Dr. Magryta: The importance of fats
Fats are a macronutrient found in nature in animals and plants as the major storage form of energy. Fat provides many vital functions for humans including the provision of an energy source, organ insulation, cell membrane fluidity, and a storage site for toxins until the body has the ability to metabolize and clear them.
Fats are a very important part of the human diet and have been the subject of some vilification over the last 50 years because of questionable science quality that ushered in an era of low fat foods in order to protect against heart disease. This unfortunately produced a whole supply of sugar, salt and flour laden foods to replace the flavorful fats that disappeared from the market. The result of these changes to the American food supply has been associated with a worsening of obesity, diabetes and heart disease nationally.
Fat has become misunderstood by the general populace. In order to understand this we need to break fats down into a few types: 1) monounsaturated 2) polyunsaturated 3) saturated. Each type is important and they are each distinguished from the other by a slight change in chemical structure.
Monounsaturated fats are found in olives, avocados, sunflower seeds, nuts and canola oil. They are the least controversial and a significant part of the heart and pancreas healthy Mediterranean diet. The intake of olive oil in particular continues to be associated with better health outcomes especially for cardiovascular disease. (Estruch et. al. 2018)(Martinez-Galiano et. al. 2018)
Polyunsaturated fats are very important and broken up into two subgroups: omega 3 and omega 6. The omega 3 fat type is found predominantly in cold water oily fish like sardines, mackerel and salmon as well as flax seeds and walnuts. The omega 6 variety is found in vegetables and their oils. Examples are oils from corn, soy, nuts and seeds. The omega 3 variety contains the fatty acids DHA and EPA that are critical for immune and brain function.
The omega 6 variety is also necessary but has the effect on the body in a pro inflammatory way which is great if you are ill or have an injury. The real problem with the omega 6 fats is thought to be that we get too many of them and the end result appears to be increased inflammation from the processed American foods that are loaded with the omega 6 oils and excess sugars. This is hotly debated with research on both sides of the fence. (Akerele et. al. 2016)(Coletta et. al. 2010)(Greenberg et. al. 2008)(Haghiac et. al. 2015)(Innes et. al. 2018)(Koletzko et. al. 2007)(Mennitti et. al. 2015)(Zhang et. al. 2011)
The truth with polyunsaturated fats is likely at the balance point. We historically ate much less omega 6 fats and more omega 3 types and likely rarely in combination with refined carbohydrates. With the advent of processed vegetable oils and their addition to many foods, the ratio has swung toward the omega 6 side potentially creating a problem in certain individuals. (Blasbalg et. al. 2011) I think that rebalancing this ratio makes prudent sense.
Saturated fats are found in animal products like red meats, dairy and palm or coconut oils. They are currently the topic of much debate regarding their health and safety. One camp completely believes that they are unhealthy and promoting heart disease and other issues while another camp disagrees and believes that these fats are good and necessary in moderation. As with most things the answer is likely in the middle somewhere.
The general human health data noted that some reviews have come out showing that replacing saturated fat with omega-6 fats has a heart healthy effect. (Mozaffarian et. al. 2010) Others have shown no difference to mortality, heart disease and diabetes risk. (DeSouza et. al. 2015)
Regarding saturated fat, I believe that it comes down to volume. It is highly unlikely that animal fats are inherently bad for us. Looking at the Tsimane Indians and the Blue Zone populations, they did consume saturated fats but in very small volumes and that this dietary pattern seemed to be associated with the greatest longevity.
Dr. Chris Magryta is a physician at Salisbury Pediatric Associates. Contact him at email@example.com