Monday, January 12, 2009

Chillies and evolution

Just the other day I was watching my wife eat. As usual, she always has a lot of cili padi mixed in with her food. Saying that she can eat spicy food is an under statement. She even eats maggi mee with cili padi.

As I was watching her eat all that chillies I was wondering about evolution. Plants have fruits to distribute their seeds. Animals eat it then shit it out. Normally, fruits will be sweet or something an animal would want to eat. Chillies however are different, they're spicy and repel animals. The only animal that eats them are birds.

So I started to search around the internet for answer and I found it on the BBC website in this article below:

Chillies: The Burning Question Scientists in the United States have
discovered the reason why chillies are so hot. They say that the chilli plant
repels animals, which will not spread the seeds, whilst birds, which ensure
effective dispersal, are not put off.

But if birds eat chillies and mammals don’t - why do we like them? Science
In Action investigates.

Plant Manipulation

Many plants have ripe, fleshy, coloured fruit in order to attract animals that will eat them and then disperse their seeds in droppings. However, the chilli plant has developed another way of ensuring its
seeds are spread far and wide.

What raises the roof of your mouth when you eat a chilli is a substance
called capsaicin. This stimulates the areas of the skin and tongue that normally
sense intense heat and pain, falsely telling the brain that the area affected is
burning. New research carried out by scientists in Arizona, has discovered that
this characteristic peppery taste repels certain animals – which are no good at
dispersing the seeds.

Digestion And Dispersal

To find out what happens in the wild the scientists observed the eating
habits of the local animals living around a group of wild-growing chillies in
Arizona. They found that desert mice and rats avoided spicy chillies, but birds
fed almost exclusively on the plants.

The researchers also noted that when birds ate the chillies, many seeds
germinated, but there was no germination after mice had eaten the chilli seeds.
This is thought to be because seeds pass through a birds’ digestive systems very
quickly and come out unharmed, whereas in mice, rats and other mammals, the
seeds don’t make it out in one piece as they are broken down by the acidic
juices during digestion.

The researchers suggest that chilli plants have evolved to produce
capsaicin as a repellent for animals, which will ensure their future survival,
whilst still allowing birds to eat their seeds.Human TasteSkilful play by the
chilli, but if birds eat chillies and mammals don’t - why do humans like the hot
stuff? According to Paul Sherman from Cornell University in New York, people may have initially eaten spices because they tasted good, but they also recognised
their health giving properties. He explains:

‘There is tremendous evidence that spices are anti-microbial. Of 30
commonly used spices, at least half of them kill or inhibit 75% of the bacteria
they have been tested on.’

‘Certain ones, garlic, onion, allspice and oregano kill or inhibit
everything that they have been tested on in the laboratory.’Sherman reached his
conclusion after he had studied a range of recipes from different parts of the
world. In particular he wanted to see whether different amount of chillies and
other spices are used in meat as opposed to vegetable dishes. The idea being
that if humans use spices to inhibit or kill food born pathogens, more would be
needed to perform the same job in a meat product than a vegetable product.
Sherman details his findings:

‘We went back to all our cook books and looked at the 2,900 vegetable
recipes and found that in 36 out of 36 countries worldwide, spices are used less
frequently in vegetable recipes. This was across the board in every single

Luckily for those of us with delicate palates, the decision to add a pinch
or spoonful of chilli powder to our dishes is also determined by another product
of evolution - free will.

So there you have it, Chillies is good for their anti-bacterial properties. I however have a different theory. I think people who like to eat chillies like pain... either that, or they have the same tastebuds as birds. Anyway, if I ever do eat chillies now I always end up shitting it out as soon as possible. It goes into the toilet bowl and straight into the sewers. No chance of the seeds surviving there.

I can just imagine the first humans who tried eating chilli sitting around a camp fire in the evening cooking their dinner having this conversation:

caveman 1: this sabertooth tiger you're roasting over the fire taste kind of dull.
caveman 2: (reaches over and plucks a few chillies from a nearby tree) here, try rubbing some of this berries and rub it into the meat.
caveman 1: what kind of red berries are these? Smells funny (rubs in the 'berries' into the meat).
caveman 2: Give it a bite and try it.
caveman 1: No way, why I always have to try the new food? It was my turn the last time we had to eat those strange mushrooms. I had strange dreams for a week!
caveman 2: Okay, okay... past it over (takes a bite) oh shit!
caveman 1: what, it taste like shit? reminds me of the time you made me try that lump we found
caveman 2: No! My mouth's burning... this berry it's... it's hot!
caveman 1: That good eh? (takes a bite and chokes)
caveman 2: (shakes unconscious caveman 1) Dude? Dude, you okay? I meant hot as in my mouth's burning, not hot as in great

Well, I didn't say the first attempt when well. I assume a few of our early ancestors probably died trying dangerous food like poisonous toads and eating skunk ass.


Kieron Middleton said...

The fiery sensation of chillis is caused by capsaicin, a potent chemical that survives both cooking and freezing, but apart from the burning sensation it also triggers the brain to produce endorphins, natural painkillers that promote a sense of well being.

That might explain why some people enjoy the burning sensation so much!

Paul Melville said...

Although chilli has capsaicin, or body has evolved a counter punch. Our brain can learn which foods contain lots of nutrients despite having a bitter or hot taste, in response it overrides the taste buds with a hit of dopamine! this gives us a pleasure sensation, meaning that although the first time we eat chilli we dislike it, over time, as our brain learns it is actually full of vitamin c and antioxidants, we come to enjoy chilli and even crave it. The difference between you and your wife is that her brain has either adapted faster or had more chilli and learned this adaptation more.

A similar dopomine over ride is used for other bitter foods like dark chocolate and blue cheese.