ILSI North America Research Articles

Workshop report: Toward the development of a human whole stool reference material for metabolomic and metagenomic gut microbiome measurements

IntroductionTo date, there has been little effort to develop standards for metabolome-based gut microbiome measurements despite the significant efforts toward standard development for DNA-based microbiome measurements.ObjectivesThe National Institute of Standards and Technology (NIST), The BioCollective (TBC), and the North America Branch of the International Life Sciences Institute (ILSI North America) are collaborating to extend NIST’s efforts to develop a Human Whole Stool Reference Material for the purpose of method harmonization and eventual quality control.MethodsThe reference material will be rationally designed for adequate quality assurance and quality control (QA/QC) for underlying measurements in the study of the impact of diet and nutrition on functional aspects of the host gut microbiome and relationships of those functions to health. To identify which metabolites deserve priority in their value assignment, NIST, TBC, and ILSI North America jointly conducted a workshop on September 12, 2019 at the NIST campus in Gaithersburg, Maryland. The objective of the workshop was to identify metabolites for which evidence indicates relevance to health and disease and to decide on the appropriate course of action to develop a fit-for-purpose reference material.ResultsThis document represents the consensus opinions of workshop participants and co-authors of this manuscript, and provides additional supporting information. In addition to developing general criteria for metabolite selection and a preliminary list of proposed metabolites, this paper describes some of the strengths and limitations of this initiative given the current state of microbiome research.ConclusionsGiven the rapidly evolving nature of gut microbiome science and the current state of knowledge, an RM (as opposed to a CRM) measured for multiple metabolites is appropriate at this stage. As the science evolves, the RM can evolve to match the needs of the research community. Ultimately, the stool RM may exist in sequential versions. Beneficial to this evolution will be a clear line of communication between NIST and the stakeholder community to ensure alignment with current scientific understanding and community needs.

Establishing What Constitutes a Healthy Human Gut Microbiome: State of the Science, Regulatory Considerations, and Future Directions

ABSTRACTOn December 17, 2018, the North American branch of the International Life Sciences Institute (ILSI North America) convened a workshop “Can We Begin to Define a Healthy Gut Microbiome Through Quantifiable Characteristics?” with >40 invited academic, government, and industry experts in Washington, DC. The workshop objectives were to 1) develop a collective expert assessment of the state of the evidence on the human gut microbiome and associated human health benefits, 2) see if there was sufficient evidence to establish measurable gut microbiome characteristics that could serve as indicators of “health,” 3) identify short- and long-term research needs to fully characterize healthy gut microbiome–host relationships, and 4) publish the findings. Conclusions were as follows: 1) mechanistic links of specific changes in gut microbiome structure with function or markers of human health are not yet established; 2) it is not established if dysbiosis is a cause, consequence, or both of changes in human gut epithelial function and disease; 3) microbiome communities are highly individualized, show a high degree of interindividual variation to perturbation, and tend to be stable over years; 4) the complexity of microbiome-host interactions requires a comprehensive, multidisciplinary research agenda to elucidate relationships between gut microbiome and host health; 5) biomarkers and/or surrogate indicators of host function and pathogenic processes based on the microbiome need to be determined and validated, along with normal ranges, using approaches similar to those used to establish biomarkers and/or surrogate indicators based on host metabolic phenotypes; 6) future studies measuring responses to an exposure or intervention need to combine validated microbiome-related biomarkers and/or surrogate indicators with multiomics characterization of the microbiome; and 7) because static genetic sampling misses important short- and long-term microbiome-related dynamic changes to host health, future studies must be powered to account for inter- and intraindividual variation and should use repeated measures within individuals.

Nutrients in the US Diet: Naturally Occurring or Enriched/Fortified Food and Beverage Sources, Plus Dietary Supplements: NHANES 2009–2012

ABSTRACTBackgroundNutrients are added to the diet through fortification/enrichment and dietary supplements (DSs). Meeting the US Dietary Reference Intakes (DRIs) varies by nutrient and population subsegments.ObjectiveThe aim of this study was to assess the relative role of naturally occurring, enriched/fortified, and DS sources of 15 micronutrients with reference to the DRIs.MethodsWe used the NHANES 2009–2012 (≥2 y old, n = 16,975) data, the ILSI North America Fortification database, and the National Cancer Institute usual intake method.ResultsPrevalence of nutrient intake from naturally occurring sources below the Estimated Average Requirement (EAR) varied from 5% for vitamin B-12 to 100% for vitamin D, with ≥40% of the population below the EAR for 8 of the 14 nutrients (ages ≥2 y). With enrichment/fortification, the percentage below the EAR decreased to the following for vitamins A (35%), C (34%), and B-6 (7%), folate (8%), thiamin (5%), riboflavin (3%), niacin (1%), and iron (2%). Nutrients from DSs further improved intakes related to the EAR for 12 nutrients (ages ≥2 y). For 9–18-y-olds, the percentages of nutrient intakes below the EAR were 14–50% higher than for 2–8-y-olds. The Tolerable Upper Intake Level (UL) was exceeded among children aged 2–8 y for folate (41.7%), niacin (10.1%), and zinc (39.9%), whereas among ages ≥2 y and 9–18 y no prevalence of intakes over the UL exceeded 10%.ConclusionsFortification/enrichment constitutes a meaningful contribution to reducing the percentage of individuals with less than the EAR for their demographic. These data underscore the need to encourage better dietary patterns to improve the intake of nutrients at risk of low intake.

“The safety of sodium reduction in the food supply: A cross-discipline balancing act”—Workshop proceedings

ABSTRACTThis workshop, jointly presented by the ILSI North America Technical Committees on Food Microbiology and Sodium, aimed to provide greater knowledge and appreciation of the opportunities and challenges facing the food industry in answering the public health community's call to reduce sodium levels in the food supply. One major challenge is finding effective substitutes for the various antimicrobial and functional roles that sodium plays across different food categories. Sodium plays a critical role in retarding the growth of pathogens and food spoilage bacteria. Moreover, taste is an important factor for consumers when they choose food products, and the flavor changes that occur when salt is reduced or replaced must be considered and ingredients and processes adjusted accordingly. The workshop provided a platform for a multidisciplinary discussion among the microbiology, food science, nutrition, and public health communities to share progress and propose solutions, including the formation of public-private partnerships, to develop coordinated and comprehensive strategies. This paper provides an overview of the issues raised, rather than a specific summary of workshop discussions. The Food and Drug Administration's Draft Guidance for Industry on voluntary sodium reduction and the 2015 US Dietary Guidelines for Americans were released subsequent to the workshop and are also discussed.

A Risk-Based Strategy for Evaluating Mitigation Options for Process-Formed Compounds in Food: Workshop Proceedings.

Processing (eg, cooking, grinding, drying) has changed the composition of food throughout the course of human history; however, awareness of process-formed compounds, and the potential need to mitigate exposure to those compounds, is a relatively recent phenomenon. In May 2015, the North American Branch of the International Life Sciences Institute (ILSI North America) Technical Committee on Food and Chemical Safety held a workshop on the risk-based process for mitigation of process-formed compounds. This workshop aimed to gain alignment from academia, government, and industry on a risk-based process for proactively assessing the need for and benefit of mitigation of process-formed compounds, including criteria to objectively assess the impact of mitigation as well as research needed to support this process. Workshop participants provided real-time feedback on a draft framework in the form of a decision tree developed by the ILSI North America Technical Committee on Food and Chemical Safety to a panel of experts, and they discussed the importance of communicating the value of such a process to the larger scientific community and, ultimately, the public. The outcome of the workshop was a decision tree that can be used by the scientific community and could form the basis of a global approach to assessing the risks associated with mitigation of process-formed compounds.

Meta‐Regression Analysis of the Effect of Trans Fatty Acids (TFAs) on LDL‐Cholesterol

The Food and Drug Administration (FDA) published a Federal Register notice tentatively determining that partially hydrogenated oils (PHOs, the primary dietary source of industrial TFAs – iTFAs) are no longer generally recognized as safe (GRAS) when used in food. This determination was based on the conclusion that there is no threshold intake for iTFA that would not increase an individual's risk of coronary heart disease, based primarily on research showing iTFAs increase LDL‐cholesterol (LDL‐C) at high levels of intake. A meta‐regression analysis was conducted on the relationship between changes in TFA intake and changes in plasma LDL‐C, building on an evidence map designed to capture all relevant data. The purpose of this analysis was to describe the dose‐response in the range of the human data, particularly the low‐intake region. An advantage of the weighted regression (i.e., meta‐regression) is greater accuracy, since studies with smaller variance are given more weight. A variety of different mathematical expressions were fit to the data to determine which one best fit the data. Variability was very large, particularly at low TFA intake, indicating TFA intake is not the primary determinant of LDL‐C levels at low TFA intake. No significant differences were found in the mathematical fit of models across a wide range of shapes, from very flat initial slope to very steep initial slope. Thus, the mathematical modeling cannot inform our understanding of the shape of the dose‐response curve even in the range of human data, and determine whether a threshold exists. Instead, as is generally the case, one needs to rely on a mode of action evaluation.This work was sponsored by the ILSI North America PHO Task Force.

A Partnership for Public Health: Branded Food Products Database

Assessing the nutritional health of Americans depends on comprehensive data regarding the nutrient composition of foods. USDA, ILSI North America, and the ATIP Foundation have formed a Public-Private Partnership (PPP) to enhance public health by augmenting the USDA National Nutrient Database with nutrient composition of branded and privatelabel data. A PPP provides the framework to convene the expertise to compile this nutrient data,secure the private sector engagement in providing this information, obtain the broad-based constituent funding necessary for maintenance, and provide timely information for nutrition, agricultural, and diet-related health policy on the nutrient composition of the food supply.

McCormick Science Institute Science Summit—Spices and Herbs

Johanna T. Dwyer, DSc, RD, is a professor of medicine and community health at Tufts University School of Medicine, Boston, Massachusetts. The author is a member of the McCormick Science Institute’s Scientific Advisory Council; owns stock in McCormick & Company, Inc; is the editor of Nutrition Today; and is a public trustee of ILSI North America. Correspondence: Johanna T. Dwyer, DSc, RD, Frances Stern Nutrition Center Box 783, Tufts Medical Center, 800 Washington St, Boston, MA 02111 ([email protected]).

Tuberculosis treatment modifies iron status without iron intervention (389.8)

Iron biomarker patterns identify tuberculosis (TB) risk, but evidence of the evolution of iron biomarkers from treatment initiation to disease resolution is limited. Plasma/serum ferritin, hepcidin and soluble transferrin receptor (sTfR) were measured in 45 Gambians diagnosed with TB (active disease) at treatment initiation, 2 and 6 months and compared to 42 tuberculin skin test (TST)+ (infection only, no disease) and 44 TST‐ (uninfected) controls. At treatment initiation, median ferritin (164.5 ng/ml), hepcidin (84.0 ng/ml), and sTfR (29.4 nM) identified active disease compared to infected (ferritin 29.3 ng/ml, P<0.001; hepcidin 19.8 ng/ml, P<0.001; sTfR 23.0 nM, P=0.005) and uninfected (ferritin 23.3 ng/ml, P<0.001; hepcidin 24.2 ng/ml P<0.001; sTfR 18.6 nM, P<0.001) levels, which were similar. Ferritin, hepcidin and sTfR decreased significantly during the first two months of treatment and remained at these levels until treatment completion. Understanding fluctuations in iron distribution driven by infection and immune activation will inform the clinical management of TB, particularly in global regions with high burdens of iron malnutrition. Additionally, nutritional iron interventions to alleviate co‐existing iron insufficiency and iron deficiency anemia may be most effective if targeted after immune or infection‐driven iron redistribution stabilizes after 2 months of TB treatment.Grant Funding Source: ILSI North America, National Science Foundation Graduate Research Fellowship Program

Sodium to potassium ratio and food choices of U.S. adults (384.7)

The relationship between sodium (Na) and potassium (K) has been studied extensively; however, research is limited on the range of intake of sodium to potassium ratio (Na/K) consumed in the U.S. The purpose of this research was to examine the typical ranges of Na, K, and Na/K and the food choices contributing to Na and K across different ratios. Study sample included nationally representative data for adult (20+yr) males (n=5450) and females (n=5731) participating in What We Eat in America (WWEIA) NHANES 2007‐2010. Dietary intake data were obtained from an in‐person 24‐hour recall collected using the 5‐step USDA Automated Multiple‐Pass Method. WWEIA Food Categories were used to define food and beverages as consumed. Mean Na/K was 1.5 (0.01) for males and 1.4 (0.01) for females. Fewer than 2% of adults met the recommended Na/K of 0.49 (2300mg Na/4700mg K). Distribution of Na/K at the 10th, 25th, 50th, 75th and 90th percentile was 0.8, 1.0, 1.4, 1.8, and 2.2, respectively for males; and 0.7, 1.0, 1.3, 1.7 and 2.1 for females. Among individuals with Na/K <1.0 vs Na/K 蠅 1.0, milk and dairy foods contributed 8% vs 6% of daily Na and 12% vs 9% of daily K. Mixed dishes contributed 22% vs 31% of daily Na and 11% vs 20% of daily K, respectively. Fruit and vegetables contributed 12% vs 6% of total daily Na and 25% vs 18% of daily K. These data highlight the importance of food choices to achieve improved sodium to potassium ratios in the U.S. population.Grant Funding Source: ARS,USDA with partial support from ILSI North America

A Web‐based Food Value Analysis Application to Compare Foods at Different Levels of Processing

Numerous factors influence consumer food purchasing decisions including cost, convenience, taste, nutrition, shelf‐life, and food safety risk. We developed a web‐based application for use by nutrition educators to assist consumers in comparing attributes of foods prepared from home recipes to processed forms (e.g., frozen, canned, dry mix). Multiple databases were used to create the attributes of interest: the USDA Food and Nutrient Database for Dietary Studies (FNDDS) and National Nutrient Database for Standard Reference (SR) for selecting foods; FNDDS, SR, and Gladson Nutrition Database for nutrient values using equivalent serving sizes across food forms; USDA MyPyramid Equivalents Database for food groups; Center for Nutrition Policy and Promotion Food Prices Database and Nielsen Homescan data for prices per serving; popular cookbooks for preparation and cooking time; and extension publications and package use‐by dates for shelf‐life and food safety concerns. Based on their preferences, consumers can compare foods at different levels of processing and choose those that can help meet dietary guidelines given constraints they may have on their budgets, time, and food preparation skills. Funding provided by ILSI North America.

Human gut microbiota and its relationship to health and disease

Probiotics are live microorganisms that confer a health benefit on the host when administered in appropriate amounts. Over 700 randomized, controlled, human studies have been conducted with probiotics thus far, with the results providing strong support for the use of probiotics in the clinical prevention or treatment of gastrointestinal tract disorders and metabolic syndrome. The present review is based on webinar presentations that were developed by the American Gastroenterological Association (AGA) in partnership with the International Scientific Association for Probiotics and Prebiotics (ISAPP) and the North American branch of the International Life Sciences Institute (ILSI North America). The presentations provided gastroenterologists and researchers with fundamental and current scientific information on the influence of gut microbiota on human health and disease, as well as clinical intervention strategies and practical guidelines for the use of probiotics and prebiotics.

Decision-Making for Recommendations and Communication Based on Totality of Food-Related Research, an ILSI North America-sponsored Workshop at the Omni Shoreham Hotel, Washington, DC, December 15, 2008

INTRODUCTION The extended abstracts in this report are based on presentations from the Workshop on Decision-Making for Dietary Recommendations and Communication Based on Totality of Food-Related Research, which was organized and sponsored by the Technical Committees on Food and Chemical Safety, Lipids, and Carbohydrates of the North American Branch of the International Life Sciences Institute (ILSI North America) and partially supported by the American Meat Institute Foundation. The workshop was held at the Omni Shoreham Hotel in Washington, DC, on December 15, 2008. The aims of this workshop were to educate the nutrition and food safety communities about current practices in the field of epidemiology regarding the interpretation of weak associations and to stimulate a dialogue around improving the transparency and approaches to the use of epidemiological data in combination with other types of data for the development of public health recommendations. The workshop provided an overview of epidemiological methods, provided case-study examples of applications, and reviewed appropriate interpretation and application of epidemiological data and decision making for recommendations.

Integrating the Totality of Food and Nutrition Evidence for Public Health Decision Making and Communication

The interpretation and integration of epidemiological studies detecting weak associations (RR <2) with data from other study designs (e.g., animal models and human intervention trials) is both challenging and vital for making science-based dietary recommendations in the nutrition and food safety communities. The 2008 ILSI North America “Decision-Making for Recommendations and Communication Based on Totality of Food-Related Research” workshop provided an overview of epidemiological methods, and case-study examples of how weak associations have been incorporated into decision making for nutritional recommendations. Based on the workshop presentations and dialogue among the participants, three clear strategies were provided for the use of weak associations in informing nutritional recommendations for optimal health. First, enable more effective integration of data from all sources through the use of genetic and nutritional biomarkers; second, minimize the risk of bias and confounding through the adoption of rigorous quality-control standards, greater emphasis on the replication of study results, and better integration of results from independent studies, perhaps using adaptive study designs and Bayesian meta-analysis methods; and third, emphasize more effective and truthful communication to the public about the evolving understanding of the often complex relationship between nutrition, lifestyle, and optimal health.

The definition of dietary fiber – discussions at the Ninth Vahouny Fiber Symposium: building scientific agreement

A definition for dietary fiber was adopted in June 2009 by the Codex Alimentarius Commission based on the recommendation for endorsement of the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) in November 2008. The definition listed three categories of carbohydrate polymers that are not hydrolyzed by the endogenous enzymes in the small intestine of humans. However, the definition left the inclusion of carbohydrates with degrees of polymerization (DP) in the range of 3 and 9 to the discretion of national authorities and left the ‘physiological effect(s) of benefit to health’ as undefined. The ILSI Europe and ILSI North America's committees on dietary carbohydrates organized a forum at the Ninth Vahouny Fiber Symposium in 2010 to discuss these implementation issues with the objective of building scientific consensus on how to resolve them. The results of this session are encouraging and indicated that the scientific community agrees on maintaining a worldwide consensus regarding the inclusion of non-digestible carbohydrates with ≥DP3 as dietary fiber and on a core, non-exhaustive list of beneficial physiological effects that dietary fibers have. These results are consistent with previous worldwide agreements.

Functional foods for health promotion: state-of-the-science on dietary flavonoids�Extended abstracts from the 12thAnnual Conference on Functional Foods for Health Promotion, April 2009

The extended abstracts in this report are based on presentations from the 12(th) Special Conference on Functional Foods for Health Promotion, cosponsored by the North American branch of the International Life Sciences Institute (ILSI North America) Project Committee on Flavonoids and the American Society for Nutrition at the Experimental Biology meeting in April 2009. The theme of this year's special conference was "State-of-the-Science on Dietary Flavonoids." The conference began with a general introduction and overview of flavonoids and their presence in the diet as well as the estimated intake levels in the US population. Subsequent presentations addressed issues pertaining to study design and interpretation, mechanisms of action, and the potential health impacts related to inflammation, the vasculature, and the brain. The present summary of the current science indicates that dietary flavonoids, particularly flavanols, show promising potential for reducing cardiovascular disease risk via reduction of inflammation and improvement in vascular function. However, the existing data must be interpreted cautiously, with consideration given to the compound tested (i.e., parent or metabolite), the use of controls, and the practicality of the concentrations used. While more data are needed on the long-term health impacts of dietary flavonoids in humans, including the efficacious dose, current data indicate it may soon be possible to develop public health messages about flavonoid-rich foods.

Letter to the Editor

Letter to the Editor

Comparison of conjugated linoleic acid (CLA) and conjugated nonadecadienoic acid (CNA) with regard to lipid metabolism in mice

It has been reported that conjugated nonadecadienoic acid (CNA) exhibits modulation of body fat with mechanisms that are similar to those of CLA. In this current investigation, we compared the effects of CNA and CLA on various feeding period, in particular studying lipid metabolism from white adipose tissue. One hundred thirty 10 week‐old male CD‐1 mice were fed a semi‐purified powdered diet with 20% total fat based on the AIN‐93 diet. After a 2‐week adaptation period, mice were randomly assigned into control and 2 treatment groups (0.5 w/w% CLA and 0.1 w/w% CNA). Relative mRNA expression of peroxisome proliferator‐activated receptor‐γ (PPAR‐γ), acetyl‐CoA carboxylase (ACC), fatty acid synthase (FAS), hormone‐sensitive lipase (HSL), and glucose transporter 4 (GLUT4) were determined at week 0, 2, 4, 8, and 12 by real time PCR from the white adipose tissue. The effect of CNA treatment on total adipose tissue mass was less effective than CLA over time. HSL mRNA expression was significantly increased by CNA at week 8 and 12, while CLA had no effect at any time point. PPAR‐γ expression was significantly decreased by both CNA and CLA after week 2 and 4, respectively, and the decreased expression of PPAR‐γ was maintained for 12 weeks. FAS expression was enhanced by CNA during week 4 and 8 and by CLA at all time points. ACC expression was increased by CNA longer than 8 weeks, while CLA increased it at all time points. GLUT4 expression was decreased at week 8 by CNA but not by CLA. In conclusion, CNA reduces body fat mass similar to CLA. Although CNA shares mechanisms with CLA on body fat control and lipid metabolism, there were differences in the effects on lipid metabolism between CNA and CLA over time. Supported by AHA SDG and ILSI North America

Conjugated nonadecadienoic acid (CNA) shares similar molecular mechanisms with conjugated linoleic acid (CLA)

Previously, conjugated nonadecadienoic acid (CNA) has been shown to reduce body fat dose‐dependently and it was more effective than CLA in mice. In this study, we hypothesized that the effects of dietary CNA on expression of genes involving fat and energy metabolism are similar to CLA's. Fifty female 129Sv/J retired breeders were housed in individual wire‐bottomed cages in a windowless room with a 12‐h light‐dark cycle and fed a semi‐purified powdered diet based on the AIN‐93 diet with 20% total fat. After a week adaptation period, mice were randomly assigned into control and 4 groups of treatment (0.5% of CLA, 0.01%, 0.05%, or 0.1% of CNA as weight of diet). Peroxisome proliferator‐activated receptor‐γ (PPAR‐γ), acetyl‐CoA carboxylase (ACAC), fatty acid synthase (FAS), lipoprotein lipase (LPL), hormone‐sensitive lipase (HSL), glucose transporter 4 (GLUT4), and uncoupling protein‐2 (UCP‐2) from white adipose tissue, and PPAR‐α from the liver were quantified by real‐time quantitative PCR. The mRNA expressions of FAS, ACAC, UCP‐2, and PPAR‐γ in the adipose tissue were decreased by CLA as well as CNA. Meanwhile HSL expression was enhanced by CNA but not by CLA. Hepatic PPAR‐α mRNA expression was increased by both CNA and CLA. Overall, the effects of 0.1% dietary CNA on expression of genes involving fat and energy metabolism were similar to that of 0.5% dietary CLA. This supports our hypothesis that dietary CNA has an effect similar to CLA on lipid metabolism at the molecular level, however, differences on lipolysis may help explain the improved efficacy of CNA on body fat reduction compared to CLA. Supported by AHA SDG and ILSI North America

Flavonoids and Heart Health: Proceedings of the ILSI North America Flavonoids Workshop, May 31–June 1, 2005, Washington, DC1, , ,

This article provides an overview of current research on flavonoids as presented during a workshop entitled, “Flavonoids and Heart Health,” held by the ILSI North America Project Committee on Flavonoids in Washington, DC, May 31 and June 1, 2005. Because a thorough knowledge and understanding about the science of flavonoids and their effects on health will aid in establishing dietary recommendations for bioactive components such as flavonoids, a systematic review of the science of select flavonoid classes (i.e., flavonols, flavones, flavanones, isoflavones, flavan-3-ols, anthocyanins, and proanthocyanidins) was presented. The objectives of the workshop were to 1) present and discuss current research on flavonoid intake and the relation between flavonoids and heart health; 2) develop information that could lead to expert consensus on the state-of-the-science of dietary intake of flavonoids on heart health; and 3) summarize and prioritize the research needed to establish the relations between specific flavonoids and heart health. Presentations included the basics of the biology of flavonoids, including the types and distribution in foods, analytical methodologies used to determine the amounts in foods, the bioavailability, the consumption patterns and potential biomarkers of intake, risk assessment and safety evaluation, structure/function claims, and the proposed mechanism(s) of the relation between certain flavonoids and heart health endpoints. Data presented support the concept that certain flavonoids in the diet can be associated with significant health benefits, including heart health. Research gaps were identified to help advance the science.