Bad Science

[lavendersparkle]

There's a science story doing the rounds and the way that it is being reported is really pissing me off. Here's an example from the Telegraph Vegan Diet Increases risk of birth defects, scientists warn.

What's wrong with this story? Well, the headline and the fist paragraph are both flat out lies. You can tell this because when you actually read the news story you find that they never actually quote any scientists saying that a vegan diet increases the risk of birth defects. If any scientists had actually said that, and it's their headline, wouldn't they, ya know, actually provide any evidence that this were the case. Instead they quote that B12 deficiency in early pregnancy increases the risk of birth defects and a scientist recommending that B12 supplements be recommended to women who are likely to conceive in the same way that folic acid is. The closest the Telegraph gets to substantiating its headline is to point to that B12 is found in "meat, eggs and milk" conveniently forgetting to mention that it's also found in yeast extract and lots of foods marketed to vegan are fortified with it. In fact, B12 deficiency is very rare even among vegans, because you only need a tiny amount, and tends to effect people past childbearing age. Furthermore, when studies have been done on pregnant vegans they show no worse outcomes, and young babies tend to do a bit better than average because a higher proportion of vegans breastfeed compared to omnivorous mums.

This article is following one of the classic Bad Science Reporting formulas. You get a press release with some findings which had been indicated by previous studies and has some public health implications yawn yawn. Then you realise that you can turn it into a Story by connecting the implications to a convenient scapegoat. Got a story about sunlight exposure and vitamin D? Make it about burqas. Got a story about B12 deficiency? Make it about vegans. Write a sensationalist headline blaming your chosen scapegoat and then cunningly use sub-clauses to make your connection without quite putting words in the researchers mouths.

I'd usually blame this on journalists being scum but I'm a bit suspicious. This story was reported with the same spin in several places. I'm a bit suspicious the the sexing up may have occurred before it crossed the journo's desk. A couple months ago there was a news story everywhere about research which might lead to a prenatal test for autism and how we should have a discussion about the ethical dilemmas such a test might present. I friend of mine who works in medical research in Cambridge later told me that the actual research that the story was loosely based upon a) confirmed findings which had been sort of found before an b) only showed quite weak relationship.* However, if you're related to Ali G, weakly confirming a relationship which we already sort of knew about and has no clinical applications doesn't have to get in the way of being in the international press. So the research group called lots of media outlets, fed them the abortion spin and the press jumped on the story.

This kind of spin is annoying because a) it's dishonest and b) it misleads the public about information which might be important to their decision making. The Telegraph headline is irresponsible because it will lead to more pregnant vegans getting hassle about their diet and omnivorous women thinking that B12 efficiency is something that they're immune to. A much better headline would be "Scientists recommend women take B12" or "B12 deficiency associated with birth defects". Those headlines would have been honest and might have actually changed people's behaviour in a way that might improve their pregnancy outcomes.

Edit: Here's a link to the abstract of the study. Some interesting points to note:
It doesn't mention vegetarians or vegans at all, they measured B12 deficiency through blood samples during pregnancy rather than looking at diet.
It states that previous studies have established a link between B12 deficiency and birth defects and this study only aimed to quantify the already known relationship. So an honest headline would read "Link between B12 and birth defects measured more accurately than in previous studies".

*As they described it there was a scatter graph with a cloud of dots that were sort of upward sloping enough that you could fit a line but not enough to mean that any level of testosterone couldn't be seen with any level of autism.

Comments

[naath.livejournal.com]

The intertubes tell me that the only vegan sources of B12 are manufactured, is it possible to eat yeast-things in the right way so as to get B12? or do you actually have to take supplements/eat 'fortified' food?

Of course everyone needs B12, and B12 supplements exist and can probably be taken by just about anyone. And why is this about vegans again? REPORTER FAIL.

(Personally I hate it when people say "you should take suchandsuch supplements" when what I think they ought to say is "you should ensure that you have thismuch of $thing in your diet" for those of us without moral, religious, medical or any-other reason to eat a restricted diet all needed nutrients can be found in, well, food. It might be better to tell people "folic acid is found in spinich and beans and btw if you can't/won't eat those things you can get it in pills".)

[lavendersparkle.livejournal.com]

I always thought that B12 occurred naturally in Marmite but a bit of t'internets shows that it's added. Either way 7g of Marmite contains all of the B12 and adult needs. It's also added to stuff like breakfast cereal, soya milk etc.

I don't usually take vitamins as I think I get enough nutrition from my food. If I were planning to have a baby I'd probably take them to be extra sure I wa getting everything I needed.

[fetteredwolf.livejournal.com]

Some populations are more susceptible to B12 deficiencies, this despite eating meat and eggs. Should those women not get pregnant? What absurd reporting.

[loveneverfails.livejournal.com]

Reporting on anything about pregnancy is going to be sensationalized and sometimes outright inaccurate. It's really obnoxious.

[hatam-soferet.livejournal.com]

You are writing to the Telegraph etc, right? Even if it was sexed up before it got to them, they still ought to, you know, read stuff.

[lavendersparkle.livejournal.com]

I don't really see the point. The sexing up of this story is quite mild by usual science reporting standards. Given how few science correspondents feel any qualms about spreading health scares which result in children dying of preventable diseases, I doubt they'll care much about the subtle point that 'B12 deficiency causes birth defects' + 'vegans one of the groups of people with a higher probability of B12 deficiency' does not equal 'veganism causes birth defects'. Seriously, whenever you hear a story which you know a lot about you realise that even the BBC's reporting is 50% nonsense and misleading. I've taken to getting my news from blogs and looking stuff like this up myself.

[hatam-soferet.livejournal.com]

I suppose the point would be that this one is relatively easy to debunk in a way that even real noodles can understand, but you're probably right. Blehhh.