A new study conducted by non-profit foundation the Fatty Acid Research Institute (FARI), which examines the relationship between fatty acids and health, has found no link between omega 6 and increased inflammation, News Medical reported.
The study’s publication in Nutrients comes against a backdrop of heightened interest in the health effects of seed oils, such as canola, many of which are rich in linoleic acid, an essential omega-6 fatty acid.
Some have claimed that western diets contain “too much” LA and that many modern diseases stem from the increased intake of LA over the last century, according to the 30 June report.
The new study set out to research if higher intakes of LA were linked to increased inflammation.
It used data from the Framingham Offspring Study, a longitudinal research initiative following the children of participants in an earlier Framingham Heart Study to investigate genetic and lifestyle factors influencing cardiovascular and metabolic health.
As a cross-sectional study, linoleic acid (LA) and arachidonic acid (AA) levels were measured in the same blood samples as the 10 inflammation-related biomarkers in 2,700 individuals. The relationships between the levels of these two omega-6 fatty acids and 10 separate blood/urine biomarkers of inflammation and oxidative stress were statistically evaluated.
After adjusting for other factors such as age, race, sex, smoking, blood lipid levels, blood pressure and body weight, the researchers found that higher LA levels were associated with statistically significantly lower levels of five of the 10 biomarkers. The team found no case of higher LA related to higher levels of any biomarker.
For AA, higher levels were linked with lower concentrations of four markers and, as with LA, there were no statistically significant associations with higher levels of inflammation/oxidation.
“These new data show clearly that people who have the highest levels of LA (and AA) in their blood are in a less inflammatory state than people with lower levels. This finding is exactly the opposite of what one would expect if omega-6 fatty acids were ‘pro-inflammatory’ – in fact, they appear to be anti-inflammatory,” said study investigator Dr William S Harris, FARI president, founder of OmegaQuant Analytics and Professor in the Department of Internal Medicine at the Sanford School of Medicine, University of South Dakota.
“In the flurry of news stories about the harms of seed oils – the primary sources of LA in the diet – many voices are calling for reducing Americans’ intakes of LA. This is not a science-based recommendation, and this study – in addition to many more – point in precisely the opposite direction: instead of lowering LA intakes, raising intakes appears to be a healthier recommendation,” Dr Harris added.
The study was partly funded by a grant from the Soy Nutrition Institute Global with support from the United Soybean Board.
In a separate study, led by Dr Daisy Crick from The University of Queensland’s Institute of Molecular Bioscience, researchers found that omega-3 fatty acids, popularly believed to reduce inflammation in the body, appeared to increase certain inflammatory markers, News Medical reported on 25 June.
The researchers used the Avon Longitudinal Study of Parents and Children, which collected data from people at birth through to adulthood over the past 30 years, to look at the role of omega-3 and omega-6 in the body.
Using biomarkers in the blood, the researchers measured inflammation and found higher levels of omega-3 fats – naturally occurring in oily fish and commonly taken in supplements for anti-inflammatory benefits – were associated with increased levels of inflammation.
In addition, a larger omega-6-to-omega-3 ratio was also consistently associated with higher levels of inflammatory biomarkers found in the body, the report said.
The results were confirmed using another large dataset, the UK Biobank, which included information from almost 500,000 people, Dr Crick said.
The team also applied Mendelian randomisation, a scientific technique that uses genetics to help understand cause-and-effect relationships by mimicking a randomised control trial, and found that omega-3 and omega-6 increased levels of some biomarkers of inflammation.
“Our findings suggest that the dietary fatty acids and inflammation relationship is more complex than previously thought and it might be more useful to look at the balance (or ratio) between omega-6 and omega-3 in the diet,” Dr Crick was quoted as saying.
The result was maintained when other possible influences such as triglycerides, a type of fat found in the blood, and low-density lipoprotein (LDL) cholesterol known as ‘bad’ cholesterol, were taken into consideration, she added.
However, study senior author Dr Hannah Jones of the (MRC) Integrative Epidemiology Unit at the University of Bristol, said further research using additional biomarkers was needed before drawing firm conclusions about dietary omega-3 fats.
The research was published in the International Journal of Epidemiology.
