Location: Children's Nutrition Research Center
2023 Annual Report
Objectives
Objective 1: Determine if antinutrients in plant foods impact the gut microbiome.
Subobjective 1A: Using mice feeding studies, analyze the interaction between antinutrient content in plant-based diets and gut microbiota.
Subobjective 1B: Assess the impact of plant-based antinutrient content on animal and human microbiomes using in vitro systems.
Objective 2: Utilize a germ-free murine model to determine the inter-relationships between microbial gut ecology, plant anti-nutrients and host mineral bioavailability.
Approach
Unique plant diets differing in antinutrient content can be used along with 16S ribosomal RNA sequencing to determine how bacterial populations fluctuate as a function of antinutrients. Calcium (Ca) is often sequestered as an oxalate salt making it an 'antinutrient' and bio-unavailable. Medicago truncatula contains insoluble calcium oxalate crystals making it a poor source of dietary Ca. However, a M. truncatula mutant lacking oxalate crystals in the leaf tissue is an excellent source of Ca and allows the preparation of diets that differ in a single plant mutation to be used to analyze the impact of oxalate on the microbiome. Using primary cell culture models from both humans and mice will provide further insights into the impact of antinutrients on microbial composition. Meanwhile, mice reconstituted with either a microbiome associated with an antinutrient replete or antinutrient deficient diet, but consuming equivalent diets, will be analyzed for differences in calcium, iron, and zinc absorption.
Progress Report
Consuming calcium reduces bone loss and decreases the risk of fractures. Although milk is a good source of calcium, people don’t drink enough milk and need additional calcium from various dietary sources. Plant-based diets could be a good source of calcium, but many plants have high levels of calcium that do not get metabolized by the consumer. A specific plant may have high levels of calcium that could be good for bone development, but substances in the plant make it impossible for the consumer to use this calcium; spinach is such a plant. Spinach has antinutrients that block the ability of the consumer to utilize healthy calcium. In Sub-objective 1A using a plant like spinach, researchers at the Children’s Human Nutrition Center in Houston, Texas, have developed ways to remove the antinutrients making pant diets contain more calcium that consumers can use. Our long-range goal will be to make spinach varieties that lack this antinutrient.
In Sub-objective 1B these plant-based diets, have been used to investigate whether plant diets differing in antinutrients can improve the gut microbiome and act as a replacement for probiotics. The idea is that removing the antinutrients from plant-based diets enhances the composition of the gut microbiome to improve gut health. Beneficial gut bacteria can improve bone health, diminish the risk of heart disease, and lower the chance of obesity.
In Sub-objective 1A, we have made progress in demonstrating that the microbiome of female mice responds differently to removing antinutrients in a plant-based diet than the male mice. The females appear to use these different bacteria from the modified diets to improve their bone health, while the male mice do not respond to the modified diets with any changes in their bone health.
In Sub-objective 1B, we have identified gut bacteria in the female mice that may be causing improved bone health. One avenue of future research will be to use these bacteria in probiotics to improve bone health in both males and females. Another goal is understanding the differences between males and females regarding this bacteria-mediated calcium utilization. In Objective 2, we want to make plant-based diets with high calcium levels that can improve the gut microbiome and help build stronger bones.
Accomplishments
