You know what to eat to protect your heart, right? Lots of veggies and whole grains, and no fried food. Not according to the latest study in the British Medical Journal on tens of thousands of people in Spain. The study followed these folks over 12 years, and found that even those who consumed the most fried food had NO increased risk of heart disease or cardiovascular events ! Rick and I both wax incredulous in this week's podcast and YouTube. Let's look more closely at the study.
Researchers recruited almost 41,000 people from a multitude of areas within Spain, including both urban and rural settings, with an eye toward maximizing potential variability in diet. Subjects were 29 to 69 years of age at study entry. Data on food intake was obtained for each participant by a trained interviewer using a standardized questionnaire. Consumption of a number of foods and cooking methods, including frying, was collected. Data on frying methods as well as types of oil used was also gathered.
Data on physical activity, smoking, educational level, and the presence or absence of other conditions like high blood pressure or elevated cholesterol was obtained. The study followed subjects for a median of 11 years, during which time 606 coronary heart disease events and 1135 deaths from all causes occurred. Analysis revealed that when subjects were grouped into quartiles depending on the amount of fried food they consumed, it had no impact on the risk of heart disease. Also irrelevant was the type of oil used for cooking.
Now what's the caveat? Most of the people in this study used olive oil for frying, and the remainder used sunflower oil. We've seen from any number of studies that olive oil in particular appears to confer heart benefits when it is used for cooking. Moreover, using olive oil for frying in comparison to solid oils results in fewer trans fats, also implicated in heart disease, being generated. The authors also make the point that fried food consumption is not a proxy for fast food as it would be in the US or some other countries, as frying is common both in the home and when eating elsewhere. Since fast food restaurants often reuse cooking oils many times, and reusing oils results in more trans fat formation, this may explain a deleterious impact on heart health of fast food.
For now, Rick and I agree that this is really a paradigm shift for us, and maybe we're too set in our ways to start eating more fried foods. Clearly, the subject deserves further study as previous research has been largely observational, and this is the first large, prospective study to come across the transom. Other studies this week on PodMed include Avastin and breast cancer, again (!) in NEJM, and two studies from JAMA: PFCs and compromised immune response, and use of PPIs in kids with asthma. Until next week, y'all live well.