New evidence raises questions about fatty acids

  • March 17, 2014
New evidence raises questions about fatty acids

A new study raises questions about current guidelines which generally restrict the consumption of saturated fats and encourage consumption of polyunsaturated fats to prevent heart disease.

A new study raises questions about current guidelines which generally restrict the consumption of saturated fats and encourage consumption of polyunsaturated fats to prevent heart disease.

The research was published in the journal Annals of Internal Medicine.

An international research collaboration led by the University of Cambridge analysed existing cohort studies and randomised trials on coronary risk and fatty acid intake. They showed that current evidence does not support guidelines which restrict the consumption of saturated fats in order to prevent heart disease. The researchers also found insufficient support for guidelines which advocate the high consumption of polyunsaturated fats (such as omega 3 and omega 6) to reduce the risk of coronary disease.

Furthermore, when specific fatty acid subtypes (such as different types of omega 3) were examined, the effects of the fatty acids on cardiovascular risk varied even within the same broad ‘family’ – questioning the existing dietary guidelines that focus principally on the total amount of fat from saturated or unsaturated rather than the food sources of the fatty acid subtypes.

Gates Cambridge Scholar Dr Rajiv Chowdhury [2009], the lead author of the research at the University of Cambridge, said: “These are interesting results that potentially stimulate new lines of scientific inquiry and encourage careful reappraisal of our current nutritional guidelines.

“Cardiovascular disease, in which the principal manifestation is coronary heart disease, remains the single leading cause of death and disability worldwide. In 2008, more than 17 million people died from a cardiovascular cause globally. With so many affected by this illness, it is critical to have appropriate prevention guidelines which are informed by the best available scientific evidence.”
 
For the meta-analysis, the researchers analysed data from 72 unique studies with over 600,000 participants from 18 nations. The investigators found that total saturated fatty acid, whether measured in the diet or in the bloodstream as a biomarker, was not associated with coronary disease risk in the observational studies. Similarly, when analysing the studies that involved assessments of the consumption of total monounsaturated fatty acids, long-chain omega-3 and omega-6 polyunsaturated fatty acids, there were no significant associations between consumption and cardiovascular risk.

Interestingly, the investigators found that different subtypes of circulating long-chain omega-3 and omega-6 fatty acids had different associations with coronary risk, with some evidence that circulating levels of eicosapentaenoic and docosahexaenoic acids (two main types of long-chain omega-3 polyunsaturated fatty acids), and arachidonic acid (an omega-6 fat) are each associated with lower coronary risk.

Similarly, within saturated fatty acid, the researchers found weak positive associations  between circulating palmitic and stearic acids (found largely in palm oil and animal fats, respectively) and cardiovascular disease, whereas circulating margaric acid (a dairy fat)  significantly reduced the risk of cardiovascular disease.

Additionally, when the authors investigated the effects of omega-3 and omega-6 fatty acid supplementations on reducing coronary disease in the randomised controlled trials, they did not find any significant effects – indicating a lack of benefit from these nutrients.

Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, which helped fund the study, said: “This analysis of existing data suggests there isn’t enough evidence to say that a diet rich in polyunsaturated fats but low in saturated fats reduces the risk of cardiovascular disease. But large scale clinical studies are needed, as these researchers recommend, before making a conclusive judgement.

“Alongside taking any necessary medication, the best way to stay heart healthy is to stop smoking, stay active, and ensure our whole diet is healthy – and this means considering not only the fats in our diet but also our intake of salt, sugar and fruit and vegetables.”

Picture credit: www.freedigitalphotos.net and zole4.

Latest News

Provost wins top Royal Society award

Gates Cambridge Provost Professor Barry Everitt has been selected for the Royal Society’s premier award in the biological sciences. Professor Barry Everitt FMedSci FRS has been awarded the Croonian Medal and Lecture 2021 for his research on the application of his findings on brain mechanisms of motivation to important societal issues, such as drug addiction. […]

Addressing energy injustice in the Global South

A new framework which uses artificial intelligence to analyse textual data on energy use and behaviour could help policymakers develop a deeper understanding of energy injustices in the Global South. The study, Grounded reality meets machine learning: A deep-narrative analysis framework for energy policy research, was led by Gates Cambridge Scholar Ramit Debnath [2018] and is published in the journal Energy Research […]

Scholar wins top German prize for PhD thesis

A Gates Cambridge Scholar has won a prestigious international award for her PhD dissertation on the relationship between offshore finance and state power. Dr Andrea Binder was named winner of the Körber Foundation’s German Dissertation Award 2020 for social sciences. The prize, one of the most highly endowed for young researchers from Germany, honours excellent PhD research which […]

Developing a farm for impact model

Shadrack Frimpong has not yet started his PhD, but already his and his team’s work has earned him awards from the Queen, the Clinton Foundation and the Muhammad Ali Foundation. The awards are for their outstanding work in creating a potential new development model for rural crop-growing communities starting from Shadrack’s own village in Ghana. […]