The recommended maximum amount of cannabidiol (CBD) that healthy adults should consume a day has been reduced from 70mg to 10mg in precautionary advice from the food safety watchdog.
The Food Standards Agency (FSA) and Food Standards Scotland said the guideline was reviewed following a reassessment by two independent science committees of safety evidence, including the potential for adverse effects such as liver damage or thyroid issues.
The updated advice was based on the average lifetime exposure to products containing CBD.
The FSA published advice to consumers in February 2020 recommending that healthy adults with a body weight of 70kg should limit CBD consumption to no more than 70mg per day. The level set was based on "limited evidence" where CBD was studied as a medicine and where the dosage was determined by balancing the benefit of the drug with potential side-effects.
CBD Has Entered the Food Chain
However, more recently, CBD had entered the food sector, and could now be found in a wide range of products including beverages, such as beers and spirits, edible oils as food supplements, 'chewables', and confectionary.
A joint subgroup of the Advisory Committee on Novel Foods and Processes (ACNFP) and the Committee on Toxicity (COT) has since reviewed safety evidence submitted by the CBD industry.
As a result, the sub-committee stated that somnolence and liver effects were the focus of most concern. Correspondingly, it recommended a provisional acceptable daily intake of 10mg of CBD per day for an average 70kg adult, equivalent to approximately four to five drops of an oil-based supplement product containing 5% CBD of ≥98% purity.
The FSA acknowledged that some products available on the market will have a higher dose of CBD per serving than 10mg a day and recommended that consumers check labels and consider their daily intake in light of the updated advice.
The food safety watchdog said it continued to advise that CBD should not be taken by people in vulnerable groups, including children, people taking medication — unless under the care of a medical professional — and those who are pregnant, breastfeeding, or trying to conceive.
Professor Robin May, chief scientific advisor at the FSA, said: "The more CBD you consume over your lifetime, the more likely you are to develop long-term adverse effects, like liver damage or thyroid issues. The level of risk is related to how much you take, in the same way it is with some other potentially harmful products such as alcoholic drinks.
"We encourage consumers to check the CBD content on the product label to monitor their overall daily consumption of CBD and consider if they wish to make changes to how much they take based on this updated advice."
Emily Miles, CEO of the Food Standards Agency said: "We understand that this change to our advice will have implications for products currently on the market that contain more than 10mg of CBD per serving. We will be working closely with industry to minimise the risk, to ensure consumers are not exposed to potentially harmful levels of CBD."