We often struggle to keep our fats straight (e.g., polyunsaturated fats / PUFAs vs. monounsaturated fats / MUFAs; EPA vs. DHA; omega-3s vs. omega-6) and remember which to embrace and which to avoid. Which oils should we cook with? Are all saturated fats bad? When we saw that some of our subscribers had similar questions, we decided to dive deeper and create a quick primer on the topic.
This is what we found.
A Review on Fatty Acids
Fats are one of the main types of macronutrients found in our food. Dietary fats are made of a glycerol molecule (purple) attached to three fatty acids (blue). When we speak about which fats are good for our health, we’re talking about fatty acids, which consist of a carboxyl chemical group attached to a carbon chain. The image below shows the basic structure of a fat:
Fats are classified in many ways, but most of the research we found examines dietary fats bysaturation. Accordingly, dietary fat comes in two chemical forms:
Saturated—no double bonds in the fatty chain, solid at room temperature, linked to increasing LDL cholesterol and risk of heart disease and stroke. Butter and coconut oil are saturated fats.
Unsaturated—has double bonds in the fatty chain, liquid at room temperature, linked tolower total cholesterol and increased HDL (good) cholesterol. Plant and seed oils are unsaturated fats.
**Note: Trans fats are a type of unsaturated fat that occurs naturally in some foods (e.g., cattle and sheep milks and meats), but is mostly associated with processed foods (e.g., cookies, baked goods, etc). These fats have a different configuration around the double-bond in their fatty chain which makes them rigid at room temperature and thus, they behave like saturated fats. Trans fats are detrimental to health and have been banned from use in the US by the FDA.
Source: van Ginneken, Vincent & Verheij, Elwin & Greef, Jan. (2019).
The category of unsaturated fats is further broken down into two sub-classifications, depending on the number of double-bonds present in their fatty chain:
Monounsaturated (MUFA)—have one double-bond in their fatty chain and are liquid at room temperature. Olive oil and canola oil are high in MUFAs.
Source:Jeremiah Farias Nutrition
Polyunsaturated (PUFA)—have more than one double-bond in their fatty chain and are liquid at room temperature. Includes omega-3 and omega-6 fats. Walnuts and fish oils are high in PUFAs.
Source:Jeremiah Farias Nutrition
For a deeper review of dietary fats and their chemical make-up, check out this video.
What The Research Says
Research on the chemical forms of fats has not always been linear. In the late 1940s scientists noticed acorrelation between fat intake and cholesterol levels, prompting what would become the “low-fat” diet craze that remained popular through the end of the century.
Not only was low-fat touted as good for preventing heart disease, it was also promoted as being good for weight loss. While neither of these claims is necessarily untrue, subsequent research on nutrient metabolism and hundreds of feeding studies have shown that all fat is not bad and thatany diet that reduces energy intake will result in weight loss.
Correlation with heart disease
As research has delved into the different forms of fat, we continue to see a correlation between fat consumption and heart disease. Trans fats have proved to be some of the most detrimental types of fats for our health.
According tothis study for every 2% of calories from trans fat consumed daily, the risk of heart disease rises by 23%. We’ve also learned over the last two decades thatanoverconsumption of saturated increases cholesterol levels and promotes plaque formation in the arteries.
The discovery of mono- and polyunsaturated fats and their roles in theMeditteranean dietadded an additional layer to the heart disease conversation; we know now that both of these types of fat are beneficial for heart health as well as weight control and even longevity.
A Key Nutrient
Aside from disease prevention, fats are a key nutrient in our diet and are used to build our cell membranes, promote healthy brain function and serve as precursors for hormones. Because of this, most people should aim to consume a diet that contains amix of saturated and unsaturated fats to support health.
Recommendations for daily fat consumption vary based on a variety of factors including age, gender, body size, activity levels, and health status.
A good rough estimate we found suggests consuming 20-35% of your daily calories from fat and keeping saturated fat to less than 10% of your daily intake.
Having said that, we each process lipids differently so the ideal amount of fat calories in our diet might be a very personal thing. The key is to establish a baseline, like the one suggested here, and then experiment by ratcheting up and down the amount of fat calories you consume while observing how your body reacts.
Is Omega-3 Health Protective?
When it comes to fat consumption, no dietary fat seems to get as much attention as omega-3s. As mentioned above,omega-3 fatty acids are a type of PUFA and are named for the location of their first double bond in the carbon chain.
Of all the types of omega-3 fats, theessential fatty acids (EFAs) are of particular concern when it comes to human health because they can only be obtained from diet. Human EFAs include:
- α-Linolenic acid (ALA) —used for energy and as an EPA and DHA precursor. Dietary sources include flax, walnuts, hemp, and soybean oils.
- Eicosapentaenoic acid (EPA) —used in the production of signaling molecules called eicosanoids that help reduce inflammation. Dietary sources include fatty fish (e.g., herring, salmon) and algae. Conversion of EPA from ALA is low so it must be supplemented.
- Docosahexaenoic acid (DHA) — important for integrity of skin and retinas, brain health, and has links to heart disease, cancer, and other chronic disease prevention. Dietary sources include fatty fish (e.g., herring, salmon) and algae. Like EPA, conversion of DHA from ALA is low and needs to be supplemented in the diet. Clickhere to learn more about this critical form of omega-3 in the FoundMyFitness podcast.
According to theNIH Office of Dietary Supplements, the majority of the scientific research that has been done on omega-3s focuses on EFAs. We lovedthis video by Rhonda Patrick hitting some of the main findings regarding the effect of EPA and DHA on inflammation. One of our key takeaways was that these two EFAs help to resolve the inflammatory immune response by serving as precursors for specialized pro-resolving mediators (SPM).
Without sufficient EPA and DHA, there can be delays in resolving inflammation which has implications forendothelial dysfunction(linked to heart disease, high blood pressure, and stroke) as well as thecytokine storm (linked to immune dysfunction and COVID-19 deaths).
Of the additional research that has been done, omega-3s have been linked to the prevention of cardiovascular disease, cancer, and dementia/Alzheimer’s disease. Here’s a quick summary of what we found reported in the literature:
Cardiovascular disease (CVD)
Some of the first clinical studies of omega-3s and CVD occurred in the late 1980s and found their roots in the hypothesis that omega-3 is cardioprotective (i.e., reduces the heart’s susceptibility to arrhythmias, lowers triglycerides, lowers blood pressure, decreases platelet aggregation).
Preliminary studies showed favorable effects of omega-3 on CVD and CVD risk factors, and most subsequent research confirms that omega-3 consumption is beneficial for heart health. Fish oil has been shown to lower triglycerides and reduce the risk of adverse cardiac events in people with low omega-3 intakes.
Cardioprotective effects of omega-3 supplementation appear stronger in people with a history of heart disease than in healthy adults. The FDA has yet to approve health claims that EPA and DHA specifically reduce the risk of heart disease and has restricted supplement companies from recommending intakes of these EFAs above 2g/d.
Clinical trials on omega-3s and cancer prevention rest on the hypothesis that because omega-3s have anti-inflammatory properties and have the potential to inhibit cell growth factors, they might be protective against cancer. The results of observational studies have been inconclusive and show differing effects based on cancer site, gender, and genetic risk.
There has been some evidence to suggest that higher intakes of omega-3 reduce the risk of breast and colorectal cancers, but a large clinical trial later concluded that omega-3 supplements did not reduce cancer risk overall, nor did it reduce the risk of breast, prostate, or colorectal cancers.
Dementia and AD
Some scientists hypothesize that omega-3s may protect cognitive function by helping to maintain brain function and cell-membrane integrity through DHA. While much research has been conducted, systematic reviews and meta-analysis of randomized clinical trials have not shown omega-3 supplementation to affect cognitive function in healthy older adults or in people with Alzheimer’s disease when compared to controls.
Claims that omega-3 can improve mild cognitive issues need to be corroborated by clinical trials before making any definitive confirmations about their efficacy. There is also some evidence that omega-3s, namely ALA, are neuroprotective and helppreserve grey matter and cognition as we age.
- Mixed omega-3 supplement reduced the risk of advanced age-related macular degeneration (AMD) in people with intermediate or advanced AMD
- Combination therapy of omega-3 plus pharmacotherapy may help reduce symptoms of rheumatoid arthritis
- One meta-analysis of 26 studies found a 17% lower risk of depression in participants with higher dietary fish intake
- Anew meta-analysis of 17 prospective cohort studies found that long chain omega-3s, except ALA,were associated with about a 15 to 18% lower risk of total mortality comparing the top to the bottom quintiles of aggregate data
The fact that the study of the benefits of omega-3s spans such a broad range of applications, together with the preponderance of positive (or neutral) results of many studies, particularly around heart health, makes us confident that omega-3 fatty acids offer some health benefit.
Omega-3 is also an important source of the essential fatty acids (EFAs) we need, so a diet that includes nuts, seeds, fatty fish, and/or a EPA/DHA supplement can work to benefit your life- and healthspan.
If you are looking for help with what to look for in an Omega-3 supplement,we spent 40 hour researching exactly that so you wouldn’t have to.
What’s the deal with omega-6?
Another form of omega fat that gets a considerable amount of attention and sparks quite a bit of debate about its role in health is omega-6. Like omega-3s, the omega-6 fatty acids are PUFAS.
Inside the omega-6 family, the only fat considered an EFA in humans is Linoleic Acid (LA). This fatty acid is used to produce arachidonic acid in the liver, which is important for fat metabolism as well as being a substrate for eicosanoid signaling molecules. Dietary sources of LA include plant and seed oils like soybean, corn, and canola oil.
Research on omega-6 has primarily focused on overconsumption in the western diet (through use of highly processed seed oils) and its effects on health. According to one article we read, “In 1909, we got about 2.7% of our calories from linoleic acid. By 1999,it was 7.2%.” The number is probably higher today.
The concern with this high level of LA consumption is understandable. High intakes of omega-6 have been shown toincrease the risk of high blood pressure in diabetics and can raise triglycerides in adults. Onereview even showed that an increase in omega-6 can lead to chronic diseases, like obesity.
The associations of omega-6 with negative health outcomes have some scientists and health gurus calling for a time-out on its consumption altogether. A quick search of the medical literature yields many articles suggesting that omega-6 increases inflammation in the body and should be eliminated from the diet all together. At first glance, this might seem like a good idea because the associations found in all the observational studies on omega-6 have been less than stellar, but association doesn’t mean causation.
With that in mind, removing all the omega-6 from your diet could be an over-correction. In fact, based on what we found, eliminating all sources of omega-6 from the diet also removes all sources of LA from the diet. Because LA is an omega-6 EFA, this is especially dangerous and likely to result inessential fatty acid deficiency, compromising cell membranes and other aspects of your health.
Additionally, as much as we can tell, reviews and meta-analyses that looked at aggregates of data from multiple studies on omega-6 (checkhere andhere for example) don’t show any association between omega-6 and increased levels of inflammation, particularly as it relates to LA. In fact, these studies (here andhere) suggest that LA has no effect on serum markers of inflammation at all.
The research on omega-6 is obviously muddled and requires additional studies and clinical trials to produce definitive conclusions. In the meantime, we’ve found that nutritionists appear to take a more balanced approach when it comes to omega-6 consumption and tend to focus on keeping a healthy ratio of omega-3 to omega-6 in the diet.
Current recommendations consider omega-6 intake of 5-10% of your daily calories as safe. As always, the best starting point is to have a balanced diet of whole foods while reducing intakes of processed foods as much as possible.
While broad guidelines are helpful, the reality is that we all process foods differently based on our genetics and metabolism. Some people thrive on high fat diets while others do better with lower fats and higher carbs. To learn more about your specific nutrient needs, a nutrigenomic test can give you the information you need to identify areas of deficiency or opportunities for optimization.
What About Cooking Oils?
When it comes to finding a cooking oil, the same rules apply as when you’re consuming whole foods. MUFAs and PUFAs are considered healthier alternatives to saturated fats, but a balance of dietary fats is likely to turn out the best results for your health.
To help you choose a cooking oil we found this classic Mark Sisson article:The Definitive Guide to Oils. It is interesting to know that all oils have a mix of PUFAs, MUFAs, SFAs, omega-3s and omega-6s.
The guideline is to optimize for lower PUFA / omega-6 proportions vs. MUFAs.
Thisarticle fromthe Cleveland Clinic also stood out to us because of its emphasis on knowing the smoke points of the oils you use. Using the right oil for the right cooking temperature will help you avoid toxic fumes and free radicals that are release when oil burns and could be potentially damaging to your cells.
High Smoke Point Oils
According to the article, oils with high smoke points are best for searing, browning and deep frying (not recommended for heart health).
Medium-High Smoke Point Oils
Oils with medium smoke points are good for baking and stir-frying.
Medium / Low Smoke Point Oils
Oils with low smoke points are best used for light sautéing, sauces and baking at low-temperatures.
There is a lot of information to process when it comes to dietary fats. The most important takeaway is that some fats are healthier than others, but a balance of fats in the diet is likely to result in better health for you in the long run.
Go Deeper:For a real master class on Omega-3s and the latest trends in research listen to this Peter Attiaepisode with Dr. William Harris, one of the leading researchers of the benefits of Omega-3s.
Share your experiences with dietary fats, omega-3, or omega-6 with us, or let us know anything we may have left out:firstname.lastname@example.org
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