Written by Dave Poole, all rights reserved
(First appeared on Freeflight List).
Just to put this right, without wishing to embark upon a series of lengthy discourses
barely tangential to purposes of this list, theobromine. Although one of a group of
methylxanthines along with theophylline and caffeine, theobromine is not a stimulant in
itself. Although stimulants such as caffeine are harmful due to their effects upon the
central nervous system and tendency to cause arrhythmia as well as increasing blood
pressure, they are not necessarily critically harmful in the very first instance.
Theobromine above certain concentrations is and dependent upon this, can kill
within 24 - 36 hours. Even low concentrations such as are found in many milk
chocolate products and confectionery, may well have long term, accumulative and eventually
fatal consequences.
There is no documented research being carried out at this time, but it would appear that
from the scant evidence available, theobromine affects the ways in which cells are bonded
together as well as the bonding between those cells. Its effects upon fine capillary
blood vessels are catastrophic with localised and generalised haemorrhaging occurring
within the cardio-vascular and respiratory systems. Effectively, affected animals bleed to
death internally and there is no cure or remedy with the onset of symptoms.
Generally theobromine in confectionery chocolate is of a very low concentration
typically 1 - 2 mg per gram, whereas in good quality 'Belgian' style chocolate this can
rise to 20+mg per gram. At these higher concentrations, theobromine has killed
larger animals such as dogs. Symptoms associated with theobromine poisoning include:
hyperactivity, vomiting, fits, irregular heart beat and very dark droppings caused by
internal bleeding. Also, there is good reason to suspect that the liver also suffers
as a result of theobromine poisoning - again probably due to the break down of the
capillary blood vessels within.
In 1998 a large, healthy labrador in South Devon, England collapsed and died suddenly, as
a result of eating an estimated 60 grams of Belgian chocolates that had been left on a
coffee table by it's owner. Later that year, a 12 year old Green wing Macaw in West
Cornwall, England died 15 hours after eating two Swiss 'truffle' type chocolates each
weighing no more than 8 grams. Cats, dogs and African Grey parrots in America have
also been reported to have died as a result of eating good quality chocolates.
An active and healthy, 'rescue' Blue and Gold Macaw of about 14 years, whose
diet was (apart from a daily chocolate chip 'cookie') quite acceptable, suddenly died.
Post mortem results revealed chronic heart and liver disease with evidence of low
grade hemorrhaging and scarring that appeared to have occurred over a considerable period
of time.
It has been argued that since theobromine if not immediately fatal, is excreted from the
system and is therefore non-residual, low levels such as are found in chocolate biscuits,
fudge bars etc. are harmless. This is an entirely foolhardy and ridiculous view to take.
If theobromine can affect cell bonding in high doses, low, non-fatal doses may
progressively weaken those bonds over the years.
Unfortunately it appears that no-one has yet felt the need to research this fully and so
any evidence is at best fragmented. Normally I would discount anecdotal instances,
however I do feel that in the cases of the Greys, cats and dogs cited in the US, the
information came from reliable sources not normally prone to 'third-party elaboration'.
>My original letter was in response to advice (sic) given by the secretary of
>the Parrot Society (UK) saying that it was alright to give parrots chocolate!
Well, I'm jolly glad you did respond because that advice given by the secretary of the
Parrot society was absolutely erroneous, highly dangerous and extremely irresponsible.
People like this, with their antediluvian attitudes, continue to propagate the UK's
reputation for living in 'the Dark Ages' when it comes to parrot keeping.
Dave Poole
TORQUAY UK