Dietary Fats: The Role Of Omega-9, Omega-6, And Omega-3 Fatty Acids

Fats are an essential component to a healthy diet, besides contributing to the flavor and texture of many foods, including seeds, fruits, dairy, eggs, fish, and any other of what we usually consider the most comforting foods on the planet, such as chocolate. Including some types of fat in the diet can help reduce cholesterol levels and decrease the risk for cardiovascular events and other metabolic chronic diseases.

The single elements composing a specific fat profile in nature are called ‘fatty acids.’
There are two major types of fatty acids: saturated and unsaturated. While saturated fats tend to be solid at room temperature, the unsaturated ones are more fluid for a slight difference in their physicochemical structure. Double bounds of hydrocarbon molecules make them more unstable to pack together and more likely to scour one against the other.

Unsaturated fatty acids with one double bond are called monounsaturated fatty acids (MUFAs); unsaturated fatty acids with more than one double bond are called polyunsaturated fatty acids (PUFAs).
Within the unsaturated fats are what we hear as the ‘Omegas:’ Omega-3s, Omega-6s, and Omega-9s. Omega-3 and omega-6 fatty acids are PUFAs, while omega-9 fatty acids are usually MUFAs. The omega numbers reference how many carbons away from the fatty acid chain’s methyl end that the first carbon-carbon double bond appears. If the double bond is three carbons away, it’s called an omega-3 fatty acid; if it’s six or nine away, it’s called an omega-6 or omega-9 fatty acid, respectively.

Omega-3 and omega-6 are also ‘essential fatty acids,’ which means humans must ingest them to keep the balance with an optimized metabolism, as the body cannot synthesize them from other nutrients.

A big misconception surrounding fats is that when one eats a particular food, they only eat one type of fat. Fats and oils are, in fact, a mixture of different kinds of fatty acids, some containing more saturated fats, others more unsaturated portions, among which omega-6 and omega-3 fatty acids are more prevalent in certain foods.

Knowing which food sources are high in the different kinds of fat can help us choose foods higher in the heart-healthy MUFAs and PUFAs and lower in saturated fats. That’s what the best available scientific evidence on heart health tells us anyway: to emphasize the types of fat we eat rather than the amounts of fat we eat.

Omega-3 fatty acids are known for their benefit to heart health and come in both plant and animal forms.
Alpha-linolenic acid (ALA) is a plant form of omega-3, found in flaxseeds, chia seeds, walnuts, soybeans, etc. ALA is essential because it can only be obtained in the diet.
Omega-3s also include eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are the marine forms of omega-3 fatty acids, commonly found in cold-water fatty fish like salmon, herring, sardines, and mackerel. These fatty acids can be made from the plant-sourced ALA in the body, but the conversion rate isn’t efficient. Because of this and the fact that EPA and DHA are strongly correlated with cardiovascular disease prevention, getting EPA and DHA pre-formed is the best bet.

Omega-3 fatty acids gained the attention of researchers in the late 1970s during observational studies of Greenland Inuits. The low occurrence of coronary heart disease (CHD) in Inuits was attributed to their traditional diet, rich in marine animals and fish. Other population studies have also shown that cultures with high fish consumption, such as Japan or the Mediterranean basin, have similarly low CHD mortality rates. Discoveries like these jumpstarted a massive body of research on omega-3 fatty acids and their effects on human health.

A growing body of research examines the effects of omega-3s in different areas concerning physical and mental health, such as certain types of cancers, neurological disorders, arthritis, and infant neurocognitive development. Omega-3 fatty acids have, in fact, natural anti-inflammatory properties; yet, avoiding excesses—even for essential nutrients—is the key to a balanced diet.

The U.S. Food and Drug Administration (FDA) ruled that intakes of EPA and DHA (the omega-3 fatty acids from fatty fish and algae) of up to three grams per day are Generally Recognized as Safe (GRAS) for inclusion in the diet. Doses of greater than five grams of EPA and DHA per day are generally not recommended by the FDA due to evidence that intake at those levels may lengthen the bleeding time in susceptible people.
In Europe, dietary recommendations for EPA and DHA based on cardiovascular risk considerations for adults are between 250 and 500 mg per day.

Omega-6 fatty acids include linoleic and arachidonic acid. Sources of linoleic acid include vegetable oils, nuts, and seeds; arachidonic acid is found in meat and eggs. Along with the omega-3 ALA, linoleic acid is the other essential fatty acid.

In contrast to omega-3s and omega-6s, omega-9 fatty acids are usually monounsaturated and can be made in the body, making them nonessential fatty acids. Fats highest in omega-9 fatty acids are some of the healthiest, such as extra-virgin olive oil, because they are the most stable to oxidation against the high temperatures during cooking and frying, minimizing the formation of harmful compounds, such as acrylamides.

Translated into real-life best practice, all types of ‘omega’ fats are suggested to include in our diets. The secret to healthy nutrition is choosing the best food source that can create a balance lacking in the diet. Omega-6s and omega-3s are essential and need to be included through certain foods; omega-9s like oleic acid in extra-virgin olive oil are the best for cooking and frying thanks to their excellent resistance to oxidation and a long shelf-life.
Omega-3 fats from marine foods are particularly recommended to consume at least once-twice a week over plant based-only sources. Also, fish is the only nonplant-origin food positively impacting the global path to sustainable diets, according to the EAT-Lancet report on the proposal of guideline for a ‘planetary health diet’ to adopt by 2050:

Did you know the difference between the types of omega fats? What specific foods that include them are you consuming more or considering more—for a healthier and more sustainable diet?