Plenty of confusion surrounds dietary fats and their role in a healthful diet. This is not surprising considering all the conflicting information. In the early 80s there was a shift in the American diet to decrease fat intake and rely more on carbohydrates as the basis of our diet. This trend resulted, in part, from studies that purportedly linked fat intake, particularly saturated fat intake, to cardiovascular disease risk. Interestingly however, as fat intake decreased, rates of obesity and chronic diseases started to rise. Obesity rates in the US had been relatively consistent until 1980, around 12-14%. The 1980's saw a drastic increase to 22-25%, and now adult obesity rates exceed 35% of the population in five states, 30% in 25 states, and 25% in 46 states. (1) Along with obesity, chronic disease rates have increased exponentially. Diabetes rates have doubled in the last 20 years and more than 29 million American have diabetes and 86 million have prediabetes. (1) So why are we seeing an increase in obesity and chronic disease even on low fat diets?
In truth, fats are an essential and healthful part of our diet. The incidence of obesity and chronic diseases is not due to our fat intake, but to consuming calories from the wrong sources, nutrient imbalances, and INFLAMMATION. Choosing the right fat depends on its application. If you are looking for a fat to cook with you would choose one with a high smoke points to decrease the number of carcinogenic agents produced, but if you are making a salad dressing, you could use an oil with a lower smoke point and optimal ratio of fatty acids.. Always keep in mind you need an optimal ration of various fatty acids such as omega 3 and 6 (discussed in more detail here), and the manner in which a fat is processed and stored is also very important.
As with most things, moderation and variety are key. Make sure to check out our resource page for recommendations on books and other great resources to strengthen your knowledge about fats and how important they are to health and wellness.
(1) Trust for America's Health and the Robert Wood Johnson Foundation (2018, April 26) The State of Obesity Retrieved from https://www.stateofobesity.org
We have all heard about omega 3 fatty acids and their health benefits, but not everyone understands what an omega 3 fatty acid is and why they are important for our health. I have found that understanding the rational behind a recommendation often improves compliance, so here is a brief explanation of common fatty acids, and why consuming a variety is so important.
Omega 3 fatty acids are required for normal metabolism and are an essential fatty acid, meaning we can not produce them on our own. The three main types of omega 3 fatty acids are ALA, EPA, and DHA. ALA is found in plant sources such as flax seeds and EPA and DHA are found largely in marine sources and pasture raised animals. Our bodies are capable of producing the longer chain omega 3 fatty acids (EPA and DHA) from ALA but the process is not very efficient (only about a 15% conversion rate), so a diet high in foods containing all three omega 3s (ALA, EPA, and DHA) are encouraged.
Omega 6 fatty acids, also called “n-6”, are polyunsaturated fatty acids with a double bond at the sixth carbon atom. They are essential for human health, but as with omega-3s, our bodies are unable to produce them. Due to the high consumption of vegetable oils, the typical American gets more than enough omega 6s. And it is this high intake of omega 6 and low intake of omega 3 that is a major contributing factor in the spread of inflammation and chronic disease.
Omega 9 fatty acids (oleic acid) are polyunsaturated fatty acids with a double bond at the ninth carbon. Unlike omega 3 and omega 6, our bodies produce omega 9 fatty acids, so we do not have to be as diligent about including them in our diets. As you can see in the chart provided, omega 9 fatty acids are quite common and are particularly high in olive oil.
While I state that there is no bad fat with the exception of trans fats, it is also important to note that ratio of different fats is very important to optimal health. A great deal of research has looked at the importance of our ratio of omega-3 to omega-6 fatty acids. It is thought that our ancestor’s dietary ratio of omega 6 to 3 was approximately 1/1. Current estimations are that a typical western diet has an omega 6 to 3 ratio closer to 15/1 or higher. Why such a change? If you look at the diagram below you will see commonly used fats in a typical western diet. As you can see, two major contributors to our calories are also very high in omega 6 fatty acids…CORN and SOY. Next time you stroll through the isles at the grocery store, randomly pick up a few products and read the ingredient list. Chance are you will find either corn or soy,or a product produced from them, listed. I am not saying that corn and soy can not be part of a healthful diet, but again, we go back to balance. Also, you must take into account that the majority of corn and soy produced in the United States is genetically modified.
You may all be asking…why does it matter...how does this impact my health? An optimal ratio of omega 6 to 3 fatty acids (around to 2:1) is believed to reduce inflammation, and inflammation is the driving force of chronic diseases. The research is plentiful, and shows a positive effect of an improved ratio on conditions such as asthma, arthritis, cancer and heart disease, just to name a few. A recent study published in the Journal of Experimental and Therapeutic Medicine did a meta-analysis (review of available research on a particular topic) and found that the majority of studies concluded a diet rich in omega 3s, and limited omega 6s, had a positive outcome on the reduction of risk of breast cancer (1). The optimal ratio varies with different chronic diseases, but the consistent finding is the closer the ratio is to 1:1 the more positive the outcome for chronic disease.
Looking at the chart provided above, if you compare canola oil to corn oil you can see that canola oil has an omega 6 to 3 ratio of 21/11 (approximately 2/1) and corn oil has a ratio of 57/1, and HUGE difference!! One thing to be aware of, is that a large majority of canola is genetically modified, so try to select a GMO free or organic option and choose cold processed, expeller pressed canola oil.
As mentioned before, fats found in whole foods are your best options, such as nuts, avocados, pastured meats, eggs, olives, etc. When you consume fats in their whole food forms, you increase the nutrient density of your diet and the fats are more stable and less likely to become oxidized. When you are using oils, select organic or non-gmo options and expeller pressed. Fats are an essential part of a healthy diet so make sure to consume a variety of healthy fats daily!
Trans fats have received a great deal of attention the last decade when the scientific community began observing alarming parallels in trans-fat consumption and the risk of chronic diseases, such as heart disease and diabetes. This purportedly healthful alternative to saturated fat turned out to be a wolf in sheep’s clothing. In 2015 the FDA banned trans fats from the food supply, however this ban was not to go into effect until June 2018. Well, the date came and went, and the ban was not implemented. There is now a proposed rule to extend the compliance dates for manufacturers with $10 million or more in annual food sales to Jan. 1, 2020. Companies with less than 10 million dollars in sales would have until 2021. It is important to realize there are currently trans fats on our supermarket shelves and may be for the foreseeable future, despite the FDA's claim to ban them. Also, even a product claiming 0 grams of trans fats can still have small amounts (less than 0.5g of trans fats per serving).
If you really want to make sure your diet is free of these pesky miscreants, you have to be proactive. Read the nutrient label. Trans fats are not as easy to spot as one might think. A quick scan of the ingredient label on most processed foods reveals trans fats lurking under the name hydrogenated oils. Synthetic trans fats are produced from the hydrogenation of unsaturated fats like vegetable oil. The addition of hydrogen causes the common cis configuration to change to a trans configuration, thus the name trans fats. It is important to note, that there are two types of trans fats. One that is unsaturated and occurs naturally in our foods in small amounts and the other that is synthetically produced and has garnered negative attention. The naturally occurring trans fats seem to be benign in small amounts (which is how they occur in nature). Another reminder that nature and not food laboratories do a better job of producing healthful foods with just the right proportion of nutrients.
To keep track of the FDA's ruling on trans fats use the link below. Make sure to read all sections!
FDA, (2018, February 27) Final Determination Regarding Partially Hydrogenated Oils (Removing Trans Fats) Retrieved from https://www.fda.gov/Food/IngredientsPackagingLabeling/FoodAdditivesIngredients/ucm449162.htm
Sarah Burnett, MS, RDN, LD