Two decades after the fat-free craze of the 90s, we now seem to be in the “every-fat-is-good for you” craze where it is ok to add that tablespoon of balsamic vinaigrette on top of your carb-free salad. However, does the new research support the belief that high-fat foods are good for your overall health and fitness? While no food science researcher or dietitian supports eating deep-fried anything or drizzling a full cup of olive oil on top of your salad, eating the right fats in the right amounts can certainly benefit your health and maximize your fitness. In this article, we examine the research evidence and nutrition data on five oils that can optimize your biomarkers if you properly incorporate them into your diet and monitor your lipids using InsideTracker.
Sorting Out the Fats
Before we look at the oils themselves, we need to cut through some fat: what are cooking oils and which biomarkers do they affect? Edible cooking oils are fats derived from sources such as vegetables, seeds, and animal fats that can be safely used in food preparation. Because oils are fats, there has been a lot of research investigating the impact of their consumption on your body’s levels of lipids. Lipids, which are a functionally diverse group of molecules that repel water, are most commonly found in the bloodstream in one of two forms. The first is triglycerides, which is a fatty acid that stores energy for later use. These molecules can be broken down into the sugar glucose to create fuel for the body. If triglyceride levels increase above your optimal range, this can increase the risk of cardiovascular illnesses and other life-threatening diseases [1]. The other important class of lipids is cholesterol. These molecules have a variety of functions in your body such as maintaining cell membrane integrity and building hormones. They are most commonly transported by two classes of lipoproteins called high-density lipoprotein and low-density lipoprotein. It is important to emphasize that while they are often referred to as “HDL cholesterol” and “LDL cholesterol”, these molecules themselves are not cholesterol.
Clinicians agree that elevated levels of HDL and lower levels of LDL are good for your health [2]. However, recent research has called into question the fact that all LDL cholesterol is “bad” for you. As a lipoprotein, LDL can come in different forms- each with different effects on your health. A research study from 1988 showed that having elevated levels of small, dense LDL is three times more likely to lead to heart disease than normal LDL [3]. Additionally, more recent research shows that oxidation of LDL by substances called free radicals increases the risk of cardiovascular illness [4]. Thus, oxidized LDL is more harmful to you than standard LDL. While more research needs to be done to investigate this association between heart disease and different forms of LDL, measuring levels of all forms of LDL cholesterol is still a very useful indicator of cardiovascular fitness. Unfortunately, only a small percentage of InsideTracker users have an optimal level of LDL based on their specific internal biochemistry.
Below we look at research suggesting how eating five different types of oils- extra virgin olive, canola, macadamia nut, avocado, and walnut- might enhance your lipid profile along with some other key biomarkers. We also give some recipes you can use so you can reap their benefits. Remember, though- you won’t get healthier if you go beyond your daily recommended number of calories. Additionally, the only way to know whether regularly consuming these oils is beneficial for your internal biochemistry is to try them yourself and carefully monitor what effects they have on your lipid biomarkers and overall health using InsideTracker.
Olive Oil: Does “Extra Virgin” Make a Difference?
If there is any oil that gets press about its supposed health benefits from the media, it is the Mediterranean staple olive oil. Nutritionally, this makes sense- olive oil is high in heart-healthy polyunsaturated and monounsaturated fats and contains vitamins not found in other oils. And you may have heard that it comes in an extra heart-healthy form called extra virgin olive oil. But what does the literature say?
Indeed, some research suggests that extra virgin olive oil- which is packed with anti-aging compounds called “polyphenols”- might be particularly beneficial to your health. In a crossover, controlled trial, clinical scientists assigned 200 men with healthy cholesterol profiles to consume 25 mL/day of 3 olive oils with either low, medium or high phenol content for three weeks. The olive oil with the medium amount of phenols had similar content to “common” olive oil while the oil with high content had a similar amount of polyphenols as “extra virgin” olive oil. At the end of the trial, researchers uncovered a direct relationship between polyphenol consumption and reduction in oxidized-LDL- the form of LDL most strongly linked to cardiovascular illness [5]. They surmised these health benefits result from a compound called “oleocanthal.” These findings suggest that extra virgin olive oil might be extra special in preventing cardiovascular illness due to its high polyphenol content and favorable lipid composition.
A study from 2004 also lends support to the claim that extra virgin olive oil benefits your lipid profile. Researchers conducted a randomized control trial on 30 healthy volunteers and provided each of them with olive oil of varying amount of phenols ranging from 0 to 150 mg/Kg. Olive oils were administered over three periods of 3 weeks preceded by two-week “washout periods” where subjects consumed an olive-oil free diet. At the conclusion of the study, researchers noted that subjects that consumed extra virgin olive oil experienced the greatest protection from LDL oxidation and increase in HDL cholesterol [6]. More specifically, these subjects experienced decreases in oxidized LDL-c by 51.23% and increases in HDL-c by 5.1% while the others experienced no significant changes in their lipid profiles [6]. These findings suggest that substituting high phenol olive oil for other fats in one’s diet might optimize levels of cholesterol.
How to use it: You still can’t pile on cups of your favorite olive oil based dressing on top of your salad. However, feel free to swap out blue cheese or ranch dressing for a balsamic vinaigrette alternative- complete with a metabolism-boosting vinegar. Additionally, you can toss in a tablespoon of olive oil with a little bit of butter to stir-fry your favorite vegetables and proteins. Click here to discover more recipes from trusted brand California Olive Ranch and here to learn which Trader Joe’s olive oil brands you should buy.
Key Takeaways: Swapping out some soybean oil or butter for an equal amount of extra virgin olive can decrease your levels of oxidized LDL and triglycerides and increase levels of HDL. Thus, olive oil might help you optimize your lipid profile and maximize your health and fitness.
Canola Oil: Common and Controversial but Possibly Healthy
Canola oil is one of the commonly used oils in the US. While there is no “canola” plant, this Canadian oil is derived from a genetically modified version of the rapeseed plant. Because it is made from an unnatural source, some nutrition experts have vilified it as an unhealthy oil. Thus, it remains embroiled in controversy- but what does the research say?
Despite not being a natural food or sounding as sexy as extra virgin olive oil, canola oil certainly has some heart-healthy benefits at least in comparison to other vegetable oils and fat products high in saturated fats. In 2013, researchers conducted a meta-analysis of 31 high-quality research studies that compared using canola oil instead of saturated fatty acids. They found consistent evidence that replacing canola oil for fats rich in saturated fats can have heart-healthy benefits [7]. More specifically, the studies as a whole unveiled that using canola oil as an alternative can decrease total cholesterol, LDL, and maintain- but not lower- levels of triglycerides [7]. Because of these research findings, the FDA officially stated that "…replacing a similar amount of saturated fat in the diet without increasing calories" is a viable alternative [8]. And we agree- canola oil is a good substitute in your diet for unhealthier cooking fats such as lard and soybean oil if you aren’t increasing your overall calories.
How to use canola oil: This very affordable oil can be used to fry or bake pretty much anything. However, it can also be used to make dressings, dips, and other great liquid-based food. Click here to learn 826 different recipes for this oil that sometimes gets a bad rap.
Key Takeaways: Canola oil is a common, cheap, and versatile substitute for other oils high saturated fatty acids. Evidence supports that it can optimize your lipid profile by lowering total cholesterol while keeping HDL cholesterol levels healthy. However, unlike some of other oils we examine, it is not likely to reduce your levels of triglycerides.
Advocating for Avocado Oil
By virtue of its name, avocado oil is extracted from the key ingredient of guacamole: avocados. While there are no credible research studies assessing the health benefits of this oil, there are several examining the heart-optimizing impacts of avocadoes on your lipid biomarkers.
In a one-week long 1995 study, researchers recruited a total of 67 subjects - 30 adults with normal cholesterol and 37 with elevated cholesterol- and arranged them into two groups. The first group, which consisted of 15 adults with healthy levels of cholesterol and 30 with elevated levels, were provided with a 2000 calorie diet that included avocado. The second group, which consisted of 7 adults with elevated cholesterol and 15 with healthy levels of cholesterol, consumed a diet with the same number of calories but different kinds of fat calories. Before the study, researchers evaluated the baseline levels of these lipids.
After the intervention, there was a 16% decrease in total serum total cholesterol level after the avocado diet in healthy subjects. In contrast, total cholesterol increased in healthy subjects after the control diet. In the high cholesterol subjects that consumed the avocado-based diet, researchers noted an optimization of lipid profiles. Specifically, they experienced a decrease in serum total cholesterol (17%), LDL-cholesterol (22%) and triglycerides (22%), and increase of HDL-cholesterol (11%) levels. In contrast, researchers noted no significant changes in the control diet [9]. These findings suggest that avocados can quickly and significantly improve the entire lipid profile of individuals with BOTH clinically optimized, acceptable, AND elevated levels of certain lipids such as triglycerides and cholesterol. However, this benefit is more pronounced in those with elevated triglycerides and elevated cholesterol. While this research study was short in its duration, it suggests that avocados can quickly optimize your lipid profile- a benefit that may extend to its oil.
A more recent research study from 2014 suggests that avocados are particularly beneficial to optimizing your LDL cholesterol. In it scientists recruited 45 relatively healthy, overweight participants with LDL-c in the 25th to 90th percentiles. They provided each subject with one of the three diets of each equal calories for 5 weeks: a lower-fat diet (LF: 24% fat) and 2 moderate-fat diets (34% fat) providing similar foods and macronutrients. However, one of the moderate-fat diets included one fresh Hass avocado (136 g) per day the moderate-fat diet mainly used high oils rich in unsaturated fatty acids to match the fatty acid content of one avocado. Compared with baseline, the reduction in LDL-C and non-high-density lipoprotein (HDL) cholesterol on was greatest in the subjects who consumed avocado is part of their diet. Furthermore, only subjects that consumed the avocado diet significantly decreased LDL particle number, small dense LDL cholesterol- the kind that is particularly bad for your health- and the ratio of LDL/HDL (by 6.6%) from baseline [10]. These findings suggest that the heart benefits of avocados “extend beyond their heart-healthy fatty acid profile” and that perhaps avocado oil might have these benefits as well.
How to Use it: You can use avocado oil for dips, dressings, and cooking anything from vegetables to low-fat chicken at low heat. Click here to discover more recipes from Olivado Extra Virgin Avocado Oil- a brand we recommend due to its preservation of natural substances in avocados.
Key Takeaways: Avocados are a research-proven food that improves levels of TC, HDL, LDL (especially the bad kind!), and triglycerides. Thus, using avocado oil as a substitute in your diet for less healthy oils such as soybean oil might prove beneficial to your heart health.
Walnut Oil and Wellness
Along with avocados, walnuts are probably one of the best sources of heart-healthy fats for you. And there I plenty of research to back that up. In a 2009 study, researchers recruited 25 men with elevated level of cholesterol and triglycerides and provided them with three different but equal calorie diets for four weeks each. The first diet was a control diet and consisted of no walnut and fish. The second diet included 113g of salmon twice per week. The final diet included daily consumption of 42.5 g of walnuts per day. When researchers compared the lipid profiles of the subjects compared with their baseline values, they observed that the decrease in total cholesterol and LDL cholesterol was strongest in those that consumed walnuts [11]. In fact, they had experienced a reduction by 11% in LDL compared to their baseline values- much greater than the other two diets [11]. People who ate walnuts also experienced modest reduction in triglycerides, though not as strong as those who consumed the fish oil diet. Additionally, subjects who ate walnuts experienced the greatest optimization of ratios of total cholesterol:HDL cholesterol and LDL cholesterol:HDL cholesterol [11]. Overall, these findings suggests that walnut are particularly beneficial to your cardiovascular health and fitness.
The researchers of the study surmised that walnuts benefit human health through their high content of unsaturated fats called omega-3s and antioxidant nutrients. Walnut oil has a very similar fat, antioxidant, and micronutrients composition to walnuts. Perhaps using it can reap similar lipid-optimizing benefits as walnuts.
How to Use it: Walnut oil has a nutty flavor and is an ideal backbone for salad dressings as well as an add-on to spruce up steak and fish. Because it has a low smoke point and turns bitter when heated, it is best used uncooked.
Key Takeaways: Walnuts substantially lower LDL cholesterol and total cholesterol, and also decrease triglycerides and elevate HDL cholesterol. Walnut oil, which has very similar nutritional content to walnuts, might also benefit your cardiovascular system.
Macadamia Oil: Maximizing Metabolism
The Research: We know macadamias for their golden color and buttery taste. But recent research suggests that the oil extracted from them, which is one of the richest sources of omega-9 acids, might be particularly beneficial to your metabolism and well-being. In a 2013 study, researchers provided two cohorts with a total of 34 subjects with one of two 3-week long interventions. The first intervention consisted of a high palmitic acid diet with a dietary fat composition similar to an American diet. The second intervention consisted of a low-palmitic acid and high-oleic acid diet similar to the dietary fat composition of the Mediterranean diet. After each intervention, researchers monitored their physical activity, resting energy expenditure, and profile of mood states (POMS) to assess overall psychological well-being.
During the high oleic acid intervention, physical activity was higher in 15/17 members of cohort 1 and 12/12 members of cohort 2. The resting energy expenditure in the fed state was higher by 3.0% for Cohort 1 and 4.5% higher in the fasted state for Cohort 2 [12]. Additionally, the POMS test indicated a better mood in people who consumed the low-fat diet. These findings suggest that using oils high in omega-9 fatty acids, such as macadamia oil, can help boost your metabolism, physical activity, and optimize your mood in comparison to a conventional diet rich in saturated fats.
How to Use it: This shelf-stable nut oil has a higher smoke point than other healthy oils and be used to lightly saute carrots and broccoli or broil fish. Learn some recipes for this common Hawaiian staple here. (Note: It’s a tad bit more expensive than the other oils on our list!)
Key Takeaways: Because Macadamia oil is very rich in Omega-9 acids, swapping it in for an unhealthy fat such as corn oil may boost your metabolism and physical activity. However, more research needs to be done on omega-9 fatty acids and macadamia oil itself to evaluate its potential benefits.
Using Oils for Health
Oils come in many different forms- some of which are healthy and some of which are not. We cut through the fat and presented the research on which oils can optimize your lipid profile- along with some tips on how to seamlessly add them into your diet. Remember, though: you won’t see these benefits if you exceed your daily recommended allowance of calories or don’t get your carbs and protein! Now it is up to you to you to make the change. Click below to learn where your baseline lipids stand today and which oils are best for you based on YOUR personalized health and individual biochemistry.
List of References
[1] Miller, Michael, et al. "Triglycerides and cardiovascular disease a scientific statement from the American Heart Association." Circulation 123.20 (2011): 2292-2333.
[2] Manninen, Vesa, et al. "Joint effects of serum triglyceride and LDL cholesterol and HDL cholesterol concentrations on coronary heart disease risk in the Helsinki Heart Study. Implications for treatment." Circulation 85.1 (1992): 37-45.
[3] Meisinger, Christa, et al. "Plasma oxidized low-density lipoprotein, a strong predictor for acute coronary heart disease events in apparently healthy, middle-aged men from the general population." Circulation 112.5 (2005): 651-657.
[4] Parthasarathy, Sampath, et al. "Oxidized low-density lipoprotein." Free Radicals and Antioxidant Protocols. Humana Press, 2010. 403-417.
[5] Castañer, Olga, et al. "The effect of olive oil polyphenols on antibodies against oxidized LDL. A randomized clinical trial." Clinical Nutrition 30.4 (2011): 490-493.
[6] Marrugat, Jaume, et al. "Effects of differing phenolic content in dietary olive oils on lipids and LDL oxidation." European journal of nutrition 43.3 (2004): 140-147.
[7] Lin, Lin, et al. "Evidence of health benefits of canola oil." Nutrition reviews 71.6 (2013): 370-385.
[8] Gillingham, Leah G., Sydney Harris-Janz, and Peter JH Jones. "Dietary monounsaturated fatty acids are protective against metabolic syndrome and cardiovascular disease risk factors." Lipids 46.3 (2011): 209-228.
[9] López, Ledesma R., et al. "Monounsaturated fatty acid (avocado) rich diet for mild hypercholesterolemia." Archives of medical research 27.4 (1995): 519-523.
[10] Wang, Li, et al. "Effect of a Moderate Fat Diet with and Without Avocados on Lipoprotein Particle Number, Size and Subclasses in Overweight and Obese Adults: A Randomized, Controlled Trial." Journal of the American Heart Association 4.1 (2015): e001355.
[11] Rajaram, Sujatha, et al. "Walnuts and fatty fish influence different serum lipid fractions in normal to mildly hyperlipidemic individuals: a randomized controlled study." The American journal of clinical nutrition 89.5 (2009): 1657S-1663S.
[12] Kien, C. Lawrence, et al. "Substituting dietary monounsaturated fat for saturated fat is associated with increased daily physical activity and resting energy expenditure and with changes in mood." The American journal of clinical nutrition 97.4 (2013): 689-697.
