The Dietary Inflammatory Index Is Associated with Colorectal Cancer Risk in the Multiethnic Cohort

The Dietary Inflammatory Index is associated with elevated white blood cell counts in the National Health and Nutrition Examination Survey

White blood cells (WBCs) are considered a reliable biomarker of inflammation. Elevations in both WBCs and pro-inflammatory cytokines are associated with several chronic conditions. Diet is a strong moderator of inflammation and WBCs. The purpose of this study was to examine the association between the Dietary Inflammatory Index (DII®) and WBCs using data from the United States National Health and Nutrition Examination Survey (NHANES). NHANES is a cross-sectional study that occurs in two-year cycles. Respondents from five cycles (n = 26,046) with available data on diet (collected through a single 24-h dietary recall [24HR]) and WBCs (derived using the Coulter method) were included. The DII (theoretical range is about -8 to +8) was derived from the micro and macronutrients calculated from the 24HR. Linear regression models, using survey design procedures, were used to estimate adjusted mean WBC (i.e., total, lymphocytes, monocytes, and neutrophils) counts and percentages by DII quartiles. Among all participants no statistically significant difference in WBCs were observed when comparing DII quartile 4 (most pro-inflammatory) to quartile 1 (most anti-inflammatory). However, a one-unit increase in the DII was associated with a 0.028 (1000 per µL) increase in total WBCs (p = .01). Additionally, a 0.024 increase in neutrophils (p < .01) was observed for a one-unit increase in the DII. In the group of participants with normal body mass index (BMI, 18.5-24.9 kg/m²), those in DII quartile 4 had higher levels of total WBCs compared to subjects with normal BMI in DII quartile 1 (7.12 vs. 6.88, p = .01). Similar comparisons were observed for monocytes and neutrophils. However, these relationships were not observed for participants who were overweight or obese, which are pro-inflammatory conditions. Normal-weight individuals consuming more pro-inflammatory diets were more likely to have elevated WBCs. Because of its cross-sectional design, NHANES cannot inform directly on temporal relations, thus limiting causal inference. Future research is needed to examine the impact of anti-inflammatory diet adoption on lowering levels of WBCs, in addition to other inflammatory mediators.

The Inflammatory Potential of the Diet at Midlife Is Associated with Later Healthy Aging in French Adults

Background

While low-grade chronic inflammation has been suggested as a major modulator of healthy aging (HA), no study has yet investigated the link between the inflammatory potential of the diet and multidimensional concepts of HA.

Objective

We aimed to evaluate the association between the inflammatory potential of the diet at midlife, as measured by the Dietary Inflammatory Index (DII), and HA assessed 13 y later.

Methods

We analyzed data from 2796 participants in the French Supplémentation en Vitamines et Minéraux Antioxydants (SU.VI.MAX) study aged 45-60 y at baseline (1994-1995) and initially free of diabetes, cardiovascular disease, and cancer. During the trial phase of the study (1994-2002), participants received either a placebo or a daily nutritional dose of antioxidant supplement (120 mg vitamin C, 6 mg β-carotene, 30 mg vitamin E, 100 μg Se, 20 mg Zn). HA was assessed in 2007-2009, and defined as having no major chronic disease, good physical and cognitive functioning, independence in daily activities, no depressive symptoms, good social health, good overall self-perceived health, and no function-limiting pain. The DII was calculated based on repeated baseline 24-h dietary records. Its association with HA was assessed by robust-error-variance Poisson regression, providing RR estimates.

Results

After adjustment for potential confounders, higher DII scores (reflecting a more proinflammatory diet), were associated with a decreased likelihood of HA: RRtertile 3/tertile 1 = 0.85 (95% CI: 0.74, 0.99); P-trend = 0.03. Secondary analyses revealed that this association was only significant among participants who had been in the placebo group during the trial phase: RRtertile 3/tertile 1 = 0.80 (95% CI: 0.64, 1.00); P-trend = 0.04.

Conclusions

This study suggests that a proinflammatory diet may lower the probability of overall HA. The SU.VI.MAX trial was registered at www.clinicaltrials.gov as NCT00272428.

Utilizing Dietary Micronutrient Ratios in Nutritional Research May be More Informative than Focusing on Single Nutrients

The 2015 US dietary guidelines advise the importance of good dietary patterns for health, which includes all nutrients. Micronutrients are rarely, if ever, consumed separately, they are not tissue specific in their actions and at the molecular level they are multitaskers. Metabolism functions within a seemingly random cellular milieu however ratios are important, for example, the ratio of adenosine triphosphate to adenosine monophosphate, or oxidized to reduced glutathione. Health status is determined by simple ratios, such as the waist hip ratio, or ratio of fat mass to lean mass. Some nutrient ratios exist and remain controversial such as the omega-6/omega-3 fatty acid ratio and the sodium/potassium ratio. Therefore, examining ratios of micronutrients may convey more information about how diet and health outcomes are related. Summarized micronutrient intake data, from food only, from the National Health and Nutrition Examination Survey, were used to generate initial ratios. Overall, in this preliminary analysis dietary ratios of micronutrients showed some differences between intakes and recommendations. Principles outlined here could be used in nutritional epidemiology and in basic nutritional research, rather than focusing on individual nutrient intakes. This paper presents the concept of micronutrient ratios to encourage change in the way nutrients are regarded.

Ageing: from inflammation to cancer

Ageing is the major risk factor for cancer development. Hallmark of the ageing process is represented by inflammaging, which is a chronic and systemic low-grade inflammatory process. Inflammation is also a hallmark of cancer and is widely recognized to influence all cancer stages from cell transformation to metastasis. Therefore, inflammaging may represent the biological phenomena able to couple ageing process with cancer development. Here we review the molecular and cellular pathway involved in age-related chronic inflammation along with its potential triggers and their connection with cancer development.

Dietary Patterns and Colorectal Cancer Risk: A Review of 17 Years of Evidence (2000-2016)

PURPOSE OF REVIEW

Colorectal cancer (CRC) is a global public health problem, with an estimated 1.4 million cases diagnosed worldwide in 2012. Evidence suggests that diet may be important for primary prevention.

RECENT FINDINGS

The 2017 WCRF/AICR Continuous Update Project on colorectal cancer concluded that there is convincing evidence linking several individual dietary factors with CRC risk but the evidence for dietary patterns was limited and inconclusive. Also, previous reviews and meta-analyses have not critically synthesized various dietary patterns. This review synthesized data from dietary patterns studies over a 17-year period from 2000 to 2016.

SUMMARY

We included 49 studies (28 cohort and 21 case-control) that examined the association of index-based and empirically-derived dietary patterns and CRC risk. A synthesis of food group components comprising the different index-based and empirically-derived patterns revealed two distinct dietary patterns associated with CRC risk. A "healthy" pattern, generally characterized by high intake of fruits and vegetables, wholegrains, nuts and legumes, fish and other seafood, milk and other dairy products, was associated with lower CRC risk. In contrast, the "unhealthy" pattern, characterized by high intakes of red meat, processed meat, sugar-sweetened beverages, refined grains, desserts and potatoes was associated with higher CRC risk. It is notable that the number of food groups, the intake quantity, the exact types of foods in each food group, differed between populations, yet the two dietary patterns remained consistent across regions, especially in empirically-derived patterns, an indication of the high reproducibility of these patterns. However, findings for CRC risk in both index-based and empirically-derived patterns, differed by sex, with stronger associations among men than women; study design, a higher proportion of case-control studies reported significant findings compared to prospective studies. Consuming a dietary pattern high in fruits and vegetables and low in meats and sweets is protective against CRC risk. However, important questions remain about mechanisms underlying differences by sex; life-course timing of exposure to dietary patterns; interaction of dietary patterns with the microbiome or with lifestyle factors including physical activity; and elucidation of subsite differences.

Dietary Inflammatory Index and Colorectal Cancer Risk-A Meta-Analysis

Diet and chronic inflammation of the colon have been suggested to be risk factors in the development of colorectal cancer (CRC). The possible link between inflammatory potential of diet, measured through the Dietary Inflammatory Index (DII^®), and CRC has been investigated in several populations across the world. The aim of this study was to conduct a meta-analysis on studies exploring this association. Data from nine studies were eligible, of which five were case-control and four were cohort studies. Results from meta-analysis showed a positive association between increasing DII scores, indicating a pro-inflammatory diet, and CRC. Individuals in the highest versus the lowest (reference) DII category showed an overall 40% increased risk of CRC with moderate evidence of heterogeneity [relative risk (RR) = 1.40, 95% confidence interval (CI): 1.26, 1.55; I² = 69%, p < 0.001]. When analyzed as a continuous variable, results showed an increased risk of CRC of 7% for a 1-point increase in the DII score. Results remained unchanged when analyses were restricted to the four prospective studies. Results of our meta-analysis support the importance of adopting a healthier anti-inflammatory diet in preventing CRC. These results further substantiate the utility of DII as tool to characterize the inflammatory potential of diet and to predict CRC.

Nutrition, inflammation and cancer

Quantitative and qualitative aspects of nutrition have a profound effect on leukocytes and thereby affect proinflammatory carcinogenic effects or anticancer immune responses. As a result, nutrition affects the incidence, natural progression and therapeutic response of malignant diseases, both in humans and in preclinical animal models. Here we discuss the molecular mechanisms through which alimentary cues modulate metabolic, microbial and neuroendocrine circuitries and thus affect the probability of developing premalignant lesions that progress to clinically manifested disease and the response to therapeutic intervention. We examine each of the connections that compose the triangle of nutrition, immunological and inflammatory reactions and cancer while focusing on the mechanistic aspects of these relationships.

Meta-analysis of the association between the inflammatory potential of diet and colorectal cancer risk

OBJECTIVES

The inflammatory potential of diet has been inconsistently linked to colorectal cancer (CRC) risk. This meta-analysis aimed to evaluate the association of the inflammatory potential of diet, as estimated by the dietary inflammatory index (DII) score, with CRC risk.

MATERIALS AND METHODS

The PubMed and Embase databases were searched for relevant studies from inception to February 2017. All cohort and case-control studies investigating the association of the DII score with CRC risk were selected.

RESULTS

Four prospective cohorts and four case-control studies, which enrolled a total of 880,380 participants, were included. The pooled adjusted risk ratio (RR) of CRC for the highest DII score versus the lowest category was 1.43 (95% confidence interval [CI]: 1.26-1.62). When stratified by study design, the RRs for the case-control and cohort studies were 1.27 (95% CI: 1.16-1.38) and 1.81 (95% CI: 1.48-2.22), respectively. Subgroup analysis showed that individuals with the highest category of DII score were independently associated with CRC risk in men (RR=1.51; 95% CI: 1.29-1.76), women (RR=1.25; 95% CI: 1.10-1.41), colon cancer (RR=1.39; 95% CI: 1.19-1.62), and rectal cancer (RR=1.32; 95% CI: 1.01-1.74). However, the pooled RR was 1.07 (95% CI: 0.87-1.31) for rectal cancer among the prospective cohort studies.

CONCLUSIONS

As estimated by a high DII score, pro-inflammatory diet is independently associated with increased CRC risk. This finding confirms that low inflammatory potential diet may reduce CRC risk. However, the gender- and cancer site-specific associations of the DII score with CRC risk need to be further investigated.