Modification to the List of Permitted Supplemental Ingredients to enable the use of milk thistle seed extract (silymarin)
Notice of modification – List of Permitted Supplemental Ingredients
Reference number: M-SIS-25-02
January 30, 2025
Background
Supplemented foods, including supplemental ingredients, are regulated in Canada under Part B of the Food and Drug Regulations (FDR).
Permitted supplemented food categories, as well as permitted supplemental ingredients along with their conditions of use, are set out in the List of Permitted Supplemented Food Categories and List of Permitted Supplemental Ingredients, respectively, which are incorporated by reference into the FDR.
A petitioner can request that Health Canada approve a new supplemental ingredient, a new condition of use for an already approved supplemental ingredient, or a change to the approved supplemented food categories by filing a supplemental premarket submission with the department's Food and Nutrition Directorate. Health Canada uses this premarket approval process to determine whether the scientific data supports the safety of supplemental ingredients in supplemented foods sold in Canada or supports the safety of the proposed change to the supplemented food categories. Ongoing monitoring by the Food and Nutrition Directorate may also prompt modifications to the lists based on emerging health risks, new scientific data, or outcomes of health risk assessments.
Issue
The Food and Nutrition Directorate identified milk thistle seed extract for further assessment as a supplemental ingredient since it was present in product(s) previously eligible for sale as food under Temporary Marketing Authorizations.
Rationale
Health Canada's Food and Nutrition Directorate completed a safety assessment of milk thistle seed extract. The assessment concluded that information related to chemistry, nutrition, toxicology, and allergenicity supports the safety of milk thistle seed extract for use as a supplemental ingredient in supplemented foods.
The milk thistle seed extract that Health Canada has permitted, as a result of the aforementioned safety assessment, is derived from the seeds of milk thistle, Silybum marianum (L.) Gaertn., and is standardized according to the content of silymarin. The available toxicological and clinical evidence supports the safe consumption of milk thistle seed extract as a supplemental ingredient by the general population of healthy adults, up to the equivalent of 600 mg silymarin on a daily basis, and up to 200 mg silymarin in a single serving. Sources of exposure to silymarin and/or milk thistle seed extract in the diet are not common, and so were not considered in establishing the conditions of use.
Health Canada has concluded that milk thistle seed extract (silymarin)Footnote 1, when used as a supplemental ingredient in accordance with the conditions of use outlined in Part IV of the List of Permitted Supplemental Ingredients (and as listed in the table below), does not pose any toxicological or nutritional concerns. There is a potential for sensitization and/or allergic reactions associated with the ingestion of silymarin by individuals who have allergies to members of the aster (Asteraceae) plant familyFootnote 2. Therefore, cautionary labelling to alert individuals with allergies to plants in the aster family is warranted.
For additional information, refer to the Summary of Health Canada's safety assessment of milk thistle seed extract for use as a supplemental ingredient.
Consultation
Health Canada published a Notice of proposal to enable the use of milk thistle seed extract (silymarin) as a supplemental ingredient in foods on October 7, 2022, which was open for public comment for 75 days. Health Canada received comments from one industry stakeholder during the consultation period, which ended on December 20, 2022. These comments are summarized below. Health Canada's response follows each comment.
Summary of stakeholder comments and Health Canada responses
Comment on milk thistle seed extract used as a conventional food ingredient
Stakeholder comment: Request that Health Canada clarify if milk thistle seed extract containing a silymarin content lower than 65% can be used in ordinary foods as a conventional food ingredient without the milk thistle seed extract automatically being assumed to be added as a supplemental ingredient or the food automatically being regulated as a supplemented food.
Health Canada's response: Milk thistle seed extract, as well as its primary constituent silymarin, do not have a history of safe use as food ingredients. Therefore, the only permitted use of milk thistle seed extract is as a supplemental ingredient in accordance with the conditions set out in the List of Permitted Supplemental Ingredients.
Health Canada would be prepared to consider a request to evaluate other conditions of use for milk thistle seed extract, and modify the List of Permitted Supplemental Ingredients, if it is accompanied by a complete pre-market submission.
Outcome: Proposal maintained.
Comment on compositional requirements of milk thistle seed extract
Stakeholder comment: Request that Health Canada clarify why they are imposing a minimum silymarin content of 65%, and to eliminate this requirement.
Health Canada's response: The silymarin composition range (both minimum and maximum levels) for milk thistle seed extract is based on the composition of the test articles used in the toxicity studies that support its safe use as a supplemental ingredient. Removing the minimum silymarin specification for milk thistle seed extract is not supported by the available safety data.
Health Canada would be prepared to consider a request to evaluate other conditions of use for milk thistle seed extract, and modify the List of Permitted Supplemental Ingredients, if it is accompanied by a complete pre-market submission.
Outcome: Proposal maintained.
Comments on overconsumption, maximum use levels, mandatory cautionary statements
Stakeholder comment: Health Canada's proposed approach is for an ingredient used in foods, not a prescription drug where overconsumption can pose a substantive health risk. The approach needs to recognize that good manufacturing practices can be used to ensure consumers get the food products they are seeking without undue health risk.
Health Canada's response: The conditions Health Canada set for milk thistle seed extract (silymarin) regarding maximum use levels and cautionary statements related to consumption, when used as a supplemental ingredient, are based on the outcome of an evaluation that reviewed publicly available safety data and applied standard risk assessment practices. This stakeholder comment did not specify which good manufacturing practices the food industry would use that would be effective at mitigating the risk of overconsumption, explain how these practices would be effective in mitigating the risk, nor indicate how Canadian consumers could be assured that all companies would follow such practices.
Outcome: Proposal maintained.
Stakeholder comment: The cautionary statement "For adults only (18 years of age or older)" is overly conservative. Health Canada should remove the proposed labelling requirement, or modify it to "Not recommended for those under 14 years old", consistent with the statement for other supplemental ingredients.
Health Canada's response: By requiring cautionary labelling, Health Canada is able to accommodate the sale of food products of interest to industry while mitigating the health concern about certain ingredients being overconsumed or consumed by sensitive subpopulations, consistent with the approach the Department uses for supplemented foods.
The cautionary statement "For Adults only (18 years of age or older)" is intended to prevent consumption of milk thistle seed extract (silymarin) by the sensitive subpopulations of children, and adolescents under 18 years of age, when it has been added to food as a supplemental ingredient, and is necessary because of the following:
- No developmental toxicology studies meeting international standards for toxicological testing were identified in the publicly available literature to support the safety of milk thistle seed extract for consumption by children, or adolescents under 18 years of age; and
- No clinical studies were identified in the publicly available literature to support the safety of milk thistle seed extract for consumption by children, or adolescents under 18 years of age.
The paucity of toxicological and clinical data in children, and adolescents under the age of 18, supports the requirement of the cautionary statement "For Adults only (18 years of age or older)" for use of milk thistle seed extract (silymarin) as a supplemental ingredient.
Outcome: Proposal maintained.
Comment on implementation and enforcement
Stakeholder comment: Health Canada should provide a minimum of four years as a transition period for manufacturers to bring products into compliance with the final regulatory requirements.
Health Canada's response: Health Canada's Proposal to enable the use of milk thistle seed extract (silymarin) as a supplemental ingredient in foods indicated that products that have a valid authorization for market access will be allowed a transition period, after the coming into force of the regulations, that ends December 31, 2025. This transition period allows market access to continue for these products and provides time for the food industry to make the necessary changes to comply with the regulatory requirements for supplemented foods.
Outcome: Proposal maintained.
Modifications to the List of Permitted Supplemental Ingredients
Since the conclusions of the safety evaluation remain as described in the Notice of Proposal, Health Canada has permitted the use of milk thistle seed extract (silymarin) as a supplemental ingredient in supplemented foods by adding the entry as shown in Part IV of the List of Permitted Supplemental Ingredients. Minor modifications have been made to the milk thistle seed extract (silymarin) listing wording in the Notice of Proposal to align with similar entries in the list. For example, in column 4 (b), the term "daily" has been revised to "per day" in the cautionary statement. These changes do not alter the permitted uses of the supplemented food categories or the supplemental ingredient.
| Supplemental ingredient | Conditions of use | ||||
|---|---|---|---|---|---|
| Item no. | Column 1 Description Footnote i |
Column 2 Permitted in |
Column 3 Maximum amounts and units per serving of stated size Footnote ii |
Column 4 |
Column 5 Other |
| Part IV: Other supplemental ingredients | |||||
| M.1 | Milk thistle seed extract (silymarin) | Foods belonging to a category listed in the List of Permitted Supplemented Food Categories | 200 mg silymarin |
|
Milk thistle seed extract (silymarin) is a dry extract, fluid extract, tincture, decoction, or infusion of Silybum marianum (L.) Gaertn. seeds and:
The amount in milligrams of silymarin from milk thistle seed extract must be declared under the "Supplemented with" heading in the Supplemented Food Facts table. |
|
|||||
Other relevant information
Characteristics of the milk thistle seed extract that Health Canada has permitted for use as a supplemental ingredient are set out as conditions in Column 5 of the List of Permitted Supplemental Ingredients (as shown in the table above). Column 5 specifies what milk thistle seed extract is, how it is obtained, and its minimum and maximum silymarin content. These conditions, in part, form the basis of Health Canada's determination that milk thistle seed extract is safe for use as a supplemental ingredient in supplemented foods.
Milk thistle seed extract, as well as its primary constituent silymarin, do not have a history of safe use as food ingredients, and therefore the only permitted use of milk thistle seed extract is as a supplemental ingredient in accordance with the conditions set out in the List of Permitted Supplemental Ingredients.
Implementation and enforcement
The above modification came into force January 30, 2025, the day it was published in the List of Permitted Supplemental Ingredients.
Under the transitional provisions of the Regulations Amending the Food and Drug Regulations and the Cannabis Regulations (Supplemented Foods), products that have a valid authorization for market access are allowed a transition period, since the coming into force of the regulations, until December 31, 2025. The transition period allows the food industry continued market access and provides time to make the necessary changes to comply with the requirements of the regulations for supplemented foods (for additional information, refer to Supplemented foods: Regulations and compliance).
The Canadian Food Inspection Agency is responsible for the enforcement of the Food and Drugs Act and its associated regulations with respect to foods.
Contact information
Health Canada's Food and Nutrition Directorate is committed to reviewing new scientific information on the safety of permitted supplemental ingredients, including milk thistle seed extract (silymarin). Anyone wishing to submit an inquiry or new scientific information on the use of this supplemental ingredient may do so in writing, by regular mail or electronically. If you wish to contact the Food and Nutrition Directorate by email about milk thistle seed extract (silymarin), please use the words "Milk thistle extract (M-SIS-25-02)" in the subject line of your email.
Supplemented Foods
Bureau of Nutritional Sciences
Food and Nutrition Directorate
251 Sir Frederick Banting Driveway
Postal locator 2203E
Tunney's Pasture
Ottawa ON K1A 0K9
Email: supplementedfoods-alimentssupplementes@hc-sc.gc.ca
Notes
- Footnote 1
-
This naming convention denotes that milk thistle seed extracts used as a supplemental ingredient be a standardized preparation of silymarin.
- Footnote 2
-
The aster (Asteraceae) family includes, but is not limited to, artichokes and common thistle.
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