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Impact of Ingested Live Microbes on Health: An evidence Map


Human gut microbiome research has linked imbalances in the gut microbiota with several suboptimal health conditions. Consequently, the application of dietary interventions including foods (i.e., fermented foods [FFs]) and food supplements (i.e., probiotics) that contain live microorganisms to positively impact the gut microbiota and, in turn, health, has been the subject of much attention. Evidence indicates that consumption of FFs as well as probiotics can be protective against a wide range of ailments. However, despite the large body of evidence relating to the health benefits of specific probiotics and FFs, there is an absence of recommended dietary allowances (RDA) relating to the consumption of live microbes. This is partly due to an incomplete understanding of the more general health benefits imparted by ingesting live microbes. To address this, the research team will conduct an in-depth evidence mapping exercise to understand the breadth of evidence linking ingestion of live microbes with potential health benefits. This evidence mapping exercise will form a key step in a process towards determining the merits of recommending a level of live microbe intake that can be linked to positive health outcomes.

Institution: Agriculture and Food Development Authority, Republic of Ireland
Principal Investigator: Paul Cotter, PhD
Year Awarded: 2020

Learn more about our work on Live Dietary Microbes with this summary handout.

Read More: Mapping the Available Evidence on the Impact of Ingested Live Microbes on Health: A Scoping Review Protocol

Read More: The Impact of Live Dietary Microbes on Health: A Scoping Review

View this project on the Center for Open Science's Open Science Framework.

This project was supported by the IAFNS Gut Microbiome Committee


Specific Essential Amino Acid Intakes and Health Benefits Among Older Adults

Protein and specific amino acid intakes are among the lifestyle factors that can mitigate muscle loss among older adults. Lean mass is associated with metabolic and functional health in older age. Clear linkages between specific amino acids and health outcomes will inform future recommended intakes. Furthermore, comparing the composition of essential amino acids in differing eating patterns (recommended as well as popular trends) can identify opportunities to improve essential amino acid intakes.

Institution: Florida State University
Principal Investigator: Claire Berryman, PhD
Year: 2020

Read More: Amino Acid Intake And Conformance With The Dietary Reference Intakes In The United States: Analysis Of The National Health And Nutrition Examination Survey, 2001–2018

View this project on the Center for Open Science’s Open Science Framework.

This work was supported by the IAFNS Protein Committee.

The Identification of Microbially-Derived Metabolites as Biomarkers: What Changes of Which Metabolites Matter for Health?

Identifying microbially‐derived metabolites that may serve as biomarkers for health, or metabotyping, is a necessary step to understanding the role of the microbiome in human health. Ultimately, knowing what metabolites (including presence and quantity) matter for health can inform development of a nutritional strategy for health benefits and the prevention of adverse health outcomes such as metabolic syndrome, type 2 diabetes, and cardiovascular disease. The specific questions to be addressed in this project are: 1) What diet‐derived and gut‐derived metabolites and/or metabotypes have been linked to specific health outcomes or are markers of health outcomes?; and 2) What types of evidence are available on the relationship between those metabolites/metabotypes and specific health outcomes?

Institution: Johns Hopkins University
Principal Investigator: Karen Robinson, PhD
Year Awarded: 2020

Read More: Diet-Related And Gut-Derived Metabolites And Health Outcomes: A Scoping Review

This project was supported by the IAFNS Gut Microbiome Committee

Development of a Research Framework for Evidence-Based Assessment of Potential Carcinogens in Human Diets

Risk assessment of chemicals that are potentially carcinogenic in humans often relies on extrapolation from carcinogenicity bioassays. There is a growing belief in the scientific community that evidence-based risk assessment can replace historical, over-protective guidance-based approaches. However, there is no consensus within the scientific community on an approach or framework for the application of an evidence-based risk assessment. This project will develop such an approach by, first, categorizing potential exposure and mode of action scenarios leading to a carcinogenic response, followed by development of a framework based on sectoral examples such as hepatically activated electrophiles that are potential genotoxic carcinogens.

Institution: Cardno ChemRisk
Principal Investigator: Andrew Maier, PhD, DABT
Year Awarded: 2020

This project is supported by the IAFNS Food and Chemical Safety Committee.

Guiding Principles for Sodium Reduction Strategies in Food: A Compendium

Significant knowledge exists about sodium reduction in foods, some of which is captured in Food & Drug Administration guidance documents. But progress made to date has not been captured in a publicly accessible format, and where it is available, it is not in a domain typically accessed by the public health community. Developing a compendium of available tools—including their possibilities, challenges and nuances—relevant to product development would be informative across stakeholders with an interest in addressing this persistent public health concern. This project will result in a publication that will provide evidence-based tools available for sodium reduction, organized by specific food categories to conjoin the wide range of resources into a compendium relevant to food industry applications.

Institution: University of Illinois at Urbana-Champaign
Principal Investigator: Soo-Yeun Lee, PhD
Amount: $80,000
Year Awarded: 2020

Read more:

View this project on the Center for Open Science's Open Science Framework.

Access the Sodium Reduction Science and Strategies Database here.

Learn more about the IAFNS Sodium in Foods and Health Implications Committee.

Effect of Low-Calorie Sweetener Intake on Glycemic Response

Globally, dietary guidance recommends reducing added and total sugars in the diet to reduce caloric intake and chronic disease. Low-calorie sweeteners (LCS) present an option for reducing calories while providing sweetness in the diet, but questions remain regarding the effects of LCS on health, including its effects on glycemic response and diabetes. This project will systematically review randomized controlled trials to determine the relationship between LCS and glycemic response in adults.

Institution: Glycemia Consulting Inc.
Principal Investigator: 
John Sievenpiper, BASc, MD, MSc, PhD, FRCPC
Year Awarded: 2020

Read more: The Effect of Non-Nutritive Sweetened Beverages on Postprandial Glycemic and Endocrine Responses: A Systematic Review and Network Meta-Analysis

Learn more about the IAFNS Low-Calorie Sweeteners Committee.

Standardizing Method and Development of Normal Values to Measure Human Small Intestinal and Colonic Permeability

Maintaining—or restoring to normal—gut barrier function is not currently recognized as a physiologic benefit of fiber consumption, in part due to lack of agreement by experts in the field on how to define and measure normal gut barrier function in human nutrition research. An IAFNS sponsored expert panel published an article in 2019 summarizing the foundational science related to normal gut structure and function as well as how to measure it. The panel’s recommended next step is to standardize a method for measuring gut permeability in human subjects and apply the method to initiate the process of quantifying the range of distribution in the general healthy public. The objective is to assess whether variation in the range of fiber representing typical to recommended intakes in the American diet is a critical factor in establishing this standardized method.

Institution: Mayo Clinic
Principal Investigator: Michael Camilleri
Date: 2019

Read more: Development and Validation of Test for 'Leaky Gut' Small Intestinal and Colonic Permeability Using Sugars in Healthy Adults

View this project on the Center for Open Science's Open Science Framework.

This project is supported by the IAFNS Carbohydrates Committee.

Metabolic and Physiological Properties of Rare Sugars Review Paper

Rare sugars are monosaccharides or disaccharides that exist in small quantities in nature and have unique metabolic and physiological properties that help distinguish them from more commonly consumed sugars like fructose and glucose. Due to their unique properties, rare sugars offer potential health benefits as part of an overall healthy diet pattern, including slower intestinal absorption rate, lower caloric contribution, improved glycemic response, prebiotic function and lower risk of tooth decay. However, the scientific literature does not contain a publication that highlights potential physiological benefits and describes the unique properties of several rare sugars within a single document. The aim of this work is to develop a narrative overview summarizing the metabolic and physiological properties of uniquely metabolized sugars as compared to the primary monosaccharides and disaccharides in the diet.

Institution: Toronto 3D Knowledge Synthesis & Clinical Trials Foundation
Principal Investigator: John Sievenpiper, PhD
Year: 2019

Read more: Rare Sugars and their Health Effects in Humans: A Systematic Review and Narrative Synthesis of the Evidence from Human Trials

View this project on the Center for Open Science’s Open Science Framework.

This project was supported by the IAFNS Carbohydrates Committee.

Global Comparison of How Short-Term Blood Glucose Response to Food is Measured and Translated

The wide range of methods used to describe the impact of food on short-term glycemic response makes it challenging to apply research results broadly, including but not limited to its use on food labels. The choice of approach should be informed by selecting a validated method that translates into a meaningful consumer and public health message. Informed decision-making, rather than historical use, can lead to increased global consistency in both choice of method and translation on labels. The aim of this project is to define short-term glycemic response, collect various measurement methods, and create tables that reflect those methods and possible messages.

Institution: Paula Trumbo, PhD
Principal Investigator: Paula Trumbo, PhD
Year Awarded: 2019

Read more: Global Evaluation of the Use of Glycaemic Impact Measurements to Food or Nutrient Intake

This project is supported by the IAFNS Carbohydrates Committee.

Associations Between Blood Fatty Acids and Sleep Duration: A Pooled Analysis of Prospective Cohort Studies

Sleep is a key lifestyle factor that both affects and is affected by diet. Data pooled from studies in the FORCE consortium will be examined to determine the relationship between blood fatty acid levels and either too much or too little sleep.

Institution: University of British Columbia
Principal Investigator: Rachel Murphy, PhD
Year Awarded: 2018

Read more: PUFA ω-3 and ω-6 Biomarkers and Sleep: A Pooled Analysis of Cohort Studies on Behalf of the Fatty Acids and Outcomes Research Consortium (FORCE)

This work was supported by IAFNS Dietary Lipids Committee.