By Dr. Liat Engel
As we left off in our discussion from last month about good and bad fat – you are what you eat… what is the meaning behind this message? 20 years ago fat was considered the first thing to eliminate for better health or weight loss and would have been the last element in our diets considered as “medicine.” However, as the research and clinical outcomes have unfolded over the past two decades, we have actually discovered how vital the good fats are to the health of our brains, nerves, hormones, metabolism and so much more. Some of these health benefits were discussed in last month’s issue of our newsletter, but just in case you missed it here is a quick review:
Health Benefits – During infancy and childhood, fat is necessary for normal brain development. Cholesterol is the building block for hormone production. Throughout life, fat is essential to provide energy and support growth. In fact, fat is the most concentrated source of energy available to the body. Our hair, skin and nail health – nerve health – and of course cardiovascular health all rely heavily on good sources of healthy fats to function optimally. Now let’s see how this topic can be made of practical use in our kitchens. Understanding the importance of avoiding refined oils and saturated fatty acids is to maintain a healthy kitchen. And now we will discuss how to use unsaturated fatty acids in cooking and storage so that they remain safe and healthy for our bodies.
The first step here is a discussion regarding oxidation and antioxidants. Generally oxidation is the process where oxygen is released from a molecule and termed as a “free-radical” which is extremely harmful to our tissues and is known to be “carcinogenic,” meaning that they promote the development of cancer in our bodies. On the flip side, “anti-oxidants” are known as the champions in scavenging these oxidized free-radicals and thereby offer protective elements to our cells. When oxidation happens in fat it is called lipid-peroxidation and the free-radicals released are therefore termed as “lipid-peroxides.” The reason this is important in understanding the role of fat as medicine is because lipid molecules in fats are extremely sensitive to oxidation, and if improperly used during cooking they will release toxic levels of such lipid peroxides that are highly mutagenic in nature. Therefore it is essential that when considering which oil to consume, you must first factor in how you plan to use it in your cooking so as to avoid flooding your body with such harmful oxides.
High heat cooking, such as frying or grilling, rapidly oxidizes the antioxidant content of most oils and releases those harmful lipid peroxides. Frying quickly turns healthy oil into the toxic form of trans-fat. Grilling fish, chicken, beef or pork at high heat also oxidizes the lipids in the animal fat so it’s preferred to cook until medium rare and avoid reaching a point where the meat has reached the point of well-done or charred.
The preferred way to cook meat in high heat is in an enclosed environment where steam can be maintained and prevent oxidation of the fat. Generally, steaming or boiling food where water is an element in the cooking process is a healthier form of cooking. An example of this is when cooking eggs since scrambling the yolk releases all of the cholesterol into a high heat environment which exposes it to becoming oxidized. Therefore it is best to eat eggs that have been boiled or poached.
When it comes to baking, sautéing and stir-frying, the recommendation is to avoid using polyunsaturated fatty acids such as corn, soybean, safflower and sunflower oils for frying or high-temperature cooking (350-400°F) in order to minimize the formation of these potentially toxic lipid peroxides. The idea is to use the more heat and oxygen resistant monounsaturated oils because they are more stable against oxidation than polyunsaturated fatty acids. The recommended monounsaturated oils that can withstand high smoke points in cooking above 400°F in order of heat resistance are Avocado oil, Apricot oil, Rice Bran oil, Grape Seed oil, and Coconut oil. Although Olive oil is also monounsaturated, it’s considered to be a medium smoke point oil that should only be used to lightly sauté food over medium heat (140-180°F). In addition, the use of garlic and onions for frying will minimize free radical damage because of their sulfur content.
Ideally however, the best way to use oil in the diet for nutritional reasons is to take it raw/cold on top of foods during meals. Extra virgin olive oil is a great example of this. This oil is extremely fragile in heat because it has many delicate plant compounds and although poses to be safe for cooking at medium heat, it will however lose much of its nutritious and antioxidant value when heated at all. If ingested in its raw form it has been found to be protective to our heart and vascular systems due to its phenolic antioxidant content. This antioxidant in virgin olive oil helps to prevent cardiovascular disease because it specifically reduces atherosclerosis in our blood vessels. Consumption of a Mediterranean diet that includes fat intake as 30-40% of total energy is rich in olive oil and has been shown to improve blood sugar, reduce systolic blood pressure, lipid levels and reduce markers of inflammation. Extensive research has shown that in comparison to a traditional low-fat diet, these proportions can be considered a viable alternative for preventing and treating cardiovascular disease.