Archive for category Food is totally science
So, California’s planning a referendum on the labelling of genetically modified food. The Guardian has covered this not in it’s regular news pages, but in its Comment is Free section, under the title “How California’s GM food referendum may change what America eats“.
The article is mostly an opinion piece – fair enough – but there’s one statistic buried in there that leapt out at me.
While researchers have not yet found a “smoking gun”, which would prove that GM foods as a class are dangerous, there are troubling signs that they may be a factor in the recent epidemic of food allergies. Soon after GM soy was introduced to the UK, for example, soy allergies escalated by 50%.
The link there doesn’t go to a scientific paper, but to a piece on “News. Controversy. Opinion.” site Opposing Views, and their figures seem to come, ultimately, from American Academy of Environmental Medicine, a group that has some decidedly quackish views on topics like water fluoridation, vaccines and “Multiple Chemical Sensitivity” (a scientifically unfounded belief that everything in modern society contains toxins). It’s not impossible to support some outlandish ideas while being right about things, of course, but it does ring some alarm bells.
Neither article links to any of the studies it referenced, but with a bit of digging, I found this piece at Academics Review which seems to be dealing with the same statistic. Go there if you want the full takedown, but in a nutshell, it refers to marketing information from a group called “York Nutritional Laboratories” (which sell food allergy testing kits) the rise was in people with a particular antibody, not those who reported allergies and the study didn’t find any connection (the rise simply happened at a similar time to the introduction of GM, although it actually took place before GM soy became mainstream).*
I decided to have a look on Google Scholar for papers looking in the allergenicity of GM soy. There are plenty of studies and review papers looking into this – one, two, three, four, five – and all the ones I’ve found so far suggest that genetic soybeans and GM soybeans pose exactly the same risk of allergy (though as far as I can tell, these are all animal trials. There isn’t much data on human soy allergies out there).
In this case, the claim that GM soy may be responsible for a rise in allergies seems to be simply wrong.
* For the other major claim in Opposing View’s piece, about baby rats dying from eating GM soy, see this peer review of the paper, originally from Nature Biotechnology , which expresses grave concerns about the unusually high numbers of deaths in the control group – it looks like bad care killed the rats, not the soy)
Hey! I know it’s been a while since I blogged. Hopefully you haven’t missed me too much. Anyway.
Prunes are not a laxative, EU rules, says today’s Telegraph, endowing the EU with frankly godlike powers. Did someone in Brussels snap their fingers and magically prunes suddenly ceased to be laxatives?
Let’s help the Telegraph and suggest a more accurate headline. Perhaps…
Prunes are not a laxative, science suggested two years ago
The laxative effect of prunes is one of those things that “everyone knows”. Certainly MEP and frequent talking head Roger Helmer agrees, claiming:
“The euro is burning, the EU is falling apart and yet here they are: highly-paid, highly-pensioned officials worrying about the obvious qualities of water and trying to deny us the right to say what is patently true.”
Ignoring the fact that this study was carried out in mid-2009, before the Euro crisis kicked off, Roger Helmer has an interesting definition of “patently true”.
The study looked at the scientific evidence for the effectiveness specifically of dried prunes. There were two studies of the effectiveness of dried prunes in humans at the time:
“Daily Consumption of Dried Plum by Postmenopausal Women Does Not Cause Undesirable Changes in Bowel Function” by Edmund Lucas et al and “Consumption of prunes as a source of dietary fiber in men with mild hypercholesterolemia” by Lesley Tinker et al. Lucas found that there was no significant difference between apples and prunes in stool bulk, consistency, frequency or pain, and Tinker found a difference in stool weight between prunes and grape juice, but no effect on consistency or frequency.
A third study they looked at, “Prune juice has a mild laxative effect in adults with certain gastrointestinal symptoms” showed that as you can probably guess from the title, prune juice did appear to have laxative effects – hence why they only talk about dried plums in the report.
Now, it’s possible that dried prunes are laxative – a much more recent study (albeit one funded by the “California Dried Plum Board”) from 2011 found that prunes appear to work better than the laxative psyllium at relieving constipation – but at the time this report was written, it simply would not have been accurate to say that, based on the body of available evidence, prunes were any better at keeping you “regular” than any other sort of fruit.
(The Telegraph also claims that the EU banned claiming that drinking water could prevent dehydration. Read the actual article, and the very last paragraph reveals that they’re talking about clincal dehydration, which is normally caused by disease rather than by not drinking enough fluids and that “This claim is trying to imply that there is something special about bottled water which is not a reasonable claim”)
Edit: Just found this excellent post by Martin Robbins about the dehydration claim.
A number of papers this week (Daily Express*, Daily Mail, Daily Mirror, Daily Telegraph, Wales on Sunday) have all carried the same story, claiming that, in the words of the Daily Mail, “NHS officials pay £32 for gluten-free bread that costs £2.25 in the shops”.
Though it’s not impossible that a big organisation like the NHS has inefficient bread-buying schemes, it seems a bit unlikely that something as widely prescribed as gluten-free bread is being bought for more than 10 times its shelf price. So where did the figures come from?
Well, it looks like the story comes from this Welsh government data about prescriptions. Sure enough, if you look it says that the 27 prescriptions of a particular type of bread, Lifestyle Gluten-Free High-Fibre Brown, cost £32.27 each.** But doctors aren’t prescribing one loaf of bread at a time.
The important column is the one marked “quantity”, which tells you how many grams of bread were prescribed. For Lifestyle Gluten-Free High-Fibre Brown, doctors prescribed a total of 123,600 grams. Divided between the 27 people, that’s 4,577 grams each, or about 11 loaves of bread per person. So that £32.27 figure is the cost of buying 11 loaves of bread, not 1, and as the Welsh government points out, it works out at around £2.82 per loaf. This is still slightly more than the cheapest online cost of the bread, so I assume there is still room to bring prescription costs down, but NHS Wales is certainly not spending more than £30 on a loaf of bread.
* Turns out James Delingpole writes for The Express too. Huh.
** If you want to check for yourself, it’s in section G-O under the name “Lifestyle_G/f H/fbre Bread Brown”.
(Hat tip to @TomChivers)
Look at me, boldly breaking press embargoes to bring you the FACTS. What IS the formula for the perfect cup of tea?
You might have thought that George Orwell answered that fairly conclusively years ago, but if you did then you are clearly an idiot. After all, George Orwell was just an author, journalist and political campaigner. What the hell do writers know about tea?! No, to answer this question we need the help of cargo cult science!
Good thing Cravendale’s taken the hit and hired scientists from Northumbria University to tell us the secret of good tea. Spoiler warning: the answer’s “Cravendale”.
Some of the more sceptical among you might be wondering how they tested this, and how awfully convenient it was that this research, which appears to have been funded by Cravendale, just happened to prove that Cravendale made the best cup of tea. Well, how can you argue with this experimental methodology:
Following the brewing process, teabags were removed and varied amounts of semi-skimmed Cravendale milk [0ml, 5ml, 10ml] were added to samples for our sensory advisory panel.
The panel’s results reveal that the ideal amount of milk to be added is 10ml.
Yep! They compared Cravendale milk to no milk at all, and shockingly found that Cravendale tastes better than nothing. This must prove Cravendale is the best milk ever, QED.
Incidentally, 10ml isn’t much milk at all, really – it’s less than half a single measure of spirits, after all. You’d think that if you were trying to test the ideal amount of milk to put in tea, you’d try everything from “no milk at all” to “nothing but milk”, but to be fair I guess the scientists involved had more important things to do than indulge the bizarre PR-driven whims of a milk filtration company.
There’s no mention of sugar in the paper, and certainly no mention of anything more exotic – a spoonful of honey, a dollop of cream, or a splash of lemon, for instance. I assume Cravendale hasn’t figured out how to filter sugar or lemon juice yet. They have however found time to make some truly groundbreaking progress in the field of thermodynamics, however:
The optimum temperature to drink tea at is 60°C. With the addition of Cravendale milk, our brews were able to reach the optimum temperature after just six minutes, two minutes faster than regular black tea.
Yes, adding a cold liquid to a hot liquid will in fact cool the hot liquid down! Of course, this only works with Cravendale milk – as everyone knows, if you add regular supermarket own-brand milk to tea, the tea just keeps getting hotter and hotter!
Still, all this stuff about “things cooling down over time” is pretty state of the art – I mean, Isaac Newton only figured out his law of cooling 300 years ago. Thank goodness Cravendale is on the cutting edge.
Anyway, based on all this research, the scientists at Northumbria have come up with a formula for the perfect cup of tea. Are you ready for this piece of extremely rigorous mathematics? Here goes:
TB + (H2O @ 100°c) 2minsBT + C(10ml) 6minsBT = PC (@ OT60°c)
where TB = teabag, BT = brewing time, C = Cravendale milk, OT = optimum temperature and PC = perfect cuppa.
Look how science-y that is! There are letters and numbers and plus signs all over the place! And they say “H2O” instead of “water” – only a true scientist would do that! Also according to that formula you should keep your tea brewing for 6 more minutes after you add the milk which sounds like a one-way trip to astringency-town to me, but then I’ve never written my tea making instructions down in the form of algebra, so what do I know?
This “research” has been embargoed until tomorrow morning – let’s see if any of the papers are stupid enough to run with it.
Anyway, this was quite a long post, so you should probably treat yourself to a nice cup of tea now. Just remember to use own-brand milk.
The Telegraph today carries an article promising that you can “Think yourself thinner with the fantasy diet“.
To the article’s credit, at least it’s not just someone flogging a diet (this time). This report is about a study, recently published in Science, which showed that people who imagined eating M&Ms repetitively ate fewer M&Ms at the end of the study than people who imagined simply moving the M&Ms or putting coins in a washing machine.
So far, so interesting. But is it a diet?
When people were asked to imagine eating M&Ms but were given pieces of cheese, thinking about food didn’t have any statistically significant effect on their appetite. You need to be thinking very hard, and very specifically, about the food that you’re about to eat. Even when it did have an effect, we’re talking about handfuls of M&Ms. As Dr Carey Morewedge, study leader, says:
I do not want to blow out of proportion the efficacy of the imagery induction, as [the 50% drop] meant that participants tended to eat 2-6 grams of candy when they imagined eating the food or cheese rather than 4-12 grams of candy or cheese.
I’m not sure how much weight you’d loose by cutting your M&M consumption by 2 to 6 grams per day, but I don’t think it would be very much.
The idea that there should be some magic bullet to weight loss is a surprisingly common one. This week, the magic cure the Mail is pushing is a type of crystal called “Sensa” which, it claims, makes food more flavoursome, so people eat less but feel as full. (Edit: The Telegraph is now reporting on it too, and their article is even more one sided than The Mail‘s)
So far, so what? Every diet pill on the planet claims to do that.
Ah, but, The Mail claims, there’s SCIENCE behind it:
In scientific tests, obese participants who used the flavourless, ‘Sensa Tastant’ crystals lost an average of two stones in six months.
Others lost an average of just two pounds.
Sure enough, the website of Sensa does provide links to the study, and it does appear to back up what the Mail claims at first glance. But there’s a problem.
The study, Use of Gustatory Stimuli to Facilitate Weight Loss, carries the name of just one scientist – Dr. Alan Hirsch. Hirsch happens to be not only the researcher who performed this experiment, but also the inventor of the crystals. One other study, “Efficacy Determination of Weight Loss through Use of Crystal Tastants“, claims to be by an independent lab, but there’s no authors listed for the study and it doesn’t appear anywhere on the internet apart from the Sensa website and a couple of mirrors, which makes this claim impossible to verify. In an interview with ABC News, Hirsch claims the second study was carried out by the distributor of the Sensa, in which case the researchers were perhaps less independent than implied.
Neither of these papers have published in a peer reviewed journal – nor, in fact are they proper papers. Instead, they’re just posters for use at a conference. As a result, they really don’t go into the experiments in any details, glossing over all the awkward details. For example, the papers do not give the distributions of weight loss. It’s all very good and well claiming that on average people lost on average 30 lbs, but unless you know what the spread is, it’s pretty useless. Did everyone lose 30 lbs, or did a few people lose 100 lbs and everyone else lose nothing?
Nor does it explain how the “control” group was controlled. In Hirsch’s study, there was no placebo. As far as I can tell, the control group is simply a collection of obese individuals who had no particular intention to lose weight. The people who actually took Sensa on the other hand were people who definitely did want to lose weight. Given that a) participants actually had to pay $49 per month to take part in the 6 month trial and b) people weren’t weighed in the lab but instead simply reported their weights to the scientists at the end of the study, there’s more than enough reasons for people to exaggerate their weight-loss to the researchers. Who wants to admit to wasting $300, after all?
Furthermore, only 1436 participants out of 2437 actually completed the trial; over 40% dropped out. It’s reasonable to assume that people who did not lose weight would stop taking the Sensa – after all, they’re paying $49 per month for it! This would weed out anyone who did not find Sensa worked and, over time, you’d be left only with the people who did lose weight – whether that was due to Sensa or not.
Finally, and most damningly, the experiments have never been peer reviewed. Dr Hirsch claimed at one point that the Endocrine Society had reviewed and approved his work. In fact, they simply allowed him to give a presentation at a conference, and were “surprised and troubled by the promotional nature of his presentation“.
ABC showed the papers to researchers, both professors at prestigious US university. One claimed the study has “negative value”, while the other said “says there is no scientific proof that Sensa works and believes the study was done to justify a commercial product”. Pretty damning.
It’s always possible that maybe a proper independent lab will pick up this study and prove without a doubt in a properly controlled experiment that Sensa works. At the moment though, I think it’s safe to say that the scientific evidence that the Mail so proudly touts is rather lacking.