Location: Obesity and Metabolism Research
2024 Annual Report
Objectives
The following research project addresses a key unmet need of the USDA Human Nutrition Program, namely to test the metabolic impact of the Dietary Guidelines for Americans (DGA) --which has immediate nutrition policy implications. To achieve this goal, project scientists have designed an interdisciplinary effort leveraging tools from analytical chemistry, biochemistry, clinical nutrition, endocrinology, exercise biology, genetics, molecular biology, physiology, and psychological/CNS-based assessments - applying cutting edge phenotyping tools alongside complementary basic research experiments.
Objective 1: Determine if achieving and maintaining a healthy body weight is the key health promoting recommendation of the Dietary Guidelines for Americans (DGA).
Sub-objective 1A: Determine if achieving and maintaining a healthy body weight improves cardiometabolic risk in persons at-risk for metabolic disease.
Sub-objective 1B: Determine if chronic stress, stress system responsiveness, and diet quality interact to influence metabolic responses and if these responses can be sustained over time.
Sub-objective 1C: Determine the eating behavior characteristics, including dietary restraint, food cravings and preferences, motivation for food choice, and satiety response to a meal challenge to evaluate a) how diet interventions affect these variables b) which behavioral variables are associated with adherence to prescribed diet during the fully controlled interventions (mos 1 & 2) and during the partially controlled interventions (mos 3-6) c) and body weight changes during the follow-up period.
Sub-objective 1D: Determine how weight loss and diet interact to influence lipoprotein particle metabolomic structure and their association with
cardiometabolic risk factors.
Objective 2: Identify hepatic gene polymorphisms associated with metabolic response to diets. This objective complements and integrates with Objective 1, which systematically tests the effect of the DGA. Objective 2 studies are designed to identify genetic sources of variation and their impact on metabolism in response to diet using a population of mice with defined genetic diversity to answer the following sub-objectives:
Sub-objective 2A: Identify gene-diet interactions affecting adiposity and hepatic fat accumulation.
Sub-objective 2B: Identify changes in gut microbiome composition associated with resistance to weight loss.
Sub-objective 2C: Determine how atherogenic risk mechanisms alter lipoprotein particle lipidomic structure in cardiometabolic disease models.
Objective 3: Develop Reference Values for mineral and vitamin concentrations in human milk, which will improve estimates of recommended nutrient intakes for breastfeeding infants and their mothers.
Objective 4: Investigate the health benefits of alternative proteins foods in the context of a healthy diet.
Approach
Objective 1 Hypotheses: 1A1: Consuming a DGA diet pattern for 8 wk will improve cardiometabolic risk factors, primarily insulin sensitivity and lipid profiles, compared to a typical American diet (TAD); 1A2: Cardiometabolic improvements resulting from the DGA diet will be greater in overweight/obese women when energy intake is restricted to result in weight loss; 1B: Phenotypic differences in psychological stress will partly explain variation in metabolic responses to a healthy diet; 1C1: Hunger, circulating ghrelin, and snack selection following a meal challenge will be greater with energy-restricted diets; 1C2: Adherence to the DGA diets will be better than adherence to the TAD diets when controlled for eating behavior, cognitive function, and subjective satiety; 1C3: Body weight changes in the follow-up period will associate with endocannabinoid tone, craving, and increased palatable food intake independent of intervention group; 1D1: Weight loss-induced metabolomic changes in plasma particles will decrease LDL region pro-atherogenic character, while increasing HDL anti-atherogenic character; 1D2: Diets rich in fruits, vegetables, and omega-3 fatty acids will reduce the 8 wk concentrations of non-enzymatically generated oxygenated lipids in LDL region lipoproteins.
Objective 2 Hypotheses: 2A: Reduction in adiposity associated with dietary change is due to both genetic and dietary interactions; 2B: Gut microbial diversity will affect the weight loss response in a genetically diverse mouse population; 2C: Dietary manipulations will differentially change the lipoprotein oxylipins and ceramide composition in atherosclerosis prone vs. resistant cardiometabolic disease mouse models.
A Randomized Control Trial will address hypotheses under Objective 1. This trial will be an intervention with human volunteers randomized to one of four parallel diet groups: 1. participants will consume a diet based on the Dietary Guidelines for Americans (DGA) and maintain energy balance; 2. participants will consume a control diet based on the typical American diet (TAD) and maintain energy balance; 3. participants will consume a DGA diet, restricted in calories to stimulate body weight loss; and 4. participants will consume a TAD, restricted in calories in order to stimulate body weight loss.
A complementary mouse experiment will address Objective 2 hypotheses. This study will use diets formulated to match the diet types used in Objective 1 for the TAD and DGA. Four experimental groups will be tested: Ad libitum DGA diet; energy restricted DGA diet; ad libitum TAD diet; and energy restricted TAD diet. This study utilizes a systems genetic approach using genetic reference panels to assess gene x diet interactions that affect both the susceptibility to obesity and the resistance to weight loss.
Objective 3 Hypothesis: Reference Values for vitamins and minerals in human milk can be established by measuring the range of concentrations in milk from well-nourished women who are not consuming additional micronutrients through supplements or fortified foods.
Progress Report
This is the final report that documents the progress for the life of project 2032-51530-025-000D, which began March 2019, titled, "Improving Public Health by Understanding Diversity in Diet, Body, and Brain Interactions." Under this project, Objectives 1 and 2 were implemented to addresses a key unmet need of the USDA Human Nutrition Program, which is to test the metabolic impact of the Dietary Guidelines for Americans (DGA), which has immediate policy implications. Sub-objective 1A determines if achieving a healthy body weight is the key health promoting recommendation of the DGA. In 2019, significant progress was made in developing and training the study team, obtaining approval from the University of California Institutional Review Board, and establishing study operating procedures. However, commencement of the Objective 1 human intervention study was stalled for two plus years due to COVID-19 and progress was interrupted by maximized telework due to Covid 19 and related loss of research personnel. In May of 2023, study test visits were reinstated and are currently ongoing with seven participants now successfully completing both phases (intervention and post-intervention) of this intervention study. More recently in 2024, 10 additional participants were successfully recruited, screened, and consented. Four of these 10 started the diet intervention, and four completed the diet intervention phase and are currently in the post-intervention phase. Two participants are being scheduled to start the intervention. Recruitment and screening are ongoing. In 2024, a newly developed contract with a communications and marketing firm (Schatz Strategy Group) was implemented to broaden recruitment efforts. Due to the COVID-19-based significant stoppage of this intervention, this Objective 1 human intervention study was approved to continue in the next project cycle with completion in 2026. Sub-objectives 1B-1D progress are dependent on the completion of the Sub-objective 1A diet and physical activity human intervention study. Objective 1 subordinate projects: (1) Project 2032-51530-025-035R investigated metabolomic signatures of thiamine deficiency in mice and Laotian children. A thiamine deficiency mouse study was completed and reported, and metabolic signatures of marginal to deficient thiamine states in Laotian children were identified. Progress expands on parent project Sub-objective 1A; (2) An NIH-funded subordinate project, 2032-51530-025-065R, characterized function of a kidney transport protein with researchers at the University of California San Francisco. Reports were published showing sex-dependent shifts in bile acid levels in SLC22A24-transgenic mice and describing the functional impact of an SLC22A10 gene polymorphism in the great apes. This knowledge will facilitate interpretation of postprandial changes in lipids and associated metabolism from future work conducted under Sub-objective 1B; (3) In a subordinate project, ARS researchers in Davis, California, in collaboration with the University of California-San Francisco and Davis, and Johns Hopkins University, investigated associations between diet, gut microbial metabolism, and multiple sclerosis (MS) relapse in pediatric patients. Associations were found between serum lipids and risk of multiple sclerosis relapse and levels of nerve damage and multiple sclerosis disease activity, and (2) between gut microbiome derived metabolites and disease activity. This project expands on Sub-objective 1D.
Objective 2, “Identify hepatic gene polymorphisms associated with metabolic response to diets”, complements and integrates with Objective 1. Studies using a population of mice with defined genetic diversity were designed to identify genetic sources of variation and their impact on diet-induced changes in metabolism. Sub-objective 2A experiments aim to identify gene-diet interactions affecting adiposity and liver fat. In experiment 1, a genetically diverse outbred (DO) population of 300 mice (females = 150, males = 150) were fed a typical American diet (TAD) or Dietary Guidelines for Americans (DGA) diet. Preliminary results suggest an influence of sex, but not diet, on body weight. Body fat % was not affected by sex or diet. However, in certain mice, diet affected both body weight and body fat %, which supports a critical need for considering personalized approaches for improving health outcomes. In experiment 2, a genetically diverse population of Collaborative Cross mice were divided into four groups: TAD ad libitum, TAD+25% caloric restriction, DGA diet ad libitum and DGA diet+25% caloric restriction. From each diet group there are five males and five females per strain with a total of four strains (40 mice total). This study was finished, and data analyses are ongoing. Sub-objective 2B aims to identify whether gut microbiome composition changes explain diet-induced weight loss resistance in mice. Study diets were developed, and the Institutional Animal Care and Use Committee (IACUC) application was approved. Currently, one-third of the fecal and cecum samples had DNA isolated for 16S analysis of microbial communities. The remaining analysis will be completed by Jan 2025. Sub-objective 2C evaluates lipidomic characteristics of lipoprotein particles in atherogenic risk mouse models.
To date, ARS researchers in Davis, California, refined and optimized the liquid chromatography tandem mass spectrometry lipidomic methods transferred from the Baker Institute of Melbourne, Australia and trained personnel in the application of this novel lipidominc method. Atherosclerotic mouse plasma was obtained for initial evaluations, personnel was trained to conduct lipoprotein fractionation and collection techniques on modern hardware, and esterified oxylipin analysis procedures were improved. Objective 2 subordinate project: For project 2032-51530-025-049R, ARS researchers in Davis, California, in collaboration with researchers at the University of California, Davis, performed a meta-analysis from five different studies of the genetic regulation of trimethylamine N-oxide (TMAO) in 1,482 female and male DO mice aged 6-44 weeks. Results showed that gene by sex and gene by diet interactions regulating plasma TMAO have important ramifications for genome-wide association studies (GWAS) assessing complex traits in humans.
The following progress was made on Objective 3, “Develop Reference Values for mineral and vitamin concentrations in human milk, which will improve the Agricultural Research Information System”. In 2019, ARS scientists in Davis, California, completed human milk sample collections from 7-100% of test visits across the first 8.5 months postpartum, in four countries. At an ARS facility in Davis, California, methods were developed for the rapid nutrient analysis in human milk. A database was finalized. In 2019, ARS researchers in Davis, California, validated a method for measuring hundreds of metabolites in milk. In 2020, ARS researchers received additional funding from the Bill & Melinda Gates Foundation to expand analyses, acquire equipment and service contracts, support data analysis and publication meetings, and add a new study (E-MILQ; 2032-51530-025-039T) on milk composition during the first month postpartum in the same four field sites. Although the ARS lab in Davis, California, was closed and collection of milk and other samples were stalled due to COVID-19, milk analyses were completed in 1,734 samples for vitamin B12, thiamin, other B vitamins and macronutrients; 310 for plasma B12, vitamin D and folate; and 1700 for markers of inflammation. In FY 2023, methods for 13 macro- and trace minerals analysis in milk were developed and applied using an Inductively Coupled Plasma-Mass Spectrometer. Of the 2,574 milk samples collected through FY 2022, analyses were 100% complete for B vitamins, macronutrients, metabolomics, and minerals. Significant progress was made in data management and graphical expression of pooled milk nutrient data from the four research sites. In support of Sub-objective 3B, a follow-on study, project 2032-51530-025-039T, was conducted by ARS researchers in Davis, California, who collected additional milk and plasma from 65 maternal-infant dyads in each of the same four MILQ sites during the first month of lactation. In 2024, analysis of human milk samples from the MILQ and E-MILQ studies continued and are complete except for ~30% of the vitamin A and E analyses. Seven articles describing the new RVs and other results are in progress and will be submitted for publication in 2024. Objective 3 subordinate projects: (1) Project 2032-51530-025-085H analyzed the effects on milk of micronutrient (MN) supplements given by collaborators at Johns Hopkins University to Bangladeshi women during pregnancy and three months of lactation. Supplementation with 15 nutrients were reported to increase choline, riboflavin, niacin and vitamin B6 in milk but not thiamin, and showed supplements must be continued during lactation to improve milk MN; (2) Project 2032-51530-025-090H, by Harvard University, compared regular vs. high dose supplementation with multiple MN in pregnancy and/or lactation on maternal and infant B vitamin status in Tanzania. Milk MN is measured by ARS scientists in Davis, California. An article published in 2023 reported a high prevalence of low milk B12, improved by maternal B12 supplementation in either pregnancy or lactation. The ARS laboratory is now measuring B vitamins in plasma, work to be completed by October 2024; (3) in a subordinate study (2032-51530-025-077H), ARS scientists in Davis, California, are collaborating with the International Milk Composition Consortium (IMiC) to analyze MN in human milk collected from nutritional supplement interventions in four countries. Analyses are complete except for vitamin A, which will be finished in 2024.
Accomplishments
1. Hunger sensations and time restricted eating. In a study of long-distance runners, time restrictive eating (TRE) was shown to result in reduction in body fat without loss of lean mass, but is it sustainable as a diet pattern that limits eating time to only 8 hours per day? A study of hunger and satiety by ARS researchers in Davis, California, in collaboration with researchers at University of California-Davis, was conducted to test if TRE affected hunger ratings compared to a more normal eating pattern. In this study food intake was closely monitored by the researchers. Results indicated that the TRE pattern was associated with increases in feelings of hunger and thoughts about food. In contrast, there were no differences between TRE and normal pattern in measures of known hunger or satiety hormones. Considering that perceived hunger persisted over a 4-week period, prolonged use of TRE could be problematic if hunger overtakes a prudent approach to eating when food intake is not monitored, potentially compromising healthy body weight.
2. Inter-individual differences in fasting and postprandial monocyte numbers are linked to metabolism, the postprandial cortisol response, and vascular function. Monocytes are innate immune cells that are continuously produced in bone marrow which enter and circulate the vasculature. In response to nutrient scarcity, monocytes migrate back to bone marrow where upon refeeding they are re-released back into the bloodstream to replenish the circulation. In humans, the variability in monocyte behavior in response to fasting and refeeding has not been characterized. A study by ARS researchers in Davis, California, was conducted to examine the possibility of this variability in fasting and postprandial monocyte numbers. This study identified three distinct monocyte groups, with one atypical group characterized by relatively high fasting monocyte counts which decreased after meal consumption. The other groups aligned with a more typical paradigm of monocyte dynamics, which is characterized by lower fasting monocyte counts and higher numbers in response to refeeding. Study participants displaying the atypical monocyte dynamics also had lower whole-body carbohydrate oxidation rates, lower HDL-cholesterol levels, delayed postprandial declines in salivary cortisol, and reduced postprandial peripheral microvascular endothelial function. These unique characteristics were not explained by group differences in age, sex, or BMI. In conclusion, these results highlight distinct patterns of monocyte responsiveness that may (1) be linked to cortisol and metabolic status, and (2) partly explain person-to-person differences in cardiovascular health.
3. The impact of tree nut consumption on metabolism and associated metabolic markers. Tree nut consumption is associated with health benefits, but how these benefits are manifest is not well understood. A collaborative study between ARS researchers in Davis, California, and the University of California Davis and Merced revealed unique bioactive lipids in walnuts that possibly help explain how nut consumption influences human health. In another human intervention trial, eight weeks of almond consumption enriched plasma lipids in unsaturated fatty acids while accelerating their clearance, altered bioactive lipid profiles, improved vitamin E status and influenced energy metabolism of both people and their gut microflora, modulating their responses to dietary sugar intake. Together, these data demonstrate that tree nuts contain factors beyond their classically recognized antioxidant and quality fat profiles, and these additional factors may influence the physiological control of energy metabolism and glucose regulation in healthy humans.
4. Advances in the understanding of thiamine metabolism. Thiamine (vitamin B1) deficiency can cause severe neurological and cardiovascular disease, and populations with limited access to high quality diets or afflicted with poor intestinal absorption (e.g., the aged, alcoholics) are at higher risk for thiamine deficiency. In addition, medications which share the thiamine transport machinery may exacerbate these risks. In collaboration with research teams at the University of California campuses in San Francisco and Davis, and Tufts University in Boston, ARS researchers in Davis, California, determined that: 1) the anti-bacterial drug trimethoprim can negatively impact thiamine status by inhibiting the thiamine transporter-2 (THTR2) and the organic cation transporter 1; 2) THTR2 is critical for thiamine uptake and dependent metabolism in the brain, and that classical blood-based biomarkers of thiamine status fail to identify this issue; 3) thiamine deficiency in mice negatively impacts metabolism differently in different tissues, showing influences on areas with both known and unknown dependencies on thiamine; 4) the plasma metabolome of children with thiamine responsive disorders and clinical thiamine deficiency differ from a thiamine sufficient control group, but not each other. These results highlight a key pathway for better understanding the impacts of thiamine insufficiency and provide novel clinical biomarkers to identify individuals suffering from this condition.
Review Publications
Salvador, A.C., Huda, N.M., Arends, D., Elsaddi, A.M., Gacasan, C.A., Brockmann, G.A., Valdar, W., Bennett, B.J., Threadgill, D.W. 2023. Analysis of strain, sex, and diet-dependent modulation of gut microbiota reveals candidate keystone organisms driving microbial diversity in response to American and ketogenic diets. Microbiome. 11. Article 220. https://doi.org/10.1186/s40168-023-01588-w.
Golden, C.D., Zamborain-Mason, J., Levis, A., Rice, B.L., Allen, L.H., Hampel, D., Hazen, J., Metcalf, C.J., Randriamady, H.J., Shahab-Ferdows, S., Wu, S., Haneuse, S. 2024. Prevalence of micronutrient deficiencies across diverse environments in rural Madagascar. Frontiers in Nutrition. 11. Article 1389080. https://doi.org/10.3389/fnut.2024.1389080.
Smith, T.J., Arnold, C.D., Fischer, P.R., Trehan, I., Hiffler, L., Sitthideth, D., Stein-Wexler, R., Yeh, J., Jones, K.S., Hampel, D., Tancredi, D.J., Schick, M.A., Mcbeth, C.N., Tan, X., Allen, L.H., Sayasone, S., Kounnavong, S., Hess, S.Y. 2024. A predictive model for thiamine responsive disorders among infants and young children: Results from a prospective cohort study in Lao People's Democratic Republic. Journal of Pediatrics. 268. Article 113961. https://doi.org/10.1016/j.jpeds.2024.113961.
Wang, D., Shahab-Ferdows, S., Lweno, O.N., Hampel, D., Method, B., Yelverton, C.A., Nguyen, C.H., Aboud, S., Allen, L.H., Fawzi, W.W. 2023. The effects of prenatal and postnatal high-dose vitamin B-12 supplementation on human milk vitamin B-12: A randomized, double-blind, placebo-controlled trial in Tanzania. The American Journal of Clinical Nutrition. 119(3):730-739. https://doi.org/10.1016/j.ajcnut.2023.07.023.
Christensen, S.H., Rom, A.L., Greve, T., Lewis, J.I., Frøkiær, H., Allen, L.H., Mølgaard, C., Renault, K.M., Michaelsen, K.F. 2023. Maternal inflammatory, lipid and metabolic markers and associations with birth and breastfeeding outcomes. Frontiers in Nutrition. 10. Article 1223753. https://doi.org/10.3389/fnut.2023.1223753.
Reyes, S.M., Brockway, M., McDermid, J.M., Chan, D., Granger, M., Refvik, R., Sidhu, K., Musse, S., Monnin, C., Lotoski, L., Geddes, D., Jehan, F., Kolsteren, P., Allen, L.H., Hampel, D., Eriksen, K.G., Rodriguez, N., Azad, M.B. 2023. Human milk macronutrients and child growth and body composition in the first 2 years: A systematic review. Advances in Nutrition. 15(1). Article 100082. https://doi.org/10.1016/j.advnut.2023.06.005.
Williams, A.M., Brown, K.H., Allen, L.H., Dary, O., Moorthy, D., Suchdev, P.S. 2023. Improving anemia assessment in clinical and public health settings. Journal of Nutrition. 153:S29-S41. https://doi.org/10.1016/j.tjnut.2023.05.032.
Yee, S., Ferrández-Peral, L., Alentorn-Moron, P., Fontsere, C., Ceylan, M., Koleske, M.L., Handin, N., Artegoitia Etchev, V.M., Lara, G., Chien, H., Zhou, X., Dainat, J., Zalevsky, A., Sali, A., Brand, C.M., Wolfreys, F.D., Yang, J., Gestwicki, J.E., Capra, J.A., Artursson, P., Newman, J.W., Marquès-Bonet, T., Giacomini, K.M. 2024. Illuminating the function of the orphan transporter, SLC22A10, in humans and other primates. Nature Communications. 15. Article 4380. https://doi.org/10.1038/s41467-024-48569-7.
Shen, C., Newman, J.W., Elmassry, M.M., Borkowski, K., Chyu, M., Kahathuduwa, C., Neugebauer, V., Watkins, B.A. 2023. Tai Chi exercise reduces circulating levels of inflammatory oxylipins in postmenopausal women with knee osteoarthritis: Results from a pilot study. Frontiers in Medicine. 10. Article 1210170. https://doi.org/10.3389/fmed.2023.1210170.
Virupakshaiah, A., Ladakis, D., Nourbakhsh, B., Bhargava, P., Dilwali, S., Schoeps, V., Borkowski, K., Newman, J.W., Waubant, E. 2023. Several serum lipid metabolites are associated with relapse risk in pediatric-onset multiple sclerosis. Multiple Sclerosis Journal. 29(8):936-944. https://doi.org/10.1177/13524585231171517.
Borkowski, K., Seyfried, N.T., Arnold, M., Lah, J.J., Levey, A.I., Hales, C.M., Dammer, E.B., Blach, C., Louie, G., Kaddurah-Daouk, R., Newman, J.W. 2023. Integration of plasma and CSF metabolomics with CSF proteomic reveals novel associations between lipid mediators and central nervous system vascular and energy metabolism. Scientific Reports. 13. Article 13752. https://doi.org/10.1038/s41598-023-39737-8.
U-Din, M., de Mello, V.D., Tuomainen, M., Raiko, J., Niemi, T., Fromme, T., Klavus, A., Gautier, N., Haimilahti, K., Lehtonen, M., Kristiansen, K., Newman, J.W., Pietiläinen, K.H., Pihlajamäki, J., Amri, E., Klingenspor, M., Nuutila, P., Pirinen, E., Hanhineva, K., Virtanen, K.A. 2023. Cold-stimulated brown adipose tissue activation is related to changes in serum metabolites relevant to NAD+ metabolism in humans. Cell Reports. 42(9). Article 113131. https://doi.org/10.1016/j.celrep.2023.113131.
Snodgrass, R.G., Stephensen, C.B., Laugero, K.D. 2024. Atypical monocyte dynamics in healthy humans in response to fasting and refeeding are distinguished by fasting HDL and postprandial cortisol. American Journal of Physiology - Endocrinology and Metabolism. 327(2):E229-E240. https://doi.org/10.1152/ajpendo.00158.2024.