My last post looked at the rather pleasant idea that chocolate might contain something that helps Parkinsonism. It also touched upon the potential of more widespread benefits of chocolate that might help everyone. I linked to a report of a study at the University of Nottingham which suggested that high levels of flavanols in chocolate drinks can temporarily increase brain functionality. The abstract for that study can be found here.
Flavanols are an example of an antioxidant, and I must confess that that makes the alarm bells go off in my head, probably because of the amount of pseudoscience spouted by (among others) the vendors of dietary supplements on the subject of these chemicals.
The Antioxidant Myth
There is a medical myth surrounding antioxidants, nicely busted by Ben Goldacre in his fabulous book, Bad ScienceBad Science. There’s a good online article here, too – this one’s written by Professor D Colquhoun, FRS, a professor of Pharmacology at UCL (University College, London). Colquhoun includes a handy link to a PDF of a New Scientist article entitled “The Antioxidant Myth” (you would have to be a subscriber to read this article on New Scientist’s Web site).
The current view on antioxidants is that, packaged in a pill, they do no good at all, and may instead do harm, particularly in large quantities. Foods containing antioxidants may have some beneficial effects – but the reasons for this are unknown. One suggestion is that the fibrous nature of vegetables promotes a slow release of the antioxidants.
Personally, I remain sceptical. The study at Nottingham was exceedingly small (16 volunteers were involved), but did seem to point to the possibility of there being some benefits from cocoa with exceptionally high flavanol content. Something similar to this, incidentally, can be purchased online from Mars Botanical (disclaimer: I’m not saying that this does anything; just that it is there).
Other Chemicals in Chocolate
Chocolate – or, more accurately, the cocoa bean – is complex stuff. It contains hundreds of different chemicals, several of which are pharmacologically active. The following list is not exhaustive, but includes the most commonly mentioned chemicals.
Theobromine is the stuff that is toxic to dogs and other animals (technically, it is also toxic to humans, but we are larger and we metabolize theobromine faster than other animals). While it seems that data hs not been published on the toxicity of theobromine on birds, it is generally assumed that chocolate – more specifically theobromine – is poisonous to birds.
Caffeine. Does chocolate contain caffeine? The author of xocoatl.org (a fairly comprehensive site “all about chocolate”), claims that it does not, and that it is “persistent urban legend” that chocolate does contain caffeine. He says that theobromine is often confused with caffeine, and that some commercially produced chocolate has caffeine added to it. However, xocoatl is a lone voice; from what I read elsewhere, it seems likely that chocolate may contain small quantities of caffiene.
Anandamide. This substance resembles THC (tetrahydrocannabinol), a chemical found in marijuana. Both substances activate the same receptor and consequently cause dopamine to be released. In addition to its importance in Parkinson’s Disease, dopamine is well known for inducing a feeling of well-being, or even a ‘high’. Anandamide does break down rapidly, but chocolate also contains compounds that prevent the breakdown of anandamide, thus prolonging the good feelings.
Histamine. Histamine is important to our immune responses; it is also a neurotransmitter that regulates sleep. It’s inflammatory effect can be a problem in conditions such as hay fever. Chocolate reputedly contains high enough levels of histamine to trigger migraines.
Beta-phenylethylamine. Another substance that promotes the production of dopamine, phenylethylamine is actually available as a food supplement; as such, it is sold with claims that it promotes weight loss, longevity and improved brain functionality. It can also cause migraines, along with histamine, theobromine and caffeine.
Interestingly, it is stated in the Wikipedia article that:
phenethylamine is rapidly metabolized by the enzyme MAO-B, preventing significant concentrations from reaching the brain, thus contributing no perceptible psychoactive effect without the use of a monoamine oxidase inhibitor (MAOI)
Of course, to nudge this post slightly back on-topic, I am taking a monoamine oxidase inhibitor in the form of Rasagiline (brand name Azilect).
The Feel-Good Factor
Chocolate makes you feel good. It does, doesn’t it? More so than other sweet things, more so than other sources of caffeine. I don’t think that scientists have discovered the precise reasons for this, yet (but there are many theories involving several of the psychoactive compounds listed above), but if chocolate makes you feel good, then it certainly can’t all be bad.