Cocoa and the brain

There is a small possibility an extract of cocoa could help older people be better at certain memory tasks - but the trial done so far is not good enough to show this.

A paper published in October 2014 was reported in the media as showing that cocoa helped put off age-related memory decline. As is often the case, while the actual paper was interesting, and highlighted something worthy of further investigation, what it demonstrates is more complex than the simple headline suggests, and at this stage offers substantive proof of benefits.

In the trial, a group of healthy people aged between 50 and 69 were split into four groups. Two groups spent three months on a diet that was high in cocoa, two on a low cocoa diet. At least, that's how the paper describes it - in reality the 'high cocoa' group took a supplement of 99mg of cocoa flavanols. To get this much naturally you would have to eat 25 individual chocolate bars (not recommended!) - I don't know how much that is in cups of cocoa, but I suspect it's a lot. Each group was also divided into half that were sedentary and half that took regular exercise.

The scientists then looked at two things - how a particular part of the brain responded in an fMRI scanner, and how well the test subjects did at two memory tests. What they found was that those on a high cocoa diet did significantly better at one of the memory tests - the equivalent, it was claimed, of being almost 30 years younger.

This is interesting, but it isn't enough yet to suggest we should all get out and start consuming lots of cocoa flavanols. The test groups were small with only 8 to 11 people in each. This doesn't mean that the results are meaningless, but it does suggest further tests are required. It has also been pointed out that the claim that result is statistically significant is doubtful. The value isn't what most scientists would consider significant - the results could be obtained in error with about 50 per cent probability, which isn't good enough to be considered useful.

What was claimed to be observed is that the cocoa increased blood flow to the dentate gyrus region of the hippocampus in the brain, which is thought to have a role in memory handling. In the trial, the high cocoa group did better at a memory test where they had to remember whether a shape they were shown was one of 40 they had just seen in a sequence. But they didn't do any better in a test where they had to recall words from a list, 60 minutes after three attempts to learn it.

Another oddity of the trial is that no improvement was found in those who performed exercise, even though in a previous trial by the same experimenters had found a benefit. This doesn't rule out the findings, but does emphasise the need to repeat the trial, several times and with bigger groups. Oh, and the authors declared no personal interest, but it wasn't strongly flagged up that the study was funded by the Mars chocolate company.

There seems to be some evidence here that this cocoa-sourced substance might help with the short-term recognition of shapes, which is something we get worse at as we get older. This can't be a bad thing if true. But it isn't a miracle cure for the way that ageing effect our memories, and taken on its own, this trial is not enough even to be sure of that.

You can see the full paper at Nature Neuroscience, though you would need a subscription to read more than a summary. It is Enhancing dentate gyrus function with dietary flavanols improves cognition in older adults - Adam M Brickman, Usman A Khan, Frank A Provenzano, Lok-Kin Yeung, Wendy Suzuki, Hagen Schroeter, Melanie Wall, Richard P Sloan & Scott A Small - Nature Neuroscience (2014) doi:10.1038/nn.3850

Could dinosaur DNA provide cures for human diseases?

Despite Jurassic Park, we can't use dinosaur DNA for anything, because we haven't got any, but we could learn something from the way dinosaurs survived injuries.

In July 2014, the Daily Mail carried a headline 'Could dinosaur DNA provide cures for serious human illness? Ancient fossils reveal evidence of powerful immune systems beating diseases such as cancer.' This seems very impressive - and there is an interesting health story here, but the headline is totally misleading.

Researchers examining a 72 million year old dinosaur skeleton had found evidence that it had survived serious injuries that a mammal would not be able to survive, and speculated that it might be that the animals had healing abilities that could be of benefit, if we could discover the mechanisms behind them. The only way this would be possible is if similar effects can be found in modern day relations of dinosaurs. The closest living relations are birds, but it has been suggested that a better model would be alligators and crocodiles, which are much more distantly related, but which do seem to resist infection despite living in bacteria-loaded environments.

However, the headline itself is pure science fiction. Despite the entertaining possibilities of Jurassic Park, dinosaur DNA simply doesn't exist any more. DNA deteriorates with time, and however it is preserved, it cannot last longer than around 6 to 7 million years. (The oldest sample found to date isn around half a million years old.) As the dinosaurs died out 65 million years ago, dinosaur DNA can't do anything for us at all.

Why food ingredients can have more than 100 percent

It's always a good idea to take a look at the ingredients lists on processed food, but it won't always make a lot of sense.

If you look at some food packaging, you will see that the manufacturers have something in common with the X-Factor. They believe that it's possible to give 110%.

There are two significant oddities in the ingredients list, for instance, of my cereal. One is the matter of nuts. Because it says that the product contains 10.5% nuts when in fact the true contents is only 0.3% - that's quite a big error. This is because neither peanuts nor coconut are actually nuts. But we'll let them off, because there is probably some sort of convention that allows them to come under this heading. (It can't just because they have 'nut' in their name, as 'Honey Nut Shredded Wheat', the cereal in question, has 'nut' in its name. So if that were the rule, the contents should read '100% nuts'.)

But the more interesting oddity is the maths. You might wonder what the problem is. With 84.1% wheat, 10.5% nuts and 2.8% honey, that still allows 2.6% for the other bits and pieces. But ingredients lists don't work like that. They have to be specified in order of weight - so there is more sugar than there is nuts, the list just doesn't mention how much sugar. With a minimum of 10.6% sugar, that makes a minimum contents of 108%.

We can get some idea of the quantity of sugar from the nutritional information. We are told that 100g of the product contains 15.9g of sugar - but we can't just take this number as the missing figure, as it will also include the sugar in the honey and molasses. So reasonably we can guess that the 'sugar' percentage is in the 10.6-12% range.

So what is going on? Thankfully, Nestlé has been helpful on the subject and told me this:

The basic maths does not add up and unfortunately this situation is replicated across many foods as they try to comply with QUID (Quantitative Ingredient Declaration) legislation. The complication comes from the requirement to list the amount of ingredients as they are added to the formula at each step. It is called the ‘mixing bowl’ rules.
In a simple process, this works well and the ingredients add up to 100%. In a process with many steps, and where moisture is lost in intermediate drying and toasting stages, the maths becomes more complex and illogical, and 100% is hard to achieve.   Each product must be viewed in isolation, and its manufacturing method affects the final result as well as the ingredients used.
We have to comply with 'The Food Labelling Regulations 1996' and its amendments.  There are two amendments which detail how we should declare the quantities of ingredients used, and the key requirement is in the second of these Amending Regulations, which states; 'Where the food has lost moisture as a result of treatment, the indication of quantity of the ingredient or category of ingredients used shall be expressed as a percentage which shall be determined by reference to the finished product”. 

 So there you have it. The percentages can't really be taken as sensible detailed information, just a broad brush guide. This doesn't of course, explain why peanuts and coconuts are nuts (no doubt another regulation), or why there is no percentage against sugar - but it does help us understand what is going on to allow Nestlé (and other food manufacturers) to give 110%.

Phone chargers and the environment

A plugged-in phone charger with no phone attached does use electricity - but not very much.

We are often warned of the dangers to the environment of leaving phone chargers plugged into the mains because they are still using current. This can seem a little counter-intuitive. After all, an electrical socket doesn't leak electricity when there's no plug in it, so why should a phone charger, if there is no phone attached?

Unlike the socket, the charger has something at work even if there is no phone present. The charger has to convert the high voltage AC current of your mains down to the low voltage DC used to charge a phone. This involves passing the mains current through a transformer, and transformers have two complete electrical circuits, one for the input and one for the output. This means that the input circuit does use power, even if there is no device to receive the output. (Contrast this with the electrical socket, where the circuit is broken unless something is plugged in.)

However, the power usage of such a charger when not in use is tiny - around 0.1 watts. Compare that with a traditional bright light bulb at 100 watts - it's 1/1000th the amount. So by all means unplug your phone charger when not in use, but don't think it's going to make a big difference. You can do far, far more by switching to LED light bulbs, fitting double glazing, turning the heating down by 1 degree, insulating your house better and all the other ways that are traditionally recommended for saving energy.

What happens to fingernails and hair after death

I have included this slightly gruesome story under 'fun' rather than 'health' as it isn't a matter of practical concern, just curiosity.

It's often said that human fingernails and hair continue to grow after death, allowing artists who specialise in the grotesque to envisage strangely hairy and long-nailed corpses. In a sense 'grow' is the wrong word for these extremeties made up of a tough, structural protein called keratin (skin, hooves, horns and beaks are also made of different assemblies of keratin). This is because they aren't alive, so can't strictly grow, but rather are constructed by specialist cells in the body.

If we get past the word, though, the idea itself has no basis. The processes that produce hair and nails require a living body to provide the raw materials and to power the production with glucose. Although there aren't any detailed scientific studies testing for this, there is no reason to think that hair and nails would continue to grow, as there is no mechanism to 'power' their production once the body has died. It's a myth.

It has been suggested that the myth originated because skin contracts as it dries and may seem to make hair and nails a little longer a little while after death. According to the British Medical Journal, the myth has certainly been around since the late 1920s, when it was mentioned in the novel All Quiet on the Western Front.

Does water go off?

There is often amusement caused by seeing bottled water with a 'best before' or 'use by' date. Surely water doesn't go off? 

It's a neat paradox that pure water doesn't go off - but water still should only be consumed relatively soon after obtaining it.

This goes both for tap water, once poured, and bottled water, once opened. In both cases it is best kept in the fridge and should be consumed within a couple of days. It's not that water itself can degrade. It's a very simple chemical compound, H₂O - surely about the best known there is - with one oxygen atom and two hydrogen atoms. And the water itself will be exactly the same after a year. The trouble is that lots of living things need water, and like water as an environment in which to live. There are plenty of airborne bacteria, fungus spores and more that are floating around all the time. Once water is exposed to air it will start to accumulate these and, over time, you will get yourself a nice colony, some of which is likely to be bad for you.

If you have no choice but to drink water that has been kept for more than a couple of days (of course, unopened bottled water is fine up to its best before date), boil it for several minutes first.

Phytoceramides

Yet another important natural compound that has roles to play in the skin in the body, but that is highly unlikely to have significant benefits when taken as a supplement.

It sometimes seems there's a new wonder chemical, touted by an American MD via his or website every 10 minutes that is claimed to have anti-aging or skin restoring properties. Look up phytoceramides online and you will find plenty of capsules containing this wonder material which, it is claimed, will 'fake a facelift'.

Ceramides play an important role in the skin, along with other long molecules like cholesterol, helping retain moisture and keep the skin firm. But as we have found so often, simply eating a substance does not mean that it will be magically transported to the appropriate parts of the body to support the naturally occurring versions. As far as your digestive system is concerned, ceramides are just another kind of fat to be broken down.

Applied to the skin, ceramides can help retain moisture - but no better than vaseline or any cheap and cheerful moisturiser. And taken as a supplement, there are no scientific trials demonstrating any benefit.