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Creatine, Carnitine and Carnosine in Vegetarians

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ClinicalTrials.gov Identifier: NCT03194334
Recruitment Status : Completed
First Posted : June 21, 2017
Results First Posted : February 28, 2019
Last Update Posted : February 28, 2019
Sponsor:
Information provided by (Responsible Party):
University Ghent

Brief Summary:

Balanced vegetarian diets are popular and contain health-promoting characteristics. A balanced lacto-ovo-vegetarian diet differs in nutrient intake from an omnivorous diet, e.g. by increased intake of fibre, magnesium and antioxidants, but lower intake of omega-3 fatty acids and vitamin B12. However, the impact of reduced to near absent intake of carnitine, carnosine and creatine in a vegetarian diet is less well established and could be relevant in relation to muscle function, exercise capacity and sports performance. Few longitudinal intervention studies investigating the effect of a vegetarian diet on the availability of these compounds currently exist.

This study aimed therefore to investigate the effect of of transiently switching omnivores onto a vegetarian diet for 6 months on muscle and plasma creatine, carnitine and carnosine homeostasis.

We hypothesized that homeostasis of creatine and carnosine would be disrupted when their dietary intake was missing. For carnitine, however, we hypothesized that homeostasis can be maintained given its slow turnover rate and its presence in some non-meat nutrients. A second aim was to investigate whether supplementation of creatine and beta-alanine (the rate-limiting precursor of carnosine synthesis), concurrently with a lacto-ovo-vegetarian diet, was able to correct for potentially emerging deficiencies.


Condition or disease Intervention/treatment Phase
Dietary Modification Behavioral: Vegetarian diet Dietary Supplement: creatine Dietary Supplement: Placebo Dietary Supplement: Beta-alanine Not Applicable

Detailed Description:

Forty healthy female omnivores will be included in this 6-month intervention study. Exclusion criteria are smoking, chronic use of medication, athletes participating in competitions, vegetarianism or eating meat or fish less than 5 times a week. The study is scheduled over a period of 6 months and measurements will be performed 1 week prior to the intervention (0M), after 3 months (3M) and within the last week (6M). Ten women will continue their omnivorous diet throughout the entire study (controls) and the other 30 subjects will switch to a lacto-ovo-vegetarian diet for 6 months. The vegetarian group will be split in 2 groups, matched for age, weight, height and baseline carnosine concentrations in soleus and gastrocnemius medialis muscles. Fifteen of them will be supplemented with beta-alanine and creatine (Veg+Suppl) and the other 15 women will receive a placebo (Veg+Pla). A co-worker, not involved in the study design and analysis, will perform the randomisation and will prepare the containers with supplements. With regard to supplementation, the study is double-blind placebo-controlled. The lacto-ovo-vegetarian diet consists of vegetables, fruits, seeds, grains, meat substitutes, eggs and dairy products and the exclusion of meat, poultry and fish. Subjects will complete a 3 day food diary at the start and after 3 months and will receive nutritional advice by a dietician during the study to prevent deficiencies in macronutrients and micronutrients. Furthermore, vegetarian recipes will be provided by email to support the subjects in their vegetarian diet.

The supplementation protocol includes simultaneously daily oral administration of creatine monohydrate (Creapure®, AlzChem AG, Germany) and slow-release beta-alanine (Carnosyn®, Natural Alternatives International, San Marcos, USA) or a placebo (maltodextrin, Natural spices, France). The supplements are considered as safe and efficacious. The Veg+Suppl group ingests 1 g of creatine monohydrate (2 capsules of 500 mg) and 0.8 g of beta-alanine (1 Carnosyn® tablet) each day during the intervention period. The Veg+Pla group will be supplemented with an identical number of capsules and tablets of maltodextrin. All subjects are asked not to take any other supplements than those provided by the current study. Compliance will be checked by asking the subjects to return the containers and counting the pills that are left. The control group, who will remain on an omnivorous diet, will not receive any supplements.

Before (0M), after 3 (3M) and 6 months (6M), subjects will perform an incremental cycling test, a fasted venous blood sample and 24hr urine will be collected, a muscle biopsy of the vastus lateralis muscle will be taken and muscle carnosine content will be determined by 1H-MRS.

A two-way analysis of variance (ANOVA) will be used to evaluate plasma and urinary metabolite concentrations, muscle carnosine, muscle biopsy metabolite concentrations, time to exhaustion (TTE) and VO2max with 'group' (Veg+Suppl; Veg+Pla; control) as between-subject factor and 'time' (0M; 3M; 6M) as within-subject factor (SPSS statistical software, SPSS Inc, Chicago, USA). For the analysis of capillary lactate and pH, measurements before and after the incremental cycling test were included as another within factor (start; end). In case of significance, analyses were repeated for each group separately and pairwise comparisons were used to compare the different time points. Values will be presented as mean ± SD and statistical significance threshold will be set at p ≤0.05.


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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 40 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: The study was scheduled over a period of 6 months. Of the 40 subjects, 10 women will continue their omnivorous diet throughout the entire study (controls) and the other 30 subjects will switch to a lacto-ovo-vegetarian diet for 6 months. The vegetarian group will be split in 2 groups, matched for age, weight, height and baseline carnosine concentrations in soleus and gastrocnemius medialis muscles. Fifteen of them will be supplemented with beta-alanine and creatine (Veg+Suppl) and the other 15 women will receive a placebo (Veg+Pla).
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Masking Description: A co-worker, not involved in the study design and analysis, will perform the randomisation and will prepare the containers with supplements. Only the control group will know that they are part of the control group (continuing omnivorous diet). For the vegetarian groups, subject will not know whether they are in the supplemented group or not because placebo supplements will be used
Primary Purpose: Basic Science
Official Title: Effect of a 6-month Vegetarian Diet in Omnivorous Women on Body Creatine, Carnitine and Carnosine Stores
Actual Study Start Date : December 2012
Actual Primary Completion Date : June 2013
Actual Study Completion Date : June 2013

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Vegetarian Diet

Arm Intervention/treatment
No Intervention: Control
continued their omnivorous diet throughout the entire study
Experimental: Veg+Pla
vegetarian + placebo: switch to a lacto-ovo-vegetarian diet for 6 months and are supplemented with placebo pills instead of beta-alanine and creatine
Behavioral: Vegetarian diet
Other Name: lacto-ovo-vegetarian diet

Dietary Supplement: Placebo
pills

Experimental: Veg+ creatine and beta-alanine
switch to a lacto-ovo-vegetarian diet for 6 months and are supplemented with 1 g of creatine monohydrate (2 capsules of 500 mg) and 0.8 g of beta-alanine (1 Carnosyn® tablet) each day
Behavioral: Vegetarian diet
Other Name: lacto-ovo-vegetarian diet

Dietary Supplement: creatine
1g creatine/day

Dietary Supplement: Beta-alanine
0.8g beta-alanine per day




Primary Outcome Measures :
  1. Fasted Plasma Beta-alanine Concentration [ Time Frame: 6 months ]
    Fasted venous plasma beta-alanine concentration (precursor for carnosine) at 0, 3 and 6 months of the intervention

  2. Gastrocnemius Carnosine Concentration [ Time Frame: 6 months ]
    Gastrocnemius carnosine concentration at 0, 3 and 6 months of the intervention

  3. Soleus Carnosine Concentration [ Time Frame: 6 months ]
    Soleus carnosine concentration at 0, 3 and 6 months of the intervention

  4. Plasma Creatine Concentration [ Time Frame: 6 months ]
    Plasma creatine concentration at 0, 3 and 6 months of the intervention

  5. Plasma Creatinine Concentration [ Time Frame: 6 months ]
    Plasma creatinine at 0, 3 and 6 months of the intervention

  6. Plasma Guanidinoacetate Concentration [ Time Frame: 6 months ]
    Plasma guanidinoacetate at 0, 3 and 6 months of the intervention

  7. Urinary Creatinine Concentration [ Time Frame: 6 months ]
    Urinary creatinine at 0, 3 and 6 months of the intervention

  8. Muscle Creatine Concentration [ Time Frame: 3 months ]
    Muscle total creatine concentration in vastus lateralis muscle at 0 and 3 months of the intervention

  9. Plasma Carnitine Concentration [ Time Frame: 6 months ]
    plasma free carnitine concentration at 0, 3 and 6 months of the intervention

  10. Plasma Acetylcarnitine Concentration [ Time Frame: 6 months ]
    plasma acetylcarnitine concentration at 0, 3 and 6 months of the intervention

  11. Plasma Total Carnitine Concentration [ Time Frame: 6 months ]
    plasma total carnitine concentration (free + acetyl) at 0, 3 and 6 months of the intervention

  12. Muscle Carnitine Concentration [ Time Frame: 3 months ]
    muscle free carnitine concentration in vastus lateralis muscle at 0 and 3 months of the intervention

  13. Muscle Acetylcarnitine Concentration [ Time Frame: 3 months ]
    muscle acetylcarnitine concentration in vastus lateralis muscle at 0 and 3 months of the intervention

  14. Muscle Total Carnitine Concentration [ Time Frame: 3 months ]
    muscle total carnitine concentration (free + acetylcarnitine) in vastus lateralis muscle at 0 and 3 months of the intervention


Secondary Outcome Measures :
  1. Vitamin D Status [ Time Frame: 6 months ]
    Serum 25-Hydroxyvitamin D concentration at 0, 3 and 6 months of the intervention

  2. Urinary Biomarker for Meat Intake: Pi-methyl-histidine [ Time Frame: 6 months ]
    urinary pi-methyl-histidine concentration at 0, 3 and 6 months of the intervention

  3. Urinary Biomarker for Meat Intake: Tau-methyl-histidine [ Time Frame: 6 months ]
    urinary tau-methyl-histidine concentration at 0, 3 and 6 months of the intervention

  4. Urinary Biomarker for Meat Intake: Anserine [ Time Frame: 6 months ]
    urinary anserine concentration at 0, 3 and 6 months of the intervention

  5. VO2max [ Time Frame: 6 months ]
    VO2max during incremental cycling test performed at 0, 3 and 6 months

  6. Time to Exhaustion [ Time Frame: 6 months ]
    Time to exhaustion during incremental cycling test performed at 0, 3 and 6 months

  7. Capillary Lactate [ Time Frame: 6 months ]
    capillary lactate at the start and at the end of the incremental cycling test performed at 0, 3 and 6 months

  8. Capillary pH [ Time Frame: 6 months ]
    capillary pH at the start and at the end of the incremental cycling test performed at 0, 3 and 6 months



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • women

Exclusion Criteria:

  • smoking, chronic use of medication or taking supplements, athletes participating in competitions, vegetarianism or eating meat or fish less than 5 times a week

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03194334


Sponsors and Collaborators
University Ghent
Investigators
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Principal Investigator: Wim Derave, Professor University Ghent

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
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Responsible Party: University Ghent
ClinicalTrials.gov Identifier: NCT03194334     History of Changes
Other Study ID Numbers: EC/2012/666
First Posted: June 21, 2017    Key Record Dates
Results First Posted: February 28, 2019
Last Update Posted: February 28, 2019
Last Verified: October 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No
Plan Description: individual data will not be made available to other researchers

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by University Ghent:
vegetarianism
creatine
carnosine
carnitine