The importance of maintaining a low omega-6/omega-3 ratio to reduce the risk of autoimmune diseases, asthma, allergies and fibromyalgia

Source: NIH (National Library of Medicine) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8504498/

Summary

Until about 100 years ago, the omega-6/3 ratio was about 4:1 or less. However, the typical Western diet today provides an omega-6/3 ratio of about 20:1 in favor of omega-6, which favors supraphysiologic inflammatory responses and promotes chronic low-level inflammation. The excessive consumption of linoleic acid, mainly from industrial omega-6 seed oils, and the lack of long-chain omega-3 fatty acids in the diet create a pro-inflammatory, pro-allergic, pro-thrombotic state. Reducing the omega-6/3 ratio, especially by reducing the intake of refined omega-6 seed oil and increasing the intake of marine omega-3 fatty acids, can effectively reduce inflammation, allergies, autoimmune reactions and even the symptoms of fibromyalgia.

Introduction

Marine omega-3 fatty acids have been consumed by our ancestors for millions of years. During the Paleolithic era, the intake of marine omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was around 660-14,250 mg/day, compared to only 100-200 mg/day today. The omega-6/3 ratio has increased from about 4:1 in the Paleolithic period to 20:1 today. Over the past 100 years, intake of the omega-6 fatty acid linoleic acid has more than doubled in the U.S., largely due to increased consumption of omega-6-rich seed oils such as soybean, corn and safflower oil. This increase has been accompanied by a rise in numerous autoimmune, inflammatory and allergic diseases and conditions such as fibromyalgia.

Rheumatoid arthritis

Rheumatoid arthritis is a chronic inflammatory autoimmune disease in which the immune system attacks the lining of the joints, causing joint inflammation and pain. Clinical studies have suggested that omega-3 fatty acids may play a role in improving rheumatoid arthritis. A meta-analysis of 17 randomized controlled trials concluded that omega-3 polyunsaturated fatty acids (PUFAs) are effective in improving symptoms in patients with rheumatoid arthritis, inflammatory bowel disease and dysmenorrhea. A diet low in arachidonic acid (less than 90 mg/day) has also been shown to reduce the clinical signs of inflammation in patients with rheumatoid arthritis, and these effects were enhanced by the addition of a fish oil supplement.

Ulcerative colitis and Crohn's disease

Ulcerative colitis and Crohn's disease are chronic inflammatory diseases characterized by the infiltration of neutrophils and mononuclear cells into the affected parts of the intestine. Interleukin-8 (IL-8) is a chemokine that recruits neutrophils into inflammatory tissue. Patients with active inflammatory bowel disease have a mucosa that contains more IL-8. Linoleic acid activates arachidonic acid pathways and increases pro-inflammatory arachidonic acid metabolites, suggesting that the omega-6 polyunsaturated fatty acid linoleic acid may have pro-inflammatory effects, particularly in individuals with inflammatory bowel disease.

Fibromyalgia and the importance of the omega-6/omega-3 ratio

Fibromyalgia is a chronic disorder characterized by widespread musculoskeletal pain, fatigue and tenderness in localized areas. Although the exact cause of fibromyalgia is not fully understood, it is thought to involve an abnormal pain processing system. Recent studies have suggested that inflammation may play a role in the pathogenesis of fibromyalgia. The imbalance in the omega-6/3 ratio may exacerbate inflammation and contribute to the symptoms of fibromyalgia.

Omega-3 fatty acids, particularly EPA and DHA, have been shown to have anti-inflammatory properties. A study published in the journal Pain found that omega-3 supplementation reduced pain intensity and improved functional capacity in patients with fibromyalgia. Another study in the Journal of Clinical Rheumatology reported that omega-3 supplementation led to a significant reduction in the number of pressure points and improved quality of life in fibromyalgia patients.

These findings suggest that maintaining a low omega-6/3 ratio through dietary modifications and supplementation with marine omega-3 fatty acids may help alleviate the symptoms of fibromyalgia by reducing inflammation and improving overall well-being.

Allergies

The increase in the omega-6/3 ratio was associated with the increase in the prevalence of "hyperallergic" atopic conditions and other allergic diseases such as rhinoconjunctivitis, allergic asthma and atopic eczema. The parent omega-3 fatty acid alpha-linolenic acid (ALA) and the parent omega-6 fatty acid linoleic acid compete for the same enzymes. A high dietary intake of linoleic acid reduces the elongation of ALA to EPA and DHA. The bioactive metabolites formed from omega-6 are more inflammatory compared to the omega-3 pathway, leading to a "hyperallergic" state due to an increase in reactive leukotrienes formed from the omega-6 pathway.

Omega-3 fatty acids during pregnancy reduce allergic diseases in offspring: Clinical studies

Randomized controlled trials have found significant reductions in allergic disease in offspring when long-chain omega-3 PUFAs were administered during pregnancy. A systematic review and meta-analysis concluded that pregnant women who consume adequate amounts of EPA/DHA may be able to reduce their risk of allergic disease in their children. Ensuring an optimal long-chain omega-6/3 ratio during pregnancy, before the fetal immune system is programmed for an allergic phenotype, may be an important strategy to prevent allergic diseases in the offspring.

Asthma

Asthma has increased in incidence in recent decades, possibly due to a reduction in dietary omega-3 intake. A higher dietary omega-6/3 ratio in pregnancy is associated with a higher risk of allergic rhinitis in the offspring at five years of age. A low intake of ALA and total omega-3 PUFAs during pregnancy is associated with an increased risk of asthma in the offspring. Eating fish more than two to three times per week has been shown to reduce the incidence of persistent wheeze by 66 %, eczema by 37 % and positive skin prick test for house dust mites by 35 %.

Omega-3 fatty acids and asthma: clinical studies

A randomized, double-blind study with 39 asthmatic children (8-12 years old) over six months compared the effect of fish oil capsules (omega-3 group) with safflower oil capsules (omega-6 group). Most of the children were already taking inhaled corticosteroids and beta-agonists. The omega-3 group ate more fish than the omega-6 group.

The omega-3 group received 900 mg of EPA/DHA per day, while the omega-6 group received around 1.35 grams of safflower oil per day. After three and six months, the omega-3 group showed an increase in omega-3 fatty acids in the blood, while the omega-6 group showed no significant changes.

Tumor necrosis factor (TNF)-alpha decreased significantly in the omega-3 group, while it increased slightly in the omega-6 group. The number of eosinophils (a type of white blood cell) decreased in the omega-3 group, while it increased in the omega-6 group. This indicates a reduction in airway inflammation due to omega-3 fatty acids.

Asthma severity was lower in the omega-3 group, but not significantly lower than in the omega-6 group. The study suggests that higher doses of omega-3 fatty acids (three to four grams per day) may have better anti-inflammatory effects. Longer studies with larger sample sizes are needed to determine the clinical benefits of omega-3 fatty acids for asthma patients.

A recent randomized trial in 98 patients with obesity and uncontrolled asthma found that four grams/day of omega-3 PUFAs significantly reduced asthma-related telephone contacts by 66 %. Despite this benefit, the others concluded that omega-3 PUFAs did not improve most asthma-related outcomes (such as leukotriene E4, forced expiratory volume capacity in one second and asthma exacerbations at six months). Therefore, further studies are needed to determine the benefits of marine omega-3 fatty acids in asthma patients.

Conclusion

Reducing the omega-6/3 ratio during pregnancy may reduce allergic conditions in offspring. Possible benefits for patients with asthma. Larger clinical studies needed to confirm. Increase in omega-6/3 ratio may have led to more allergic and autoimmune diseases. High omega-6/3 ratio causes inflammatory reactions and chronic inflammation. Excessive consumption of linoleic acid from industrial omega-6 seed oils and lack of omega-3 fatty acids leads to pro-inflammatory state. Pro-inflammatory state promotes allergies, thrombosis and autoimmune diseases. Can promote cytokine storms during viral infections.

Many people have a deficiency of long-chain Omega-3 fatty acidswhich calls for increased education on the importance of a higher intake of marine omega-3 fatty acids. Supplementation and fortification of foods and consumption of seafood can help to increase omega-3 intake. At the same time, intake of omega-6 PUFAs, especially from highly refined vegetable oils such as soybean and corn oil, should be reduced to decrease the unfavorable omega-6/3 ratio and inflammatory conditions.

Further sources:

ScienceDirect: The importance of the ratio of omega-6/omega-3 essential fatty acids https://www.sciencedirect.com/science/article/abs/pii/S0753332202002536

Artemis P. Simopoulos M.D.: Omega-6/Omega-3 Essential Fatty Acid Ratio and Chronic Diseases https://www.tandfonline.com/doi/abs/10.1081/FRI-120028831

ScienceDirect: The Omega-6:Omega-3 ratio: A critical appraisal and possible successor https://www.sciencedirect.com/science/article/abs/pii/S095232781830067X