Conserved and variable responses of the gut microbiome to resistant starch type 2

Resistant starch type 2 (RS2), a dietary fiber comprised solely of glucose, has been extensively studied in clinical trials and animal models for its capacity to improve metabolic and systemic health. Because the health modulatory effects of RS2 and other dietary fibers are thought to occur through modification of the gut microbiome, those studies frequently include assessments of RS2-mediated changes to intestinal microbial composition and function. In this review, we identify the conserved responses of the gut microbiome among 13 human and 35 animal RS2 intervention studies. Consistent outcomes of RS2 interventions include reductions in bacterial α-diversity; increased production of lumenal short-chain fatty acids; and enrichment of Ruminococcus bromii, Bifidobacterium adolescentis, and other gut taxa. Different taxa are usually responsive in animal models, and many RS2-mediated changes to the gut microbiome vary within and between studies. The root causes for this variation are examined with regard to methodological and analytical differences, host genetics and age, species differences (eg, human, animal), health status, intervention dose and duration, and baseline microbial composition. The significant variation found for this single dietary compound highlights the challenges in targeting the gut microbiome to improve health with dietary interventions. This knowledge on RS2 also provides opportunities to improve the design of nutrition studies targeting the gut microbiome and to ultimately identify the precise mechanisms via which dietary fiber benefits human health.     

Effects of dietary fiber and its components on metabolic health

Dietary fiber and whole grains contain a unique blend of bioactive components including resistant starches, vitamins, minerals, phytochemicals and antioxidants. As a result, research regarding their potential health benefits has received considerable attention in the last several decades. Epidemiological and clinical studies demonstrate that intake of dietary fiber and whole grain is inversely related to obesity, type two diabetes, cancer and cardiovascular disease (CVD). Defining dietary fiber is a divergent process and is dependent on both nutrition and analytical concepts. The most common and accepted definition is based on nutritional physiology. Generally speaking, dietary fiber is the edible parts of plants, or similar carbohydrates, that are resistant to digestion and absorption in the small intestine. Dietary fiber can be separated into many different fractions. Recent research has begun to isolate these components and determine if increasing their levels in a diet is beneficial to human health. These fractions include arabinoxylan, inulin, pectin, bran, cellulose, β-glucan and resistant starch. The study of these components may give us a better understanding of how and why dietary fiber may decrease the risk for certain diseases. The mechanisms behind the reported effects of dietary fiber on metabolic health are not well established. It is speculated to be a result of changes in intestinal viscosity, nutrient absorption, rate of passage, production of short chain fatty acids and production of gut hormones. Given the inconsistencies reported between studies this review will examine the most up to date data concerning dietary fiber and its effects on metabolic health.     

Fiber and Prebiotics: Mechanisms and Health Benefits

The health benefits of dietary fiber have long been appreciated. Higher intakes of dietary fiber are linked to less cardiovascular disease and fiber plays a role in gut health, with many effective laxatives actually isolated fiber sources. Higher intakes of fiber are linked to lower body weights. Only polysaccharides were included in dietary fiber originally, but more recent definitions have included oligosaccharides as dietary fiber, not based on their chemical measurement as dietary fiber by the accepted total dietary fiber (TDF) method, but on their physiological effects. Inulin, fructo-oligosaccharides, and other oligosaccharides are included as fiber in food labels in the US. Additionally, oligosaccharides are the best known “prebiotics”, “a selectively fermented ingredient that allows specific changes, both in the composition and/or activity in the gastrointestinal microflora that confers benefits upon host well-bring and health.” To date, all known and suspected prebiotics are carbohydrate compounds, primarily oligosaccharides, known to resist digestion in the human small intestine and reach the colon where they are fermented by the gut microflora. Studies have provided evidence that inulin and oligofructose (OF), lactulose, and resistant starch (RS) meet all aspects of the definition, including the stimulation of Bifidobacterium, a beneficial bacterial genus. Other isolated carbohydrates and carbohydrate-containing foods, including galactooligosaccharides (GOS), transgalactooligosaccharides (TOS), polydextrose, wheat dextrin, acacia gum, psyllium, banana, whole grain wheat, and whole grain corn also have prebiotic effects.     

Relationship between molecular structure of cereal dietary fiber and health effects: focus on glucose/insulin response and gut health

Epidemiological and animal data show associations between whole grain and dietary fiber intakes and disease risk reduction. Dietary fiber can be considered a "black box" since its molecular structure can vary significantly. Limited data are available linking the health effects of dietary fiber to certain molecular structures. The present review was conducted to examine the existing knowledge of structure/effect relationships with a focus on human intervention studies that examined the relationships between the molecular structure of cereal dietary fiber and both the blood glucose and insulin responses and gut health. An extensive search of the existing literature was conducted using the PubMed database for the period 1993-2008. Of 48 publications originally identified using the search criteria, 13 provided molecular information in conjunction with fiber type. Several indications show a link between molecular structure and physiological effects. Limited data from human intervention trials are available to verify hypotheses derived from in vitro studies that relate the molecular structure of cereal dietary fiber to both insulin and glucose response and gut health.     

Position of the American Dietetic Association: health implications of dietary fiber

It is the position of the American Dietetic Association that the public should consume adequate amounts of dietary fiber from a variety of plant foods. Populations that consume more dietary fiber have less chronic disease. In addition, intake of dietary fiber has beneficial effects on risk factors for developing several chronic diseases. Dietary Reference Intakes recommend consumption of 14 g dietary fiber per 1,000 kcal, or 25 g for adult women and 38 g for adult men, based on epidemiologic studies showing protection against cardiovascular disease. Appropriate kinds and amounts of dietary fiber for children, the critically ill, and the very old are unknown. The Dietary Reference Intakes for fiber are based on recommended energy intake, not clinical fiber studies. Usual intake of dietary fiber in the United States is only 15 g/day. Although solubility of fiber was thought to determine physiological effect, more recent studies suggest other properties of fiber, perhaps fermentability or viscosity are important parameters. High-fiber diets provide bulk, are more satiating, and have been linked to lower body weights. Evidence that fiber decreases cancer is mixed and further research is needed. Healthy children and adults can achieve adequate dietary fiber intakes by increasing variety in daily food patterns. Dietary messages to increase consumption of high-fiber foods such as whole grains, legumes, fruits, and vegetables should be broadly supported by food and nutrition professionals. Consumers are also turning to fiber supplements and bulk laxatives as additional fiber sources. Few fiber supplements have been studied for physiological effectiveness, so the best advice is to consume fiber in foods. Look for physiological studies of effectiveness before selecting functional fibers in dietetics practice.     

Defining Nutritional and Functional Niches of Legumes: A Call for Clarity to Distinguish a Future Role for Pulses in the Dietary Guidelines for Americans

Legume food crops can contribute to the solution of diet-related public health challenges. The rich diversity of the botanical family Fabaceae (Leguminosae) allows legumes to fill numerous nutritional niches. Pulses (i.e., a subgroup of legumes including chickpeas, cowpeas, dry beans, dry peas, and lentils) are a nutrient-dense food that could play a key role in eliminating the dramatic underconsumption of dietary fiber and potassium, two dietary components of public health concern, all while maintaining a caloric intake that promotes a healthy weight status. However, incorrect use of terminology—in the commercial and scientific literature as well as in publications and materials prepared for the consuming public—creates confusion and represents a barrier to dissemination of clear dietary guideline messaging. The use of accurate terminology and a simple classification scheme can promote public health through differentiation among types of legumes, better informing the development and implementation of nutritional policies and allowing health care professionals and the public to capitalize on the health benefits associated with different legumes. Although inconsistent grouping of legumes exists across countries, the recently released 2020–2025 Dietary Guidelines for Americans (DGA) were chosen to illustrate potential challenges faced and areas for clarification. In the 2020–2025 DGA, pulses are included in two food groups: the protein food group and ‘beans, peas, lentils’ vegetable subgroup. To evaluate the potential of pulses to contribute to intake of key dietary components within calorie recommendations, we compared 100 kilocalorie edible portions of pulses versus other foods. These comparisons demonstrate the unique nutritional profile of pulses and the opportunity afforded by this type of legume to address public health concerns, which can be greatly advanced by reducing confusion through global harmonization of terminology.     

Alternative Dietary Fiber Sources in Companion Animal Nutrition

The US has a pet population of approximately 70 million dogs and 74 million cats. Humans have developed a strong emotional bond with companion animals. As a consequence, pet owners seek ways to improve health, quality of life and longevity of their pets. Advances in canine and feline nutrition have contributed to improved longevity and well-being. Dietary fibers have gained renewed interest in the pet food industry, due to their important role in affecting laxation and stool quality. More recently, because of increased awareness of the beneficial effects of dietary fibers in health, as well as the popularity of functional foods and holistic and natural diets, alternative and novel carbohydrates have become widespread in human and pet nutrition. Fiber sources from cereal grains, whole grains and fruits have received increasing attention by the pet food industry and pet owners. While limited scientific information is available on the nutritional and nutraceutical properties of alternative fiber sources, studies indicate that corn fiber is an efficacious fiber source for pets, showing no detrimental effects on palatability or nutrient digestibility, while lowering the glycemic response in adult dogs. Fruit fiber and pomaces have good water-binding properties, which may be advantageous in wet pet food production, where a greater water content is required, along with low water activity and a firm texture of the final product. Rice bran is a palatable fiber source for dogs and may be an economical alternative to prebiotic supplementation of pet foods. However, it increases the dietary requirement of taurine in cats. Barley up to 40% in a dry extruded diet is well tolerated by adult dogs. In addition, consumption of complex carbohydrates has shown a protective effect on cardiovascular disease and oxidative stress. Alternative fiber sources are suitable ingredients for pet foods. They have been shown to be nutritionally adequate and to have potential nutraceutical properties.     

Pulse consumption, satiety, and weight management

The prevalence of obesity has reached epidemic proportions, making finding effective solutions to reduce obesity a public health priority. One part of the solution could be for individuals to increase consumption of nonoilseed pulses (dry beans, peas, chickpeas, and lentils), because they have nutritional attributes thought to benefit weight control, including slowly digestible carbohydrates, high fiber and protein contents, and moderate energy density. Observational studies consistently show an inverse relationship between pulse consumption and BMI or risk for obesity, but many do not control for potentially confounding dietary and other lifestyle factors. Short-term (≤1 d) experimental studies using meals controlled for energy, but not those controlled for available carbohydrate, show that pulse consumption increases satiety over 2-4 h, suggesting that at least part of the effect of pulses on satiety is mediated by available carbohydrate amount or composition. Randomized controlled trials generally support a beneficial effect of pulses on weight loss when pulse consumption is coupled with energy restriction, but not without energy restriction. However, few randomized trials have been conducted and most were short term (3-8 wk for whole pulses and 4-12 wk for pulse extracts). Overall, there is some indication of a beneficial effect of pulses on short-term satiety and weight loss during intentional energy restriction, but more studies are needed in this area, particularly those that are longer term (≥1 y), investigate the optimal amount of pulses to consume for weight control, and include behavioral elements to help overcome barriers to pulse consumption.     

2型糖尿病患者膳食纤维摄入量与肠道菌群的关联——基于一项随机对照试验的数据再分析

目的 分析2型糖尿病患者膳食纤维摄入量与肠道菌群的关联,发现相关差异菌群,为改善患者日常饮食,调节肠道菌群,促进健康提供依据。方法 采用横断面研究设计,以参与一项健康素养和体力活动干预随机对照试验的356名2型糖尿病患者为研究对象。总热能和膳食纤维摄入量基于3 d 24 h膳食调查数据和中国食物成分表计算。对粪便菌群DNA进行16S rDNA V4高变区测序,采用Qiime2软件进行生物信息学分析。多变量线性回归模型(multivariate analysis by linear models, MaAsLin)方法和广义线性模型用于获得与膳食纤维摄入量有关的肠道菌群。结果 研究对象的膳食纤维摄入量处于较低水平,中位摄入量(四分位间距)仅7.4(5.5, 9.7) g/d。未发现膳食纤维摄入量高低与肠道菌群Alpha多样性有关,但基于Jaccard距离矩阵(PERMANOVA P=0.016)计算的Beta多样性在两组间差异有统计学意义。低膳食纤维摄入组有较高丰度的梭杆菌属(Fusobacterium)、柯林斯菌属(Collinsella)和普雷沃菌属(Prevotella),而高膳食...     

Resistant Starch Content in Foods Commonly Consumed in the United States: A Narrative Review

Resistant starch (RS; types 1 to 5) cannot be digested in the small intestine and thus enters the colon intact, with some types capable of being fermented by gut microbes. As a fiber, types 1, 2, 3, and 5 are found naturally in foods, while types 2, 3, and 4 can be added to foods as a functional ingredient. This narrative review identifies RS content in whole foods commonly consumed in the United States. Scientific databases (n=3) were searched by two independent researchers. Ninety-four peer-reviewed articles published between 1982 and September 2018 were selected in which the RS was quantified and the food preparation method before analysis was suitable for consumption. The RS from each food item was adjusted for moisture if the RS value was provided as percent dry weight. Each food item was entered into a database according to food category, where the weighted mean±weighted standard deviation was calculated. The range of RS values and overall sample size for each food category were identified. Breads, breakfast cereals, snack foods, bananas and plantains, grains, pasta, rice, legumes, and potatoes contain RS. Foods that have been cooked then chilled have higher RS than cooked foods. Foods with higher amylose concentrations have higher RS than native varieties. The data from this database will serve as a resource for health practitioners to educate and support patients and clients interested in increasing their intake of RS-rich foods and for researchers to formulate dietary interventions with RS foods and examine associated health outcomes.     

Dietary fiber and body weight

OBJECTIVE: This review provides an update of recent studies of dietary fiber and weight and includes a discussion of potential mechanisms of how dietary fiber can aid weight loss and weight maintenance. METHODS: Human studies published on dietary fiber and body weight were reviewed and summarized. Dietary fiber content of popular low-carbohydrate diets were calculated and are presented. RESULTS: Epidemiologic support that dietary fiber intake prevents obesity is strong. Fiber intake is inversely associated with body weight and body fat. In addition, fiber intake is inversely associated with body mass index at all levels of fat intake after adjusting for confounding factors. Results from intervention studies are more mixed, although the addition of dietary fiber generally decreases food intake and, hence, body weight. Many mechanisms have been suggested for how dietary fiber aids in weight management, including promoting satiation, decreasing absorption of macronutrients, and altering secretion of gut hormones. CONCLUSION: The average fiber intake of adults in the United States is less than half recommended levels and is lower still among those who follow currently popular low-carbohydrate diets, such as Atkins and South Beach. Increasing consumption of dietary fiber with fruits, vegetables, whole grains, and legumes across the life cycle is a critical step in stemming the epidemic of obesity found in developed countries. The addition of functional fiber to weight-loss diets should also be considered as a tool to improve success.     

Dietary fiber and bowel function in tube-fed patients.

In tube-fed patients, dietary fiber is often used to manage constipation/diarrhea. Dietary fiber consists of water-soluble and insoluble plant compounds that are resistant to digestion by small-bowel enzymes but are fermented to varying degrees by colonic bacteria. Many physiologic effects of fiber may be related to the degree of fermentation. Few controlled studies of fiber-containing tube feedings have been performed. These studies have limitations and are nondefinitive as to whether fiber prevents or controls constipation/diarrhea. Constipation in tube-fed patients has not been shown to respond to mixed soluble/insoluble fiber in the few studies performed to date. Likewise, fiber may be of only limited benefit in controlling diarrhea in acute illness because of such factors as stress or medication. Fiber does play a role in maintaining gut integrity in all patients, whether they have diarrhea or not. Fiber may be recommended as part of a standard tube-feeding regimen to help assure gut mucosal integrity but not specifically to treat constipation/diarrhea. Further studies are necessary before the role of fiber in the management of constipation/diarrhea in tube-fed patients is determined.     

Consumption of Dry Beans, Peas, and Lentils Could Improve Diet Quality in the US Population

The US Department of Agriculture's MyPyramid guidelines introduced a near doubling of the dietary recommendations for vegetables. These recommendations target specific subgroups of vegetables, including dry beans and peas. Dry beans and peas provide an array of nutrients and phytochemicals that have been shown to have beneficial health effects, yet consumption levels in the United States are quite low. Few studies have examined the influence of legume consumption on nutrient intakes. Therefore, the purpose of this study was to assess nutrient and food group intakes of dry bean and pea consumers compared to nonconsumers. Dietary intake data from the 1999-2002 National Health and Nutrition Examination Survey for adults aged ≥19 years was used. Results show that on any given day only 7.9% of adults are consuming dry beans and peas; Mexican Americans or other Hispanics are more likely to be consumers than nonconsumers. Consuming approximately ½ c dry beans or peas resulted in higher intakes of fiber, protein, folate, zinc, iron, and magnesium with lower intakes of saturated fat and total fat. These data support the specific recommendation for dry beans and peas as part of the overall vegetable recommendation. Increased consumption of dry beans and peas—economical and nutrient-rich foods—could improve the diet quality of Americans.     

Prebiotics,Fermentable Dietary Fiber,and Health Claims

Since the 1970s, the positive effects of dietary fiber on health have increasingly been recognized. The collective term “dietary fiber” groups structures that have different physiologic effects. Since 1995, some dietary fibers have been denoted as prebiotics, implying a beneficial physiologic effect related to increasing numbers or activity of the gastrointestinal microbiota. Given the complex composition of the microbiota, the demonstration of such beneficial effects is difficult. In contrast, an exploration of the metabolites of dietary fiber formed as a result of its fermentation in the colon offers better perspectives for providing mechanistic links between fiber intake and health benefits. Positive outcomes of such studies hold the promise that claims describing specific health benefits can be granted. This would help bridge the “fiber gap”—that is, the considerable difference between recommended and actual fiber intakes by the average consumer.     

Impact of the proposed definition of dietary fiber on nutrient databases

Many definitions of dietary fiber exist worldwide, some based on analytical methods and others physiologically based. In March 2001, the Food and Nutrition Board, Institute of Medicine of the National Academy of Sciences released proposed definitions for dietary fiber developed by a panel of experts. The panel held three meetings and a workshop to review existing definitions of dietary fiber, review methods to measure dietary fiber, and receive input from scientists, food companies, consumers, and other interested parties on their viewpoints on a definition for dietary fiber. Based on the Panel's deliberations, the following definitions were proposed:

• Dietary Fiber consists of nondigestible carbohydrates and lignin that are intrinsic and intact in plants.
• Functional Fiber consists of isolated, nondigestible carbohydrates that have beneficial physiological effects in humans.
• Total Fiber is the sum of Dietary Fiber and Functional Fiber.
• What impact will these definitions have, if adopted? Currently, dietary fiber is defined as compounds that are isolated by analytical dietary fiber methods accepted by the Association of Official Analytical Chemists (AOAC) rather than a formal definition that includes fiber's role in human health. New methods will need to be developed to reflect the accepted definitions for dietary fiber. Additionally, the committee felt that the terms “soluble” and “insoluble” fiber are not meaningful and should no longer be used in labeling. Finally, compounds such as resistant starch and inulin, which do not qualify as dietary fiber under current AOAC methods could be considered Functional Fiber if they show beneficial physiological effects in humans.

     

Therapeutic Potential of Various Plant-Based Fibers to Improve Energy Homeostasis via the Gut Microbiota

Obesity is due in part to increased consumption of a Western diet that is low in dietary fiber. Conversely, an increase in fiber supplementation to a diet can have various beneficial effects on metabolic homeostasis including weight loss and reduced adiposity. Fibers are extremely diverse in source and composition, such as high-amylose maize, β-glucan, wheat fiber, pectin, inulin-type fructans, and soluble corn fiber. Despite the heterogeneity of dietary fiber, most have been shown to play a role in alleviating obesity-related health issues, mainly by targeting and utilizing the properties of the gut microbiome. Reductions in body weight, adiposity, food intake, and markers of inflammation have all been reported with the consumption of various fibers, making them a promising treatment option for the obesity epidemic. This review will highlight the current findings on different plant-based fibers as a therapeutic dietary supplement to improve energy homeostasis via mechanisms of gut microbiota.     

The public health rationale for increasing dietary fibre: Health benefits with a focus on gut microbiota

Dietary fibre can be considered an essential macronutrient which feeds our gut microbiota, thus enabling the optimal functioning of this ‘virtual organ’. Recommended daily intakes range from 25 to 38 g/day. However, most individuals fail to reach this target and may consume <50% of the recommended amount. Poor dietary fibre intake is associated with an imbalanced gut microbiota leading to reduced diversity and increased abundance of non‐beneficial microorganisms at the expense of beneficial ones. Inflammation is a recognised physiological effect of such a microbiome structure and is a common denominator in several non‐communicable diseases associated with the Western lifestyle/developed world including obesity, cardiovascular disease, type 2 diabetes and colorectal cancer. Yet increasing dietary fibre intake can reduce risk factors associated with these diseases and may even improve prognosis. Several food manufacturers have now developed strategies to increase the fibre content of foods. However, research gaps still remain. In particular, dietary fibre is composed of various non‐digestible carbohydrates and the exact effect of each of these on the gut microbiota is currently unknown. The links between dietary fibre and disease risk are generally associative. Understanding the biological mechanisms will require deeper insight into the impact of the gut microbiota on health. Furthermore, gut microbiota research has shown significant inter‐individual variation meaning that some individuals may not respond to certain dietary fibres owing to the absence of specific microorganisms. Understanding how the different fibre types influence the microbiota, combined with knowledge of an individual’s microbiota, should lead to fibre‐led, microbiota‐based dietary advice.     

Relationship of prebiotics and food to intestinal microflora

Dietary carbohydrates that escape digestion in the small intestine, undergo bacterial fermentation in the colon. This process affects the microbial ecology of the gastrointestinal tract and influences gut metabolism and function. Prebiotics are non-digestible but fermentable oligosaccharides that are specifically designed to change the composition and activity of the intestinal microbiota with the prospect to promote the health of the host. Dietary fiber and non-digestible oligosaccharides are the main growth substrates of gut microorganisms. Their fermentation results in the acidification of the colonic contents and the formation of short chain fatty acids which serve as fuels in different tissues and may play a role in the regulation of cellular processes. Prebiotics specifically stimulate the growth of endogenous microbial population groups such as bifidobacteria and lactobacilli which are perceived as being beneficial to human health. In spite of the interesting nutritional properties of prebiotics it is questionable whether a wholesome diet rich in fruit and vegetables needs to be supplemented with prebiotics for optimal health effects.     

Diet manipulation and prevention of aging, cancer and autoimmune disease

PURPOSE OF REVIEW: Dietary supplementation and other dietary regimens have become increasingly popular in the US population. Information regarding how different dietary constituents interact when consumed simultaneously is needed. This review examines the recent literature on how different dietary constituents may interact physiologically when consumed in combination. Furthermore, the potential human relevance of calorie restriction and nonclassical function of vitamin E is discussed. RECENT FINDINGS: Long-term calorie restriction in monkeys has shown similar beneficial effects as has been shown in rodents. Limited calorie restriction studies in humans have shown promise in reducing the incidence of heart disease and breast cancer. The combination of calorie restriction and omega-3 fatty acids may be a more potent antiinflammatory diet than either regimen alone. The type of fiber that is most protective against colon cancer may be dependent on the type of dietary fat consumed simultaneously. Vitamin E derivatives that possess no antioxidant activity may be potent inhibitors of cancer, but not normal, cell growth. SUMMARY: Dietary modification has shown its greatest beneficial effect when started prior to or immediately after the onset of disease. Also, understanding how the subtypes or isoforms of nutrients function is important since their physiological effects may be drastically different. It is important to understand the entire dietary profile of an individual when making dietary recommendations because one nutrient, or dietary ingredient, may enhance or cancel out the beneficial effects of another dietary ingredient.     

Effect of Gut Microbial Enterotypes on the Association between Habitual Dietary Fiber Intake and Insulin Resistance Markers in Mexican Children and Adults

Dietary fiber (DF) is a major substrate for the gut microbiota that contributes to metabolic health. Recent studies have shown that diet–metabolic phenotype effect might be related to individual gut microbial profiles or enterotypes. Thus, the aim of this study was to examine whether microbial enterotypes modify the association between DF intake and metabolic traits. This cross-sectional study included 204 children (6–12 years old) and 75 adults (18–60 years old). Habitual DF intake was estimated with a Food Frequency Questionnaire and biochemical, clinical and anthropometric data were obtained. Gut microbiota was assessed through 16S sequencing and participants were stratified by enterotypes. Correlations adjusting for age and sex were performed to test the associations between dietary fiber components intake and metabolic traits. In children and adults from the Prevotella enterotype, a nominal negative correlation of hemicellulose intake with insulin and HOMA-IR levels was observed (p < 0.05), while in individuals of the other enterotypes, these associations were not observed. Interestingly, the latter effect was not related to the fecal short-chain-fatty acids profile. Our results contribute to understanding the enterotype influence on the diet–phenotype interaction, which ultimate could provide evidence for their use as potential biomarkers for future precision nutrition strategies.