Healthy fats could raise risk of sudden heart death new study finds

Oily fish, nuts and avocados—prized for being sources of ‘healthy’ fats—may not be as good for us as previously believed, scientists have claimed. 

The key culprit, according to Australian researchers, is fats in these foods known as omega-3—which studies have previously suggested protect heart health. 

However new evidence suggests omega-3 is linked to inflammation in the body, increasing the risk of obesity, type 2 diabetes and even a heart attack. 

The findings come from a major study involving 2,800 participants in the landmark Avon Longitudinal Study of Parents and Children (ALSPAC), also known as Children of the 90s—one of the most detailed long-term health studies ever carried out.

Researchers have followed the health of over 14,000 families in the Avon area since 1991, when the mothers were first recruited during pregnancy. The latest research looked at data collected when the children turned 24. 

After accounting for lifestyle factors such as smoking, scientists found that diets rich in omega-6 were associated with higher levels of GlycA—a blood biomarker linked to chronic inflammation, cancer and heart problems.

Omega-6, found in vegetable and seed oils, has, in recently years, increasingly been associated with poor heart health. 

However, surprisingly, the researchers also found increased GlycA in those who consumed foods rich in omega-3 fats, which are usually considered ‘heart healthy’.

Professor Thomas Holland, from the RUSH institute for Healthy Aging, Chicago, who was not involved in the study, told Medical News Today the results were ‘unexpected’. 

He added: ‘Omega-3s are found in dark fatty fish, like salmon and sardines, and in plant-based foods like flaxseeds, chia seeds, and walnuts. 

‘Most people think of them as calming to the immune system. Yet in this study, higher omega-3 levels were linked to more inflammation, not less.’

Lead author of the study, Professor Daisy Crick, an expert in molecular science from Queensland University, said: ‘Our findings suggest that it’s not as simple as “omega-3 is anti-inflammatory and omega-6 is pro-inflammatory”.’

She added that simply upping omega-3 intake may not be enough to cut inflammation or protect against heart disease. 

‘Improving the balance between the two fats could be a better method for people who want to reduce inflammation in their bodies,’ she said.

The study, published in the International Journal of Epidemiology, calls for further research to better understand how different fatty acids affect long-term health.

Seed oils—such as sunflower, soybean and rapeseed—are high in polyunsaturated fats and have long been promoted as a ‘heart healthy’ alternative to saturated fats like butter and lard.

But Professor Holland warned that rising consumption of seed oils could be fuelling obesity, heart disease, type 2 diabetes and even autoimmune conditions.

Around 6.3 million people in the UK are thought to have raised cholesterol, which if left untreated can cause heart attacks and strokes, and seed oils may be contributing to this, Prof Holland suggested.  

It comes as alarming figures last year revealed that premature deaths from heart attacks and strokes had reached their highest level in more than a decade.

MailOnline has previously highlighted how the number of young people, under 40, in England being treated for heart attacks by the NHS is on the rise.

Cases of heart attacks, heart failure and strokes among the under-75s has tumbled since the 1960s.

This is believed to be due to plummeting smoking rates, advanced surgical techniques and breakthroughs such as stents and statins.

But now, rising obesity rates, and its catalogue of associated health problems such as high blood pressure and diabetes, are thought to be one of the major contributing factors.