The Science behind our Daily Diets | Earth Science

All decaffeination methods start with this, the green or unroasted coffee bean. Most methods use water to get the caffeine out of the bean. Then a chemical solvent is often used to get the caffeine out of the water. The solvent is then removed and the remaining water is dried off. There are two possible chemical solvents that can be used in this process, both of them technically speaking toxic, but by the time the process is complete, they're found at such vanishingly low levels that they are below the European regulated safe limit. But to avoid any solvents, there are other methods that some manufacturers use to remove the caffeine. One alternative uses a charcoal filter. Another uses carbon dioxide at extremely high pressures. So you can choose solvent-free coffee if you want, but there's not any evidence that it's actually healthy. There is, however, something else that you should be aware of if you're thinking of going decaf. Your decaf may not contain any chemical nasties, but you might be surprised to know that it probably does contain some caffeine. A 2006 study conducted in Florida found that nine out of the ten decafs they tested had at least some caffeine in them. So the two-shot decaf latte that you're drinking might contain as much caffeine as a can of Coke. Today, nearly one in five of us choose to drink a milk substitute, and more than a quarter of Brits believe they are healthier than dairy milk. But are they really? We're going to look at two of the most popular, soya and almond. Any milk substitute is going to have to work pretty hard to match it. Take protein, for example. In milk, in soya, there's tons of it. But look at almond, hardly any at all. So look at the calcium in the milk here. We've got tons in dairy, and we've also got loads in soya and almond. But in dairy, it occurs naturally. In soya and almond, it's been added. And studies show that the natural calcium found in cow's milk is easier to absorb than the fortified calcium found in the soya and almond alternatives. Perhaps one of the least known constituents of milk is iodine. Now, most of us run a little low on iodine, especially pregnant women. But studies have shown that children who have low levels of iodine are at risk of lower cognitive development. And if you have a look here at our three glasses, you can see that dairy milk is a great source of iodine, but in soya and almond milk, there'll be hardly any. Soy milk contains phytoestrogens, which are good for women going through the menopause and for prostate health in older men. There's also an argument that says plant-based fats are better for us than dairy fats, but that's an ongoing debate. Red wine is thought to be good for you because it's made using the grape skin, which contains a family of chemicals called polyphenols. These have been the source of intense study for decades, and one has been probed more than most. Resveratrol. This is an East African killifish. Let's call him Arthur. Arthur is a handsome beast, but sadly, his time on this Earth is short, just a few months. But that's useful for scientists who study longevity. So the scientists ran an experiment to see if giving resveratrol to fish like Arthur made them live longer, and what they found was that the fish in the experiment, given the resveratrol, lived up to 40% longer. Now that's pretty astonishing, if you're an African killifish. What you'll find if you read beyond those headlines that say something like a glass of red wine a day keeps the doctor away, is that at the bottom of the article, it will say that the experiments were actually done on a fish like Arthur, a worm, a fruit fly, or sometimes just cells in a dish. And even if we do one day discover that resveratrol has significant beneficial effects on people, there's still a catch when it comes to getting it from wine. This is a glass of Pinot Noir, happens to be from the Yarra Valley in Australia. Now Pinot Noir is a light red with low acidity, medium tannins, and some of the highest levels of resveratrol of any wine in the world, at around 10mg per litre. Unfortunately, though, most of the studies on resveratrol have been done using capsules like this. And in order to get as much resveratrol out of my wine as there is in this capsule, I would need to drink all of these bottles here. So I'd better get going. Arsenic is well known as a poison, but most of us don't realise it occurs naturally in soil and water, so tiny amounts can get into food. Levels tend to be higher in rice because it's grown under flooded conditions. The EU brought in new regulations on the levels allowed in rice products. I must admit, Andy, it had never ever occurred to me that there was arsenic in rice. And does it matter? I mean, the sort of doses you find it in, does it really affect your health? Totally. We know that low levels of chronic exposure to arsenic causes a wide range of disease, and over lifetime exposure leads to increased risks of cancer. We know that if you have low levels of exposure during infancy, that it causes a range of other developmental problems. What sort of things? Immune development, its growth rate development, its IQ development, are all linked to arsenic exposure. Andy has tested levels of arsenic in different types of rice and compared them with other cereal crops. He found that white basmati rice has five times as much arsenic as wheat or barley. Other white rice typically has ten times the amount, and brown rice, twenty times. The legal limits for arsenic in children's rice products, like baby rice, are set at half the adult amount. But puffed rice cereals don't have to meet the child requirements because they are deemed as not being directly marketed at children. The Food Standards Agency also advises that children under four and a half should not be given rice drinks, as these too contain arsenic. The aptly named microwave oven uses microwave radiation to heat food. All that these microwaves do is cause water molecules in the food to vibrate, generating heat that spreads through the surrounding molecules. Now, it has been claimed that this damages proteins and destroys nutrients in our food. But is any of this true? Well, the short answer is yes. But that's not as terrible or as unusual as it sounds. Actually, what happens in a microwave is no different from what happens on a stove. Heating, by any method, changes proteins and nutrients. In fact, when you boil vegetables in water, you can lose even more goodness because the nutrients that were in the veg tend to end up in the water, which you then throw away. So if you want to cook in a way that best preserves nutrients, what you actually need are shorter cooking times that limit the exposure to heat and a cooking method that uses as little water as possible. And when you look at it like that, a microwave is a good bet. In fact, studies looking at vitamin C have shown that levels in food can be higher after microwave cooking than after boiling. So if you like using the microwave, carry on. In some cases, your food might actually be more nutritious. So I've come to an independent food laboratory in Kent. They've agreed to conduct a special test for us. They're going to check the calorie count on some popular foods that we've bought at random from different supermarkets. First, we have to take each product and make a consistent mix of its ingredients. This gloop goes off to be analysed in the lab and separated into its different chemical constituents, which are measured precisely. OK, so first up, a pork pie. So the makers have said 370 calories per portion, and we found 410. So it's a 40-calorie difference. That's about 10%, yeah. Right. Well, the pork pie has 40 calories more per portion. A pasta, pasta bake. OK, nice ready meal. It does look good, actually. Manufacturers say 667, you guys say 670. So that's bang on. That's very, very close. Now, our value for the pasta bake was spot on, but the others varied by up to 10%. This may seem surprising given how precise the labels appear, but actually it's within government guidelines. And that's because the number of calories will change slightly from packet to packet. A really good example of how additives can be fairly obvious in foods is salad dressings. Now, first up, if I make my own at home, all I'm going to put in is, you know, a bit of olive oil and vinegar. And then I always bung in a bit of mustard. And then just give it a good stir. And that does the job. No additives needed. Now, oil and vinegar don't mix, but the mustard in my dressing, A, tastes really good, but B, it acts as an emulsifier. And what that means is that there's a chemical in the mustard that bridges the gap between oil molecules and vinegar molecules that essentially repel each other and essentially makes my dressing into an emulsion. But that doesn't last very long. Now, as my salad dressing settles, you can see all the different components. The oil and the vinegar are separating. And also all the mustard seeds have settled to the bottom. But if I show you an equivalent salad dressing that comes from a shop, there's no separation whatsoever and all the seeds are suspended throughout. It looks very different. But I need just one secret ingredient to get my DIY dressing bottle ready. Now, this is E415, or xanthan gum. And it's a very popular additive. It's used in hundreds of salad dressings and sauces. And it comes from this little bacteria, xanthomonas campestris. And it's what causes the black spots on broccoli and cabbage. And it uses this gum-like substance that it secretes to attach to the leaves of the vegetables. But when that gum is dried out, it looks like this. And if I add a little bit to my dressing and stir, look at that already. I can notice a bit of a difference. The gum further emulsifies the dressing but also surrounds the molecules of oil and vinegar, stabilising the mixture so that the oil and vinegar can't separate back out. But xanthan is also a thickener. It's also made my dressing a lot more viscous and that means that all the mustard seeds are now sort of permanently suspended in my dressing. And suddenly, these two don't look that dissimilar anymore. Because it's so thick, I can even water it down. Which not only makes it cheaper to produce, it also gives you a fraction of the calories per teaspoon. So if I were to take a supplement, would it in fact do me any good? Well, I'm going to take one and find out. The pill I've taken is a typical multivitamin, containing high doses of most of the vitamins, especially vitamin C, which is the most popular single vitamin supplement sold. To see if it's doing me any good, I took a sample of my blood from before the pill to measure the amount of vitamin C in my body from my diet. Now, to see what happens to the supplement I've taken, I'm collecting all my urine for 24 hours as a lovely present for a team here at the University of East Anglia, led by Professor Bill Fraser. Apparently I've produced so much urine that it wouldn't fit on the urine measuring scales. Don't know how to feel about that. Slightly proud, maybe a little bit ashamed as well. Bill's team get to work analysing my body fluids. They start with the vitamin levels in my blood before I took the pill. This will reveal how much vitamin C I was getting just from my normal food and drink. My normal diet was providing me with all the vitamin C my body needed. But what happened when I tried to top it up with a supplement? How much of the vitamin in the pill would remain in my body and how much would pass straight through? From the tablet, we extracted about 425mg. Your urine contained over 530mg of vitamin C, so you've passed the tablet and a little bit more, which is probably what you've taken in your diet. Basically my body was full of as much vitamin C as it can hold and anything else I put in, I just peed out. You've peed it out, the majority of it's been peed out.