The Science of Christmas

As Christmas is nearly upon us let’s take a quick look at the science behind some of our Christmas traditions.

Can Santa really deliver all those presents? Roger Highfield suggests in his book about the science of Christmas ‘Can Reindeer Fly?’ that in order for Santa to deliver all the presents in time he would have to achieve such high speeds that the forces on his body would be 17,500 times greater than gravity on the surface of the Earth, crushing him into singularity. Yet as Roger rightly points out: ‘Santa is not dead. He delivers presents every year, as reliably as Rudolph’s nose is red.’
But why exactly does Rudolph’s nose glow so bright? Despite being able to withstand crushing forces, Santa has been unable to cure the common cold.
Reindeer noses contain elaborate and highly concentrated folded membranes that act as heat exchangers. Cold air, when inhaled, is rapidly warmed by the blood in these membranes. Exhaled warm air is cooled by the same process. This helps reindeer retain heat and minimise moisture loss. However, it is this moist and warm environment that is a perfect home for parasites and bacteria, including 20 that have been identified as unique to reindeer. Odd Halversen of the University of Oslo suggested in the journal Parasitology Today that the “celebrated discolouration” of Rudolph’s nose is probably due to a parasitic or bacterial infection of his respiratory system.
Following the magical arrival of presents from time-stricken Santa and his snot-ridden reindeer, the gastronomic heart of the holiday lies in Christmas dinner. But why does it taste so good?
Rudolph’s red nose may be due to a parasitic or bacterial infection

The Maillard reaction is the reason roasted meat is so appealing. Discovered by French chemist Louis Camille Maillard in 1912, the reaction occurs when sugar molecules are heated with amino acids, just like inside your Christmas feast. Hundreds of different flavour compounds are formed during the reaction as the carbonyl group of the sugar reacts with the amino group of the amino acid to form N-glycosylamine, which via a spot of chemical trickery known as the Amadori rearrangement produces ketosamines. The rich flavours we associate with roasted meat are produced by ketosamines, as are melanoidins that give the golden brown colouring.

But as your reach for your second or third helping of that turkey spare a though for your poor genes. Dr David Topping of CSIRO- Australia’s national science agency- warns that over consumption of nutrients can affect your DNA by the production of excess molecular oxygen species. Turkey seems to confound this potential genetic onslaught as it is high in dietary protein. “We’ve shown that increasing the amount of protein will increase genetic damage to cells that line the large bowel”, explains Topping. But it seems Christmas magic abounds, as you can avoid this form of DNA damage by eating a specific dietary polysaccharide- commonly known as the potato. Topping says that starch which is not digested in the small intestine can produce protective compounds in the gut that prevent the damage.
For the less carnivorous, Brussel sprouts are almost as much a tradition at Christmas dinner as the big roast bird. Packed with vitamins A and C, folic acid and fibre what’s not to like? Well, overcooking them releases a chemical that gives a sulphurous smell, which puts a lot of people off. But the lovers and the haters of this vegetable may be divided by their genes. A chemical found in sprouts tastes very bitter to people with one version of the TAS2R38 gene, while other carrying a different version can’t taste it at all.
But before Santa arrives and we get down to all that dinner and merriment there’s decorations to be put up. While a fake Christmas tree may be more environmentally friendly, here’s a new reason to appreciate the real thing: Researchers from Finland have identified a group of anti-inflammatory compounds in the bark of Scotch pine trees – widely used as Christmas trees – that could be developed into drugs for treating arthritis and pain. Kalevi Pihlaja, a chemistry professor at the University of Turku and lead author of the study said that “In the future, this may mean that people with arthritis may ease their pain by eating food supplements made from Christmas trees.” Researchers found that the extract not only inhibited nitric oxide production, an excess of which has been linked to arthritis and circulatory problems, but also inhibited prostaglandin production, which has been linked to arthritis and pain.
So what tips can we glean from science for surviving the festive season? Well, firstly if you want to leave a little something for Rudolph as a thank you on Christmas Eve for that death defying delivery of your presents, perhaps a box of Kleenex and some Vaporub would be better than a carrot. Secondly, when the proud cook triumphantly produces the Christmas feast this year don’t fall victim to an embarrassing faux pas – be sure to compliment them on their perfectly timed Maillard reaction. Also make sure there are plenty of spuds on the go if you want to spare your genome from a foul fate. Finally, after Christmas when the cold is getting to your joints, remember to grind down that Christmas tree to mine its medicinal properties. Merry Christmas.
P.S. If you have a science-minded member of the family that blames the L-tryptophan in the turkey for their inability to stay awake and help with the dishes, you can explain that although it is true this amino acid regulates sleep, it only has a visible effect on an empty stomach and in the absence of other amino acids, so there’s no reason not to get up and don a pair of marigolds.
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