We have a love-hate relationship with oils: they make our food taste great, but with their high fat content, it is quite easy to pack on the pounds if we aren’t careful. Although there is lots of information on oils, a lot of it is quite confusing. This makes a simple task, like choosing a good cooking oil, seem quite challenging. Let’s dig in to find a good answer.
What can fat do for me?
Despite what we may think, fat is a vital nutrient we need in order to survive. We use fat to:
- Provide energy we need to live by aiding digestion
- Transport nutrients within the body
- Absorb vitamins (vitamins A, D, E and K need fat to be absorbed)
- Nourish the brain
- Produce hormones that allow the body to function optimally
All fats are not equal
Fats and oils are grouped based on their structure and how we use their energy. Saturated fats are able to stick together in neat little rows,1 which is why saturated fats are solid at room temperature. On the other hand, unsaturated fats have kinks (the technical term is double bonds) that make them bounce around. So, unsaturated fats form liquids at room temperature.1 This is an easy way to tell the difference between the two.
Both saturated and unsaturated fats occur naturally. Trans fats DO NOT. Trans fats are artificially made through “hydrogenation,” which makes unsaturated fats stable so they can last longer on grocery shelves.
Trans fats behave like saturated fats and are solid at room temperature. Unfortunately, trans fats are really bad for us because they are strongly linked to heart disease.2 Scientist have tried to decrease the damage by “partially hydrogenating” fats; a common ingredient in packaged foods and desserts. However, be aware- these partially hydrogenated oils still have trans fats.
Why does this matter?
Think about the fat living in your cells or moving through your bloodstream. Which would you rather have coursing through your arteries: liquid oil or lard? Our cell walls are made primarily of fat, which needs to be flexible to take up nutrients and get rid of waste. Solid fat is not flexible. Solid or inflammatory fat in our bloodstream can “clog” up our arteries, raising our risk for heart attacks and strokes. The only exception to this is cold pressed organic coconut oil, which is solid at room temperature.
Unsaturated fats can be monounsaturated or polyunsaturated fatty acids, MUFAs and PUFAs for short. MUFAs are found in animal and plant foods, while PUFAs are found mostly in plant based foods. Many MUFA oils are actually quite good for you. Studies link MUFAs to better heart health as it increases good cholesterol (HDL) and decreases the bad (LDL).3 So, it is important to choose oils with higher amounts of MUFAs.
PUFAs are essential fatty acids. This is because:
- Our bodies can’t make them and
- We need them to live.
The only way to get PUFAs is to eat them.
PUFAs are grouped based on the “omega” classification. The “omega” tells us where the “kink” is in the fat and determines its shape. Omega- 3s have a “kink” closer to the end of the fat while omega-6s have that kink earlier (and omega-9s, which are often MUFAs, have the kink even earlier).1 This makes a world of difference, as the location of this “kink” drastically changes how the fat affects our health!
Omega 3 Oils
You’ve probably heard of the many heart benefits of omega 3s. In fact, you or someone you know likely has taken fish oil capsules, which are packed with omega 3s. Omega 3s are anti-inflammatory, packed with antioxidants, and are heart healthy. But, did you know that there are 3 different types, and they are not all the same?
ALA (alpha-linolenic acid) is a type of omega 3 found in plant foods like seeds, grains, and vegetable oils. It is definitely not the best omega 3 out there. We can’t use ALA as it is. Instead, we have to convert it to one of the other omega 3s. What’s more, we are not good at this! We convert less than 15% of ALA4 to the healthier omega 3 fats.
Beware vegetable oil claiming high omega 3 levels- it is probably high in ALA only (for exceptions, see below). ALA does not improve heart health and it does not help us lose weight or improve signs of heart disease like cholesterol levels or blood pressure.5
The other two are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which are the good-for-you omega 3s. They are found in fatty fish like salmon and sardines4, and are in your fish oil supplements. These are the omega 3s that are tightly linked with good heart outcomes.6
Not only do EPA and DHA decrease heart disease, they improve eye and brain function and may help ward off Alzheimer’s disease. They are also anti-inflammatory and help to treat chronic inflammatory illnesses like rheumatoid arthritis. Needless to say, these claims should have you running to the grocery store to pick up these wonder foods.
And you have good reason to! We should eat at least 1 gram, and upwards of 3 grams, daily depending on baseline health.6 Unfortunately, most Americans get less than one- tenth of the recommended amounts!4 We all have some catching up to do!
Historically, vegetarians had drawn the short stick because we believed omega 3s were only in fish. But, there is now good news for vegetarians and vegans. Research shows that algae, not fish, is the original source of omega 3s. Fish eat the algae, which is how it gets into our fish oil supplements! Vegetarians (and meat-eaters) can go direct to the source to naturally get DHA.
Infant formulas and other foods are already supplemented with algae for these very benefits. Now, on the market are algae oil supplements, DHA enriched canola oil and even algal oil for cooking! However, be aware that some of these supplements may be genetically engineered with unclear consequences for consumers.
Omega 6 oils
Omega 6s are also essential fatty acids, so we must eat them. They are easily found in grains and vegetable oils, as well as chickens and eggs.
There is some controversy around omega 6 fats like linoleic acid (LA). The American Heart Association (AHA) recommends 5-10% of our food should come from omega 6s. However, while research suggest that these fats don’t help or hurt our hearts, others suggest they can be bad for us, especially at higher percentages.7
The reason for the negative press on omega 6s is because they increase inflammation. LA starts off a cascade in our body that primes us to be inflamed!7 This is why omega 6s are called “pro-inflammatory.” When you have the flu or a wound, inflammation is a great response. But, if you are inflamed for a long time, it can lead to a host of problems. This is why high amounts of omega 6s are linked to heart disease, cancer, and auto-immune diseases like rheumatoid arthritis.8
The Battles of the Omegas
As mentioned before, we need both types of PUFAs. The question is: how much of each? Nutritionists don’t have set guidelines, but we know that we eat far too many omega 6s compared to omega 3s. Generally, Americans eat anywhere from 15 to 20 times as many omega 6s as omega 3s!
For most of our history, humans ate the same amount of omega 3s as omega 6s. A drastic change happened because we stopped eating fish and started eating a lot of grains and cooking with vegetable oils. The problem when we eat too much omega 6s is that omega 6s and omega 3s go through the same steps in our bodies to produce their effects, whether this leads to inflammation or decreases it!
So, if we eat lots of omega 6s, our bodies runs out of the tools it needs to convert omega 3s into inflammation fighting machines.8 Studies confirm this; a high omega 6 and low omega 3 diet increases heart disease and death.
Anything else to know about oils?
Yes! Before you obsess over omegas, take a look at how your oil is made. “Refined” oils are made using high temperatures and toxic solvents. Trans fats are a byproduct of these high temperatures. Virgin oils, which are cold pressed or mechanically extracted, have less trans fats and more nutrients.9
Also important is that while many oils (and other processed foods) claim to be trans-fat free, the US allows foods to be labeled “trans-fat free” if there is less than half a gram of trans fats per serving.1 This means that if you eat enough of these oils, you will eat quite a lot of trans fat over time. As we know, this can dramatically increase our risk of heart disease and death.
Read your labels! If any of the ingredients are “partially hydrogenated,” expect that there are hidden trans fats.2 Always check to see if the label states how the oil is made. If it does not say “cold pressed” or “expeller pressed,” then it is probably refined and comes with added trans-fat.
Which Oils are Best for Cooking?
You should choose oils that have more MUFAs than PUFAs and a low ratio of omega 6s to omega 3s10 (you should strive for an equal amount of omega 6s and omega 3s). Another important concept is the smoke point, if you plan on sautéing or frying your food. The smoke point is the temperature at which the oil starts to burn and oxidize (or go rancid).
Refined oils have higher smoke points because they have already been exposed to high temperatures and are more stable but much less nutritious. On the other hand, “virgin” oils are less stable and are better used in low temperature cooking or cold (like a salad dressing).
Let’s take a look at specific oils:
This oil has a good amount of MUFAs at sixty percent with only twice as many omega 6s as omega 3s. It is also low in saturated fats. Be aware that canola oil is often refined, so look for “expeller pressed.” Canola oil is often genetically engineered and it is unknown how that will affect the nutrients (or us) in the long run. Always choose expeller-pressed canola oil, but remember that this will reduce the smoke point.
This is the go to nutritious oil and is part of the heart healthy Mediterranean diet. It is seventy percent MUFA! It contains only ten percent PUFA, which is mostly omega 6s, but since it is so little, it is likely ok. Remember if you get the virgin oil, the smoke point is only about 360 deg F which is medium heat.
This is a newer oil that is expeller pressed and comes from algae. It has a good ratio of MUFA to PUFAs and has a quite a high smoke point at 485 deg F. It has a very neutral flavor. A quick note, algal cooking oil does not have all of the benefits of algal oil supplements, as the DHA is removed from the cooking oil to achieve the excellent smoke point.11
Camellia (green tea) seed oil
Used for thousands of years in the East, camellia seed oil is more than sixty percent MUFA with low amounts of saturated fat. In addition, studies show it has good antioxidant properties.12 It has a high smoke point of 485 deg making it a great oil for cooking.
Enjoy cooking with healthy, good-for-you oils!
- Indiana University. The kinds of fats and why it matters to you. Retrieved at: http://www.indiana.edu/~oso/Fat/Definitions.html
- O’keefe S, Gaskins-Wright S, Wiley V, Chen I. Levels of trans geometrical isomers of essential fatty acids in some unhydrogenated US vegetable oils. J Food Lipids. 1994 Sep.
- Pérez-Jiménez F, López-Miranda J, Mata P.. Protective effect of dietary monounsaturated fat on arteriosclerosis: beyond cholesterol. Atherosclerosis. 2002 Aug;163(2):385-98.
- Kris-Etherton P, Harris W, Lawrence J. Fish consumption, fish oil, omega-3 fatty acids and cardiovascular disease. Circ. 2002 Nov; 106(21): 2747-2757.
- Wendland E, Farmer A, Glasziou P. Effect of alpha linolenic acid on cardiovascular risk markers: a systematic review. Heart. 2006 Feb;92(2):166-9.
- Breslow JL. n-3 fatty acids and cardiovascular disease. Am J Clin Nutr. 2006 Jun;83(6 Suppl):1477S-1482S.
- Jones P, Senanayake V, Pu S, et. al. DHA-enriched high-oleic acid canola oil improves lipid profile and lowers predicted cardiovascular disease risk in the canola oil multicenter randomized controlled trial. Am J Clin Nutr. 2014 Jul;100(1):88-97.
- Simopoulos AP. The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Exp Biol Med. 2008 Jun;233(6):674-88.
- Morrison M, Mudler P, Stavro P et al. Replacement of Dietary Saturated Fat by PUFA-Rich Pumpkin Seed Oil Attenuates Non-Alcoholic Fatty Liver Disease and Atherosclerosis Development, with Additional Health Effects of Virgin over Refined Oil. PLoS One. 2015; 10(9): e0139196.
- Grund M. What is the desirable ratio of saturated, polyunsaturated and monounsaturated fatty acids in the diet? Am J Clin Nutr. 1997 Oct;66(4 Suppl):988S-990S.
- Bernstein AM, Ding EL, Willett WC et al. A meta-analysis shows that docosahexaenoic acid from algal oil reduces serum triglycerides and increases HDL-cholesterol and LDL-cholesterol in persons without coronary heart disease. J Nutr. 2012 Jan;142(1):99-104.
- Wei CC, Yen PL, Chang ST et al. Antioxidative Activities of Both Oleic Acid and Camellia tenuifolia Seed Oil Are Regulated by the Transcription Factor DAF-16/FOXO in Caenorhabditis elegans. PLoS One. 2016 Jun 8;11(6):e0157195.
Goldberg RJ, Katz J.A meta-analysis of the analgesic effects of omega-3 polyunsaturated fatty acid supplementation for inflammatory joint pain. Pain. 2007 May;129(1-2):210-23. Epub 2007 Mar 1.
Mente A, de Koning L, Shannon H et. al. A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart Disease. Arch Intern Med. 2009 Apr;169(7):659-669.
Shinto L, Quinn J, Montine T et al. A randomized placebo-controlled pilot trial of omega-3 fatty acids and alpha lipoic acid in Alzheimer’s disease. J Alzheimers Dis. 2014;38(1):111-20.
Widmer R, Flammer A, Lerman LO2 et al. The Mediterranean diet, its components, and cardiovascular disease. Am J Med. 2015 Mar;128(3):229-38.
Simopoulos AP. The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Parmacother. 2002 Oct; 56(8): 365-79.
Russo G. Dietary n-6 and n-3 polyunsaturated fatty acids: from biochemistry to clinical implications in cardiovascular prevention. Biochem Pharmacol. 2009 Mar 15;77(6):937-46.