Creatine, Carnitine and Carnosine in Vegetarians

Effect of a 6-month Vegetarian Diet in Omnivorous Women on Body Creatine, Carnitine and Carnosine Stores

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.

Study Overview

• Status: Completed
• Conditions: Dietary Modification
• Intervention / Treatment: Behavioral: Vegetarian diet; Dietary supplement: Placebo; Dietary supplement: creatine; Dietary supplement: Beta-alanine

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.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / 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 Names: 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 Names: lacto-ovo-vegetarian diet; Dietary supplement: creatine; 1g creatine/day; Dietary supplement: Beta-alanine; 0.8g beta-alanine per day

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fasted Plasma Beta-alanine Concentration	Fasted venous plasma beta-alanine concentration (precursor for carnosine) at 0, 3 and 6 months of the intervention	6 months
Gastrocnemius Carnosine Concentration	Gastrocnemius carnosine concentration at 0, 3 and 6 months of the intervention	6 months
Soleus Carnosine Concentration	Soleus carnosine concentration at 0, 3 and 6 months of the intervention	6 months
Plasma Creatine Concentration	Plasma creatine concentration at 0, 3 and 6 months of the intervention	6 months
Plasma Creatinine Concentration	Plasma creatinine at 0, 3 and 6 months of the intervention	6 months
Plasma Guanidinoacetate Concentration	Plasma guanidinoacetate at 0, 3 and 6 months of the intervention	6 months
Urinary Creatinine Concentration	Urinary creatinine at 0, 3 and 6 months of the intervention	6 months
Muscle Creatine Concentration	Muscle total creatine concentration in vastus lateralis muscle at 0 and 3 months of the intervention	3 months
Plasma Carnitine Concentration	plasma free carnitine concentration at 0, 3 and 6 months of the intervention	6 months
Plasma Acetylcarnitine Concentration	plasma acetylcarnitine concentration at 0, 3 and 6 months of the intervention	6 months
Plasma Total Carnitine Concentration	plasma total carnitine concentration (free + acetyl) at 0, 3 and 6 months of the intervention	6 months
Muscle Carnitine Concentration	muscle free carnitine concentration in vastus lateralis muscle at 0 and 3 months of the intervention	3 months
Muscle Acetylcarnitine Concentration	muscle acetylcarnitine concentration in vastus lateralis muscle at 0 and 3 months of the intervention	3 months
Muscle Total Carnitine Concentration	muscle total carnitine concentration (free + acetylcarnitine) in vastus lateralis muscle at 0 and 3 months of the intervention	3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vitamin D Status	Serum 25-Hydroxyvitamin D concentration at 0, 3 and 6 months of the intervention	6 months
Urinary Biomarker for Meat Intake: Pi-methyl-histidine	urinary pi-methyl-histidine concentration at 0, 3 and 6 months of the intervention	6 months
Urinary Biomarker for Meat Intake: Tau-methyl-histidine	urinary tau-methyl-histidine concentration at 0, 3 and 6 months of the intervention	6 months
Urinary Biomarker for Meat Intake: Anserine	urinary anserine concentration at 0, 3 and 6 months of the intervention	6 months
VO2max	VO2max during incremental cycling test performed at 0, 3 and 6 months	6 months
Time to Exhaustion	Time to exhaustion during incremental cycling test performed at 0, 3 and 6 months	6 months
Capillary Lactate	capillary lactate at the start and at the end of the incremental cycling test performed at 0, 3 and 6 months	6 months
Capillary pH	capillary pH at the start and at the end of the incremental cycling test performed at 0, 3 and 6 months	6 months

Collaborators and Investigators

• Sponsor: University Ghent
• Investigators: Principal Investigator: Wim Derave, Professor, University Ghent

Publications and helpful links

General Publications

• Van Dyck D, Herman K, Poppe L, Crombez G, De Bourdeaudhuij I, Gheysen F. Results of MyPlan 2.0 on Physical Activity in Older Belgian Adults: Randomized Controlled Trial. J Med Internet Res. 2019 Oct 7;21(10):e13219. doi: 10.2196/13219.
• Blancquaert L, Baguet A, Bex T, Volkaert A, Everaert I, Delanghe J, Petrovic M, Vervaet C, De Henauw S, Constantin-Teodosiu D, Greenhaff P, Derave W. Changing to a vegetarian diet reduces the body creatine pool in omnivorous women, but appears not to affect carnitine and carnosine homeostasis: a randomised trial. Br J Nutr. 2018 Apr;119(7):759-770. doi: 10.1017/S000711451800017X.

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2012
• Primary Completion (Actual): June 1, 2013
• Study Completion (Actual): June 1, 2013

Study Registration Dates

• First Submitted: June 15, 2017
• First Submitted That Met QC Criteria: June 20, 2017
• First Posted (Actual): June 21, 2017

Study Record Updates

• Last Update Posted (Actual): February 28, 2019
• Last Update Submitted That Met QC Criteria: October 25, 2018
• Last Verified: October 1, 2018

More Information

Terms related to this study

• Keywords: carnosine; carnitine; creatine; vegetarianism
• Other Study ID Numbers: EC/2012/666

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No
• IPD Plan Description: individual data will not be made available to other researchers

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No