Mainstream science is finally admitting they got it all wrong – but millions upon millions of people are suffering the consequences of corrupt/junk science. Maybe some consequences would teach them to be more careful and not use humanity as a big experiment.
Conventional nutritional advice varies a bit depending on who you ask, but there are a few constants. One is the importance of limiting saturated fat in favour of polyunsaturated fat. Most Governments, doctors and dieticians would therefore have us eschew foods such as red meat, dairy products and butter in favour of vegetable oils, oily fish and margarine.
This week saw the publication of the largest and most comprehensive review to assess the relationship between specific dietary fats and heart health, as well as the evidence for the supposed benefits of supplementing the diet with polyunsaturated fats [1]. The study was carried out by researchers from the University of Cambridge and MedicalResearchCouncil,University of Oxford, Imperial College London, University of Bristol, Erasmus University Medical Centre and Harvard School of Public Health, and was partly funded by the British Heart Foundation.
The study brought together two types of evidence:
1. Epidemiological evidence
Evidence where associations between different fats in the diet and risk of heart disease were assessed.
This sort of evidence itself came in two types:
a. studies where associations between dietary intake of specific fats and heart disease were assessed
b. studies where associations between body levels of specific fats (e.g. as measured in the blood) and heart disease were assessed
2. Randomised controlled trials
Where individuals were treated with specific dietary fats to see what effect this had on heart disease risk over time.
45 epidemiological and 27 randomised controlled trials were pooled in this review. The total number of subjects involved in these studies was more than 650,000.
Here’s a summary of the results:
Epidemiological studies of dietary fat and heart disease risk:
Saturated fats – No association
Monounsaturated fats – No association
Omega-3 fats – No association
Omega-6 fats – No association
Trans fatty acids – Increased risk
Epidemiological studies of body levels of specific fats and heart disease risk:
Saturated fat – No association other than one specific type of saturated fat (margaric acid) that was associated with reduced risk
Monounsaturated fat – No association
Omega-3 fats – Reduced risk
Omega-6 fats – No association other than arachidonic acid (found in meat, eggs and dairy products) which was associated with reduced risk
Trans fatty acids – No association
Randomised controlled trials of supplementation with:
Alpha-linolenic acid (a type of omega-3 fat found in plants including flaxseed/linseed) – No reduction in risk
Omgea-3 fats such as those found in oily fish – No reduction in risk
Omega-6 fats such as those found in vegetable oils – No reduction in risk
The authors of the review conclude:
…the pattern of findings from this analysis did not yield clearly supportive evidence for current cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of saturated fats. Nutritional guidelines on fatty acids and cardiovascular guidelines may require reappraisal to reflect the current evidence.
Should we be surprised?
