Consumption of fried foods and risk of coronary heart disease: Spanish cohort of the European Prospective Investigation into Cancer and Nutrition study
BMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e363 (Published 24 January 2012) Cite this as: BMJ 2012;344:e363
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Dear Editors,
Fried meals contain many toxins, produced when oils are burnt in elevated temperatures. [1][2][3][4][5][6][7][8][9][10][11][12][13][18][19][21][22]
More toxins originate from overheated coated frying pans. [14][15][16]
Mutagenic compounds are also detected in kitchen air! [17][20]
It is interesting to read that ALL cause mortality after 11 years is not elevated in those people consuming high quantities of fried foods.
It means that these toxins did not increase incidences of oesophageal, gastric, pancreatic, hepatic, intestinal, rectal, lung, bladder, prostate or renal cancers.
As regards cardiovascular events, though, I wouldn't be so relaxed.
Endothelial damage takes time to become severe enough. Insults are added, little by little, until the patient has a fatal episode.
All patients recruited in this study were young enough not to have reached critical endothelial status.
Furthermore, follow up was only for 11 years.
It would be interesting to have results in 20 or 30 years.
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Competing interests: No competing interests
Participants with a lower fried food intake had a higher prevalence of diabetes mellitus, hyperlipidaemia, hypertension and cancer (table). They were more often sedentary at work or not working, in menopause and former smokers. Thus, the health condition of the lowest quartile appears to be worse than the other participants. I question whether this could have induced a lower intake of fried foods.
Competing interests: No competing interests
1/ At baseline in the higher quartile group of fried food consumption there are 50% diabetic patients and 50% less hyperlipemic and 35% less hypertensive patients; they eat 34% more calories and have the same BMI or waist circumference as the other quartiles; they drink 77% more alcohol; the women are 44% less likely to be in the menopause; they are more active and less frequently long term smokers. Despite these better risk factors, they have the same cardiovascular events or deaths as the lower quartile group of fried food consumption. Hum! It seems to be very contrarian... It is confusing that a statistical analysis was not mentioned in the tables.
2/ It means that perhaps the lower quartile group is a very high risk group at baseline in terms of cardiovascular diseases.
3/ Comparing such groups with the others is nonsense. With these disparities in known risk factors they could have eaten bacon versus spinach and the results would have been the same...
4/ As a matter of fact, the low consumption group is probably and partly a group of patients following nutritional advice because of their risk factors and/or symptomatic diseases...
Competing interests: No competing interests
Re: Consumption of fried foods and risk of coronary heart disease: Spanish cohort of the European Prospective Investigation into Cancer and Nutrition study
Health effects of frying foods in different oils: Is it a question of quality, amount or time?
We find this a very interesting study, both in design and in its development. Planning circumstances and calculated data will lead to the relevant estimates. However the study conclusion is surprising, although rarely work of this excellence is found.
In our opinion, to address these effects could be not enough when considering this protocol. The fact that no differences exist between transformations produced by frying in different types of oils is due to the various overlaps that eliminate or offset proven factors. The introduction of other underlying variables: whether biased or through nested queries, could lead to shifted interpretations of this conclusion. This will allow more light to be shed upon the well known differences due to nutritional facts affecting final conclusions.
Since it is well known e.g. the different chemical fatty acid composition of oils changes the rupture lability and transformation in frying due to double bonds. Fried olive oil, the main component of which is monounsaturated, produces fewer toxic products than those with PUFA as its main components.
There are other interesting nutritional factors: oil quality plays a role on the nutritive value of protein. This changes the amount absorbed. Also, the effect of frying affects carbohydrates.
According to the authors accepted limits, focus only on the nutritional factors:
• The third limit of the study: frying procedure influence. Sauteing uses up all the oil at once. Deep frying in an oil bath produced toxic products, which would be cumulative by reuse, but its presence is difficult to calculate, because the oil carried out is replaced by fresh oil, diminishing its concentration.
• The fifth limitation of the study: PUFA contribution from fish, would have to be regarded in the dietary history variables, beyond other possible effects.
These could lead one to conclude a wave-like role among other expressed limits.
Consumption of fried foods and risk of coronary heart disease: Spanish cohort of the European Prospective Investigation into Cancer and Nutrition study. BMJ 2012; 344 doi: 10.1136/bmj.e363 (Published 24 January 2012) Cite this as: BMJ 2012;344:e363
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Competing interests: No competing interests