An Examination of the Sex-Specific Nature of Nutrition Assessment within the Nutrition Care Process: Considerations for Nutrition and Dietetics Practitioners Working with Transgender and Gender Diverse Clients

Abstract

Continuing Professional Education (CPE) InformationThe Continuing Professional Education (CPE) quiz for this article is available for free to Academy members through the MyCDRGo app (available for iOS and Android devices) and through www.jandonline.org (click on “CPE” in the menu and then “Academy Journal CPE Articles”). Log in with your Academy of Nutrition and Dietetics or Commission on Dietetic Registration username and password, click “Journal Article Quiz” on the next page, then click the “Additional Journal CPE quizzes” button to view a list of available quizzes. Non-members may take CPE quizzes by sending a request to [email protected] . There is a $45 fee per quiz (includes quiz and copy of article) for non-members. CPE quizzes are valid for 3 years after the issue date in which the articles are published.The Nutrition Care Process (NCP) is the standardized process for nutrition and dietetics practitioners to deliver care.1Swan W. Vivant A. Hakel-Smith N. et al.Nutrition Care Process and Model update: toward realizing people-centered care and outcomes management.J Acad Nutr Diet. 2017; 117: 2003-2014Abstract Full Text Full Text PDF PubMed Scopus (112) Google Scholar,2Swan W. Pertel D.G. Hotson B. et al.Nutrition Care Process (NCP) update part 2: developing and using the NCP terminology to demonstrate efficacy of nutrition care and related outcomes.J Acad Nutr Diet. 2019; 119: 840-855Abstract Full Text Full Text PDF PubMed Scopus (33) Google Scholar Nutrition assessment is the first step of the NCP and is utilized to gather and synthesize client data that will ultimately inform a nutrition diagnosis. This step is considered an ongoing process of initial data collection, reassessment, and analysis against reference standards. The eight domains of nutrition assessment are: food/nutrition-related history; anthropometric measure; biochemical data, medical tests, and procedures; nutrition-focused physical findings; client history; assessment, monitoring, and evaluation tools; etiology category; and progress evaluation.3Academy of Nutrition and DieteticsNutrition Terminology Reference Manual (eNCPT): Dietetics Language for Nutrition Care.http://www.ncpro.orgDate accessed: July 21, 2021Google Scholar The Continuing Professional Education (CPE) quiz for this article is available for free to Academy members through the MyCDRGo app (available for iOS and Android devices) and through www.jandonline.org (click on “CPE” in the menu and then “Academy Journal CPE Articles”). Log in with your Academy of Nutrition and Dietetics or Commission on Dietetic Registration username and password, click “Journal Article Quiz” on the next page, then click the “Additional Journal CPE quizzes” button to view a list of available quizzes. Non-members may take CPE quizzes by sending a request to [email protected] . There is a $45 fee per quiz (includes quiz and copy of article) for non-members. CPE quizzes are valid for 3 years after the issue date in which the articles are published. Certain aspects of nutrition assessment are sex-specific, meaning they require nutrition and dietetics practitioners to select a male or female sex. This presents a unique question for nutrition and dietetics practitioners working with transgender and gender diverse (TGGD) clients. For the purposes of this article, we are using the term transgender to describe a person whose gender identity differs from the sex that was assigned at birth, and term gender diverse to describe a broader range of gender identities that may be more complex or fluid. As detailed in the client history domain of the electronic Nutrition Care Process Terminology, the term sex refers to a person’s sex assigned at birth based on the assessment of external genitalia, reproductive organs, chromosomes, and gonads, whereas the terms gender or gender identity refer to a person’s internal sense of self and how they fit into the world with respect to gender.3Academy of Nutrition and DieteticsNutrition Terminology Reference Manual (eNCPT): Dietetics Language for Nutrition Care.http://www.ncpro.orgDate accessed: July 21, 2021Google Scholar,4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google Scholar It is noteworthy that these terms may evolve over time and be interpreted differently based on cultural context and local realities.5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar Given that nutrition assessment is the seminal step in the delivery of nutrition care, the purpose of this article is to evaluate the sex-specific nature of nutrition assessment within the NCP. Our objectives are to identify the aspects of nutrition assessment that rely on biological sex, suggest approaches for nutrition and dietetics practitioners when working with TGGD clients, and illustrate the possible approaches with three sample cases. In the United States, an estimated 0.6% of adults and 0.7% of youth aged 13 to 17 years identify as TGGD.6Flores A.R. Herman J.L. Gates G.J. et al.How many adults identify as transgender in the United States?.https://williamsinstitute.law.ucla.edu/publications/trans-adults-united-states/Date accessed: March 7, 2022Google Scholar,7Herman J.L. Flores A.R. Brown T.N.T. et al.Age of individuals who identify as transgender in the United States. The Williams Institute, UCLA School of Law, 2017https://williamsinstitute.law.ucla.edu/wp-content/uploads/Age-Trans-Individuals-Jan-2017.pdfDate accessed: March 7, 2022Google Scholar Although societal understanding and acceptance is growing, marked health disparities persist among the TGGD population second to gender-based stigma and discrimination. TGGD adults in the United States are more than twice as likely to live in poverty and three times more likely to experience unemployment than the general population. Within the health care system, one-third of TGGD adults had at least one recent negative experience related to their gender identity such as verbal harassment or being refused treatment. Nearly one-quarter of TGGD adults avoided seeking needed health care due to fear of mistreatment. Due to the compounding effects of other forms of discrimination, transgender adults of color reported even higher rates of poverty, unemployment, and resulting health disparities.8James S.E. Herman J.L. Rankin S. et al.The Report of the 2015 U.S. Transgender Survey. National Center for Transgender Equality, 2016Google Scholar Nutrition-related health disparities include elevated rates of disordered eating and body dysmorphia, food insecurity, and overweight and obesity compared with cisgender populations.9Arikawa A.Y. Ross J. Wright L. et al.Results of an online survey about food insecurity and eating disorder behaviors administered to a volunteer sample of self-described LGBTQ+ young adults aged 18 to 35 years.J Acad Nutr Diet. 2021; 121: 1231-1241Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar, 10Becerra-Culqui T.A. Liu Y. Nash R. et al.Mental health of transgender and gender nonconforming youth compared with their peers.Pediatrics. 2018; 141e20173845Crossref PubMed Scopus (130) Google Scholar, 11Coelho J.S. Suen J. Clark B.A. et al.Eating disorder diagnoses and symptom presentation in transgender youth: a scoping review.Curr Psychiatry Rep. 2019; 21: 107Crossref PubMed Scopus (36) Google Scholar, 12Kirby S.R. Linde J.A. Understanding the nutritional needs of transgender and gender-nonconforming students at a large public midwestern university.Transgend Health. 2020; 5: 33-41Crossref PubMed Scopus (6) Google Scholar, 13Linsenmeyer W.R. Katz I.M. Reed J.L. et al.Disordered eating, food insecurity, and weight status among transgender and gender nonbinary youth and young adults: a cross-sectional study using a nutrition screening protocol.LGBT Health. 2021; 8: 359-366Crossref PubMed Scopus (2) Google Scholar, 14Russomanno J. Patterson J.G. Jabson J.M. Food insecurity among transgender and gender nonconforming individuals in the southeast United States: a qualitative study.Transgend Health. 2019; 4: 89-99Crossref PubMed Scopus (18) Google Scholar Disordered eating may be exacerbated among TGGD youth due to the use of food as a coping mechanism for gender-related stigma or distress.11Coelho J.S. Suen J. Clark B.A. et al.Eating disorder diagnoses and symptom presentation in transgender youth: a scoping review.Curr Psychiatry Rep. 2019; 21: 107Crossref PubMed Scopus (36) Google Scholar,13Linsenmeyer W.R. Katz I.M. Reed J.L. et al.Disordered eating, food insecurity, and weight status among transgender and gender nonbinary youth and young adults: a cross-sectional study using a nutrition screening protocol.LGBT Health. 2021; 8: 359-366Crossref PubMed Scopus (2) Google Scholar Beyond the intersection with poverty and homelessness, food insecurity may be elevated among TGGD youth and adults due to fear of discrimination at faith-based food pantries, the need to provide identification that may include a photograph or gender marker inconsistent with gender identity, the competing financial burden of food and medical care, and familial rejection.9Arikawa A.Y. Ross J. Wright L. et al.Results of an online survey about food insecurity and eating disorder behaviors administered to a volunteer sample of self-described LGBTQ+ young adults aged 18 to 35 years.J Acad Nutr Diet. 2021; 121: 1231-1241Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar,12Kirby S.R. Linde J.A. Understanding the nutritional needs of transgender and gender-nonconforming students at a large public midwestern university.Transgend Health. 2020; 5: 33-41Crossref PubMed Scopus (6) Google Scholar, 13Linsenmeyer W.R. Katz I.M. Reed J.L. et al.Disordered eating, food insecurity, and weight status among transgender and gender nonbinary youth and young adults: a cross-sectional study using a nutrition screening protocol.LGBT Health. 2021; 8: 359-366Crossref PubMed Scopus (2) Google Scholar, 14Russomanno J. Patterson J.G. Jabson J.M. Food insecurity among transgender and gender nonconforming individuals in the southeast United States: a qualitative study.Transgend Health. 2019; 4: 89-99Crossref PubMed Scopus (18) Google Scholar TGGD individuals may transition in different ways to align with their gender identity, such as socially, legally, or medically, although the types of therapeutic options, timing, and duration are variable and individualized.5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar Medical interventions are medically necessary for many transgender individuals to alleviate the psychological distress caused by gender dysphoria.5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar,8James S.E. Herman J.L. Rankin S. et al.The Report of the 2015 U.S. Transgender Survey. National Center for Transgender Equality, 2016Google Scholar Among adolescents, medical interventions may include pubertal hormone suppression to allow more time for gender identity exploration and to prevent development of secondary sexual characteristics that do not align with gender identity, followed by masculinizing or feminizing hormone therapy (HT).4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google Scholar,5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar Among adults, medical interventions may include HT and/or gender-affirming surgeries.4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google Scholar,5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar Clinical practice guidelines and standards of care published by national and international health organizations are used to guide the medical care of TGGD clients (see Table 1).Table 1Clinical practice guidelines and standards of care for transgender populationsStandards of Care for the Health of Transsexual, Transgender and Gender Nonconforming People by the World Professional Association for Transgender Health: https://www.wpath.org/Guidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People by the University of California, San Francisco: https://transcare.ucsf.edu/guidelinesClinical Practice Guidelines for the Treatment of Gender Dysphoric/Gender-Incongruent Persons by the Endocrine Society: https://academic.oup.com/jcem/article/102/11/3869/4157558 Open table in a new tab Understanding aspects of a client’s medical transition is particularly relevant to nutrition and dietetics practitioners given the nutrition-related implications that may result.15Fergusson P. Greenspan N. Maitland L. et al.Towards providing culturally aware nutritional care for transgender people: key issues and considerations.Can J Diet Pract Res. 2018; 79: 74 e9Crossref Scopus (11) Google Scholar Masculinizing and feminizing HT may result in changes to anthropometric measures (ie, body weight and waist circumference), laboratory values (ie, lipid panel and complete blood count), and diagnostic tests (ie, bone mineral density).15Fergusson P. Greenspan N. Maitland L. et al.Towards providing culturally aware nutritional care for transgender people: key issues and considerations.Can J Diet Pract Res. 2018; 79: 74 e9Crossref Scopus (11) Google Scholar, 16Fernandez J.D. Tannock L.R. Metabolic effects of hormone therapy in transgender patients.Endocr Pract. 2016; 22: 383-388Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar, 17Fighera T.M. Ziegelmann P.K. da Silva T.R. et al.Bone mass effects of cross-sex hormone therapy in transgender people: updated systematic review and meta-analysis.J Endocrine Society. 2019; 3: 943-964Crossref PubMed Scopus (19) Google Scholar, 18Rahman R. Linsenmeyer W.R. Caring for transgender patients and clients: nutrition-related clinical and psychosocial considerations.J Acad Nutr Diet. 2019; 119: 727 e32Abstract Full Text Full Text PDF Scopus (13) Google Scholar Not only are these measures expected to change with HT, but many of the reference standards rely on sex-specific values. For example, body fat is expected to decrease or increase with masculinizing and feminizing HT, respectively, which is further complicated by the sex-specific reference values for body fat percentage.5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar,19American College of Sports MedicineGuidelines for Exercise Testing and Prescription.11th ed. Wolters Kluwer, 2021Google Scholar This presents a unique question for nutrition and dietetics practitioners regarding how to best interpret a client’s data. Currently no clinical practice standards exist to guide the nutrition care of TGGD clients, although we can apply clinical reasoning and draw from advancements in the broader medical community.20Rozga M. Linsenmeyer W. Cantwell Wood J. et al.Hormone therapy, health outcomes and the role of nutrition in transgender individuals: a scoping review.Clin Nutr ESPEN. 2020; 40: 42-56Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar Various aspects of nutrition assessment require nutrition and dietetics professionals to choose between male or female biological sex. Table 2 details the sex-specific data collected within each nutrition assessment domain. These attributes may influence interpretation of the client’s data and the remaining steps of the NCP, including the nutrition diagnosis, intervention, and monitoring and evaluation. For example, the decision to interpret a TGGD adolescent’s body mass index (BMI)-for-age percentile on the growth chart for a boy or girl may influence the nutrition diagnosis for weight status as underweight, healthy weight, overweight, or obese.Table 2Sex-specific data points of nutrition assessment within the Nutrition Care Process.Nutrition assessment domainCommon data points with sex-specific reference rangesCommentsFood/nutrition-related historyEnergy needsSome predictive energy equations use sex/gender as a variable; that is, Harris-Benedict, Mifflin-St JeorDietary Reference Intake valuesThe Estimated Energy Requirements, Recommended Dietary Allowances, and Adequate Intakes for water, energy, and the energy nutrients, plus the Recommended Dietary Allowances and Adequate Intakes for vitamins and mineralsAnthropometric measuresBody fat percentageWaist circumferenceWaist-to-hip ratioBody mass index-for-age percentilesBiochemical data, medical tests, and proceduresHigh-density lipoprotein cholesterolWhen used as the clinical cutoff for clinical identification of metabolic syndromeCholesterol to high-density lipoprotein ratioHemoglobinFor patients receiving masculinizing hormone therapy: the University of California San Francisco guidelines recommend using the male reference value for the upper limit of normal and the male value for the lower limit of normal if amenorrheic.4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google ScholarFor patients on feminizing hormone therapy: The University of California San Francisco guidelines recommend using the female reference value for the lower limit of normal and the male reference value for the upper limit of normal4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google ScholarHematocritRed blood cell countFerritinCreatinineFor clients on both feminizing and masculinizing hormone therapy: The University of California San Francisco guidelines recommend using the male reference value for the upper limit of normal4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google ScholarAlkaline phosphataseBone mineral densityNutrition-focused physical findingsNoneAlthough there are no sex-specific reference values related to the nutrition-focused physical exam, changes in muscle and fat mass are expected with a medical transitionClient historyNoneThe 2-step method of sex and gender identity data is ideal to separately query sex assigned at birth and gender identityaTate CC, Ledbetter JN, Youssef CP. A two-question method for assessing gender categories in the social and medical sciences. J Sex Res. 2013;50(8):767-776.Assessment, monitoring and evaluation toolsNoneThis domain refers to an array of tools that may be used to assess for and/or monitor health and disease status, some of which may be sex-specific (ie, minimum dietary diversity for women indicator score)Etiology categoryNoneProgress evaluationNonea Tate CC, Ledbetter JN, Youssef CP. A two-question method for assessing gender categories in the social and medical sciences. J Sex Res. 2013;50(8):767-776. Open table in a new tab As depicted in Table 2, the sex-specific attributes of nutrition assessment are clustered in the first three domains. Within food/nutrition-related history, estimation of energy needs may require use of predictive energy equations where sex is a variable, such as the Harris-Benedict or Mifflin-St Jeor equations.21Harris J.A. Benedict F.G. A biometric study of basal metabolism in man.Proc Natl Acad Sci U S A. 1918; 4: 370-373Crossref PubMed Google Scholar,22Mifflin M.D. Jeor S.T. Hill L.A. et al.A new predictive equation for resting energy expenditure in healthy individuals.Am J Clin Nutr. 1990; 51: 241-247Crossref PubMed Scopus (1526) Google Scholar When evaluating adequacy of water, energy, the energy-yielding nutrients, and vitamins and minerals, certain Dietary Reference Intakes (DRI) provide sex-specific references such as the Estimated Energy Requirement, Recommended Dietary Allowances (RDA), and Adequate Intakes.23Institute of Medicine, Food and Nutrition BoardDietary Reference Intakes: The Essential Guide to Nutrient Requirements. The National Academies Press, 2006Google Scholar The DRI values for some nutrients do not vary between the male and female values, whereas others reflect a dramatic difference. For example, the RDA for vitamin D is 600 IU/day for both women and men aged 19 to 70 years, whereas the RDA for iron assumes the presence of menstruation and more than doubles for women compared with men aged 19 to 50 years (18 mg/day and 8 mg/day, respectively).23Institute of Medicine, Food and Nutrition BoardDietary Reference Intakes: The Essential Guide to Nutrient Requirements. The National Academies Press, 2006Google Scholar Within the anthropometric measures domain, body fat percentage, waist circumference, and wait-to-hip ratio rely on sex-specific reference ranges.24National Institutes of Health, National Heart, Lung and Blood Institute, North American Association for the Study of ObesityThe Practical Guide: Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. National Academies Press, 2000Google Scholar, 25National Institutes of Health, US Department of Health and Human Services, National Heart, Lunch, and Blood InstituteManaging Overweight and Obesity and Adults: Systematic Evidence Review from the Obesity Expert Panel. National Academies Press, 2013Google Scholar, 26World Health OrganizationWaist Circumference and Waist-Hip Ratio: Report of a WHO Expert Consultation. World Health Organization, 2011Google Scholar For children aged 2 to 20 years, interpretation of BMI-for-age percentiles rely on a separate growth chart for girls vs boys.27Centers for Disease Control and Prevention, National Center for Health StatisticsCDC growth charts: United States.https://www.cdc.gov/growthcharts/Date accessed: September 28, 2021Google Scholar Lastly, within the domain of biochemical data, medical tests, and procedures, interpretation of multiple laboratory values relies on sex-specific ranges, including those within a lipid panel (high-density lipoprotein cholesterol level and cholesterol to high-density lipoprotein cholesterol ratio), complete blood count (hemoglobin, hematocrit, red blood cell count, and ferritin levels), kidney function (creatinine excretion), and liver function (alkaline phosphatase level). Interpretation of bone mineral density testing relies on z and T scores relative to the average values for a person of the same age and sex.28Noland D. Litchford M. Principles of nutritional laboratory testing.in: Raymond J.L. Kelly M. Krause and Mahan’s Food & the Nutrition Care Process. 15th edition. Elsevier, 2021: 981-1001Google Scholar, 29Harris E.K. Boyd J.C. On dividing reference data into subgroups to produce separate reference ranges.Clin Chem. 1990; 36: 265-270Crossref PubMed Scopus (262) Google Scholar, 30Harris E.K. Boyd J.C. Statistical Bases of Reference Values in Laboratory Medicine. Marcel Dekker, 1995Crossref Google Scholar, 31How to Define and Determine Reference Intervals in the Clinical Laboratory: Approved Guideline. National Committee for Clinical Laboratory Standards, 2001Google Scholar The following approaches are based on clinical reasoning and drawn from the broader medical community. Given the emerging nature of transgender health research, these approaches are not finite and are likely to evolve with the growing body of science. For adolescents on pubertal suppression therapy and adolescents/adults who have not medically transitioned with HT or surgical interventions, nutrition and dietetics practitioners can utilize the reference values consistent with the client’s sex assigned at birth. Given that the predictive energy questions,21Harris J.A. Benedict F.G. A biometric study of basal metabolism in man.Proc Natl Acad Sci U S A. 1918; 4: 370-373Crossref PubMed Google Scholar,22Mifflin M.D. Jeor S.T. Hill L.A. et al.A new predictive equation for resting energy expenditure in healthy individuals.Am J Clin Nutr. 1990; 51: 241-247Crossref PubMed Scopus (1526) Google Scholar DRI values,23Institute of Medicine, Food and Nutrition BoardDietary Reference Intakes: The Essential Guide to Nutrient Requirements. The National Academies Press, 2006Google Scholar anthropometric measures,25National Institutes of Health, US Department of Health and Human Services, National Heart, Lunch, and Blood InstituteManaging Overweight and Obesity and Adults: Systematic Evidence Review from the Obesity Expert Panel. National Academies Press, 2013Google Scholar, 26World Health OrganizationWaist Circumference and Waist-Hip Ratio: Report of a WHO Expert Consultation. World Health Organization, 2011Google Scholar, 27Centers for Disease Control and Prevention, National Center for Health StatisticsCDC growth charts: United States.https://www.cdc.gov/growthcharts/Date accessed: September 28, 2021Google Scholar and reference ranges for certain biochemical data points28Noland D. Litchford M. Principles of nutritional laboratory testing.in: Raymond J.L. Kelly M. Krause and Mahan’s Food & the Nutrition Care Process. 15th edition. Elsevier, 2021: 981-1001Google Scholar, 29Harris E.K. Boyd J.C. On dividing reference data into subgroups to produce separate reference ranges.Clin Chem. 1990; 36: 265-270Crossref PubMed Scopus (262) Google Scholar, 30Harris E.K. Boyd J.C. Statistical Bases of Reference Values in Laboratory Medicine. Marcel Dekker, 1995Crossref Google Scholar, 31How to Define and Determine Reference Intervals in the Clinical Laboratory: Approved Guideline. National Committee for Clinical Laboratory Standards, 2001Google Scholar are based on clinically reported sex-specific differences, utilizing a client’s sex assigned at birth will provide the most accurate assessment for those who have not medically transitioned. This approach has been utilized in clinical practice by health care teams caring for TGGD clients.13Linsenmeyer W.R. Katz I.M. Reed J.L. et al.Disordered eating, food insecurity, and weight status among transgender and gender nonbinary youth and young adults: a cross-sectional study using a nutrition screening protocol.LGBT Health. 2021; 8: 359-366Crossref PubMed Scopus (2) Google Scholar,32Linsenmeyer W. Rahman R. Transgender and gender nonconforming youth: considerations for registered dietitian nutritionists.Weight Management Matters. 2021; 19: 8-14Google Scholar An estimated 62% of TGGD adults in the United States have medically transitioned with HT and an additional 23% plan to do so in the future. A smaller proportion have had gender-affirming surgeries (4% to 43% depending on surgery type), with orchiectomy as the most common transfeminine surgery and chest surgery as the most common transmasculine surgery.33Grant J.M. Mottet L.A. Tanis J. et al.Injustice at Every Turn: A Report of the National Transgender Discrimination Survey. National Center for Transgender Equality and National Gay and Lesbian Task Force, 2011Google Scholar Therefore, nutrition and dietetics practitioners should not assume that a TGGD client has medically transitioned based on their gender identity or expression, and should gather this information as part of their past medical history through chart review and/or the client interview. Physical changes typically begin and peak within a certain window of time after initiating HT, although the timing and scale of changes will vary among individuals. The World Professional Association for Transgender Health guidelines specify the expected time of onset and maximum effect with masculinizing HT (ie, increased muscle mass/strength, body fat redistribution, and cessation of menses) and feminizing HT (ie, body fat redistribution, decreased muscle mass/strength, and softening of skin/decreased oiliness).5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar For example, clients on masculinizing HT may experience increased muscle mass/strength starting at 6 to 12 months with an expected maximum effect at 2 to 5 years, whereas those on feminizing HT may experience decreased muscle mass/strength starting at 3 to 6 months with an expected maximum effect at 1 to 2 years.5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar Nutrition and dietetics professionals can use these guidelines to inform their decision to use the male or female reference values, especially for those that are directly related to anticipated physical changes with HT such as body fat percentage, waist circumference, waist-to-hip ratio, and the interpretation of laboratory values related to iron status. Lastly, the need to individualize nutrition assessment is especially relevant given that some clients may seek moderate changes with HT or a combination of masculine and feminine secondary sex characteristics.4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google Scholar For certain parameters of nutrition assessment, it may be reasonable to express data as a range using both the female and male reference values, especially where ranges are routinely used in clinical practice such as estimating energy or protein needs.23Institute of Medicine, Food and Nutrition BoardDietary Reference Intakes: The Essential Guide to Nutrient Requirements. The National Academies Press, 2006Google Scholar,34Linsenmeyer W. Drallmeier T. Thomure M. Towards gender-affirming nutrition assessment: a case series of adult transgender men with distinct nutrition considerations.Nutr J. 2020; 19: 1-8PubMed Google Scholar This may also be appropriate for patients on HT for a relatively short period (ie, <6 months) or who are on low-to-moderate HT regimens and therefore intentionally within the midrange between the male and female norms.4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google Scholar Nutrition and dietetics practitioners have reported this approach using case studies and clinical case series of TGGD adults, and in their interpretation of BMI percentile charts for TGGD youth.32Linsenmeyer W. Rahman R. Transgender and gender nonconforming youth: considerations for registered dietitian nutritionists.Weight Management Matters. 2021; 19: 8-14Google Scholar,33Grant J.M. Mottet L.A. Tanis J. et al.Injustice at Every Turn: A Report of the National Transgender Discrimination Survey. National Center for Transgender Equality and National Gay and Lesbian Task Force, 2011Google Scholar,35Linsenmeyer W.R. Rahman R. Diet and nutritional considerations for a FTM transgender male: a case report.J Am Coll Health. 2018; 66: 533-536Crossref PubMed Scopus (3) Google Scholar,36Kidd K.M. Sequeira G.M. Dhar C.P. et al.Gendered body mass index percentile charts and transgender youth: making the case to change charts.Transgend Health. 2019; 4: 297-299Crossref PubMed Scopus (5) Google Scholar, The following cases were developed by the authors and based on real TGGD patients seen through our clinical practices. The authors are cisgender registered dietitian nutritionists and physicians who specialize in clinical practice and research with the TGGD community. The case studies were reviewed by a trans man who is active in the lesbian, gay, bisexual, and transgender community to ensure the language presented is culturally appropriate (see the Acknowledgements). LB is a 17-year old, non-Hispanic White individual who was referred to a registered dietitian nutritionist for disordered eating. LB was assigned male at birth, identifies as nonbinary, and uses they/their pronouns. They wear both masculine and feminine clothing and are not interested in pursuing medical interventions such as HT or surgery. LB is 5-ft, 6-in tall and weighs 120 lb. Which growth chart would be most accurate to assess LB’s weight status? Given that LB has not medically transitioned, using the growth chart consistent with their sex assigned at birth (male) would provide the most accurate interpretation of their weight status. LB’s BMI is 20 based on their height and weight. Using the BMI-for-age growth chart for boys ages 2 to 20 years, LB is in the 30th percentile for BMI-for-age. Although using sex assigned at birth to assess weight status, nutrition and dietetics practitioners can honor LB’s nonbinary gender identity in a several of ways, such as using their correct name and pronouns, ensuring their medical records accurately represent their gender identity, and using gender-neutral language to describe the body if that is LB’s preference.18Rahman R. Linsenmeyer W.R. Caring for transgender patients and clients: nutrition-related clinical and psychosocial considerations.J Acad Nutr Diet. 2019; 119: 727 e32Abstract Full Text Full Text PDF Scopus (13) Google Scholar,32Linsenmeyer W. Rahman R. Transgender and gender nonconforming youth: considerations for registered dietitian nutritionists.Weight Management Matters. 2021; 19: 8-14Google Scholar The CDC growth charts are inherently limited for TGGD patients who are medically transitioning due to the binary options of boy or girl charts.27Centers for Disease Control and Prevention, National Center for Health StatisticsCDC growth charts: United States.https://www.cdc.gov/growthcharts/Date accessed: September 28, 2021Google Scholar Current standards of care do not address which growth chart to utilize.4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google Scholar,5Coleman E, Bockting W, Botzer M, et al. Standards of care for the health of transsexual, transgender, and gender-nonconforming people, version 7. Int J Transgenderism. 20212;13(4):165-232.Google Scholar Existing research has reported the strategy of assessing growth using both the boy and girl charts for TGGD patients who are medically transitioning and has underpinned the need for further research in this area.13Linsenmeyer W.R. Katz I.M. Reed J.L. et al.Disordered eating, food insecurity, and weight status among transgender and gender nonbinary youth and young adults: a cross-sectional study using a nutrition screening protocol.LGBT Health. 2021; 8: 359-366Crossref PubMed Scopus (2) Google Scholar,32Linsenmeyer W. Rahman R. Transgender and gender nonconforming youth: considerations for registered dietitian nutritionists.Weight Management Matters. 2021; 19: 8-14Google Scholar,36Kidd K.M. Sequeira G.M. Dhar C.P. et al.Gendered body mass index percentile charts and transgender youth: making the case to change charts.Transgend Health. 2019; 4: 297-299Crossref PubMed Scopus (5) Google Scholar JY is a 50-year old, African American trans man who was referred to nutrition services for nutrition assessment and suspected iron deficiency. JY was assigned female at birth, identifies as a trans man, and uses he/his or they/their pronouns. JY’s past medical history indicates he medically transitioned in his mid-20s, has been on masculinizing HT consistently for the past 25 years, and is amenorrheic. JY is training for a marathon and runs at a moderate pace approximately 10 to 15 hours per week. Their labs are provided below. Given JY’s past medical history and the University of California San Francisco guidelines (see Table 2), which reference values would be most appropriate to assess hemoglobin and hematocrit?Hemoglobin = 12 g/dLHematocrit = 37%Red blood cells = 5.0 mLPlatelet count = 250,000White blood cells = 6,000 cells/mL Given that JY medically transitioned more than 2 decades ago and is amenorrheic, it would be appropriate to use the male reference ranges for hemoglobin (13.5 to 16.5 g/dL) and hematocrit (41% to 50%). This is consistent with the University of California San Francisco guidelines for interpretation of hemoglobin and hematocrit values based on HT and amenorrheic status.4UCSF Transgender Care, Department of Family and Community Medicine, University of California San FranciscoGuidelines for the Primary and Gender-Affirming Care of Transgender and Gender Nonbinary People; 2nd edition. 2016.https://transcare.ucsf.edu/guidelinesDate accessed: July 21, 2021Google Scholar MR is a 30-year old, Hispanic trans woman seeking nutrition counseling for metabolic syndrome and weight management. MR was assigned male at birth, identifies as a trans woman, and uses she/her pronouns. She started feminizing HT 1 month ago. MR is 5-ft, 8-in tall and weighs 180 lb; she would prefer a smaller physique and expressed that she would like to lose about 30 lb. She does Pilates or yoga once a week and walks her dog for 30 minutes daily. Using the Estimated Energy Requirement equation, what are MR’s energy needs to maintain her current weight? What energy requirement would support MR’s weight loss goal? Given that MR has just started HT and energy needs are often described in a range, it would be appropriate to express her energy needs in a range using the female and male values. To maintain her current weight, she would need 2,570 to 2,850 kcal/day. To support her weight loss goal with a 500-kcal/day deficit, she would need 2,070 to 2,350 kcal/day. Multiple attributes of nutrition assessment rely on sex-specific reference values. This poses a unique question for nutrition and dietetics practitioners working with TGGD clients regarding when to use the male or female reference values. Although existing clinical care guidelines provide some guidance on the interpretation of lab values with sex-specific ranges, nutrition and dietetics practitioners must apply clinical reasoning to determine the most appropriate strategies based on the client’s stage of medical transition and the nature of the reference value. Ongoing research is needed to inform the optimal approach to deliver gender-affirming nutrition care for TGGD clients.