Fried food DOES increase your risk of coronary artery disease: Scientists discover fries block the blood vessels that supply the heart after years of ‘conflicting’ results

  • Past studies have been mixed on how fried food affects our blood vessels
  • Latest research shows eating deep-fried ‘treats’ once a week raises the risk
  • Heating oils causes blood pressure to rise and ‘good’ cholesterol to fall

Fried food really does increase your risk of getting coronary artery disease (CAD), research suggests. 

Studies have thrown up ‘conflicting’ results as to whether deep-fried treats block blood vessels. 

But a study of more than 150,000 volunteers has now proven eating fries, doughnuts or onion rings just once a week raises our risk of CAD. 

And the risk of developing the condition gets higher the more deep-fried foods you eat, scientists discovered.

Heating oils is thought to release aldehydes, chemicals which could raise blood pressure to rise and slash ‘good’ cholesterol. 

Fried foods also tend to be very high in calories and fat. Over time, this can cause arteries to become blocked, which raises the risk of a heart attack. 

Fried food, like chips, really does increase our risk of coronary artery disease (stock)

CAD – the most common form of heart disease – occurs when major blood vessels leading to the heart become damaged.  

The research was carried out by the VA Boston Healthcare System hospital, which is run by the United States Department of Veterans Affairs.  

Frying is a ‘common method of food preparation in the US’, the researchers wrote in the journal Clinical Nutrition.

More than a quarter of Americans are ‘patrons of fast-food chains where calorie-dense fast food is available’, they add. 

Deep-fried food, such as chicken tenders, has been linked to an increased risk of obesity, type 2 diabetes, heart failure and high blood pressure.

However, its affect on CAD – which affects 2.6million people in the UK and a total of 15million in the US. has been less clear.  

The researchers wrote: ‘The literature has been mixed regarding the association between fried food intake and CAD.’ 

The researchers therefore looked into how fried food impacts the health of veterans, who are ‘immensely burdened by CAD’.   

The diets of 154,663 members of the military were assessed via the Million Veteran Program (MVP), which collects data of service men and women.

The volunteers, who were made up of 90 per cent men, were asked questions like, ‘how often do you eat fried food away from home (e.g., French fries, fried chicken, fried fish)?’.

Answers ranged from less than once a week to every day, according to the results of the study led by Jacqueline Honerlaw. 

Electronic health records were then analysed to determine if the veterans, who had an average age of 64, went on to develop CAD. 

Over a follow-up period of around three years, 6,953 CAD-related deaths occurred, as well as 6,725 CAD ‘events’. 

Results revealed CAD was significantly more likely to develop if the veterans ate fried food, even if it was just once a week.

The risk increased the more frequently it was consumed. For every 1,000 veterans who ate fried food less than once a week, 14.61 developed CAD.

This increased to 16.57 among those who consumed the ‘treats’ one-to-three times a week. And it rose again to 18.28 for the participants who ate it every day. 

The veterans who were overweight or obese at the start of the study were more at risk than their healthy counterparts, the study found. 

Fried food tends to be substantially higher in fat. Many of these fats are trans, which are formed when they undergo a process called hydrogenation.

Hydrogenation can occur when oils are heated to very high temperatures, or if food manufacturers add hydrogen to their products to extend their shelf life.

This process changes the chemical structure of the fats, which makes them harder for the body to break down. 

Scientific studies have linked this process to many diseases, including type 2 diabetes and obesity.

The researchers stress the volunteers self-reported their eating habits, which could have skewed the accuracy of the results.

And the type of oil used, and duration of cooking, was not taken into account. For example, frying in olive oil for just a few minutes may cause less heart harm. 


Coronary artery disease occurs when the major blood vessels that supply the heart with oxygen and nutrients become damaged.

CAD affects more than 1.6million men and one million women in the UK, and a total of 15million adults in the US. 

It is usually due to plaque and inflammation.

When plaque builds up, it narrows the arteries, which decreases blood flow to the heart.

Over time this can cause angina, while a complete blockage can result in a heart attack.

Many people have no symptoms at first but as the plaque builds up they may notice chest pains or shortness of breath when exercising or stressed. 

Other causes of CAD include smoking, diabetes and an inactive lifestyle. 

It can be prevented by quitting smoking, controlling conditions like diabetes or high blood pressure, staying active, eating well and managing stress. 

Drugs can help to lower cholesterol, while aspirin thins the blood to reduce the risk of clots.

In severe cases, stents can be put into the arteries to open them, while coronary bypass surgery creates a graft to bypass the blocked arteries using a vessel from another part of the body.

Source: Mayo Clinic 


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