Heart Disease Risk Associated With Eating Fried Foods

The effects of frying

Foods coated in flour and fried are often high in calories. And, as the researchers point out, they taste good, which makes overeating a temptation.

Also, fried foods, particularly those from fast-food outlets, often contain trans fats. These raise levels of low-density lipoprotein, or “bad,” cholesterol and reduce levels of helpful high-density lipoprotein, or “good,” cholesterol.

In addition, the researchers point out, frying boosts the production of chemical byproducts, which can affect the body’s inflammatory response.

Scientists had already associated eating fried foods with developing obesity, type 2 diabetes, coronary artery disease, and hypertension.

However, investigations into the links between fried food and cardiovascular disease and mortality had not yielded consistent results, the authors of the present analysis observed.

As a result, they set out to provide definitive evidence that doctors could use when giving dietary advice.

Fried food intake and disease

The authors pooled the data from 17 studies, which included data from 562,445 participants and 36,727 major cardiovascular events, to assess the link with cardiovascular disease risk.

They also gathered data from six studies, involving 754,873 participants and 85,906 deaths, to look for associations between fried food and mortality.

The researchers found that, compared with respondents who ate the least amount of fried food, those who ate the most had a 28% increased risk of major cardiovascular events, a 22% increased risk of coronary heart disease, and a 37% increased risk of heart failure.

The meta-analysis also found that each additional 4-oz weekly serving of fried food increased the risk of heart failure by 12%, heart attacks and strokes by 3%, and heart disease by 2%.

The team identified no association between fried food and death from cardiovascular disease or any cause. However, this may reflect the inconsistency of previous findings and the limited amount of evidence. The authors believe that future researchers might find an association if they follow participants for longer periods.

Prof. Riyaz Patel, a professor of cardiology and consultant cardiologist at University College London, in the United Kingdom, who was not involved in the study, says the results fit with our current understanding of biology:

“We know that frying food can degrade its nutritional value, generate trans fats, which are known to be harmful, as well as increasing the calorie content of the food, all of which eventually lead to processes that can cause heart disease.”

More research needed

The researchers caution that several of the studies included in the analysis only examined the effects of one type of fried food, such as fried fish or potatoes, rather than looking at the participants’ total fried food intake. This may mean that the associations were underestimated.

Prof. Patel points out that the studies also relied on the memory of respondents, which may have resulted in under- or overestimating the amount of fried food consumed.

“Moreover, we also don’t eat foods in isolation, so it is hard to fully capture the complexity of what we eat and how, especially over many years,” he says.

“Importantly, other factors that go with eating fried food could also be contributing to risk, like a tendency to drink more sugary drinks, added salt use, eating other unhealthy foods, less exercise, smoking, and deprivation levels. Much of this data may not have been captured in prior studies so cannot be fully accounted for.”

The authors of the meta-analysis agree that identifying the exact relationships between fried food and the risk of cardiovascular disease, cardiovascular mortality, and all-cause mortality will require more research.