A recent meta-analysis revealed that the consumption of fried foods is linked to an increased risk of major cardiovascular events. Including heart attacks and strokes.
The analysis looked at the results of 19 studies. Of which 17 concerned major cardiovascular events. 6 covered all forms of mortality. The authors found that the risk increases with each additional weekly serving of 114 grams. The results of the analysis are published in the journal Heart.
In general, the Western diet is high in processed meats, saturated fats, refined sugars and carbohydrates. In addition, it is low in fruits, vegetables, whole grains and seafood. This type of diet is considered a risk factor for obesity and type 2 diabetes. In their meta-analysis, the researchers looked especially on fried foods. Indeed, they are very common in the Western diet. And their impact is strong on cardiovascular health.
The effects of frying
Flour-coated and fried foods are often high in calories. And, as the researchers point out, they taste great. This increases the temptation to overeat. Additionally, fried foods, especially those from fast food joints, often contain trans fats. These increase levels of low-density lipoprotein, or “bad” cholesterol. Conversely, it reduces levels of high-density lipoprotein, or “good” cholesterol.
Additionally, the researchers point out that frying stimulates the production of chemical by-products. Those that can affect the body’s inflammatory response. Scientists had previously associated the consumption of fried foods with the development of obesity, type 2 diabetes, coronary heart disease and hypertension. However, research on links between fried foods and cardiovascular disease and mortality had not yielded consistent results. As a result, researchers set out to provide definitive evidence. This is so that doctors can give better dietary advice.
Consumption of fried foods and heart disease
The authors pooled data from 17 studies. They included data from 562,445 participants and 36,727 major cardiovascular events, to assess the link with cardiovascular disease risk. They also collated data from six studies, involving 754,873 participants and 85,906 deaths. This time to search for associations between fried foods and mortality. The researchers found that, compared with respondents who ate the least fried foods, those who ate the most had a 28% increased risk of major cardiovascular events, 22% of coronary heart disease and 37 % heart failure.
The meta-analysis also found that each additional weekly serving of 114 grams of fried food increased the risk of heart failure by 12%. Heart attacks and strokes by 3% and heart disease by 2%.
The team did not identify any association between fried foods and death from cardiovascular disease or any other cause. However, this may reflect the inconsistency of previous results and the limited evidence available. The authors believe that future researchers might find an association if they follow the participants for longer periods of time.
According to Professor Riyaz Patel, Professor of Cardiology and Consultant Cardiologist at University College London, UK, when asked about the study: “The results match our current understanding of biology. We know that frying food can degrade their nutritional value, generate trans fats, which are known to be harmful, as well as increase the calorie content of foods, all of which ultimately lead to processes that can cause heart disease”.
More research needed
The researchers caution that several of the studies included in the review only looked at the effects of one type of fried food, such as fried fish or fried potatoes. But not the effects of all participants’ total fried food consumption. This may mean that the associations have been underestimated.
Professor Patel points out that the studies also relied on respondents’ memories. This may have led to an underestimation or overestimation of the amount of fried food consumed. “Plus, we also don’t eat foods in isolation, so it’s hard to fully grasp the complexity of what and how we eat, especially over many years,” he says.
“It is important to note that other factors that accompany the consumption of fried foods could also contribute to the risk. Like the tendency to drink more sugary drinks, the use of added salt, the consumption of other unhealthy foods, lack of exercise and smoking. Much of this data may not have been captured in previous studies and therefore cannot be fully considered.”
The authors of the meta-analysis agree that identifying the exact relationships between fried foods and cardiovascular disease risk, cardiovascular mortality, and all-cause mortality will require more research.
Sources
https://heart.bmj.com/content/early/2021/01/07/heartjnl-2020-317883#DC1
https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/trans-fat
