Healthy fats are an essential part of a nutritious diet, but there is a lot of debate on what is considered “healthy”, especially when it comes to plant-based oils. Seed oils, in particular, have been in the hot seat. Here’s what the science tells us:

Seed Oils

Seed oils are widely used by the food industry for their cost-effectiveness. These include rapeseed (canola) oil, soybean oil, corn oil, peanut oil, sunflower oil, and safflower oil. They’re typically produced via extraction using chemical solvents or in mechanical oil mills. Similar processes are used in non-seed oils like olive oil, and they are often then refined to remove impurities.

Fear v. Fact

Many wellness influencers recommend avoiding seed oils like the plague, claiming they are pro-inflammatory due to their high concentration of omega-6 polyunsaturated fatty acids. But are omega-6 fatty acids pro-inflammatory?

What We Know Now

• Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs) play essential roles in heart health, cognition, immune health, and endocrine health.
• Claims from the wellness community argue that commercially produced omega-6 PUFAs are more susceptible to oxidation compared to whole foods containing omega-6 PUFAs.
• Seed oil critics also claim that linoleic acid (one of the major omega-6 PUFAS) is typically converted to arachidonic acid in the body–a fatty acid associated with inflammation.
• While there is limited research on omega-6 FAs and general inflammation at this time, a 2022 meta-analysis of randomized controlled trials exploring the relationship between omega-6 fatty acid intake and cardiovascular health showed that Omega-6 PUFA supplementation was not associated with an increased risk of CVD morbidity and mortality. The American Heart Association presented similar findings in a 2019 Individual-Level Pooled Analysis of 30 Cohort Studies.

Do Ratios Matter?

Historically, it was thought that an ideal n-6:n-3 ratio is 4:1, meaning 1 gram of omega-3 for every 4 grams of omega-6. The Western Diet reflects an average ratio of 20:1, clearly showing a much higher intake of omega-6 partly due to the increased use of commercially used seed oils and high consumption of foods eaten away from home that are typically made with these seed oils. However, it seems that the negative impacts of this high ratio aren’t from the omega-6 fatty acids; instead, these are driven by other elements of highly processed foods, in which omega-6 fatty acids are often used.

Put it into Practice

1. Educate your patients about the health benefits of both Omega-3 and 6 fatty acids to reduce unnecessary food anxiety.
2. Explain there is not strong evidence at this time to support limiting intake of foods rich in omega-6 fats to reduce inflammation, and that they don’t need to avoid seed oils if they see them on the Nutrition Facts Label.
3. Encourage your patients to consume a balanced eating pattern that emphasizes whole food sources of Omega-3 and Omega-6 fatty acids. Explain that balance can also mean enjoying dining out or grabbing a packaged food item at the supermarket. Consider sharing our Anti-inflammatory Eating Pattern handout or our Lowering Your Blood Pressure handout.
4. If your patient is heavily reliant on highly processed foods, strategize with them to discover ways to increase their consumption of whole foods.