Tag Archives: Superfoods

Butter is good for your heart !!

10 Feb

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This story from last week interested me, as it seemed to contradict all of the health advice we’ve received for years. According to the headline replacing butter with polyunsaturated fat margarine ‘doubles heart risk‘. The story is based on a paper recently published in the British Medical Journal. The first thing that set me thinking was that the study is a reanalysis of missing data from a student conducted with Australian men between 1966 and 1973. Based on this alone it would be interesting to get students to think about whether you could generalise from a sample of Australian men from forty years ago. I may be adopting a dreadful stereotype, but I suspect that the diet of a 1960’s Australian male hugely different from today’s average thus making sensible comparisons rather difficult.

Secondly, the newspaper article is a great example for encouraging students to read all of an article. Towards the end of the article two academics are quoted who clearly don’t think the story has much strength:

Professor Tom Sanders, of King’s College London, said the study was ‘enormously underpowered’, of ‘little relevance to diets today’ and its findings had been refuted by recent better studies.

Professor Brian Ratcliffe, of  Aberdeen University, said: ‘This paper does not provide evidence for changes to the current recommendations for a healthy diet.’

FInally, this story is a lovely example of one of the key points of the rational thinking curriculum/syllabus that I’m trying to assemble. It you read through the reader comments attached to this story you can see the Naturalistic Fallacy at work. Many of the Mail’s readers seem to conclude that it is obvious that butter is more healthy than margarine because butter is ‘natural’ and margarine in ‘manufactured’. A moment’s thought exposes flawed logic of this argument, and yet it is hugely widespread.

It’s of note that the original article is freely available on the BMJ website, and thus for once academic journal paywalls aren’t actively hampering rational thinking !

Eating chocolate and drinking milk will make you a Nobel Prize winner

22 Jan

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You could hardly miss this story, as it seems to have been all over the media this week. The headline of the  Daily Mail version of the story focused on a correlation between a country’s milk consumption and the number of Nobel Laureates from the country. The story went on to cover a similar correlation between chocolate consumption and Nobel prizes. The same story appeared around the world including Bangladesh, USA (Time), Pakistan and Ghana.

You might just dismiss this story and the usual newspaper rubbish, but when you read through the story it is based on material from the Practical Neurology (A British Medical Journal publication) and from the New England Journal of Medicine. When you look at the Practical Neurology article one can feel the authors tongues firms in their cheeks and in the second line of the article they acknowledge that correlation obviously doesn’t imply correlation.

This story is useful for two different types of teaching. At a basic level it’s a nice way to illustrate the idea that correlation doesn’t imply causation. In discussion with students I’m pretty sure you could come up with a lot of possible variables that might me mediating this relationship. My own mind wanders to the figures for lactose intolerance in Asian countries being 75% plus.

At a much higher level I think there is an interesting discussion to be had about the responsibility of scientists when publishing correlational data. Whilst both the papers that this story was based on were published in peer-reviewed journals (and were thus aimed at an audience who would understand correlation and causation) it’s not unreasonable to suggest that given the subject matter both the authors and the journal editors would be aware that the popular press were likely to pick it up. Under these circumstances my question is ‘Do the authors and editors have any responsibility to consider the wider audience and their lack of understanding and correlation”? It’s all very well for us to bemoan poor science reporting in the popular press, but we ar least partially responsible ?

The ‘Mediterranean Diet’ Super Pill

7 Jan

 

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Seven days into the year, and I’ve spotted a new piece of teaching material. The front page story of today’s Daily Express is headlined ‘Super Pills is the Key to Living Longer’, and reports a small-scale study of the effects of lycopene. The story also appears in today’s Daily Mail under the headline ‘A daily tomato pill to cut heart attacks’.

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The study itself is of passing interest, but what drew my attention was the link being made with ‘The Mediterranean Diet’. The logic of the article is that lycopene is derived from tomatoes, and tomatoes are a major constitutent of the Mediterranean diet. It will be interesting to get students to reflect on this adea of the link between good health and the ‘Mediterranean Diet’. Hopefully students will be able to derive for themselves the possibility that overall ‘lifestyle’ rather than diet alone might be behind the health advatages of those living in Southern Europe. Once this has been established it’s only a small step to ask students to think about the impact of the current economic crisis in Southern Europe, with civil unrest in Greece and unemployment in Spain in excess of 25%.

However good their diet might be one suspects that the current economic woes are likely to have a much greater neagtive effect on health !

Are fish oils good for you or not ???

20 Nov

I was very impressed last week by a story in the Daily Mail finally accepting that fish oils weren’t a magical cure for any number of health problems. This made me think about ways of getting students to understand the reliability of any particular source of information. After all, reading this one article would make you think that the Mail was a useful source !

After a little thought I typed ‘fish oil’ into the search box on the Mail’s home page and came up with a whole range of ‘interesting stories, a selection of which are listed below:

11 September 2012 “Fish oil supplements ‘do NOT cut risk of heart attacks and strokes”

28 July 2012 “Are you hooked on fish oil yet? The natural wonder drug proven to treat a range of conditions”

13 June 2012 “Elderly warned that taking fish oil pills ‘does not prevent brain decline'” 

31 January 2012 “Taking fish oil during pregnancy ‘protects babies from eczema'”

28 February 2012 “New proof daily dose of fish oil does help keep your brain young”

3 January 2012 “Fish oil may hold key to leukaemia cure”

26 October 2011 “Fish oil supplements ‘can slow growth of prostate cancer cells in just four weeks'”

31 May 2011 “Fish oil could curb binge drinking by reducing desire for alcohol”

8 July 2010 “Fish oil may cut breast cancer risk ‘by a third’ 

24 May 2010 “Health news: Why pregnant women should drink more milk, tackle knee pain with sound waves and could fish oil reduce asthma?”

20 January 2010 “Is fish oil the elixir of life ?”

11 August 2009 “Could a fish oil pill add years to your life?”

22 May 2007 “Heart attack victims should take fish oil pill daily”

15 May 2006 “Fish oil ‘boosts pupil performance'”

I’m not particular interested in the research underlying all of this, (If you are there is an excellent chapter on the ‘fish oil and brain power’ story in Ben Goldacre’s book ‘Bad Science’). However this seems like a great illustration that students do not have to be experts in a particular subject to see that fish oils are unlikely to be the cure for all of these ills. It may well be, once all the research has been conducted, that fish oil does have valuable health properties but that is very different from the panacea presented above !

Contradicting your own headlines (and other stories)

14 May

I’ve written recently about newspaper science stories that seem to bear little resemblance to their original sources, but I’ve just come across an example where the headline and the text of the story seem to actively disagree with each other !

This Daily Mail story from 26th March 2012 is headlined ‘Forget your five-a-day: Popcorn has ‘more antioxidants than fruit and vegetables’, and yet if you read through the story you find the researcher warning ‘that people can’t forego their five-a-day’.

So, in this case students don’t even need to be told to read the source material, as the problems are there in the story itself. Beyond that, it’s worth asking students if they can see a bigger problem with the idea of popcorn as ‘the perfect snack food’ and thus the latest ‘superfood’. You might wonder how many students order ‘virgin’ popcorn at the local Vue ? You would suspect that various ‘sweet’ favours might be the norm, followed by ‘salted’. Ironically this article headlined ‘A 1800 calorie bag of popcorn: Cinemas urged to warn film lovers about fat-filled snacks’ strangely also appeared in the Daily Mail ?

Cake makes you lose weight !!

30 Apr

Weird diet stories often appear in the press, and serve as a really nice way for students to deploy their rational thinking skills. This particular example from the Daily Telegraph in Feb 2012 suggests that eating chocolate cake makes you lose weight.

The reported study involves two groups, both of a calorie-limited low-carbohydrate diet, where the difference between the two groups was that one ate a 300 calorie breakfast whereas the other ate a 600 calories breakfast including the chocolate cake. The cake group lost substantially more weight that the non-cake group, even though they consumed the same number of calories in total.

Students will have undoubtedly heard the advice that eating a large breakfast means you are less hungry throughout the day, but the story treats this as being some kind of amazing scientific revelation !

It’s worth asking  students to Google this story, to see just how far such ‘news’ spreads. The story originals from the Tele Aviv University in Israel, but I’ve found it being reported in India, the USA, Australia and New Zealand as well as the UK. What’s really intriguing is that nowhere in any of these stories does the idea of a group eating a 600 calorie breakfast with cake versus a group eating a 600 calorie breakfast without cake would be an actual test of the ‘cake’ hypothesis

Superfoods – Is it just correlational data ?

28 Apr

Students will probably have already come across the idea of ‘superfoods’, so this article should be easily accessible.

This Daily Mail article reports a study from a large US cohort study that suggests that eating strawberries and blueberries can stave off cognitive decline on later life. What’s of particular interest is that if the students read to the end of the Mail’s article they discover the idea that other ‘lifestyle’ variables, for example ‘exercise’, might explain the correlation between the fruit consumption and slowing of the rate of cognitive decline. Students should be able to readily recognise that people who eat more fruit might also exercise more. It seems quite bizarre that a newspaper that would publish a single article where the end of the article seems to contradict beginning of it.

This seems like a nice way to talk about correlation and causation and also a good example that just by reading all the way through newspaper articles it’s possible to spot the problems with them !

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