Impurities (Part 2)

From the universal to the purely (or impurely) human, last post. And here, if humanity is what humanity eats, then we must look at the ingredients of our food.

We've all been taught that major food groups are carbohydrates, fats and proteins. These are no idle assignments, but chemical divisions — carbohydrates, literally carbon-with-water, are sugars and their polymers such as starches; fats are the esters of glycerol, a substance that can add up to three long chains of carbonaceous substance, forming triglycerides; proteins are polymers made by stringing together large numbers of amino acids. Carbohydrates are fuel; fats are complex materials that serve to insulate and protect (and in extremis, be broken down to make more fuel); proteins are the building blocks of most of our working parts.

For bone and our electromechanical systems, we need inorganics with our organics. Mineral matter, the kind of stuff that the crematorium attendant sweeps out into an urn after the black grease of our passing has tainted the air. Without the minerals, we'd be goo, and rather insensate goo at that.

Yes, we are impurities in water, but the water would not have form without the stuff we use to shape it. Our impurities are to water as the structure of a building is to the air and light within it.

And that brings me to the issue of food safety. Food is mostly safe, and in the cases when it is not, we have only ourselves to blame. But the human body and its main metabolic organs — mostly the liver and kidneys — are able to clear most of the unwanted chemicals. The rest, presumably, consists of wanted chemicals.

Of all the carbohydrates, glucose is most prized. Without it, nothing works, since our bodies are designed to store and burn glucose. Of all the fats, animal fats are most prized, since our bodies are most equipped to move it around — after all, our own fat -is- animal fat. And of all the proteins, animal proteins are most prized, for the same reasons. We do not have the mainly-vegetable-diet construction of the ruminants; we can't digest fibre and we find it hard to extract value from plants.

However, the detractors are right to say we should cut down on animal-based food, simply because we eat too much of it. A steak should last for weeks; we shouldn't be eating a steak a week (or worse). Fat is good, but not more than a heavy spoonful a day or so. And if we aren't labourers on a farm or athletes in the Olympics, we don't need 5000-10000 kcal a day. We can get by on 1500 or so.

What I find amusing is the desire to have impure food instead of pure — sea salt instead of pure sodium chloride, honey instead of pure glucose, organic vegetables instead of those grown on ammonium nitrate and carefully-calibrated mineral content. Like the making of steel, pure foods ensure no unpleasant surprises compared to what is expected: no pollen-induced asthmatic attacks, no haemolytic attacks from allergy to added Vitamin K, no bone fractures from drinking too much added calcium and not having enough sunlight and fat.

Not that I mind impure food, perish the thought. It tastes better, even if it's not necessarily healthier.

Silly Food Ideas

I first studied food chemistry in detail when I was a third-year undergraduate. This created a foundation from which I developed a certain perspective on food claims, based on chemical analysis.

I'm just going to take a quick look at some food decisions people are passionate about:

1. honey vs refined sugar
   
2. sea salt vs industrial salt
   
3. 'organic' food vs normal food
   
4. 'processed' food vs raw food
   
5. monosodium glutamate vs 'natural' flavours
   

I am going to spend the rest of this post discussing the science behind making a rational choice to eat any of these things or not. Honey is a vastly favoured food, and quite often, it is spoken of in the same breath as 'royal jelly'. The ideas here are that a) honey is a natural sugar, and that b) stuff the queen bee feeds to baby bees to make them grow large fast will work for humans too. I think it's nonsense to say that honey is 'better' than refined sugar in any significant biochemical way.

Essentially, honey is about 80% sugar — mostly fructose (fruit sugar, about 40%), glucose (30%), maltose and sucrose. The rest is mostly water. If you ate 100 grams of sugar, you'd receive perhaps 1-3% of your daily requirement of some vitamins (e.g., for vitamin B2, you'd have to eat 3 kg to meet your daily requirement). As a sweetener, honey is approximately as sweet as table sugar. I must admit however that honey tastes a lot nicer. It is the one area in which I'd say honey is genuinely 'better'. It's good for baking too; being already a sugar syrup, it's easier to use than refined sugar or even castor sugar.

But honey can be worse. Since honey production is carried out by the random acts of insects, honey is never of a uniform composition. Sometimes, it contains allergens from pollen that some people are allergic to; sometimes, it can even contain the spores of nasty pathogens. It is basically impure sugar, and it has been marketed as if that impurity is a beneficial thing. Consider this: if pure water was analogous to pure sugar, would you drink water that was the colour of honey?

The same situation is true for sea salt. Sea salt is tastier than industrial salt or pure salt, sodium chloride. That's because it contains impurities, especially potassium salts. Potassium ions are the main reason why sea salt tastes different. For example, potassium bromide can taste sweet, salty or bitter at different concentrations; sodium chloride and bromide just taste salty at all concentrations.

However, potassium ions are what we call 'antagonistic' to sodium ions. This can be good or bad. Athletes consume potassium to relax muscles and prevent cramps; the bananas that tennis players snack on between sets are high in potassium — but the levels present in sea salt are much higher than those in bananas. Potassium salts have such a well-known relaxing effect that large doses of potassium bromide have long been used to make humans sleepy and susceptible to control. It's a good thing to read more about it.

'Organic' food is an interesting term. I don't like that term, since all the food I eat is organic (carbon-based) except perhaps mineral salts and water. People who eat 'organic' food normally mean that it's food grown with natural animal faeces instead of pure salts such as ammonium nitrate. Of course, the good part is that some 'organic' foods eschew the use of artificial insecticides in their making, which is certainly a healthy thing. I have nothing much else against 'organic' food except that I'd prefer they called it 'food grown without whatever chemicals it was grown without, and using natural faeces only'. Sometimes, 'normal' food is normal.

Which brings me to this odd idea about 'processed' food. I think humans process their food a lot, compared to other animals. We are the only species that regularly subjects food to thermal shock, charring, denaturing and tool-based mechanical alteration. Why should that be? Shouldn't food fit for all the other species on this planet be fit for us too? Maybe the raw food advocates have a point.

But can you imagine not eating processed food? No cereals, no bread, no baked goods. No cooked eggs, no steamed fish, no grilled meat. No blanched vegetables, no jams, no butter. No milk unless you get it straight from an 'organic' cow. No wine, no beer, no salted dishes. No ground pepper, no cheese, no olive oil. Haha, no thanks.

And yet, some people like to add processed flavours to their food; things like cinnamon, vanilla and umami. All these require processing (often heating and/or extraction with alcohol) to bring out the taste. Which brings me to that contentious last item.

Why are people against MSG? Some people claim to be sensitive to it with resultant bad symptoms of all kinds, but we haven't actually been able to reproduce this effect. Natural MSG occurs whenever salt encounters proteins; glutamic acid is a common amino acid present in most protein sources. Let's be clear about this: without glutamate, the brain CANNOT WORK. It is the most abundant triggering (excitatory) neurotransmitter chemical in your nervous system. And MSG is the sodium salt of glutamic acid.

At that point, some people come up to me and say, "Yeah, but sodium is bad." Sodium is bad?? No, sodium is essential. You can't think or move without sodium ions. And your body contains a bit less than 1000 mg for every kilogram of your body weight; if you weigh 60 kg, you probably have 55,000 mg of sodium in there. You need to maintain this with about 1500 mg of sodium intake a day.

So what's bad about MSG? Is it the glutamate? Is it the sodium? Can't be either. The only thing bad is consuming too much of it, just as it would be bad to drink too much water or eat too much salt or beef. It would be fatal to eat nothing but lettuce, for example. The key is moderation. I'll be honest with you. If you eat large tennis-ball sized lumps of MSG every day, you might get very sick. Then again, I can think of many other food substances of which this might be true too.

I can only believe that bad PR skills have led us to this point. The reason why MRI (Magnetic Resonance Imaging) is called that in hospitals but called 'Nuclear Magnetic Resonance' (NMR) in chemistry labs is that nobody wants to imagine being 'nuked' even though the 'nuclear' in NMR has nothing to do with radioactivity. MSG just sounds too much like a 'chemical', by which humans mean something awful and artificial, like plastic.

If we had stuck to calling MSG 'umami' from the beginning, everyone would have lauded it as an exotic oriental ingredient. But it was not to be.

All food is made of chemicals, and all cooking is chemistry. It is good for students to study food chemistry, so that all the nonsense that they read in advertisements and on boxes and labels can be purged, filtered, eliminated. Then there'll be fewer silly food ideas to go around.

Taste

Taste is three-dimensional. You can measure the taste of something along one of three axes; these three axes are somewhat analogous to the three main kinds of chemical bonding – covalent, ionic, metallic.

The first axis is bitter-sweet. A bitter substance can be diluted until it tastes sweet; many organic compounds are like that, and conversely, many sweeteners are bitter in high concentration. Life is like that; too much sweet and you will taste bitterness, but how sweet the taste of good coffee!

The second axis is salt-sour. At the extremes of this axis lie ionic solutions, ions set free in a world of water. You will find that taking a very salty liquid provokes a similar response to taking a very sour one. But this axis scales to zero – if the liquid is very very faintly salty or sour, it quenches thirst better and makes you want to drink more.

The third axis is minty-meaty. At one end you will find peppermint and other sharp aromatic buzzers of the nose; at the other end you will find the taste of amino acid compounds – glutamate and his friends. At high concentrations, they taste metallic, like crystals of the smell of reacting metal.

It is always interesting to see how our little worlds of sense and sensation are so easily reduced to theory in few dimensions. Quite often though, while the numbers and bullet points are adequate description, they are unable to capture explanation or meaning.

You drink a soup of forest mushrooms: as the glutamates and aromatics intermingle, as the salt closes circuits in your tongue, you feel pleasure. But what kind of pleasure, and why does the aroma of mushroom make you feel comfortable and intelligent? The truth may lie in your past experiences, or in your present company, or in the future expectation of garlic bread. And you may know none of this, except that the soup is great.