The number one topic of many scientific committees of the western world is cannabis and it’s potential positive and adverse health effects.
In the USA, several states, including California and Colorado permitted the use of cannabis for recreational purposes, and Canada followed last year in October. The (and the emphasis is on) legal cannabis market is valued at around 25 bn USD and projected to double over the next four years.
But the plant is not only used for medicinal and recreational purposes. It is also used in agriculture for a number of purposes. These include the bedding of farm animals, since hemp can absorb four times its own weight in liquid, so the animals stay dry longer. The one purpose that is discussed controversially now is the use of hemp in animal feed. Hemp seeds in are high in fibre, contain high-levels of unsaturated fatty acids and minerals. Such properties have the potential of increasing quality of products and in turn the revenue for farmers.
The hemp plant, however, also contains the psychoactive substance tetrahydrocannabinol – commonly referred to as THC. And here, European member states initially had different opinions what a suitable limit could be. Back in 2012, the BfR noted its commission meeting for animal feed that a zero tolerance of THC, as it was discussed at European level during that time, would not be supported. That was already after EFSA’s FEEDAP published it’s scientific opinion on the safety of hemp for use as animal feed in 2011, and proposed a 0.2% THC limit in dry matter.
Three years later, in 2015, the EFSA’s Panel on Contaminants in the Food Chain (CONTAM) offered its opinion on the risk of THC-presence in milk and other foods of animal origin. The recommendation focused on Δ9-THC, the psychoactive substance in hemp. The human studies that the panel looked at led to the conclusion that 0.036 mg Δ9-THC/kg body weight per day represents the Lowest Adverse Effect Level (LOAEL). Using an uncertainty factor (aka “safety factor”) of 30, the acute reference dose (ARfD) the panel arrived at was 1 μg Δ9-THC/kg body weight per day. The CONTAM panel concluded that “exposure to Δ9-THC via consumption of milk and dairy products, resulting from the use of hemp seed-derived feed materials at the reported concentrations, is unlikely to pose a health concern.”
Any yet, the German Federal Institute for Risk Assessment (BfR) seems to want to be certain. It recently published that it is conducting a feeding experiment using hemp. The article has the questionable title “the joint in the milk glass”. It starts to describe how ten dairy cows are standing in a shed, five of them behaving normal, the others “seem to be dazed, sleepy, uncoordinated and have stopped ruminating.” These five cows have been fed industrial hemp over several days. BfR states “It is obvious that the cows whose feed contains higher THC doses are “stoned”, making the assumption that Δ9-THC effects on humans are exactly the same in cattle. In the BfR article itself, an insert reads “Stoned from food”, which seem to already jump to conclusions, i.e. that Δ9-THC levels in several food products are too high and ideally hemp-feed in milk production should be prohibited. At the same time, it is stated that “the levels of psychoactive Δ9-THC analyzed in milk vary very strongly”, and “depend more than anything else on the industrial hemp variety fed to the animals and the duration of feeding.”
While milk is a sensitive issue, especially as food for infants, instead of prohibiting the use of hemp in dairy production, it may be more appropriate to set acceptable levels and require labelling of milk where the cattle have been fed hemp.
In any case, as the BfR article only mentions the ten cattle. It can only be hoped that BfR does not derive regulatory recommendations on a study based on only ten animals. In addition to questions about statistical (in)significance that is associated with such small numbers, BfR already acknowledges the fact that levels in milk vary strongly.
