Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item Mathematical models of the colonic microbiota: an evaluation of accuracy using in vitro fecal fermentation data(Frontiers Media S A, 2025-09-25) Geniselli da Silva V; Smith NW; Mullaney JA; Roy NC; Wall C; McNabb WC; Huang HTraditional approaches for studying diet-colonic microbiota interactions are time-consuming, resource-intensive, and often hindered by technical and ethical concerns. Metagenome-scale community metabolic models show promise as complementary tools to overcome these limitations. However, their experimental validation is challenging, and their accuracy in predicting colonic microbial function under realistic dietary conditions remains unclear. This study assessed the accuracy of the Microbial Community model (MICOM) in predicting major short-chain fatty acid (SCFA) production by the colonic microbiota of weaning infants, using fecal samples as a proxy. Model predictions were compared with experimental SCFA production using in vitro fecal fermentation data at the genus level. The model exhibited overall poor accuracy, with only a weak, significant correlation between measured and predicted acetate production (r = 0.17, p = 0.03). However, agreement between predicted and measured SCFA production improved for samples primarily composed of plant-based foods: acetate exhibited a moderate positive correlation (r = 0.31, p = 0.005), and butyrate a trend toward a weak positive correlation (r = 0.21, p = 0.06). These findings suggest that the model is better suited for predicting the influence of complex carbohydrates on the colonic microbiota than for other dietary compounds. Our study demonstrates that, given current limitations, modeling approaches for diet-colonic microbiota interactions should complement rather than replace traditional experimental methods. Further refinement of computational models for microbial communities is essential to advance research on dietary compound-colonic microbiota interactions in weaning infants.Item Sensitivity analysis of global food and nutrition modelling(Springer Nature B V on behalf of the International Society for Plant Pathology, 2025-10-18) Shippey D; Vignes M; McNabb WC; Smith NWComputational models are often used to explore the future of the global food system, including the implications for human nutrition, an essential aspect of sustainability. However, the confidence that can be placed in the outputs of these models is often poorly quantified. Here, a sensitivity analysis of the DELTA Model® - a linear mass balance model calculating global nutrient supply using global and regional food balance sheet, processing, waste, inedible portion, composition, and bioavailability datasets - is conducted. First, a one-at-a-time analysis, varying 4019 underpinning datapoints from the above datasets individually by ± 50% was conducted to identify those with the greatest impact on calculated global nutrient supply. The most influential values from this initial analysis were then carried forward into a multiple value sensitivity analysis, where all possible combinations of ± 50% variations were simulated. Values related to cereals supply, waste, and nutritional value were the most influential on model output, with selenium, cystine, and carbohydrate supply the most sensitive nutrients. When compared to global nutrient requirements, variations in the calculated supply of some nutrients led to qualitative changes from a sufficient global supply to an insufficient supply. These results, while indicative rather than precise estimates of uncertainty, emphasise the critical importance of accurate cereals data in food system models, provide insight on the degree of sensitivity of similar linear models, and should encourage broader application of sensitivity analysis in the field.Item Nutrient-adequate diets with the lowest greenhouse gas emissions or price are the least acceptable—insights from dietary optimisation modelling using the iOTA model®(Frontiers Media S.A., 2025-08-01) Tavan M; Smith NW; Fletcher AJ; Hill JP; McNabb WC; Das AOver the past decade, there has been an increasing interest in the environmental sustainability of diets because food systems are responsible for a third of the anthropogenic greenhouse gas emissions (GHGE). However, less attention has been paid to the nutrient adequacy, consumer acceptability, and affordability of such diets. Such knowledge is particularly scarce in New Zealand, where approximately 40% of adults and 20% of children may live under severe to moderate food insecurity. The iOTA Model® is a country-specific dietary optimisation tool designed to fill this gap by bringing the various aspects of diet sustainability together and providing evidence-based knowledge on not just the environmental impact of food but also its economic and nutritional sustainability. The iOTA Model® was constructed using mixed integer linear programming by integrating New Zealand-specific dietary data. Features such as digestibility and bioavailability considerations have been incorporated as part of the iOTA Model®, allowing for a more accurate estimation of nutrient supply. The model is available as an open-access tool and allows users to explore various dimensions of a sustainable diet. Eight optimisation scenarios, along with baseline diets, were investigated for adult males and females in New Zealand. Results showed that reducing dietary GHGE or price by approximately 80% was possible while meeting nutrient adequacy requirements. However, such diets deviated substantially from the baseline eating patterns, indicating lower consumer acceptability, and only included a limited variety of foods. On the contrary, diets with minimum deviation from baseline remained realistic while adhering to nutrient targets and reducing GHGE by 10 and 30% in female and male consumers aged 19–30 years, respectively, and weekly price remained below the baseline. Expansion of the model to additional countries and its open-access nature will allow independent dietary sustainability research through optimisation.Item Impacts of Food Fortification on Micronutrient Intake and Nutritional Status of Women of Reproductive Age in Africa—A Narrative Review(Elsevier Inc. on behalf of American Society for Nutrition, 2025-07-01) Coomson JB; Smith NW; McNabb WMore than two-thirds of women of reproductive age (WRA) in Africa are estimated to be micronutrient deficient. This is largely due to the widespread poor dietary quality and inadequate intakes of nutrient-dense foods to meet the heightened requirements for WRA. Food fortification is a cost-effective and highly recommended food-based approach for addressing these micronutrient deficiencies in low-income settings like Africa. The strategy has been implemented at different scales within the region for over 3 decades. We conducted a review to find evidence of the impact of food fortification implemented at various scales and across different population circumstances in Africa. We also sought to understand what factors may limit the impact of ongoing fortification programs on micronutrient status. We also explored findings regarding the knowledge and acceptability of fortified foods within the African population as a further barrier to the impact of food fortification on nutritional status. We found that fortification with iron and vitamin A was associated with the most variable impact from targeted and large-scale fortification programs. However, significant positive effects on nutritional status and serum biomarkers were found for food fortification with folate, iodine, and zinc among African women. Generally, fortified foods are acceptable to consumers; however, surveys assessing knowledge and preference for fortified foods found that WRA know little about food fortification and its benefits. Poor coverage of fortification, lower levels of fortificants than are recommended, and use of non-World Health Organization recommended fortificants limit the impact of food fortification on micronutrient intakes and status among WRA in Africa.Item Gaps in environmental and social evidence base are holding back strategic action on our national food system(Taylor and Francis Group on behalf of the Royal Society of New Zealand, 2025-07-03) Smith NW; McDowell RW; Smith C; Foster M; Eason C; Stephens M; McNabb WCWhile there is broad agreement on the challenges facing the Aotearoa New Zealand food system now and in the near future, there is less agreement on the action to be taken. Poor agreement is fuelled by gaps in both our scientific understanding of the food system and data to support our decision making, particularly in the environmental and social spaces. Filling these gaps and being transparent about scientific confidence in future predictions will strengthen the evidence base for action.Item Dietary patterns influencing the human colonic microbiota from infancy to centenarian age: a narrative review(Frontiers Media S A, 2025-06-04) Geniselli da Silva V; Roy NC; Smith NW; Wall C; Mullaney JA; McNabb WC; Benítez-Páez AOur dietary choices not only affect our body but also shape the microbial community inhabiting our large intestine. The colonic microbiota strongly influences our physiology, playing a crucial role in both disease prevention and development. Hence, dietary strategies to modulate colonic microbes have gained notable attention. However, most diet-colonic microbiota research has focused on adults, often neglecting other key life stages, such as infancy and older adulthood. In this narrative review, we explore the impact of various dietary patterns on the colonic microbiota from early infancy to centenarian age, aiming to identify age-specific diets promoting health and well-being by nourishing the microbiota. Diversified diets rich in fruits, vegetables, and whole grains, along with daily consumption of fermented foods, and moderate amounts of fish and lean meats (two to four times a week), increase colonic microbial diversity, the abundance of saccharolytic taxa, and the production of beneficial microbial metabolites. Most of the current knowledge of diet-microbiota interactions is limited to studies using fecal samples as a proxy. Future directions in colonic microbiota research include personalized in silico simulations to predict the impact of diets on colonic microbes. Complementary to traditional methodologies, modeling has the potential to reduce the costs of colonic microbiota investigations, accelerate our understanding of diet-microbiota interactions, and contribute to the advancement of personalized nutrition across various life stages.Item Protein Intake and Protein Quality Patterns in New Zealand Vegan Diets: An Observational Analysis Using Dynamic Time Warping(MDPI (Basel, Switzerland), 2025-05-26) Soh BXP; Vignes M; Smith NW; Von Hurst PR; McNabb WC; Hayes M; Naik ASBackground/Objectives: Inadequate intake of indispensable amino acids (IAAs) is a significant challenge in vegan diets. Since IAAs are not produced or stored over long durations in the human body, regular and balanced dietary protein consumption throughout the day is essential for metabolic function. The objective of this study is to investigate the variation in protein and IAA intake across 24 h among New Zealand vegans with time-series clustering, using Dynamic Time Warping (DTW). Methods: This data-driven approach objectively categorised vegan dietary data into distinct clusters for protein intake and protein quality analysis. Results: Total protein consumed per eating occasion (EO) was 11.1 g, with 93.5% of the cohort falling below the minimal threshold of 20 g of protein per EO. The mean protein intake for each EO in cluster 1 was 6.5 g, cluster 2 was 11.4 g and only cluster 3 was near the threshold at 19.0 g. IAA intake was highest in cluster 3, with lysine and leucine being 3× higher in cluster 3 than cluster 1. All EOs in cluster 1 were below the reference protein intake relative to body weight, closely followed by cluster 2 (91.5%), while cluster 3 comparatively had the lowest EOs under this reference (31.9%). Conclusions: DTW produced three distinct dietary patterns in the vegan cohort. Further exploration of plant protein combinations could inform recommendations to optimise protein quality in vegan diets.Item Micronutrient Density of the Global Food Supply(John Wiley and Sons Australia, Ltd and Nanchang University, Northwest University, Jiangsu University, Zhejiang University, Fujian Agriculture and Forestry University., 2025-04-27) Smith NW; Beal TGlobal diets are inadequate in micronutrients, leading to deficiencies and related diseases. Addressing these micronutrient shortfalls requires increasing the nutrient density of the global food supply. Inferring micronutrient supply based on food balance sheet data is widespread practice in nutrition modelling, whereas designing food-based interventions is usually done using dietary data. Here, we provide an online interactive tool for investigating the micronutrient density of food balance sheet items, to help identify appropriate food supply interventions to increase the availability of micronutrient-dense foods globally. While the tool can be used for up to 28 food components (including macronutrients), we demonstrate its use by ranking food balance sheet items based on their combined content of 17 micronutrients per 100 g or per 100 kcal. High ranking foods varied between the mass and energy lists, but included offals, seeds, nuts, seafood, and non-starchy vegetables. The tool can be used by nutrition researchers to identify foods with the potential for supplying the specific combinations of micronutrients needed by at-risk populations.Item Complementary foods in infants: an in vitro study of the faecal microbial composition and organic acid production(Royal Society of Chemistry, 2025-05-07) Geniselli da Silva V; Mullaney JA; Roy NC; Smith NW; Wall C; Tatton CJ; McNabb WCThe transition from breastmilk to complementary foods is critical for maturing the colonic microbiota of infants. Dietary choices at weaning can lead to long-lasting microbial changes, potentially influencing health later in life. However, the weaning phase remains underexplored in colonic microbiome research, and the current understanding of how complementary foods impact the infant's colonic microbiota is limited. To address this knowledge gap, this study assessed the influence of 13 food ingredients on the in vitro microbial composition and production of organic acids by the faecal microbiota in New Zealand infants aged 5 to 11 months. To better represent real feeding practices, ingredients were combined with infant formula, other complementary foods, or both infant formula and other foods. Among the individual food ingredients, fermentation with peeled kūmara (sweet potato) increased the production of lactate and the relative abundance of the genus Enterococcus. Fermentation with blackcurrants, strawberries, or raspberries enhanced acetate and propionate production. Additionally, fermentation with blackcurrants increased the relative abundance of the genus Parabacteroides, while raspberry fermentation increased the relative abundance of the genera Parabacteroides and Eubacterium. When combined with infant formula or with blackcurrants, fermenting black beans increased butyrate production and stimulated the relative abundance of Clostridium sensu stricto 1. These foods are promising candidates for future clinical trials.Item Trends in micronutrient research since the SDGs: a global perspective(Taylor and Francis Group, 2025-04-02) Akpojevwe Abafe E; Smith NW; Maxwell TMR; McNabb WCSustainable food systems have become a central focus in efforts to combat micronutrient malnutrition, with increasing recognition of their role in achieving the Sustainable Development Goals (SDGs). This article presents a bibliometric analysis of micronutrient research from 2015 to 2023, examining trends and thematic clusters within the SDGs framework. Using data from the Web of Science and science mapping techniques, the study identifies key trends and thematic clusters that highlight evolving research priorities. Four major trends emerge: the application of machine learning, the exploration of macroalgae for their micronutrient potential, the use of CRISPR/Cas9 technology in biofortification, and concerns about heavy metal contamination in food. Research clusters show a strong focus on bone health, particularly osteoporosis and vitamin D, which align with SDG 3 (Good Health and Well-being). Yet research on micronutrient deficiencies, such as those in iron, zinc, and vitamin A, remains underrepresented despite their high global impact on malnutrition, especially in low- and middle-income countries, raising concerns about whether research priorities sufficiently address the SDGs. This study highlights the need for more targeted research to align with SDG 2 (Zero Hunger) and SDG 12 (Responsible Consumption and Production). The article concludes by stressing the importance to balance cutting-edge technological advances with a renewed emphasis to address critical micronutrient gaps to improve global nutrition and align with sustainable food system goals.
