Seed Oils and Inflammation

Question:

Dr. Meletis, we have been hearing more and more that seed oils fuel inflammation. Can you explain why this is true?

Answer:

This is an excellent question. Indeed, the scientific literature points to the role of inflammation as a contributor to countless disease processes, and even premature aging, called inflammaging that is deleterious to the 37 trillions cells that make up our bodies. [i]

It is well known that seed oils contain high levels of omega-6 fatty acids, which many studies suggest may contribute to inflammation in the body. The medical literature reports:

"In general, eicosanoids derived from n-6 PUFA are pro-inflammatory while eicosanoids derived from n-3 PUFA are anti-inflammatory." [ii]

In theory and practice, if an individual consumes sufficient levels of omega-3 fatty acids, this could help offset the intake of dietary omega-6. Ultimately, it is all about a dietary balance of omega-3 and omega-6 intake.

The medical literature[iii] reports that our ancient human ancestors likely consumed an omega-6/omega-3 ratio of approximately 1:1, whereas the typical Western diet is 20:1 or even higher. The biggest problem related to omega-6 consumption is that most of us consume too much relative to our omega-3 fatty acids.

But Wait, there is More:

While seeds themselves can be considered healthy in moderation, as they are rich in phytonutrients, vitamins, and minerals, they are also rich in poly-unsaturated fatty acids (PUFA); this is why when exposed to air or heat, they can start smelling rancid, in part because they are prone to oxidation. Sadly, in processing these oils, things get worse more often than not, as these oils go through heavy refining (bleaching, heating, chemical processing), which strips away nutrients.

Common Seed Oils Include:

• Canola

• Corn

• Soybean

• Sunflower

• Safflower

• Grapeseed

• Cottonseed

• Rice bran

• Peanut oil (actually a legume)

Experts Disagree on Omega-6's Impact on Health:

Here are some studies for you to ponder. My clinical opinion is to focus on omega-3 fatty acids and lessen omega-6 fatty acids intake as they are found and hidden in far too many processed foods, such as fast food (often canola), which carries other health concerns. 

-Higher dietary intake of omega-6 contributes to inflammation and tissue damage.[iv]

-Higher omega-6 fatty acids may contribute to obesity. [v]

-Higher omega-6 fatty acids may trigger the production of pro-inflammatory substances, such as cytokines, that can worsen arthritic symptoms. [vi] 

-2015 review of the scientific literature reports that there is insufficient evidence to conclude the best ratio of omega-6/omega-3 and its impact on health. [vii]

-2017 review article states: "Regarding omega-6 PUFA, there is controversy whether their effects are pro- or anti-inflammatory." [viii]

-Believe it or not, this 2019 review study published in the journal, Circulation reported: "In pooled global analyses, higher in vivo circulating and tissue levels of LA and possibly AA were associated with lower risk of major cardiovascular events. These results support a favorable role for LA in CVD prevention." [ix]   Note: Linoleic acid (LA) refers above to omega-6.  

Examples of Sources of Omega-3 Fatty Acids:

• Ground Flaxseed (ideally organic)
• Soybeans (ideally non-GMO and organic)
• Chia Seeds (ideally organic)
• Walnuts
• Cod Liver Oil
• Herring
• Mackeral Salmon (ideally non-farmed)
• Sardines

Bottom Line:

You don't need to cut them out completely, but limiting seed oils — especially from processed foods — is a good idea. I believe in focusing less on demonizing seed oils and more on reducing processed food overall. A balanced, mostly whole-food diet is what matters. I guide my patients to ensure their omega-3 fatty acid intake far outweighs your omega-6 fatty acids. And since both are prone to oxidative damage, make sure you are consuming sufficient antioxidants and keep seed oils and all oils in a cool dark place and container, and avoid heating seed oils. Regarding plant oils, olive oil is used for low-heat cooking, and avocado oil is used for higher-heat cooking. Also, remember to check out the Environmental Working Group, a non-profit organization, www.EWG.org, to help guide your shopping to avoid pesticides, herbicides, and harmful chemical exposure. They also source the dirty dozen foods and clean 15 foods that they test annually. 

Peace and Abundant Blessings,
Dr. Chris Meletis, N.D.

About Dr. Meletis, N.D.

Chris Meletis, N.D., has more than 25 years of experience practicing natural medicine. Based in Portland, Oregon, he shares his vast knowledge with fellow healthcare providers and his patients, and generously give to those in need. A lecturer and author, Dr. Meletis as written over a dozen books and hundreds of national articles. He was named Naturopathic Physician of the Year in 2003 by the American Association of Naturopathic Physicians and was inducted into the National University of Natural Medicine Hall of Fame in 2018.