Dietary Fat Intake and Body Composition in Adults with Cystic Fibrosis Open Access

Schor, Matthea (Spring 2025)

Permanent URL: https://etd.library.emory.edu/concern/etds/w9505198g?locale=en
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Abstract

Background and Objectives: There are concerns about possible negative effects of the legacy high-calorie/high-fat diet prescribed to people with cystic fibrosis (PwCF), given general lack of consideration of types of fatty acids consumed (i.e. pro-inflammatory saturated fatty acids vs unsaturated fatty acids). We aimed to determine the relationship between dietary fatty acids and body composition in PwCF. Methods: This was a cross-sectional study of 60 adults with CF and 38 healthy controls. Body composition was assessed using dual energy X-ray absorptiometry (DEXA) for analysis of total bone mineral density (BMD), lean mass, total fat mass, and visceral adipose tissue mass (VAT). Lean mass and fat mass were standardized for height. Dietary intake was assessed with three-day food records analyzed using the Nutrition Data System for Research (NDS-R) dietary software application. Macronutrient intake was adjusted per 1000 kcal to account for differences in energy intake. Muscle strength was measured using handgrip dynamometry. Relationships between continuous variables were assessed with Spearman correlations, linear regressions, and interaction values. Results: Demographics, body composition, handgrip strength, and muscle quality were mostly similar between individuals with CF and non-CF controls. Overall, macronutrients were significantly associated with measurements of muscle and handgrip strength. Total saturated fat and total trans fatty acid as well as arachidonic and eicosapentaenoic acid (EPA) were positively associated with total BMD and lean mass index, respectively. Furthermore, the relationship between protein intake and lean mass index was significantly different between the CF group and non-CF controls. Additionally, the relationships between omega 6 fatty acids and linoleic acid were different depending on CFTR modulator intake. Discussion: Dietary omega 6 fatty acids, including linoleic acid, were positively associated with indicators of adiposity among people with CF, but only among those not taking CFTR modulators. Additionally, dietary protein was associated with measures of lean mass in individuals with CF, highlighting the importance and role protein plays in body composition. This study highlights the need for further investigation to understand the impact of CFTR modulators on the connection between diet and body composition, as well as the need for individualized dietary recommendations for people with CF.

Table of Contents

Introduction……………………………………………………………………………………................................................…1

1.1 Pathophysiology of CF………………………………………………………………......................…………………..…....1

    Figure 1: CFTR Protein Structure………………………………………………….....................…………………………...2

1.2 CF Diagnosis……………………………………………………………………….........................…………………………..4

1.3 CF Treatment.........................................................................................................................................5

1.4 CF Life Expectancy.................................................................................................................................6

1.5 CF Recommended Diet............................................................................................................................7

1.6 Linoleic Acid..........................................................................................................................................8

1.7 Objective and Hypothesis......................................................................................................................10

Materials and Methods..................................................................................................................................11

2.1 Subjects and Study Design.....................................................................................................................11

2.2 Clinical Characteristics.........................................................................................................................12

2.3 Dietary Intake......................................................................................................................................13

2.4 Body Composition................................................................................................................................13

2.5 Handgrip Strength................................................................................................................................13

2.6 Statistical Analysis...............................................................................................................................14

Results.........................................................................................................................................................15

3.1 Demographic and Clinical Characteristics..............................................................................................15

    Table 1: Demographics and Clinical Characteristics of Individuals with CF and Non-CF Controls.................16

    Table 2: Demographics and Clinical Characteristics of Individuals with CF Stratified by CFTR Modulator

Status....................................................................................................................................................17

3.2 Dietary Intake and Body Composition....................................................................................................17

    Table 3: CF Participants and Healthy Controls Dietary Intake and Body Composition..................................20

    Table 4: CF Participants and Healthy Controls Dietary Intake, By Percent...................................................21

3.3 Associations between Dietary Intake and Body Composition....................................................................21

   Table 5: Associations of Dietary Intake and Muscle and Strength Measurements among Adults with CF........22

    Table 6: Associations of Dietary Intake and Adiposity Measurements in Adults with CF...............................23

    Figure 2: Independent Relationships between Macronutrients and Body Composition, Adjusting for Age and

Sex........................................................................................................................................................24

    Figure 3: Relationships between Fatty Acids and Body Composition, Adjusting for Age and Sex....................26

3.4 Associations between Dietary Intake and Body Composition in Relation to Disease Status.........................26

    Figure 4: Relationship between the interaction of Total Protein and Disease Status vs Lean Mass Index........27

3.5 Associations between Dietary Intake and Body Composition in Relation to Modulator Status.....................27

    Table 7: CF Participants, by Modulator Status, Dietary Intake and Body Composition..................................30

    Figure 5: Relationships between dietary intake and body composition stratified by CFTR modulator status...31

Discussion....................................................................................................................................................32

4.1 Assessment of Diet and Body Composition................................................................................................32

4.2 Associations between Dietary Intake and Body Composition.......................................................................34

4.3 Study Strengths.......................................................................................................................................36

4.4 Limitations and Future Directions.............................................................................................................36

4.5 Conclusions............................................................................................................................................37

References....................................................................................................................................................38

 

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