in the highest tertile of DII® than in those in the lowest (OR 1.27, 95% CI 1.00-1.62, p for trend \u3c 0.05). This study established that more pro-inflammatory diets might be associated with lower BMD in postmenopausal Korean women

Alternative Healthy Eating Index 2010, Dietary Inflammatory Index and Risk of Mortality: Results From the Whitehall II Cohort Study and Meta-Analysis of Previous Dietary Inflammatory Index and Mortality Studies

We aimed to examine the association between the Alternative Healthy Eating Index updated in 2010 (AHEI-2010), the Dietary Inflammatory Index (DIITM) and risk of mortality in the Whitehall II study. We also conducted a meta-analysis on the DII-based results from previous studies to summarise the overall evidence. Data on dietary behaviour assessed by self-administered repeated FFQ and on mortality status were available for 7627 participants from the Whitehall II cohort. Cox proportional hazards regression models were performed to assess the association between cumulative average of AHEI-2010 and DII scores and mortality risk. During 22 years of follow-up, 1001 participants died (450 from cancer, 264 from CVD). Both AHEI-2010 (mean=48·7 (sd 10·0)) and DII (mean=0·37 (sd 1·41)) were associated with all-cause mortality. The fully adjusted hazard ratio (HR) per sd, were 0·82; 95 % CI 0·76, 0·88 for AHEI-2010 and 1·18; 95 % CI 1·08, 1·29 for DII. Significant associations were also observed with cardiovascular and cancer mortality risk. For DII, a meta-analysis (using fixed effects) from this and four previous studies showed a positive association of DII score with all-cause (HR=1·04; 95 % CI 1·03, 1·05, 28 891deaths), cardiovascular (HR=1·05; 95 % CI 1·03, 1·07, 10 424 deaths) and cancer mortality (HR=1·05; 95 % CI 1·03, 1·07, n 8269).The present study confirms the validity to assess overall diet through AHEI-2010 and DII in the Whitehall II cohort and highlights the importance of considering diet indices related to inflammation when evaluating all-cause, cardiovascular and cancer mortality risk

The relationship of plasma Trans fatty acids with dietary inflammatory index among US adults

BACKGROUND: It has been suggested that trans fatty acids (TFAs) play an important role in cardiovascular diseases. We investigated the association between plasma TFAs and the dietary inflammatory index (DII) ™ in US adults. METHODS: National Health and Nutrition Examination Survey (NHANES) participants with data on plasma TFAs measured from 1999 to 2010 were included. Energy-adjusted-DII ™ (E-DII ™) expressed per 1000 kcal was calculated from 24-h dietary recalls. All statistical analyses accounted for the survey design and sample weights. RESULTS: Of the 5446 eligible participants, 46.8% (n = 2550) were men. The mean age of the population was 47.1 years overall, 47.8 years for men and 46.5 years for women (p = 0.09). After adjustment for C-reactive protein, body-mass-index, smoking, race, age, education, and marital status in linear regressions, trans 9-hexadecenoic acid [β coefficient 0.068 (95% CI: 0.032 to 0.188)], trans 11-octadecenoic acid [β coefficient 0.143 (95% CI: 0.155 to 0.310)], trans 9-octadecenoic acid [β coefficient 0.122 (95% CI: 0.120 to 0.277)], trans 9, and trans 12-octadienoic acid [β coefficient 0.103 (95% CI: 0.090 to 0.247)] were positively associated with the DII (all p < 0.001). CONCLUSION: The association of plasma TFAs with a marker of dietary inflammation suggests an underlying mechanism in the initiation and progression of cardiovascular diseases

Increased Dietary Inflammatory Index Is Associated with Schizophrenia: Results of a Case–Control Study from Bahrain

Background: Several studies have indicated that chronic low-grade inflammation is associated with the development of schizophrenia. Given the role of diet in modulating inflammatory markers, excessive caloric intake and increased consumption of pro-inflammatory components such as calorie-dense, nutrient-sparse foods may contribute toward increased rates of schizophrenia. This study aimed to examine the association between dietary inflammation, as measured by the dietary inflammatory index (DII®), and schizophrenia. Methods: A total of 120 cases attending the out-patient department in the Psychiatric Hospital/Bahrain were recruited, along with 120 healthy controls matched on age and sex. The energy-adjusted DII (E-DII) was computed based on dietary intake assessed using a comprehensive food frequency questionnaire (FFQ). Logistic regression was used to estimate odds ratios and 95% confidence intervals, adjusting for potential confounders including age, sex, body mass index, education, employment, diabetes, hypertension, and cardiovascular disease with E-DII expressed both as a continuous variable and categorized as quartiles. Results: The mean E-DII score for the entire sample was 1.79 ± 1.52, indicating a generally pro-inflammatory diet. The cases with schizophrenia appeared to have a higher E-DII score compared to controls: 1.99 ± 1.39 vs. 1.60 ± 1.38, respectively (p = 0.009). For every one unit increase in the E-DII score, the odds of having schizophrenia increased by 62% (OR 1.62; 95% CI 1.17–2.26). Similarly, increased risk was observed when the E-DII was used as quartiles, with participants in most pro-inflammatory quartile 4 being nearly 6 times more likely to be schizophrenic than participants in the most anti-inflammatory group quartile 1 (OR 5.96; 1.74–20.38; p-trend = 0.01). Conclusions: The data suggest that a pro-inflammatory diet, as indicated by increasing E-DII score, is associated with schizophrenia. This is the first study to examine the association between the DII and schizophrenia in a Middle Eastern population. Although these results are consistent with findings from research conducted in depression, additional studies are required before generalizing the findings to other populations