Omega-3, omega-6 and omega-9 fatty acids are important dietary fats.
They all have health benefits, but finding the right balance between them is important. An imbalance in your diet can lead to a number of chronic diseases.
Here is a guide to omega-3, 6, and 9 fatty acids including:
- what they are
- why you need them
- where you can get them
Omega-3 fatty acids are polyunsaturated fats, a type of fat that your body cannot produce.
The term “polyunsaturated” refers to their chemical structure, since “poly” means many and “unsaturated” refers to double bonds. Together they mean that omega-3 fatty acids have many double bonds.
“Omega-3” refers to the position of the final double bond in the chemical structure that is three carbon atoms from the “omega” or the back of the molecular chain.
Because the human body cannot produce omega-3 fatty acids, these fats are called “essential fats”, which means that you must get them from your diet.
The American Heart Association (AHA) recommends eating at least two servings of fish a week, especially oily fish that is high in omega-3 fatty acids (1).
There are many types of omega-3 fats that differ based on their chemical shape and size. Here are the three most common:
- Eicosapentaenoic Acid (EPA): The main function of this 20-carbon fatty acid is to make chemicals called eicosanoids that help reduce inflammation. EPA can also help reduce symptoms of depression (2, 3).
- Docosahexaenoic acid (DHA): DHA is a 22-carbon fatty acid that makes up about 8% of brain weight and contributes to the development and function of the brain (4).
- Alpha-linolenic acid (ALA): This 18-carbon fatty acid can be converted to EPA and DHA, although the process is not very efficient. ALA appears to be beneficial to the heart, immune system, and nervous system (5).
Omega-3 fats are an essential part of human cell membranes. They also have other important functions including:
- Improving heart health. Omega-3 fatty acids can help control cholesterol, triglyceride, and blood pressure (6, 7, 8, 9, 10, 11).
- Mental health support. Omega-3 supplements can help treat or prevent depression, Parkinson’s and psychosis in people at risk. However, more research is needed (12, 13, 14).
- Reduction in weight and waist size. Omega-3 fats can help people manage their weight and waist size, but more research is needed (15, 16).
- Decreasing liver fat. Initial research suggests that consuming omega-3 fatty acids may help reduce the amount of fat in your liver (17, 18, 19).
- Supporting Infant Brain Development. Omega-3 fatty acids aid brain development in a fetus (20, 21).
- Fight inflammation. Omega-3 fats can help with inflammation that occurs with some chronic diseases (22, 23).
A low intake of omega-3 fatty acids compared to omega-6 fatty acids can lead to inflammation and chronic diseases such as rheumatoid arthritis, diabetes, atherosclerosis, and heart failure (24, 25).
Omega-3 fats are essential fats that you must get from your diet. They have important heart, brain, and metabolic benefits.
Omega-6 fatty acids, like omega-3 fatty acids, are polyunsaturated fatty acids. However, the final double bond is made up of six carbons from the omega end of the fatty acid molecule.
Omega-6 fatty acids are also essential, so you need to get them from your diet.
They mainly provide energy. The most common omega-6 fat is linoleic acid, which the body can convert into longer omega-6 fats like arachidonic acid (AA) (26).
Like EPA, AA produces eicosanoids. However, the eicosanoids produced by AA are more pro-inflammatory (27, 28).
Proinflammatory eicosanoids play a key role in the immune system. However, when the body makes too much, it can increase the risk of inflammation and inflammatory disease (29).
A healthy ratio of omega-6 to omega-3 fatty acids appears to be between 1 to 1 and 4 to 1 (30, 31), but studies suggest that people following a typical Western diet may consume a ratio of between 15 to 1 and almost 17 to 1 (32).
Can Omega-6 be Beneficial?
Some omega-6 fatty acids have shown benefits in treating symptoms of chronic diseases.
Gamma-linolenic acid (GLA) is an omega-6 fatty acid found in certain oils, such as:
- Evening primrose oil
- Borage oil
When consumed, much of it is converted into another fatty acid called dihomo-gamma-linolenic acid (DGLA).
Research suggests that GLA and DGLA can have some health benefits. For example, GLA can help reduce symptoms of inflammatory conditions. However, more research is needed (33).
The authors of one study concluded that taking supplements of another form of omega-6 – conjugated linoleic acid (CLA) – may help reduce fat mass in humans (34).
Omega-6 fats are essential fats that provide energy to the body. However, people should eat more omega-3 fatty acids than omega-6 fatty acids.
Omega-9 fatty acids are monounsaturated, which means they only have one double bond.
It’s located nine carbons from the omega end of the fatty acid molecule.
Oleic acid is the most common omega-9 fatty acid and the most common monounsaturated fatty acid in food (35).
Omega-9 fatty acids are not necessarily “essential” as the body can produce them.
However, eating foods rich in omega-9 fatty acids instead of other types of fat can have health benefits.
A 2015 study found that feeding mice high in monounsaturated fatty acids improved insulin sensitivity and decreased inflammation (36).
The same study found that people who ate a diet high in monounsaturated fat had less inflammation and better insulin sensitivity than people who ate diets high in saturated fat.
Omega-9 fats are non-essential fats that the body can produce. Replacing some saturated fats with omega-9 fats can benefit your health.
You can easily get omega-3, 6, and 9 fatty acids from your diet, but you need the right balance of each. The typical western diet contains more omega-6 fats than necessary and not enough omega-3 fats.
Here is a list of foods high in omega-3, 6, and 9 fatty acids.
Foods high in omega-3 fats
Oily fish is the best source of omega-3 fatty acids EPA and DHA. Other sea sources are algae oils. ALA comes mainly from nuts and seeds.
There are no official standards for the daily intake of omega-3 fatty acids, but various organizations offer guidelines. Most experts recommend an intake of 250 to 300 milligrams per day (37).
According to the Food and Nutrition Board of the US Institute of Medicine, adequate intake of ALA omega-3 fatty acids per day is 1.6 grams for adult men and 1.1 grams for adult women aged 19 and over (38).
Here are the amounts and types of omega-3 fatty acids in a serving of the following foods:
- Salmon: 4.0 grams of EPA and DHA
- Mackerel: 3.0 grams of EPA and DHA
- Sardines: 2.2 grams of EPA and DHA
- Anchovies: 1.0 grams of EPA and DHA
- Chia seeds: 4.9 grams of ALA
- Walnuts: 2.5 grams of ALA
- Linseed: 2.3 grams of ALA
Foods high in omega-6
Refined vegetable oils and foods cooked in vegetable oils contain high amounts of omega-6 fats.
Nuts and seeds also contain significant amounts of omega-6 fatty acids.
According to the Food and Nutrition Board of the US Institute of Medicine, adequate intake of omega-6 fatty acids per day is 17 grams for men and 12 grams for women ages 19 to 50 (39).
Here are the amounts of omega-6 fatty acids in 100 grams (3.5 ounces) of the following foods:
- Soybean oil: 50 grams
- Corn oil: 49 grams
- Mayonnaise: 39 grams
- Walnuts: 37 grams
- Sunflower seeds: 34 grams
- Almonds: 12 grams
- Cashews: 8 grams
Foods high in omega-9
Omega-9 fats are common in:
- Vegetable and seed oils
There are no adequate recommendations for omega-9 fatty acids as they are not required.
Here are the amounts of omega-9 fatty acids in 100 grams of the following foods:
- Olive oil: 83 grams
- Cashew nut oil: 73 grams
- Almond oil: 70 grams
- Avocado oil: 60 grams
- Peanut oil: 47 grams
- Almonds: 30 grams
- Cashew nuts: 24 grams
- Walnuts: 9 grams
The best sources of omega-3 fatty acids are oily fish, while omega-6 fatty acids and omega-9 fatty acids are found in vegetable oils, nuts, and seeds.
Omega-3-6-9 combo supplements usually provide each of these fatty acids in appropriate proportions, such as 2-to-1-to-1 for omega-3: 6: 9.
Such oils can help increase your omega-3 fat intake and improve the balance of fatty acids so that the omega-6 to omega-3 ratio is less than 4 to 1.
However, most people are already getting enough omega-6 from their diet, and the body is making omega-9. Because of this, most people do not need to supplement these fats.
Instead, it is best to focus on getting a balance of omega-3, 6, and 9 fatty acids from your diet.
This includes at least two servings of fatty fish per week and the use of olive oil in cooking and in salad dressings.
Also, try to limit your omega-6 intake by limiting your consumption of other vegetable oils and fried foods cooked in refined vegetable oils.
People who are not getting enough omega-3 from their diet can benefit from an omega-3 supplement instead of a combined omega-3-6-9 supplement.
Combined omega-3-6-9 supplements offer optimal proportions of fatty acids. However, compared to omega-3 supplements, they are unlikely to offer any additional benefits.
Similar to other oils, polyunsaturated fatty acids are easily oxidized when exposed to heat and light.
So when purchasing an Omega 3-6-9 supplement, choose one that is cold pressed. This means that the oil was extracted using limited heat, which minimizes the oxidation that can damage the fatty acid molecules.
To make sure you’re taking a non-oxidized supplement, choose one that contains an antioxidant like vitamin E.
Additionally, choose a supplement with the highest omega-3 content – ideally more than 0.3 grams per serving.
Because EPA and DHA have more health benefits than ALA, choose a supplement that uses fish oil or algae oil instead of flaxseed oil.
Choose an omega-3 supplement instead of a combined omega-3-6-9 supplement. When buying a combined supplement, choose one with a high concentration of EPA and DHA.
Combined omega-3-6-9 supplements are popular, but generally do not offer any additional benefit over omega-3 alone.
Omega-6 fatty acids are essential in certain amounts, but they are found in many foods. People following a Western diet may already be consuming too many.
In addition, the body can produce omega-9 fats, which can easily be ingested through food. So you don’t have to take them in supplement form.
Although combined supplements contain optimal proportions of omega-3-6-9, ingesting omega-3 fatty acids alone is likely to offer the most health benefits.