If headlines on your Twitter feed are telling you to cook with lard instead of vegetable oil, please don’t listen. Here’s why.
The 2015 Dietary Guidelines Advisory Committee and the World Health Organization (WHO) recommend limiting saturated fat intake to less than 10 percent of total calories per day. In fact, the 2015 recommendation isn’t much different than the original Dietary Goals for the United States published in 1977. In other words, nutrition guidance encourages you to REPLACE foods that are high in saturated fats (like butter and lard) with foods that are high in unsaturated fats (like vegetable oils). This recommendation is backed by strong evidence from randomized-control trials (the scientific gold standard!) that show replacing saturated fatty acids with unsaturated fats, especially PUFAs, significantly reduces total and LDL blood cholesterol levels. That’s a good thing for reducing your risk of heart disease.
How do you take your nutritious fats to the next level? Enjoy both PUFA (polyunsaturated fatty acid) and MUFA (monounsaturated fatty acid).
PUFAs (i.e. omega-3 and omega-6 fatty acids) are found in fish such as salmon, or nuts and seeds such as walnuts (omega-3), and soy, corn and canola (omega-6). Both are needed and have broad positive health effects, such as improving heart health and cognitive function. MUFAs (i.e. omega-9 fatty acids), like those found in almonds, avocados, olive and canola oils, also improve heart health.
While all cooking oils contain saturated fat, canola oil has the least amount. It also has the most omega-3 fatty acids of the common cooking oils. Soybean oil also contains a significant amount of omega-3 fatty acids. Olive oil, on the other hand, is known for its high MUFA content. To get a healthful blend of PUFAs and MUFAs, mix up your vegetable oils, incorporate a variety of nuts into your diet, top dishes with avocados (or as a delicious snack on their own!), and try eating oily fish more often to improve the amount of omega –3 in the diet.
Dr. Julie Jones, Distinguished Scholar and Professor Emeritus on Foods and Nutrition at St. Catherine University, emphasizes that you can “absolutely” safely eat foods cooked in vegetable oils. The most important thing is not to overheat (cause them to smoke) or overuse fats and oils. Dr. Jones says:
“At home, when oil begins to smoke, smell bad or darken, THAT is when the risk of fat breaking down occurs. My recommendation is that if your fat or oil has turned dark or if it has an off odor, throw out that food for safety- it probably won’t taste good anyway! If you’re cooking fats or oils normally, you have nothing to worry about. Focus on getting healthful fats and a balanced, diverse diet.”
Dr. Henry Chin, independent expert in food chemistry and composition and food safety, agrees. He pointed out that the study uses worst-case assumptions to say that an example meal could contain acrolein at 430 ppm, which would exceed safe levels for aldehydes. But acrolein has a reported odor threshold of 1.8 ppm. Dr. Chin explained that “it is therefore extremely unlikely that any food containing this level of acrolein would be palatable.” By the time it reaches unsafe levels, it’s far past the point of burning that anyone would be eating it. Dr. Chin also emphasized that the standards for many cooking oils include a limit for the content of aldehydes.
Reported health effects related to vegetable oil consumption are not supported by the best available scientific evidence. In fact, the latest version of the WCRF-AICR Diet and Cancer Report does not report any link to the consumption of fried foods and cancer. Dr. Julie Jones confirms that dangerous compounds form only with fats and oils that have been heavily overcooked. Avoiding vegetable oils and switching to lard and butter will not magically improve your health. Enjoy and explore a variety of heart-healthy sources of fats to balance the health and flavor of your diet.
This blog includes contributions from Kris Sollid, RD, Liz Caselli-Mechael, and Tony Flood.