Alison Campbell finds some claims about raw foods hard to swallow.

I was reading a couple of articles about ‘raw foods’ today. This is ‘raw foods’ as in ‘foods that you don’t heat above 40°C in processing them.’ It’s also as in, a vegetarian diet. (I do rather enjoy vegetarian food, but I don’t think I could eat nothing but, all the time; I like meat too much.) Anyway, what caught my eye wasn’t so much the diet programme itself but the mis-use of science to promote it. That did rather get my goat broccoli.

Apparently you should get your kids to eat their greens (along with the rest of the diet) by telling them that plants do this wonderful thing: they turn sunlight into chlorophyll and – when you eat it – it will give you extra oxygen. Sigh&#8230 This concept was repeated in the second article, which told me that raw (but not cooked) foods are ‘oxygenated’ and thus better for your brain, which needs to be fully oxygenated to work properly.

Well, yes, and so do all your other bits and pieces, and they don’t get the oxygen from food. As Ben Goldacre once said, even if chlorophyll were to survive the digestive process and make it through to the intestine, it needs light in order to photosynthesise, quite apart from the fact that you don’t normally absorb oxygen across the gut wall. And it’s kind of dark inside you.

The second shaky claim related to digestive enzymes. Because raw foods are ‘alive’ then they are full of enzymes. And so we’re told that eating them will help you to digest your meals better.

Er, no. First, because when said enzymes – being proteins – hit the low pH environment of your stomach they are highly likely to be denatured. This change in shape means that they lose the ability to function as they should, and in fact they’ll be chopped up into amino acids like any other protein in your food, before being absorbed and then used by your cells to make their own enzymes.

And second – the raw foods diet is plant-based. Yes, plants and animals are going to have some enzymes in common. I’d expect that those involved in cellular respiration and DNA replication/protein synthesis would be very similar, for example, because these are crucial processes in any cell’s life and any deviations in form and function are likely to be severely punished by natural selection. But we already have those enzymes; they’re manufactured in situ as required. In other words, even if the plant enzymes somehow made it into cells intact and capable of functioning, they’d be redundant.

However, with a very few exceptions, plants aren’t in the habit of consuming other organisms so, in regard to plant cells being a good source of the digestive enzymes required for the proper functioning of an omnivore’s gut – no, I don’t think so. No.

Some might ask, why on earth do I bother about this stuff? After all, it’s not doing any harm. But the thing is – science is so cool, so exciting; it tells us so much about the world – why do people have to prostitute it in this way? Kids (and others) are fascinated by the way their bodies’ organ systems work, and I can’t see why there seems to be a need to provide ‘simple’ – and wrong! – alternative ‘explanations’ when the real thing is so wonderful.

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