Impact of Dietary Fat and Menstrual Cycle Phases in Type 1 Diabetes

NCT07278063 | Not Yet Recruiting

• 1 other identifier: 2025-0897-1
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

This clinical trial aims to evaluate how variations in dietary fat content and hormonal status influence postprandial glycemic response in individuals with type 1 diabetes (T1D), with a special focus on women. The main objective is to clarify the impact of both factors individually and their interaction, which could inform more personalized strategies for insulin adjustment, optimizing glycemic control, and improving patient outcomes. The main objective is to investigate the effects of low-fat versus high-fat meals, sex, menstrual cycle phases, and their interaction on postprandial glycemic control in adults with T1D treated with advanced hybrid closed-loop (AHCL) insulin delivery systems. Specifically, the study will:

• Compare postprandial glycemic responses after standardized low and high-fat meals in men and women with T1D.
• Assess the differences in postprandial glycemic responses between early follicular and late luteal phases in women, using standardized meals with low and high fat content.
• Identify sex-related differences in glycemic response after equivalent meals. This research addresses the unmet clinical need for precise, tailored postprandial insulin dosing recommendations, especially among women whose insulin sensitivity fluctuates with menstrual phases. The results may contribute to sex-specific predictive models in AHCL systems, reducing acute complications and improving overall quality of life. This is a randomized controlled crossover trial in which each participant serves as her/his own control. Fifty adults will be enrolled: 25 women and 25 men. Women will undergo four mixed-meal tests in random order:
• low-fat given during the early follicular phase,
• high-fat given during the early follicular phase,
• low-fat given during the late luteal phase,
• high-fat given during the late luteal phase. The menstrual phase will be confirmed with home-based hormonal monitoring devices that function with urine sample and use a single-use test wand (MIRA system). Men will complete two mixed-meal tests (low-fat and high-fat), in randomized order. All meals will be standardized for carbohydrate content and matched in other macronutrients, except for fat (with a 30-40g difference), administered after an 8-hour fast. The day of the mixed meal test, AHCL systems will be switched from automatic to manual mode just before eating to standardize the prandial insulin dose and to avoid differences in insulin infusion rates in the postprandial state due to algorithm compensations. Continuous glucose monitoring (CGM) and hourly capillary glucose testing will measure the postprandial response. Additional fasting blood samples will assess metabolic, hormonal, and lipid markers. Optional gastric emptying studies may be performed to exclude confounding gastroparesis in selected patients. Participants will be recruited from the endocrinology outpatient unit of La Fe Polytechnic University Hospital . The projected recruitment period is from December 2025 to July 2027, with mixed-meal tests and data collection occurring between January 2026 and December 2027. Women are expected to complete the protocol in 6 weeks (4 tests), while men will require about 2 weeks (2 tests). At baseline, participants will undergo blood tests to rule out endocrine disorders and confirm sex hormone status. Women participating in the study will use the MIRA home device to monitor their hormonal levels, allowing them to accurately determine and record the phases of their menstrual cycle as part of the study protocol. During meal tests, CGM (Freestyle Libre 3) will be used uniformly among subjects. The study dependent variables will be the following:
• Postprandial glucose area under the curve - AUC\_PG\_5h
• Mean glucose level - MG
• Continuous glucose monitoring metrics - TIR, TAR, TBR
• Postprandial glucose standard deviation - SD
• Postprandial glucose coefficient of variation - CV
• Mean amplitude of glycemic excursions - MAGE
• Mean of daily differences (MODD) Independent variables are
• Type of food: Meals with either low or high fat content.
• Sex and Hormonal status: men; women during the early follicular phase; women during the late luteal phase. If successful, this study will inform the development of more sophisticated, individualized insulin dosing algorithms and AHCL system improvements, especially for women with T1D. Results may lead to more effective management strategies, reduced GV, lower incidence of complications, and increased quality of life. Insights may directly support the personalization of diabetes care and improve gender equity in treatment standards.

Conditions

Type 1 Diabetes Mellitus; Glycemic Variability; Sex Characteristics; Menstrual Cycle; Dietary Fat; Postprandial Glucose

Keywords

Type 1 diabetes; glycemic variability; advanced hybrid closed-loop systems; menstrual cycle; postprandial glucose; dietary fat; insulin sensitivity; continuous glucose monitoring; mixed-meal test; personalized insulin therapy

Outcome Measures

Primary Outcomes (1)

• Postprandial glucose area under the curve (AUC_PG_5h)

  Postprandial glucose effect of the interaction between fat intake and hormonal condition. Difference in the area under de curve during 5 hour period as a function of the fat content of the meal and the hormonal condition, expressed in mg·h/dL: Post prandial AUC\_PG\_5h in female subjects, follicular phase, low fat: FFL\_AUC\_PG\_5h Post prandial AUC\_PG\_5h in female subjects, follicular phase, high fat: FFH\_AUC\_PG\_5h Post prandial AUC\_PG\_5h in female subjects, luteal phase, low fat: FLL\_AUC\_PG\_5h Post prandial AUC\_PG\_5h in female subjects, luteal phase, high fat: FLH\_AUC\_PG\_5h Post prandial AUC\_PG\_5h in male subjects, low fat: ML\_AUC\_PG\_5h Post prandial AUC\_PG\_5h in male subjects, high fat: MH\_AUC\_PG\_5h

  5 hours after each mixed-meal test.

Secondary Outcomes (8)

• Mean glucose level (MG)

  5 hours after mixed-meal test.

• Time in range (TIR)

  5 hours after mixed-meal test

• Time above range (TAR)

  5 hours after mixed-meal test

• Time below range (TBR)

  5 hours after mixed-meal test

• Postprandial glucose standard deviation (SD)

  5 hours after mixed-meal test.

Study Arms (3)

Female1

OTHER

Female patients in early follicular phase

Other: Low Fat Mixed Meal; Other: High Fat Mixed Meal

Female2

OTHER

Female patients in late luteal phase

Other: Low Fat Mixed Meal; Other: High Fat Mixed Meal

Male

OTHER

Male patients

Other: Low Fat Mixed Meal; Other: High Fat Mixed Meal

Interventions

Low Fat Mixed Meal OTHER

The patients will eat a standardized meal designed to evaluate how their blood glucose responds to food intake under controlled conditions. This meal contains a balanced proportion of carbohydrates, proteins, and a low fat content.

Female1; Female2; Male

High Fat Mixed Meal OTHER

The patients will eat a standardized meal designed to evaluate how their blood glucose responds to food intake under controlled conditions. This meal contains a balanced proportion of carbohydrates, proteins, and a high fat content.

Female1; Female2; Male

Eligibility Criteria

• Age: 18 Years - 45 Years
• Gender Eligibility Details: Female in reproductive age with ovulatory cycles. Age-matched male subjects.
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Patients with a confirmed diagnosis of type 1 diabetes mellitus for more than 2 years, in treatment with AHCL (Advanced Hybrid Closed Loop) system treatment for at least 6 months.
• Both sexes.
• Metabolic control with HbA1c \<8%.
• BMI between 18.5 and 29.99 (normal weight to overweight).
• For women: regular menstrual cycles (21-35 days in length with variation between cycles of \<4 days) and no use of hormonal contraceptive treatment.

You may not qualify if:

• Diagnosis of diabetic gastroparesis.
• Presence of hypogonadism, anovulation, hyperandrogenism, hyperprolactinemia, pregnancy, or decompensated chronic diseases.
• Use of oral medications that alter glucose metabolism.

Sponsors & Collaborators

• Instituto de Investigacion Sanitaria La Fe: lead
• Universitat Politècnica de València: collaborator
• Hospital Universitario La Fe: collaborator

Study Sites (1)

Hospital la Fe

Valencia, Valencia, 46026, Spain

Location

Related Publications (29)

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MeSH Terms

Conditions

Diabetes Mellitus, Type 1; Insulin Resistance

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Autoimmune Diseases; Immune System Diseases; Hyperinsulinism

Central Study Contacts

Paolo Rossetti, Medicine

CONTACT

+34608109913; rossetti_paolo@gva.es

Olga Segui, Medicine

CONTACT

+34680705127; oseguicot@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Clinical Researcher

Study Record Dates

• First Submitted: November 29, 2025
• First Posted: December 11, 2025
• Study Start: May 1, 2026
• Primary Completion (Estimated): October 1, 2027
• Study Completion (Estimated): April 1, 2028
• Last Updated: March 23, 2026

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will not share

Locations

ES (1)