Saturated fat replacement linked with lower risk of heart disease: Meta analysis

29-Oct-2014 - Last updated on 29-Oct-2014 at 11:42 GMT

Our comprehensive meta-analysis provides clear evidence to support the benefits of consuming polyunsaturated fat as a replacement for saturated fat, said Harvard professor Frank Hu.

Related tags Saturated fat Nutrition Epidemiology

Swapping just five percent of calories from saturated fat with foods containing the polyunsaturated fat linoleic acid have a lower risk of heart disease, finds a new analysis of current evidence.

The Harvard-led meta-analysis, reports that people who swap just 5% of calories from foods high in saturated fat to those that are high in linoleic acid — the main polyunsaturated fat found in vegetable oil, nuts, and seeds— have 9% lower risk of coronary heart disease (CHD) events and a 13% reduction in the risk of death from CHD.

Published in Circulation, the data from the Harvard School of Public Health (HSPH) also revealed that substitution of 5% of calories from carbohydrate with linoleic acid was also associated with similar reductions in risk of heart disease.

"There has been much confusion and sensational headlines about the role of different types of fat in CHD," said senior author Professor Frank Hu. "Randomised clinical trials have shown that replacing saturated fat with polyunsaturated fat reduces total and LDL cholesterol.”

“Our comprehensive meta-analysis provides clear evidence to support the benefits of consuming polyunsaturated fat as a replacement for saturated fat,” he stated.

Analysing the evidence

Hu and his colleagues performed a systematic review and meta-analysis of prospective cohort studies to summarise the evidence for a link between dietary linoleic acid intake and CHD risk in generally healthy people. They identified 13 published and unpublished cohort studies with a total of 310,602 individuals and 12,479 total CHD events including 5,882 CHD deaths.

Results showed that dietary linoleic acid intake is inversely associated with CHD risk in a dose-response manner—meaning higher intakes of linoleic acid resulted in a lower risk of CHD.

“A 5% of energy increment in LA intake replacing energy from saturated fat intake was associated with a 9% lower risk of CHD events and a 13% lower risk of CHD deaths,” wrote the Harvard researchers.

Comparing the highest to the lowest level of consumption, dietary linoleic acid was associated with a 15% lower risk of CHD events and a 21% lower risk of CHD deaths.

These results were independent of common coronary heart disease risk factors like smoking and other dietary factors such as fibre consumption, said the team.

In practice, Hu and his team said the findings support replacing butter, lard, and fat from red meat with liquid plant oils in cooking and at the table.

“These data provide support for current recommendations to replace saturated fat with polyunsaturated fat for primary prevention of CHD,” they concluded.

Source: Circulation
Volume 130, Pages 1568-1578, doi: 10.1161/CIRCULATIONAHA.114.010236
“Dietary Linoleic Acid and Risk of Coronary Heart Disease: A Systematic Review and Meta-Analysis of Prospective Cohort Studies”
Authors: Maryam S. Farvid, Ming Ding, et al

2 comments

Its a little more complicated...

Posted by Pete Granger, 01 November 2014 - 07:27 GMT

Lowering cholesterol is only one small part of the puzzle. Moreover, minimising cholesterol oxidation may be a more important objective. I would be cautious with the majority of this Harvard advice. Follow a Mediterranean diet (fruits, vegetables, and seeds, omega3 seafoods), restrict animal fat, consume modest amounts of nuts, saturated dairy fats
(http://www.salk.edu/news/pressrelease_details.php?press_id=2055) (http://www.sciencedaily.com/releases/2014/09/140915202955.htm), saturated coconut fats, (uncooked) monounsaturated fats (extra virgin olive oil, avocado). Avoid margarine, refined seed oils, and most vegetable cooking oils - except perhaps those with a high smoke point and resistance to oxidative deterioration. That is, choose the super-refined olive oil, safflower oil, mustard oil, rice bran oil, and perhaps canola oil. Eliminate hydrogenated, and low-smoke-point vegetable oils. Minimise carbohydrates - particularly processed carbohydrates. If you eliminate saturated fat you will more likely consume more carbohydates, especially processed carbohydrates – and you will be worse off. Thus, do not pursue a low-fat diet - they produce a worse outcome. Restrict artificial sweeteners. Early research suggests they may alter gut bacteria and increase blood glucose levels.

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What are the unforeseen consequences of increasing polyunsaturated fat in the human diet?

Posted by Gerald P. McNeill PhD., 31 October 2014 - 21:10 GMT

Recommendations by policy makers to make large changes in dietary habits often lead to negative unforeseen consequences. Previous effrts to reduce saturated fat resulted lead to an increase trans fat intake with increased heart disease. Reducing fat content resulted lead to a carb increase and obesity with type II diabetes.
What research have these authors carried out to prove there will be no unitended consequences due to this huge dietary change?
Linoleic acid is 50 times more reactive to oxygen than saturated fat. Oxidation ia a major factor in diseases of ageing such as cancers and collagen function. Polyunsaturated fats are known to produce toxic aldehydes called HNE that react with proteins and DNA. The himan body is saturated with oxygen and will react with polyunsatured fats.
This is a call to policy makers to avoid yet another case of uniteded consequences causing more harm than good.