Is Betel Nut Chewing All That Bad?

I am doing some studies into larvicide properties of oils derived from plants that can be used to control mosquitoes and consequently malaria and was doing a literature search. And I came across an article regarding the use of essential oil extracted from betel leaf (daga leaf).

The study was done to find out if oil from betel leaf can treat cutaneous or wound infection caused by Chrysomya megacephala(oriental latrine fly). This fly species is also found in PNG. The experiments were set up to treat larvae of the fly with oil extracted from daga leaf. The result was the oil from daga leaf was toxic to oriental latrine fly larvae. Concentrations of 4-3% of daga leaf oil killed all the larvae exposed (100%) after exposure to 3 1/2 hours. The researchers concluded that oil from daga leaf has medicinal properties which can be further developed. The study was done in Sri Lanka.

After reading this I just thought of betel nut chewing in PNG. Betel nut chewing has been associated with mouth cancer. And more recently studied done at the Sir Buri Kidu Heath Institute has shown that betel nut chewing can cause a heart attack in susceptible individuals. I did part of the study. We showed that betel nut chewing reduces the blood supply to the heart which may precipate irregular heart beats which can cause a heart attack or can cause a sudden spasm of the heart blood vessels causing an heart attack. And on top of that betel nut chewing increases the heart rate which can complicate this process. A 70% narrowing of the lumen of the heart blood vessel is enough to cause chest pain!I think this explains why recently there have been many people in PNG collapsing and dying while chewing betel nut.

Betel nut chewing can also precipitate an acute attack of asthma in asthma patients. This is due to the action of betel nut on the smooth muscle of the bronchi (windpipe) probably by the same mechanism which causes smooth muscles of the blood vessels of the heart to go into sudden spasm. Studies on this were also done in PNG.

Than there were the other studies showing the good side of betel nut chewing. Betel nut chewing has been proposed to protect the teeth and gums. The change in  pH of the mouth and the extra calcium may have an effect here. And betel nut chewing can also be a treatment for hook worm infection. I think the mechanism here is also because of the effect of betel nut chewing on the gut smooth muscles - betel nut chewing irritates in the bowels  and can cause diarrhoea. If you are not a betel nut chewer and tried once, you probably had this experience.

Although there are many chemicals in betel nut the active chemical in buai is called Arecoline. This chemical is similar in structure to a naturally occurring chemical in the body called Acetylcholine. Arecoline is therefore called a “natural analogue” of  Acetlycholine compared to many”synthetic analogues”. This is because there are many drugs and chemicals that also have a similar structure to Acetylecholine.  

Acetylcholine has many functions but more importantly one of the main areas in the body where it acts is on smooth muscles. So Arecoline from buai which is similar to Acetylcholine will naturally also have an effect on smooth muscles of blood vessels, windpipe or the bowels. This makes sense and explains the observed effects of betel nut chewing. The other thing is that the chemical reaction between betel nut, daga and lime causes an increase in pH, which occurs in the mouth of chewers. This change in pH increases the rate at which Arecoline is absorbed from the mouth straight into the blood stream thus the effects can be immediate (and sometimes fatal).

With the association between mouth cancer and betel nut chewing, I have asked myself this question many times and the question is, “bifo tru taim ol tumbuna bin kaikai buai, ol bin gat mouth cancer tu o nogat?” (Did our ancestors had mouth cancer from chewing betel nut?) Things like lack of records (though legends and stories may help), dying at an earlier age and maybe the method of chewing betel nut or method of production of lime may have an influence. Or is it because it was present all alone but we are more aware and diagnosing this disease that there seem to an apparent increase.

I heard a rumour a few years back that lime producers were mixing fibro (asbestos)with coral to produce lime. Was this rumour actually true? We may never know because no one bothered to do some random sampling of the lime from markets and test them for the presence of asbestos. If there was such a study I am not away of it. Fibro or asbestos is now a well established carcinogen ie asbestos directly causes cancer by damaging DNA. It causes a kind of cancer of the covering of the lung known as mesothelioma. Mouth is a place where cells are dividing continuously therefore the introduction of a chemical like asbestos will damage DNA there, no questions asked! Can this rumour and the presence of fibro explain a time when the rate of cases of mouth cancer in PNG seemed to increase at an unusually high rate? Fibro or asbestos is now an internationally banned product for housing.Remember the colonial houses built with fibro?

I think betel nut itself or daga by itself can not cause all these. In-fact daga is a spice that is highly sought for in Asia and other parts of the world. PNG just need to realise this and develop this natural plant of PNG. Daga leaf also has other medicinal properties apart from the one reported in the Sri Lankan study. Now the lime. I think the method of production, the kind of coral or shells lime is produced from may be an important factor here.

And finally it is the combination of these three simingly harmless products on their own that when used together produce the beneficial (protects teeth and gum, treats hook worm infection) and the dangers associated with betel nut chewing. I am sure you will agree that the dangers far out weigh the benefits - say maybe by 100 to 1? You can give your own figure.