Increasing the vegetable intake dose is associated with a rise in plasma carotenoids without modifying oxidative stress or inflammation in overweight or obese postmenopausal women

The role of diet quality and dietary patterns in predicting muscle mass and function in men over a 15-year period

A growing body of evidence suggests that diet quality may predict muscle health. This study found that a "Traditional" dietary pattern predicted greater muscle mass, and an anti-inflammatory diet predicted greater muscle mass and better muscle function over 15 years. These findings reinforce the importance of optimising dietary behaviours for healthy ageing.

INTRODUCTION

Research investigating the roles of individual nutrients in muscle health fails to account for the synergistic relationships between foods and nutrients. This study aimed to investigate the predictive value of diet quality and dietary patterns for muscle mass and function in men over a 15-year period.

METHODS

This longitudinal study was conducted in 522 men from the Geelong Osteoporosis Study with complete dietary and muscle mass or muscle function data at both baseline and 15-year follow-up assessments. Dietary exposures were extracted from food frequency questionnaires and included the Australian Recommended Food Score, the Dietary Inflammatory Index (DII®), and three a posteriori dietary patterns: Plant-focused, Western, and Traditional (Anglo-Australian). Outcome variables included dual-energy X-ray absorptiometry-derived skeletal muscle index (SMI) and muscle function measured with the timed up-and-go (TUG) test.

RESULTS

An anti-inflammatory diet and higher scores on a Traditional dietary pattern both predicted greater SMI ((B: -0.04 (95%CI -0.08, -0.00) kg/m²) and (B: 0.12 (95%CI 0.04, 0.20) kg/m²), respectively), while a pro-inflammatory diet predicted slower TUG (B: 0.11 (95%CI 0.001, 0.21) sec) over the 15-year follow-up period. These associations remained significant following adjustment for confounding variables. There were no associations observed for other dietary exposures.

CONCLUSION

A Traditional dietary pattern higher in vegetables, wholegrain cereals, and animal protein was associated with greater skeletal muscle mass, and an anti-inflammatory diet, also rich in vegetables, fruit, and wholegrain cereals, was associated with greater skeletal muscle mass and better muscle function over 15 years.

Effect of whole foods and dietary patterns on markers of subclinical inflammation in weight-stable overweight and obese adults: a systematic review

Context

Reduction of subclinical inflammation is a potential target for chronic disease management. Adiposity is a known modifier of meta-inflammation; however, the influence of dietary factors is less clear.

Objective

This review examines evidence from human trials evaluating effects of whole foods or dietary patterns on circulating inflammatory markers in weight-stable overweight and obese adults. It is the first review to investigate effects of diet on inflammation, independent of changes in adiposity.

Data Sources

The Ovid MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched.

Data Extraction

Data extraction was conducted using the Cochrane Collaboration Handbook for Systematic Reviews of Interventions.

Data Analysis

Study quality was evaluated using the Cochrane Collaboration Risk of Bias Assessment tool. Thirty-three studies were included assessing effects of 17 foods and dietary patterns on 39 inflammatory markers.

Conclusions

Overall, foods and dietary patterns were not found to have significant effects on inflammatory markers in weight-stable individuals. Inconsistencies among studies were largely due to methodological limitations. Future research should invest in longer intervention periods and standardization of inflammatory marker panels paired with novel technologies, while ensuring anthropometric measures are monitored and adequately controls are used.

Systematic Review Registration

Prospero registration number CRD42017067765.

Effects of High Consumption of Vegetables on Clinical, Immunological, and Antioxidant Markers in Subjects at Risk of Cardiovascular Diseases

High intakes of vegetables have been associated with a lower incidence of cardiovascular diseases (CVD). However, the effect of vegetables on immune function and antioxidant status in human studies have provided contrasting results. In the present study, after a week of run-in period, 38 subjects at risk of CVD were randomly assigned to one of the following 4-week interventions: low vegetable consumption (800 g of vegetables/week) or high vegetable consumption (4200 g of vegetables/week). Vegetables included carrots, topinambur (Jerusalem artichoke, Helianthus tuberosus), tomatoes, red cabbage, and sweet peppers. Blood and salivary samples were collected before and after intervention periods. In addition to clinical, immunological, and antioxidant markers, leukocyte and lymphocyte expression of the gut-homing β7 integrin was evaluated. No significant changes were detected in clinical, immunological, and antioxidant markers in biological samples, except for an increase in white blood cell count for the low vegetable consumption group (p < 0.05). The study provides additional evidence about the uncertainty of providing a clear evidence for vegetables in modulating markers of immune function and antioxidant status. Further studies are needed in order to unravel the mechanism of effect of vegetable consumption in cardiovascular prevention.

Genetic and Common Environmental Contributions to Familial Resemblances in Plasma Carotenoid Concentrations in Healthy Families

Carotenoids have shown an interindividual variability that may be due to genetic factors. The only study that has reported heritability of serum α- and β-carotene has not considered the environmental component. This study aimed to estimate the contribution of both genetic and common environmental effects to the variance of carotenoid concentrations and to test whether their phenotypic correlations with cardiometabolic risk factors are explained by shared genetic and environmental effects. Plasma carotenoid concentrations (α-carotene, β-carotene, β-cryptoxanthin, lutein, lycopene, zeaxanthin, and total carotenoids) of 48 healthy subjects were measured. Heritability estimates of carotenoid concentrations were calculated using the variance component method. Lutein and lycopene showed a significant familial effect (p = 6 × 10^-6 and 0.0043, respectively). Maximal heritability, genetic heritability, and common environmental effect were computed for lutein (88.3%, 43.8%, and 44.5%, respectively) and lycopene (45.2%, 0%, and 45.2%, respectively). Significant phenotypic correlations between carotenoid concentrations and cardiometabolic risk factors were obtained for β-cryptoxanthin, lycopene, and zeaxanthin. Familial resemblances in lycopene concentrations were mainly attributable to common environmental effects, while for lutein concentrations they were attributable to genetic and common environmental effects. Common genetic and environmental factors may influence carotenoids and cardiometabolic risk factors, but further studies are needed to better understand the potential impact on disease development.

Dietary Pattern and Macronutrients Profile on the Variation of Inflammatory Biomarkers: Scientific Update

It is known that the dietary pattern and macronutrients profile may influence the expression and secretion of inflammatory biomarkers, and the low-grade inflammation is associated with the manifestation of noncommunicable chronic diseases. Therefore, this review aimed to present and discuss the role of dietary patterns and macronutrients on the variation of inflammatory markers related to NCD risk. Scientific evidences within the last five years based on clinical trials, case-controls, cohorts, and cross-sectional studies indicate that normocaloric, carbohydrate-moderated, low-glycemic index, protein-moderated, monounsaturated and polyunsaturated fatty acid-rich, omega-3, and low-saturated fat diets display positive effects on the inflammatory state, both in healthy individuals and in those with cardiovascular risk, although the second group seems to benefit more from changes in the dietary profile.

A diet high in carotenoid-rich vegetables and fruits favorably impacts inflammation status by increasing plasma concentrations of IFN-α2 and decreasing MIP-1β and TNF-α in healthy individuals during a controlled feeding trial

The health benefits of vegetable and fruit (VF) intake include benefits for diseases that have an inflammatory component, although the relationship between VF intake and systemic inflammatory status is unclear due to the lack of comprehensive analysis of inflammatory markers in most studies. Therefore, our hypothesis was that the consumption of carotenoid-rich vegetables and fruits in the diet would have a beneficial effect on systemic inflammation status. In this study, we determined the association between varying doses of carotenoid-rich VF intake, plasma carotenoids, and a broad array of markers including 26 cytokines and high-sensitivity C-reactive protein. Data were derived from a single-arm controlled clinical feeding trial in which healthy, nonobese individuals received a low-carotenoid prescription for 6 weeks and then consumed a provided high-VF diet for 8 weeks. Proinflammatory cytokines and plasma carotenoids were measured at baseline, at 6 weeks, and at the end of the 8-week feeding period. Maximum likelihood estimation was used to calculate overall correlations between total plasma carotenoid concentrations and the cytokines. Plasma carotenoids decreased during the low-carotenoid treatment and increased during the feeding treatment. Of the inflammatory markers measured, we found increased plasma concentrations of interferon α-2 (P = .003) and decreased macrophage inflammatory protein-1β (P = .027) and tumor necrosis factor-α (P = .012) after consumption of the carotenoid-rich diet. These results indicate that consumption of VF may be important in the maintenance of beneficial inflammatory homeostasis.

Carotenoids as biomarkers of fruit and vegetable intake in men and women

High fruit and vegetable (FAV) intake is associated with a lower prevalence of chronic diseases. Identifying the ideal number of FAV servings needed to reduce chronic disease risk is, however, difficult because of biases inherent to common self-report dietary assessment tools. The aim of our study was to examine the associations between daily FAV intake and plasma carotenoid concentrations in men and women enrolled in a series of fully controlled dietary interventions. We compiled and analysed data from a group of 155 men and 109 women who participated in six fully controlled dietary interventions and compared post-intervention fasting plasma carotenoid (α-carotene,β-carotene,β-cryptoxanthin, lutein, lycopene, zeaxanthin) concentrations with regard to the daily FAV servings consumed by the participants. We found that plasmaβ-cryptoxanthin, lutein and zeaxanthin concentrations were positively associated with daily FAV servings (P≤0·005). However, daily FAV intake was negatively associated with plasmaα-carotene (P<0·0005) and lycopene (P<0·0001) concentrations, whereas no association was noted with plasmaβ-carotene. When men and women were analysed separately, we found that for any given number of FAV servings consumed women had higher circulating lutein concentrations compared with men (P<0·01). Significant sex×FAV (P<0·0001) and sex×dietaryβ-cryptoxanthin (P<0·0005) interactions were also noted favouring higher plasmaβ-cryptoxanthin concentrations in women than in men for a given FAV consumption. Results from these fully controlled dietary feeding studies indicate that plasmaβ-cryptoxanthin and lutein concentrations can be used as robust biomarkers of FAV consumption. They also suggest the existence of sex differences influencing circulatingβ-cryptoxanthin and lutein concentrations following FAV consumption.

Comparative validity of vitamin C and carotenoids as indicators of fruit and vegetable intake: a systematic review and meta-analysis of randomised controlled trials

Circulating vitamin C and carotenoids are used as biomarkers of fruit and vegetable intake in research, but their comparative validity has never been meta-analysed. PubMed, EMBASE, CENTRAL, CINAHL and Web of Science were systematically searched up to December 2013 for randomised trials of different amounts of fruit and vegetable provision on changes in blood concentrations of carotenoids or vitamin C. Reporting followed PRISMA guidelines. Evidence quality was assessed using the GRADE system. Random effects meta-analysis combined estimates and meta-regression tested for sub-group differences. In all, nineteen fruit and vegetable trials (n1382) measured at least one biomarker, of which nine (n667) included five common carotenoids and vitamin C. Evidence quality was low and between-trial heterogeneity (I2) ranged from 74 % for vitamin C to 94 % forα-carotene. Groups provided with more fruit and vegetables had increased blood concentrations of vitamin C,α-carotene,β-carotene,β-cryptoxanthin and lutein but not lycopene. However, no clear dose–response effect was observed. Vitamin C showed the largest between-group difference in standardised mean change from the pre-intervention to the post-intervention period (smd0·94; 95 % CI 0·66, 1·22), followed by lutein (smd0·70; 95 % CI 0·37, 1·03) andα-carotene (smd0·63; 95 % CI 0·25, 1·01), but all CI were overlapping, suggesting that none of the biomarkers responded more than the others. Therefore, until further evidence identifies a particular biomarker to be superior, group-level compliance to fruit and vegetable interventions can be indicated equally well by vitamin C or a range of carotenoids. High heterogeneity and a lack of dose–response suggest that individual-level biomarker responses to fruit and vegetables are highly variable.

Carotenoids, inflammation, and oxidative stress--implications of cellular signaling pathways and relation to chronic disease prevention

Several epidemiologic studies have shown that diets rich in fruits and vegetables reduce the risk of developing several chronic diseases, such as type 2 diabetes, atherosclerosis, and cancer. These diseases are linked with systemic, low-grade chronic inflammation. Although controversy persists on the bioactive ingredients, several secondary plant metabolites have been associated with these beneficial health effects. Carotenoids represent the most abundant lipid-soluble phytochemicals, and in vitro and in vivo studies have suggested that they have antioxidant, antiapoptotic, and anti-inflammatory properties. Recently, many of these properties have been linked to the effect of carotenoids on intracellular signaling cascades, thereby influencing gene expression and protein translation. By blocking the translocation of nuclear factor κB to the nucleus, carotenoids are able to interact with the nuclear factor κB pathway and thus inhibit the downstream production of inflammatory cytokines, such as interleukin-8 or prostaglandin E2. Carotenoids can also block oxidative stress by interacting with the nuclear factor erythroid 2-related factor 2 pathway, enhancing its translocation into the nucleus, and activating phase II enzymes and antioxidants, such as glutathione-S-transferases. In this review, which is organized into in vitro, animal, and human investigations, we summarized current knowledge on carotenoids and metabolites with respect to their ability to modulate inflammatory and oxidative stress pathways and discuss potential dose-health relations. Although many pathways involved in the bioactivity of carotenoids have been revealed, future research should be directed toward dose-response relations of carotenoids, their metabolites, and their effect on transcription factors and metabolism.

The antioxidant paradox: less paradoxical now?

The term 'antioxidant paradox' is often used to refer to the observation that oxygen radicals and other reactive oxygen species are involved in several human diseases, but giving large doses of dietary antioxidant supplements to human subjects has, in most studies, demonstrated little or no preventative or therapeutic effect. Why should this be? First, the role of reactive oxygen species in the origin and/or progression of most human diseases is unclear, although they are probably important in cancer, neurodegenerative diseases and perhaps some others. Second, the endogenous antioxidant defences in the human body are complex, interlocking and carefully regulated. The body's 'total antioxidant capacity' seems unresponsive to high doses of dietary antioxidants, so that the amount of oxidative damage to key biomolecules is rarely changed. Indeed, manipulation of endogenous antioxidant levels (e.g. by supplying weak pro-oxidants) may be a more useful approach to treatment and prevention of diseases in which reactive oxygen species are important than is consumption of large doses of dietary antioxidants.

Fish to meat intake ratio and cooking oils are associated with hepatitis C virus carriers with persistently normal alanine aminotransferase levels

AIM

  Dietary habits are involved in the development of chronic inflammation; however, the impact of dietary profiles of hepatitis C virus carriers with persistently normal alanine transaminase levels (HCV-PNALT) remains unclear. The decision-tree algorithm is a data-mining statistical technique, which uncovers meaningful profiles of factors from a data collection. We aimed to investigate dietary profiles associated with HCV-PNALT using a decision-tree algorithm.

METHODS

  Twenty-seven HCV-PNALT and 41 patients with chronic hepatitis C were enrolled in this study. Dietary habit was assessed using a validated semiquantitative food frequency questionnaire. A decision-tree algorithm was created by dietary variables, and was evaluated by area under the receiver operating characteristic curve analysis (AUROC).

RESULTS

  In multivariate analysis, fish to meat ratio, dairy product and cooking oils were identified as independent variables associated with HCV-PNALT. The decision-tree algorithm was created with two variables: a fish to meat ratio and cooking oils/ideal bodyweight. When subjects showed a fish to meat ratio of 1.24 or more, 68.8% of the subjects were HCV-PNALT. On the other hand, 11.5% of the subjects were HCV-PNALT when subjects showed a fish to meat ratio of less than 1.24 and cooking oil/ideal bodyweight of less than 0.23 g/kg. The difference in the proportion of HCV-PNALT between these groups are significant (odds ratio 16.87, 95% CI 3.40-83.67, P = 0.0005). Fivefold cross-validation of the decision-tree algorithm showed an AUROC of 0.6947 (95% CI 0.5656-0.8238, P = 0.0067).

CONCLUSION

  The decision-tree algorithm disclosed that fish to meat ratio and cooking oil/ideal bodyweight were associated with HCV-PNALT.