Decision on L-carnitine and acetyl-L-carnitine as supplemental ingredients in foods

Health Canada's Food and Nutrition Directorate has assessed L-carnitine and acetyl-L-carnitine for use as supplemental ingredients. These are two of the ingredients the Food and Nutrition Directorate identified for further assessment as set out in Health Canada's Category Specific Guidance for Temporary Marketing Authorization: Supplemented Food.^{Footnote 1}

The assessment considered publicly available information, and found the data insufficient to establish acceptable conditions for use as supplemental ingredients in supplemented foods.

Consequently, Health Canada is not acceding to use of L-carnitine or acetyl-L-carnitine as supplemental ingredients. While L-carnitine is naturally present in a variety of foods consumed as part of the diet and acetyl-L-carnitine is synthesized in the body, neither have a history of use as ingredients added to food.

Health Canada is prepared to accept a request to reconsider this decision under the regulations for supplemented foods. The Appendix of this letter identifies the information required to support reconsideration.

For more information on Health Canada's decision on L-carnitine and acetyl-L-carnitine, please contact the Food and Nutrition Directorate's Submission Management and Information Unit (SMIU) (E-mail: smiu-ugdi@hc-sc.gc.ca). Please use the words "Decision on L-carnitine and Acetyl-L-carnitine" in the subject line of your e-mail.

Appendix 1 – Information to support a request for Health Canada to reconsider the decision on the use of L-carnitine or acetyl-L-carnitine as supplemental ingredients

General guidance

1. Characterise in detail the L-carnitine or acetyl-L-carnitine that is requested for use.
2. Clearly demonstrate that the toxicological and nutritional safety information apply to use of the requested L-carnitine or acetyl-L-carnitine as supplemental ingredients in supplemented foods.
3. 3. Provide full study reports of safety tests, not summaries. The reports should provide clear, detailed characterisation of the L-carnitine or acetyl-L-carnitine test material, as well as a full description of the study design, including methods used, the type and number of animals treated, the doses administered and the endpoints. Studies should also provide detailed documentation of the test results.

Toxicological information

There is some evidence that suggests that elevated concentrations of plasma trimethylamine oxide (TMAO), associated with L-carnitine intake, may be a risk factor for cardiovascular disease and accelerated atherosclerosis via the suppression of the transfer of cholesterol from peripheral tissues to the liver. Insufficient information is available to identify or derive a level of L-carnitine or acetyl-L-carnitine that would not be associated with potential adverse consequences for the general population.

1. Information characterising the effect that the diet and orally ingested L-carnitine have on gut microbiota.
2. Information about the health implications of increased plasma TMAO production, and what level of TMAO is associated with increased risk/adverse effects.

Nutritional information

1. Information on L-carnitine or acetyl-L-carnitine showing how they may affect digestion or absorption of other nutrients, especially in the intestines, and/or information on whether they could pose nutritional safety concerns if foods supplemented with L-carnitine or acetyl-L-carnitine were to be consumed frequently over a long period of time in different food matrices.

This information is required to address the safety of L-carnitine and acetyl-L-carnitine for use as supplemental ingredients in supplemented foods, not to demonstrate efficacy or to support specific health claims. For substantiation of food health claims, please see Health Canada's guidance Substantiation of Health Claims (Scientific Evidence).^{Footnote 2}