Monday 29 September 2014

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.

Wednesday 17 September 2014

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 NestlĂ© (and other food manufacturers) to give 110%.