November 9, 2015

Fish and chips might be bad for you

By

From the Herald (from the Telegraph)

Martin Grootveld, a professor of bioanalytical chemistry and chemical pathology, said his research showed “a typical meal of fish and chips”, fried in vegetable oil, contained as much as 100 to 200 times more toxic aldehydes than the safe daily limit set by the World Health Organisation.

In contrast, heating up butter, olive oil and lard in tests produced much lower levels of aldehydes. Coconut oil produced the lowest levels of the harmful chemicals.

 

That’s in the lab. In July, Professor Grootveld reported the same type of analysis for a BBC program, but on oil as actually used by home cooks. From the press release at De Montfort University

Professor Grootveld’s team found sunflower oil and corn oil produced aldehydes at levels 20 times higher than recommended by the World Health Organisation. 

Olive oil and rapeseed oil produced far fewer aldehydes as did butter and goose fat.

So, about an order of magnitude less bad than the current story.

The story talks about turning current food advice on its head. The most… the two most… among the several most important things wrong with that claim are: first, that oils high in monounsaturated fats (such as olive oil and rapeseed/canola) are the current food advice; second, that the advice to eat less saturated fat is based on studies of actual disease, not just on lab biochemistry;  third, Prof Grootveld published research on this lipid oxidation phenomenon in 1998, so his reported surprise at the findings is a bit strange; and fourth, “a typical meal of fish and chips” hasn’t been regarded as health food since basically forever.

 

 

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Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient See all posts by Thomas Lumley »

Comments

  • avatar
    Nick Melhuish

    Corrections. Current Heart Foundation advice here is to replace saturated fats with PUFAs.
    Studies of actual disease show benefit from some saturated fats. (Obvious harm from others)
    Research statisticians consistently refuse to publish data on certain cohorts of diabetics with high satfat intake and excellent clinical outcomes.
    If you would like evidence of how irresponsible some of your colleagues in medical research are please let me know.

    8 years ago