Genetics in the Effect of Caffeine on Fat Oxidation

Study Overview
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Brief Summary
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Genetic polymorphism on the effect of oral caffeine intake on fat oxidation during exercise has been studied in active and healthy population performing an incremental test on a cycle ergometer with 3-min stages at workloads from 30 to 70% of maximal oxygen uptake (VO2max). Participants performed this test after the ingestion of a) placebo; b) 3 mg/kg of caffeine; c) 6 mg/kg of caffeine. Fat oxidation rate during exercise was measured by indirect calorimetry. The influence of the CYP1A2 c.-163A>C, GSTP c.313A>G and PGC1a polymorphisms was evaluated to determine the effects on fat oxidation during exercise

Detailed Description
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Caffeine is a natural stimulant with well-recognized sports performance benefits. Aside its performance-enhancing effect, caffeine has the potential of increasing fat utilization during aerobic exercise at submaximal intensities, lowering-down the contribution of carbohydrate as a fuel. This property of caffeine may provoke a glycogen-sparing effect in the skeletal muscle and liver for exercise situations where carbohydrate availability may be a challenge. Additionally, the capacity of caffeine to enhance fat utilization during exercise could be of interest for improving health outcomes as it may increase the rate of change in body composition in exercise programs. Genetic factors like CYP1A2 c.-163A>C, GSTP c.313A>G and PGC1a c.1444G>A and C>T polymorphisms could be associated with the capacity for fat oxidation during exercise. To date, it is unknown if genetics increases fat oxidation and MFO in the same proportion during morning and evening exercise trials in women. For this reason, the aim of the present study was to evaluate the influence of the tCYP1A2, GSTP and PGC1a polymorphisms on the effect of caffeine on fat oxidation and MFO in active and healthy population. The authors hypothesised that genetics would increase fat oxidation and MFO during exercise and this effect would be of similar magnitude at several caffeine doses.

Official Title
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Influence of the Genetic Polymorphisms in the Effect of Caffeine on Fat Oxidation During Exercise

Conditions
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Genetic Predisposition, Caffeine, Fat Burn

Intervention / Treatment
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* Dietary Supplement: Acute caffeine supplementation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: To be non-smokers. To have low caffeine intake (i.e., < 50 mg of caffeine per day in the previous 2 months) To show no previous history of cardiopulmonary diseases or having suffered musculoskeletal injuries in the previous 6 months. Exclusion Criteria: To have VO2max values below 40 ml/kg/min To be sedentary

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Caffeine 3mg/kg intake<br>A dose of 3 mg/kg of caffeine (Bulk Powders, Essex, United Kingdom) was ingested before the beginning of each test. | Dietary Supplement: Acute caffeine supplementation<br>* To evaluate the influence of the time of the day (i.e., morning vs evening) on the effect of caffeine on maximal fat oxidation in women<br>|
| Experimental: Caffeine 6mg/kg intake<br>A dose of 6 mg/kg of caffeine (Bulk Powders, Essex, United Kingdom) was ingested before the beginning of each test. | Dietary Supplement: Acute caffeine supplementation<br>* To evaluate the influence of the time of the day (i.e., morning vs evening) on the effect of caffeine on maximal fat oxidation in women<br>|
| Placebo Comparator: Placebo intake<br>A dose of 3 mg/kg of placebo (Cellulose, Guinama, Valencia, Spain) was ingested before the beginning of each test. | Dietary Supplement: Acute caffeine supplementation<br>* To evaluate the influence of the time of the day (i.e., morning vs evening) on the effect of caffeine on maximal fat oxidation in women<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Genotype frequency of CYP1A2 polymorphism | Samples shall be obtained by swabbing and scraping of the buccal mucosa by the participant. The c.-163A>C (rs762551) polymorphism will be used. | Baseline | 
| Genotype frequency of GSTP polymorphism | Samples shall be obtained by swabbing and scraping of the buccal mucosa by the participant. The c.1444G>A (rs8192678) and C>T (rs17650401) polymorphisms will be used. | Baseline | 
| Genotype frequency of PGC1a polymorphisms | Samples shall be obtained by swabbing and scraping of the buccal mucosa by the participant. The c.313A>G (rs1695) polymorphism will be used. | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| FATmax | The intensity of exercise that elicits MFO | 2-months | 
| MFO | Maximal fat oxidation during exercise | 2-months | 
| RPE | Rate of percevied exertion during exercise | 2-months | 
| FAT and CHO oxidation | Fat and carbohydrates oxidation | 2-months |