Update on my life: While I was coming back home, I caught one of the neighbors (you know, the crazy ones I always complain about) peeping into somebody else’s windows. This is quite disturbing–on so many levels.
* * *
As Promised: Evil Fava Beans Which May Not Be So Evil After All (As Well As Desktop Wallpaper)
So the professor with the wacky white hair says: “Don’t eat fava beans! They’re bad for you. Fava beans contain divicine which cause oxidative stress on your red blood cells and if you have G6PD deficiency, you could get really sick and even die!”
By saying a provocative statement like that without any additional explanation, of course I have to find out exactly what fava beans are doing to make people sick. I’m not so sure about the other students. Maybe they were wishing the class would end or maybe they were rolling their eyes thinking that the professor was off his rocker and that fava beans actually cause excess gas. Actually fava beans, or any sort of beans, will cause excess gas if you don’t soak them in water. Certain types carbohydrates found in beans move to your small intestine which lacks the enzymes to digest them. Only the bacteria residing there will be able to break them down via fermentation–a process that will inevitably liberate gas.
But we’re not talking about gas. We’re talking about this G6PD thing and red blood cells. Well, if you’ve ever taken a comprehensive biology course, you’ve encountered the metabolism pathway. And if you’re actually in biology, you pretty much have the glycolysis pathway and the Kreb cycle burned into your brain. To make a tedious biochemistry story short, the goal of these pathways is to convert the glucose that you have ingested to ATP (adenosine triphosphate) which is the unit of energy used to power the processes in your cells.
In the very initial step of the pathway, glucose is converted to glucose-6-phosphate (G6P) by the enzyme hexokinase. Aha! That’s where the G, 6, and P come from. But how about the D? From G6P, the pathway branches. In one way, it eventually makes ATP. On another path, the enzyme glucose-6-phosphate dehydrogenase (G6PD) catalyzes G6P through the pentose phosphate pathway (PPP) and the resulting products are ribose-5-phosphate which will be used to make DNA and RNA and NADPH which will help reduce hydrogen peroxide.
Now we’re getting somewhere. G6PD is an enzyme that will be required to make NADPH. NADPH degrades hydrogen peroxide which is a strong oxidant–bad for the red blood cell because one of its primary functions is to carry oxygen because oxidants will cause the cell to burst. So if you don’t make enough G6PD to degrade oxidants, you will be anemic.
And what about those fava beans? The beans contain vicine and convicine which break up to divicine and isouramil when they’re being digested. In turn, these two compounds will produce hydrogen peroxide and the accompanying free radicals which will cause oxidative stress in the blood cells. So if you are deficient in G6PD and you eat fava beans, you get favism.
Amazingly enough, fava beans are particularly popular in the Mediterranean where there is a prevalence for G6PD deficiency. Why is that? Since most G6PD deficient people do not display symptoms until they eat fava beans (or do something to cause their blood cells to undergo stress) some researchers have speculated that this may help prevent malaria.
Malaria?! Now what does that have to do with fava beans? Actually, it’s a very reasonable hypothesis. Part of the malarial parasite’s lifecycle is spent maturing in red blood cells. If eating fava beans cause the cells to go anemic, the parasite will be blocked in that pathway because they will no longer be able to use the red blood cells.
And the wallpaper part? That refers to my desktop wallpaper which I changed recently. I was searching for botanical information on fava beans since I’ve never really eaten them before (you know, it’s sort of like how some people have never tried eggplant before simply because it never crossed their mind) and I ran across a comment that said they used explodingdog pictures as desktop wallpaper. Cool idea! So now this picture is on my computer.