Progress 01/01/21 to 12/31/24
Outputs
Target Audience:The target audience for this study is healthy adults between the ages of 18 and 30 years old from the Greater Lowell area. TiO2 is a food additive used extensively in the United States food supply chain, however there is little understanding of current exposure among adults. Therefore, quantitation of TiO2 exposure among U.S. adults and examination of potential negative health effects is needed. Previous research outside of the U.S. suggests young adults consume significantly higher amounts of TiO2-containing foods compared to older adult age groups. Therefore, to provide representation of exposure to this food additive, the 18 to 30-year-old age group was selected. Rigorous inclusion and exclusion criteria were used in the current study to enroll healthy participants via a screener questionnaire. Exclusion criteria were formulated based on the mechanistic actions of disease and pharmaceuticals on the gut microbiome and homeostasis. Exclusion criteria include antibiotic use in the previous six months, non-steroidal antiinflammatory (NSAID) use in the previous ten days, daily use of selective serotonin reuptake inhibitors (SSRIs) and proton pump inhibitors, current pregnancy, or conditions that alter gastrointestinal health, such as Crohn's disease, ulcerative colitis, and irritable bowel disease. Furthermore, the responses of the screener questionnaire were divided into four groups: ineligible, possible low titanium dioxide (TiO2), moderate TiO2, and high TiO2 consumption. Healthy adults were recruited from the University of Massachusetts, Lowell, and surrounding communities. There is a diverse community in northern Massachusetts with local, national, and international learners. The 2019 UML Students of Color & International Students (SOCIS) Sub-Committee report states 36% and 25.1% of the undergraduate and graduate student populations are students of color, respectively. Furthermore, of the undergraduate student population, 59.1% are Caucasian students, 12.1% are Asian students, 11.7% are Hispanic or Latino students, and 6.1% are Black, African- American, or Cape Verdean students. The University also serves 1,158 international students, making up 7.4% of the undergraduate and graduate student population. Results from the current study are thereforegeneralizable to adults without inflammatory bowel disease or other major inflammatory disease. The general audience for scientific dissemination will be scientific audiences (through scientific publication) and the local community (through research talks to the general community, hosted by the University of Massachusetts, Lowell). Changes/Problems:Manufacturers had discontinued ELISA kits we had previously developed methodology for using human stool biosamples. Therefore, we had to work with new manufacturers to find and test new kits. This was expensive. In addition, the cost of kits increased substantially since the time of the original budget submission. For these budgetary reasons, we were forced to prioritize 4 biomarkers of intestinal inflammation and permeability, when we had originally proposed to measure more biomarkers of human gut health. What opportunities for training and professional development has the project provided?Training Activities Dr. Dhimiter Bello (Co-I) mentored and trained a graduate student in the lab on the new MARS-EXPRESS machine. With this training, the graduate student was able to digest and analyze all 240 fecal samples for contained metals and minerals. Dr. Shannon Kelleher (Co-I) mentored and trained a graduate student in the lab on quantifying the gut inflammatory and permeability markers using ELISA kits. Professional Development Attendance at the IAFNS 2024 Annual Scientific Symposium, Washington DC, which was a workshop that showcased research relevant to the current project (ultra-processed food consumpion, environmental and dietary contaminants and their relation to health). How have the results been disseminated to communities of interest?Scientific output has been collated into a scientific publication which will be made publically available through NALs PubAg. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
AIM1 1) Major activities completed / experiments conducted Enrollment and completion of 80 human participants and collection of their biosamples and sociodemographic/health information. The digestion and analysis of all 240 fecal samples for minerals and metals in the stool samples (includingassessment of Tio2 exposure). 2) Data collected (per participant) Sociodemographic Self-reported health information 3 fecal samples (for gut microbiome and contaminant analysis) 3 dietary recalls 3) Summary statistics and discussion of results Overall, the high stool TiO2 group showed 8x higher stool TiO2 content compared to the low group. The high TiO2 stool group presented with lower stool moisture content, lower total calorie intake, more female representation, and greater stool frequency compared to the low TiO2 exposure group. Mean age was 22 years, BMI range 18-36 kg/m2, TiO2 in dry stool range 0.018 - 3.279 ug/mg (comparable with previous work). 4) Key outcomes or other accomplishments realized Output of the estimation of TiO2 intakes using fecal data. These data are publically available on NALs Data Commons. Peer-reviewed publication in progress. AIM 2 1) Major activities completed / experiments conducted Gut microbiome analysis is complete. 2) Data collected Data from three timepoints (three separate stool samples) have been averagedacross each participant and used in statistical analyses, as well as data for matched individual time points (TiO2 exposure matched to same time gut microbiome assessment). A complete, cleaned dataset has been created containing this data and submitted to NALs Data Commons. 3) Summary statistics and discussion of results Gut microbiota profile Comparisons across TiO2 quartiles (Q1-Q4) of multiple alpha diversity metrics, including Shannon diversity index, observed features, Pielou's evenness, and Faith's phylogenetic diversity, revealed no differences in fecal TiO2 concentration between any two quartiles (Q1 - Q4) (Kruskal-Wallis, P > 0.05, Supplemental Figures 2A, 1A-1C). In contrast to α-diversity, β-diversity analysis revealed differences in bacterial community composition between quartiles. Principal coordinates analysis (PCoA) of weighted UniFrac distance demonstrated that bacterial community compositions clustered distinctly based on TiO2 concentration (global PERMANOVA P < 0.01). There wassignificant clustering (P < 0.02) observed from a select pairwise PCoA analysis between Q1 (lowest TiO2 concentration) and Q4 (highest TiO2 concentration). 10 taxa were significantly enriched in any of the TiO2 quartiles. Two features, the Lachnoclostridium and Ruminococcus gnavus were found to be enriched within the Q4 group compared to Q1.These taxa have been implicated in gut dysbiosis and associated health conditions, making their enrichment noteworthy in the context of this study.Network analysis in Q4 samples revealed that Lachnoclostridium positively co-occurred with Sellimonas. 4) Key outcomes or other accomplishments realized Output includes graphs and tables describing the relation of TiO2 to gut microbiome features. Output includes the inclusion of this experiment in a submitted scientific, peer-reviewed publication. AIM 3 1) Major activities completed / experiments conducted One fecal sample per participant was chosen for analysis. Gut biomarkers listed above were tested for each participant. 2) Data collected A complete, cleaned dataset has been created containing this data and submitted to NALs Data Commons. 3) Summary statistics and discussion of results Measures of intestinal inflammation and permeability Markers of gut inflammation and permeability did not differ across quartiles of dry stool TiO2 (P range: 0.17 - 0.81) after controlling for confounders. 4) Key outcomes or other accomplishments realized? Output includes the inclusion of this output in a scientific, peer-review publication that has been submitted.
Publications
- Type:
Peer Reviewed Journal Articles
Status:
Submitted
Year Published:
2025
Citation:
Title: Food Grade TiO2 is Negatively Related to Gut Health in Young Adults
Please note DOI will be made available upon publication.
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Progress 01/01/23 to 12/31/23
Outputs
Target Audience: The target audience for this study is healthy adults between the ages of 18 and 30 years old from the Greater Lowell area. TiO2 is a food additive used extensively in the United States food supply chain, however there is little understanding of current exposure among adults. Therefore, quantitation of TiO2 exposure among U.S. adults and examination of potential negative health effects is needed. Previous research outside of the U.S. suggests young adults consume significantly higher amounts of TiO2-containing foods compared to older adult age groups. Therefore, to provide representation of exposure to this food additive, the 18 to 30-year-old age group was selected. Rigorous inclusion and exclusion criteria were used in the current study to enroll healthy participants via a screener questionnaire. Exclusion criteria were formulated based on the mechanistic actions of disease and pharmaceuticals on the gut microbiome and homeostasis. Exclusion criteria include antibiotic use in the previous six months, non-steroidal anti- inflammatory (NSAID) use in the previous ten days, daily use of selective serotonin reuptake inhibitors (SSRIs) and proton pump inhibitors, current pregnancy, or conditions that alter gastrointestinal health, such as Crohn's disease, ulcerative colitis, and irritable bowel disease. Furthermore, the responses of the screener questionnaire were divided into four groups: ineligible, possible low titanium dioxide (TiO2), moderate TiO2, and high TiO2 consumption. Healthy adults were recruited from the University of Massachusetts, Lowell, and surrounding communities. There is a diverse community in northern Massachusetts with local, national, and international learners. The 2019 UML Students of Color & International Students (SOCIS) Sub-Committee report states 36% and 25.1% of the undergraduate and graduate student populations are students of color, respectively. Furthermore, of the undergraduate student population, 59.1% are Caucasian students, 12.1% are Asian students, 11.7% are Hispanic or Latino students, and 6.1% are Black, African- American, or Cape Verdean students. The University also serves 1,158 international students, making up 7.4% of the undergraduate and graduate student population. Results from the current study will be generalizable to adults without inflammatory bowel disease or other major inflammatory disease. The general audience for scientific dissemination will be scientific audiences (through scientific publication) and the local community (through research talks to the general community, hosted by the University of Massachusetts, Lowell). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training Activities Dr. Dhimiter Bello mentored and trained a graduate student in the lab on the new MARS-EXPRESS machine. With this training, the graduate student was able to digest and analyze all 240 fecal samples for contained metals and minerals. Professional Development The PhD student on this project attended the Canadian Bioinformatics Workshop, 2023, in Calgary, CA. This workshop was instrumental in supporting the student's knowledge of gut microbiome bioinformatics. This knowledge has since been applied to the gut microbiome analytics for the current project. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?The statistical analyses for this project will be finalized. The data will be analyzed by the PhD student, under the direction of the PI. The UML group will continue to meet regularly with the consultant, Wrigh Labs, to continue scientific interpretation of gut microbiome analysis. In addition, a manuscript will be written describing all scientific output from this grant.
Impacts
What was accomplished under these goals?
In 2019, the European Food Safety Authority (EFSA) made a ruling that food-grade titanium dioxide (TiO2), a food additive also known as E171, must be removed from all food products by January 1, 2020, due to its toxicity in the human gut. These decisions were largely based on laboratory models. There currently is a lack of quantitative data in humans linking dietary exposure of TiO2 and internal dose in the human gut to adverse health outcomes. Therefore, this study aims to examine the potential toxicity of the TiO2 food additive in the human gut. Results from this project could provide rational for the reduction or removal of this food additive from food products in the United States. This work is relevant to populations with high TiO2 intake, such as adults with lack of access to fresh, minimally processed foods. AIM1: to define dietary TiO2 exposure by estimating dietary intakes and measuring fecal TiO2 content among 80adults. Significant activities and experiments related to aim 1 include: The digestion and analysis ofall 240 fecal samples for minerals and metals in the stool samples (including assessment of Tio2 exposure). Output of the estimation of Tio2 intakes using fecal data. AIM 2: to establish how dietary TiO2 exposure is related to the gut microbiome (phyla diversity and mechanism of action). At the time of progress report submission, all samples have been sequenced and analyzed. Gut microbiome analysis is underway. Data from three timepoints (three separate stool samples) have been averaged across each participant and used in statistical analyses. Output includes graphs and tables describing the relation of Tio2 to gut microbiome features. AIM 3: to establish how dietary TiO2 exposure is related to gut inflammation, permeability, oxidative stress, and general homeostasis. At the time of this progress report, the inflammatory biomarkers analyzed include α-1-antitrypsin, myeloperoxidase, calprotectin and lactoferrin. One fecal sample per participant was chosen for analysis. Gut biomarkers listed above were tested for each participant. A complete, cleaned dataset has been created containing this data. Output includes statistical analysis of the relation between Tio2 and each gut marker.
Publications
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Progress 01/01/22 to 12/31/22
Outputs
Target Audience:The target audience for this study is healthy adults between the ages of 18 and 30 years old from the Greater Lowell area. TiO2 is a food additive used extensively in the United States food supply chain, however there is little understanding of current exposure among adults. Therefore, quantitation of TiO2 exposure among U.S. adults and examination of potential negative health effects is needed. Previous research outside of the U.S. suggests young adults consume significantly higher amounts of TiO2-containing foods compared to older adult age groups. Therefore, to provide representation of exposure to this food additive, the 18 to 30-year-old age group was selected. Rigorous inclusion and exclusion criteria are used in the current study to enroll healthy participants via a screener questionnaire.Exclusion criteria were formulated based on the mechanistic actions of disease and pharmaceuticals on the gut microbiome and homeostasis. Exclusion criteria include antibiotic use in the previous six months, non-steroidal anti-inflammatory (NSAID) use in the previous ten days, daily use of selective serotonin reuptake inhibitors (SSRIs) and proton pump inhibitors, current pregnancy, or conditions that alter gastrointestinal health, such as Crohn's disease, ulcerative colitis, and irritable bowel disease. Furthermore, the responses of the screener questionnaire were divided into four groups: ineligible, possible low titanium dioxide (TiO2), moderate TiO2, and high TiO2 consumption. Healthy adults are being recruited from the University of Massachusetts, Lowell, and surrounding communities. There is a diverse community in northern Massachusetts with local, national, and international learners. The 2019 UML Students of Color & International Students (SOCIS) Sub-Committee report states 36% and 25.1% of the undergraduate and graduate student populations are students of color, respectively. Furthermore, of the undergraduate student population, 59.1% are Caucasian students, 12.1% are Asian students, 11.7% are Hispanic or Latino students, and 6.1% are Black, African-American, or Cape Verdean students. The University also serves 1,158 international students, making up 7.4% of the undergraduate and graduate student population. Recruitment of study participants ended December 2022 as we reached our sample size goal of 80 completed participants. Recruitment methods included email, social media postings, and QR code-embedded flyers around local college campuses and popular off-campus locations. Results from the current study will be generalizable to adults without inflammatory bowel disease or other major inflammatory disease. Changes/Problems:The ongoing COVID-19 pandemic continues to introduce challenges to staffing at UML. These staffing issues have slowed purchasing, installation and use of new equipment, hiring of graduate students and general research support. Despite these challenges, we completed 80 participants, meeting our sample size goal. In addition, we are starting laboratory assessment of biospecimens. This will lead to statistical analysis of proposed study aims in Y3, 2023. What opportunities for training and professional development has the project provided?Opportunities that have been provided for training and professional development include staff training on the use of validated dietary data recall software, how to clean data and set up a metadataset, continued lab safety training, training on use of the MARS XPRESS and ICP-MS equipment, training on ELISA kit laboratory analysis, and weekly team progress meetings. The research team holds weekly, end-of-week meetings to wrap up the prior research week and to develop goals for the subsequent week. These meetings comprise of the principal investigator, the graduate student leading the research project, and two undergraduate student researchers. Topics that have been discussed at these meetings include, but are not limited to, protocol development, recruitment of participants, best practices in dietary recall interviews, fecal collection procedures, fecal collection storage, study design, participant retention, laboratory safey procedures, laboratory protocol and laboratory data colletion best practices. How have the results been disseminated to communities of interest?A Master of Public Health graduate student presented preliminary data on the first 19 participants at the UMass Lowell Student Research Engagement Symposium, April 2022. The audience was faculty and students from UML. Data presented included understanding at present of Tio2 exposure among the first 19 participants and how this helped reshape the screening questionairre for eligibility. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, laboratory analyses will be performed using current protocol. Gutbiomarkers will be analyzed at UML. TiO2 quantification and characterization will begin at UML. In addition, statistical analysis and interpretation of differences in the gut microbiome between high and low Tio2 exposed participants will begin in the Wright Labs. To better understand and perform relevant statistical analyses, the graduate student on the research team is taking an advanced regressioncourse with the UML public health department. Other students will continue their laboratory training under the supervision of the PI and other co-Is. Statistical analyses, as outlined for aims 1-3, will begin once laboratory analyses are complete. The PI will lead these efforts, with the support the graduate student.
Impacts
What was accomplished under these goals?
In 2019, the European Food Safety Authority (EFSA) made a ruling that food-grade titanium dioxide (TiO2), a food additive also known as E171, must be removed from all food products by January 1, 2020, due to its toxicity in the human gut. These decisions were largely based on laboratory models. There currently is a lack of quantitative data in humans linking dietary exposure of TiO2 and internal dose in the human gut to adverse health outcomes.Therefore, this study aims to examine the potential toxicity of the TiO2 food additive in the human gut. Results from this project could provide rational for the reduction or removal of this food additive from food products in the United States. This work is relevant to populations with high TiO2 intake, such as adults with lack of access to fresh, minimally processed foods. AIM1: to define dietary TiO2 exposure by estimating dietary intakes and measuring fecal TiO2 content among 80adults. A) Significant activities and experiments related to aim 1 include: screening of xxx adults for study participation; enrollment of 88participants; completion of 80 participants, each with 3 full study visits (valid completers). B) Study staff conducted xxx interviews (total of 80 completed participants and 8drops/incomplete participants) which included the collection of sociodemographic, health, dietary and biospecimen data. C) ThenewMARS 6 Xpress equipment was successfully installed and calibrated in Dr. Bello's lab, end of 2022. This allowed us for a quick start in 2023 to begin to analyze all 240 fecal samples. AIM 2: to establish how dietary TiO2 exposure is related to the gut microbiome (phyla diversity and mechanism of action). At the time of progress report submission, data has not been collected for this second aim. Fecal samples collected from enrolled participants will continue to be sent to a reference laboratory for 16s rRNA sequencing. A) All 240 fecal samples have been successfully delivered to the Wright Labs. Dr. Lamendella has reported that all fecal samples contained sufficient RNA & DNA for sequencing. Gut microbiome sequencing is complete. Gut microbiome data analysis planned for Y3 (2023). AIM 3: to establish how dietary TiO2 exposure is related to gut inflammation, permeability, oxidative stress, and general homeostasis. At the time of this progress report, the inflammatory biomarkers analyzed include α-1-antitrypsin and myeloperoxidase. A) All fecal samples have been aliquoted (2 vials of stool for Tio2 assessment; 1 vial for SCFA assessment; up to 10 aliquots [dependent upon volume of stool provided by each participant]) and frozen at -80 degrees F. B) Supplies for the 5 initial gut marker assessment have been purchased [calprotectin, lactoferrin, A1AT, MPO & zonulin]. Analysis to commence Y3, 2023.
Publications
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Progress 01/01/21 to 12/31/21
Outputs
Target Audience:The target audience for this study is healthy adults between the ages of 18 and 30 years old from the Greater Lowell area. TiO2 is a food additive used extensively in the United States food supply chain, however there is little understanding of current exposure among adults. Therefore, quantitation of TiO2 exposure among U.S. adults and examination of potential negative health effects is needed. Previous research outside of the U.S. suggests young adults consume significantly higher amounts of TiO2-containing foods compared to older adult age groups. Therefore, to provide representation of exposure to this food additive, the 18 to 30-year-old age group was selected. Rigorous inclusion and exclusion criteria are used in the current study to enroll healthy participants via a screener questionnaire offered through a web service, Qualtrics XM. A healthy gut profile was chosen to eliminate confounders known to influence gut health. Exclusion criteria were formulated based on the mechanistic actions of disease and pharmaceuticals concerning the gut microbiome and homeostasis. Exclusion criteria include antibiotic use in the previous six months, non-steroidal anti-inflammatory (NSAID) use in the previous ten days, daily use of selective serotonin reuptake inhibitors (SSRIs) and proton pump inhibitors, current pregnancy, or conditions that alter gastrointestinal health, such as Crohn's disease, ulcerative colitis, and irritable bowel disease. Furthermore, the responses of the screener questionnaire were divided into four groups: ineligible, possible low titanium dioxide (TiO2), moderate TiO2, and high TiO2 consumption. Healthy adults are being recruited from the University of Massachusetts, Lowell (UML), and surrounding communities. There is a diverse community in northern Massachusetts with local, national, and international learners. The 2019 UML Students of Color & International Students (SOCIS) Sub-Committee report states 36% and 25.1% of the undergraduate and graduate student populations are students of color, respectively. Furthermore, of the undergraduate student population, 59.1% are Caucasian students, 12.1% are Asian students, 11.7% are Hispanic or Latino students, and 6.1% are Black, African-American, or Cape Verdean students. The University also serves 1,158 international students, making up 7.4% of the undergraduate and graduate student population. Recruitment methods include email, social media postings, and QR code-embedded flyers around local college campuses and popular off-campus locations. Study staff assess responses from participant screeners for eligibility. Enrollment as of 12/17/2021 included19 participants with the following demographics: average age 19.7y; 52% male, 48% female; 53% White, 21% Asian, 21% 2+ ethnicities, 5% Black. Changes/Problems:Enrollment challenges The ongoing COVID-19 pandemic continues to introduce challenges to enrolling participants in human subjects research. Participants in the current study reported difficulty scheduling time for in-person interviews and fear of getting sick. To combat this significant challenge and to meet our enrollment goal of 80 participants, the research team received IRB approval to provide a virtual option for all study interviews. The virtual option will lend better flexibility tothe research team and enrolled participants. With this virtual option,participants will be able to provide their fecal samples to the research team one of two ways:pick-up, or drop-off. Participants will schedule their next virtual visit and fecal sample delivery type at their preceding visit. Participants will still be able to participate with in-person visits if preferred. To further boost participant enrollment, study staff will recruit from four additional colleges/universities and the surrounding communities during the first and second quarters of 2022. The goal is to complete 80 participants by the end of the next reporting period. Methodological changes The original protocol required fecal samples to be returned, aliquoted, and frozen within four hours of participant production to preserve the stability of the short-chain fatty acids (SCFAs). Enrolled participants had great difficulty maintaining this four-hour window. To maintain fecal SCFA integrity while also reducing participant burden, the following changes were made to the methodological protocol: participants will now place a portion of their stool into a tube with 5 mL of 70% ethanol. Scientific literature shows suspension of fecal samples in 70% ethanol increases SCFA stability to seven days at room temperature. Once received, the samples will be frozen at -80°C, per standard protocol. This change to protocol will reduce participant burden while maintaining the integrity of the sample to answer the proposed aims of the project. Budget carryover Despite the grant start date ofJanuary 2021, the funds weremade available at the start of summer. This delayed the start of the study by 6 months. The COVID-19 pandemichas also slowed human subject enrollment. For these reasons, hiring a Research Assistant (PhD student)and effort for Co-I Tucker were delayed. We are requesting the use of these funds in project year 2022. What opportunities for training and professional development has the project provided?Opportunities that have been provided for training and professional development include staff training on the use of validated dietary data recall software (NDSR), how to perform statistical regression modeling, safety training, and weekly team progress meetings. Detailed descriptions of such training may be found under "other products." The research team holdsend-of-week meetings to wrap up the prior research week and to develop goals for the subsequent week. These meetings include the principal investigator, the Ph.D. student leading the research project, and graduate and undergraduate student researchers. Topics that have been discussed at these meetings include, but are not limited to, protocol development, recruitment of participants, best practices in dietary recall interviews, fecal collection procedures, study design, and participant retention. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, the study will continue with active participant enrollment and retention. Under the first aim, participants will continue to be recruited from the University of Massachusetts Lowell, in addition to local communities and colleges [Middlesex Community College (Bedford & Lowell, MA), Northern Essex Community College (Haverhill & Lawrence, MA), Merrimack College (North Andover, MA), and Rivier University (Nashua, NH)]. The study will work to bring participant enrollment to the final goal of 80 participants. In addition, laboratory analyses may be performed during this reporting period per established specimen stabilities. Throughout the next reporting period, inflammatory biomarkers will be analyzed in addition to immune-mediated biomarkers and reactive oxygen species. Additional TiO2 quantification and characterization will occur after enrollment is complete. To better understand and perform relevant statistical analyses, the Ph.D. student on the research team is taking a "Statistical Analysis using SAS" course with the UML mathematics department. The course description provided by the department states that the course is "an introduction to creation and manipulation of databases and statistical analysis using SAS software. SAS is widely used in the pharmaceutical industry, medical research and other areas." Collected participant samples will continue to be sent to the Wright Labs for storage and future microbiome analysis. Microbiome analyses on collected fecal samples will be done at the completion of participant enrollment to avoid batch effects on outcomes.
Impacts
What was accomplished under these goals?
IMPACT: In 2019, the European Food Safety Authority (EFSA) made a ruling that food-grade titanium dioxide (TiO2), a food additive also known as E171, must be removed from all food products by January 1, 2020, due to its toxicity in the human gut. These decisions were largely based on laboratory models. There currently is a lack of quantitative data in humans linking dietary exposure of TiO2 and internal dose in the human gut to adverse health outcomes. Therefore, this study aims to examine the potential toxicity of the TiO2 food additive in the human gut. Results from this project could provide rational for the reduction or removal of this food additive from food products in the United States. This work is relevant to populations with high TiO2 intake, such as adults with lack of access to fresh, minimally processed foods. AIM1: to define dietary TiO2 exposure by estimating dietary intakes and measuring fecal TiO2 content among 80 adults. A) Significant activities and experiments related to aim 1 include 1) ascertainment of Institutional Review Board and Institutional Biosafety Committee approvals; 2) screening of 122 adults for study participation; 3) enrollment of 21participants; 4) fecal digestion and analysisof 54 samples from 19 completed adults via MARS 6 Xpress and titanium quantification by inductively coupled mass spectrometry (ICP-MS) with the Agilent 7900. B) Data collected: study staff conducted 76 interviews (total of 19 completed participants and 2 drops) which included the collection of sociodemographic, health, dietary and biospecimen data.C) Summary statistics of the completed participants are: average age 19.7y; 52% male, 48% female; 53% White,21% Asian, 21% 2+ ethnicities,5% Black.Enrollment of additional participants is ongoing. As of 12/17/2021, the data from hypothesis 1a shows a mean TiO2 quantity of 0.079 μg/mg in the enrolled participants' fecal samples. In addition to a minimum and maximum TiO2 quantity of 0.002 μg/mg and 0.656 μg/mg, respectively. These minimum and maximum values assure high and lowTiO2 groups are being formed, as required by the hypotheses. AIM 2: to establish how dietary TiO2 exposure is related to the gut microbiome (phyla diversity and mechanism of action). A) Significant activities and experiments: at the time of progress report submission, data have not been analyzed for this second aim. Fecal samples collected from enrolled participants will continue to be sent to a collaborative laboratory for 16s rRNA sequencing after all samples have been collected. AIM 3: to establish how dietary TiO2 exposure is related to gut inflammation, permeability, oxidative stress, and general homeostasis. A) Significant activities and experiments: at the time of this progress report, the inflammatory biomarkers analyzed include α-1-antitrypsin and myeloperoxidase from 19 completed participants in 2021. B) Data collection and analysis: the data collected from 19 enrolled participants showsa mean fecal concentration for α-1-antitrypsin (AAT) of 158 mg/dL; minimum and maximum AAT concentrations of 1.1 mg/dL and 172.6 mg/dL, respectively. Myeloperoxidase (MPO) shows a mean concentration of 328 ng/mL;minimum and maximum MPO concentrations of 37 ng/mL and 1,665 ng/mL, respectively.
Publications
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