Who Shouldn't Take Omega 9? Essential Considerations

November 16, 2025 •

4 min read

According to research, the body can produce its own omega-9 fatty acids, meaning they are 'non-essential' in the diet. However, some individuals should exercise caution or avoid concentrated omega-9 supplementation, particularly those with existing health conditions, an imbalanced intake of other fats, or specific dietary concerns.

Quick Summary

This article explores specific health conditions, dietary patterns, and physiological states where omega-9 fatty acid supplementation may not be advisable. It details potential contraindications and the importance of a balanced fat intake.

Key Points

Pre-existing Heart Conditions: Individuals with a history of heart problems should be cautious, as excessive intake of any fat can increase the risk of cardiovascular disease, especially if not balanced by omega-3s.
Diabetes Management: High doses of fish oil supplements, which often include omega-9, might interfere with blood sugar control in people with diabetes.
Blood Thinners and Bleeding Disorders: Those on anticoagulant medications should consult a doctor before taking omega fatty acid supplements due to the potential risk of increased bleeding.
Unbalanced Fatty Acid Ratio: Overconsuming omega-9 without adequate omega-3 can lead to an internal buildup of fat and negate potential health benefits.
Dietary Overload: A diet already high in fats and cholesterol, paired with omega-9 supplements, can increase the risk of obesity and worsen cardiovascular health markers.
Liver Health Concerns: People with liver disease should be cautious, as fish oil supplements might increase bleeding risk.
Immune System Considerations: Very high doses of omega fatty acids could potentially weaken the immune response, which is a concern for immune-compromised individuals.

Understanding Omega-9 Fatty Acids

Omega-9 fatty acids are a group of monounsaturated fats, with the most common being oleic acid, abundant in olive oil, avocados, and nuts. Unlike omega-3 and omega-6 fatty acids, which are essential and must be obtained from food, the body can synthesize omega-9 fats. While a healthy part of a balanced diet, the primary cautions regarding omega-9 relate to overconsumption, especially when derived from supplements, and the importance of balancing it with other fats. Issues typically arise not from moderate dietary intake but from excess intake that creates an imbalance with omega-3s.

Health Conditions Requiring Caution with Omega 9

While generally safe, certain health conditions warrant a cautious approach to high-dose omega-9 intake, often delivered through supplements.

Cardiovascular Conditions: For individuals with pre-existing heart problems, excessive fat intake of any kind, including omega-9, could increase the risk of obesity and cardiovascular disease if not balanced with sufficient omega-3s. It is important to note that while the Mediterranean diet, rich in oleic acid (omega-9), is linked to better heart health, it is the overall dietary pattern, not omega-9 in isolation, that is beneficial.
Bleeding Disorders or Taking Blood Thinners: Although a primary concern with omega-3, some combination omega supplements containing all three fats can potentially increase the risk of bleeding. Individuals on blood-thinning medications like warfarin should consult a doctor before starting any fatty acid supplement.
Diabetes: High doses of fish oil (which often contains all omegas) can make it more difficult to control blood sugar levels in people with diabetes. A doctor's supervision is crucial for managing any supplementary intake.
Liver Disease: Individuals with liver disease, particularly those with existing liver scarring, may have an increased risk of bleeding with fish oil supplements. Excessive fat intake from any source can also strain the liver.
Immune-Compromised Individuals: High doses of omega fatty acids can potentially lower the body's immune system response. This could be a concern for those with already weakened immune systems, such as people with HIV/AIDS.
Familial Adenomatous Polyposis: Some studies have raised concerns that fish oil, which is often combined with omega-9, might increase the risk of cancer in individuals with this specific genetic condition. Medical consultation is mandatory.

The Importance of Balance with Omega 3 and Omega 6

The human body requires a proper balance of omega fatty acids for optimal health. The typical Western diet often contains a disproportionately high amount of omega-6 and not enough omega-3. When this imbalance is compounded by excessive omega-9 intake, it can lead to health issues.

Unbalanced Fatty Acid Ratio: Consuming too much omega-9 and not enough omega-3 can lead to an internal buildup of fat in the body, which can be a health concern.
Omega-3's Role: Omega-3 fatty acids, found in oily fish and flaxseed, are critical for anti-inflammatory processes and heart health. A balanced ratio helps regulate inflammation throughout the body.

Potential Side Effects of Overconsumption

Even though omega-9 is generally safe, overconsumption, especially from low-quality supplements or in the context of an unhealthy diet, can lead to side effects.

Gastrointestinal Distress: Some people experience digestive discomfort, such as nausea, bloating, diarrhea, or an upset stomach, from high-fat supplements.
Increased Cholesterol (in an unhealthy context): While omega-9 is often promoted for improving cholesterol profiles, excessive consumption within a diet already high in unhealthy fats can lead to raised cholesterol levels.
Obesity Risk: As a source of fat, omega-9 contributes to caloric intake. Excessive consumption, particularly in an unbalanced diet, can contribute to weight gain and increase the risk of obesity.

Comparison of Omega-3, Omega-6, and Omega-9


Feature	Omega-3	Omega-6	Omega-9
Classification	Polyunsaturated (PUFA)	Polyunsaturated (PUFA)	Monounsaturated (MUFA)
Essential?	Yes, must be obtained from diet	Yes, must be obtained from diet	No, body can produce it
Typical Intake	Often deficient in Western diets	Often overconsumed in Western diets	Easily obtained through common foods
Role in Health	Anti-inflammatory, brain health, heart health	Energy, cell growth, can be pro-inflammatory in excess	Reduces LDL ('bad') cholesterol, anti-inflammatory effect

Conclusion

While omega-9 fatty acids are a beneficial component of a healthy diet, particularly from whole food sources like olive oil and avocados, supplementation is not necessary for most people since the body can synthesize it. Individuals already consuming a balanced diet rich in healthy fats, particularly a favorable ratio of omega-3 to omega-6, are unlikely to need extra omega-9. The most significant risks are for those who use supplements without considering their overall health, including people with heart disease, diabetes, liver issues, or bleeding disorders. The key takeaway is moderation and balance; rather than focusing on isolated supplements, prioritizing a well-rounded dietary pattern that includes a variety of healthy fats is the most effective approach for overall wellness. As always, consulting with a healthcare provider before starting any new supplement is the safest course of action. For more information, see the National Center for Complementary and Integrative Health's guidelines on omega-3s, which are often bundled with omega-9 supplements.

Footnotes

: National Center for Complementary and Integrative Health. https://www.nccih.nih.gov/health/tips/things-to-know-about-omegas-for-heart-disease

Frequently Asked Questions

Women who are pregnant, planning to get pregnant, or breastfeeding should avoid combined omega-3, 6, and 9 supplements unless specifically advised by a doctor.

While omega-9 itself has fewer known interactions, omega-3 supplements (often combined with omega-9) can interact with blood thinners, blood pressure medication, and certain chemotherapy drugs. Always consult a healthcare provider before starting supplements, especially if taking other medications.

No, omega-9 fatty acids are not considered essential because the body can produce them. Most people get enough from their diet through foods like olive oil, nuts, and avocados.

An imbalance with too much omega-9 relative to omega-3 can lead to an internal buildup of fat in the body and potentially negate the health benefits of both.

While omega-9 itself is less likely to cause an allergic reaction, it is often included in combination supplements. Individuals with allergies to fish or shellfish should be cautious, as some supplements contain these ingredients.

People who should generally avoid or consult a physician before taking combined omega supplements include those who are pregnant or breastfeeding, have a history of seizures, have heart problems, have diabetes, or are about to undergo surgery.

The safest way to consume omega-9 is through dietary sources. These include extra virgin olive oil, avocados, nuts like almonds and cashews, and seeds.