Polyunsaturated fatty acids are a type of fat in certain foods.
Polyunsaturated fatty acids (PUFAs) are important for nerve function, blood clotting, brain health, and muscle strength.
They are “essential,” meaning that the body needs them to function but cannot make them, so a person must get PUFAs from their diet.
The American Heart Association (AHA) recommend that unsaturated fats make up the majority of fats in the diet. Unsaturated fats include PUFAs and monounsaturated fatty acids (MUFAs).
There are several types of PUFAs, and some are likely more healthful than others. Understanding the differences in fats and choosing foods accordingly can help a person reduce their risk of certain health problems.
In this article, learn more about polyunsaturated fats, including their benefits and foods that contain them.
There are two main types of fat: unsaturated and saturated.
Unsaturated fats have a hydrogen and carbon chain in each molecule. The name “polyunsaturated” refers to the fat’s chemical structure. PUFAs contain two or more double carbon bonds within this chain.
MUFAs — the other type of unsaturated fat — have one double carbon bond in each chain. “Poly” means “many,” whereas “mono” means “one.”
Both forms of unsaturated fat — PUFAs and MUFAs — may help reduce levels low-density lipoprotein, or “bad,” cholesterol in the body.
Unsaturated fats are in foods that contain vitamin E, a vital antioxidant.
Saturated fats, on the other hand, contain no double bonds. Being “saturated,” in this case, means that the fats contain as many hydrogen atoms as they can hold.
Saturated fats are generally solid at room temperature. These types of fats include solid fat in meats, as well as bacon grease and shortening. Polyunsaturated fats are more healthful than these options.
Isolated unsaturated fats, including PUFAs, are generally liquid at room temperature. Oils from plants and seeds, such as olive and canola oils, contain mainly unsaturated fats.
Many foods contain a mix of fats, including monounsaturated, polyunsaturated, and saturated fats. When choosing foods with more healthful fat contents, it is important to read labels carefully.
There are several types of PUFAs, primarily omega-3 and omega-6 fatty acids. Omega-9s and omega-12s are also PUFAs, but they are less common.
Omega-3 fatty acids are essential for the functioning of the body’s cells. They help with energy production and play important roles in the heart, lungs, blood vessels, and immune system.
There are three main types of omega-3s:
- eicosapentaenoic acid (EPA)
- docosahexaenoic acid (DHA)
- alpha-linolenic acid (ALA)
EPA and DHA mainly come from animal-based foods and are important for heart and brain health. While amounts can vary greatly, these omega-3s are present in:
ALA comes from plants. The body must convert ALA into EPA and DHA, but this conversion is not easy, and the body only converts a small amount.
As a result, the National Institutes of Health (NIH) say that people should focus on getting enough EPA and DHA in their diet.
However, good food sources of ALA include:
Some research suggests that humans used to eat a diet that had almost the same amounts of omega-6 and omega-3 fats.
Today, this is no longer the case. The typical Western diet, for example, includes far more omega-6s than omega-3s. One study estimates that the average ratio is 15:1. Another study suggests that it could be 20:1 or higher.
Foods high in omega-6 fatty acids include:
- safflower oil
- soybean oil
Some unhealthful foods, such as fast foods and sweets, also contain high amounts of omega-6s.
Omega-6 fatty acids can play a role in a nutritious diet. However, some research suggests that diets high in omega-6s and low in omega-3s can lead to inflammation and other health problems.
A person may, therefore, benefit from increasing the amount of omega-3s in their diet.
The following are some ways that PUFAs may improve a person’s health. Of all the polyunsaturated fats, scientists have primarily looked at the benefits of omega-3s.
Preventing heart disease
According to the NIH, consuming the omega-3s EPA and DHA can improve blood cholesterol levels.
The NIH also report that taking supplementary omega-3s can reduce the risk of death from all health conditions and particularly from cardiovascular disease.
In addition, they note that diets containing omega-3s from fish could lower heart disease rates.
Pregnancy and fetal development
Some evidence has shown that omega-3s are important for the fetal development of the brain and eyes.
Another study found that pregnant women with higher levels of DHA had babies with better problem-solving skills at 1 year of age.
The Food and Drug Administration (FDA) recommend that pregnant women eat 2–3 servings per week of low-mercury fish. Options include:
Pregnant women should avoid eating fish that contain high levels of mercury, such as king mackerel, orange roughy, shark, and swordfish.
High amounts of omega-3s are in the brain, and several studies have found a link between omega-3 consumption and better brain health.
Some evidence suggests that eating enough omega-3s can help with memory function in older adults without dementia. The authors noted that the benefit was “mild,” however.
A meta-analysis found that omega-3 fats could help slow cognitive decline in older adults.
MUFAs, like PUFAs, may lower levels of unhealthy cholesterol and reduce the risk of heart disease.
Both of these unsaturated fats exist in foods and oils that contain vitamin E, an antioxidant that most people do not get enough of, according to the AHA.
Some foods contain higher amounts of MUFAs. Examples include:
People should aim to get MUFAs and PUFAs from nutritious sources. Also, these healthful fats should replace saturated and transfats.
Consuming natural polyunsaturated fats in healthful foods does not typically carry any risk, unless the person has an allergic reaction to the food.
Many supplements contain polyunsaturated fats, such as omega-3s or a combination of omegas. A person may, for example, use fish, flax, or algal oil supplements to increase their omega-3 intake.
These supplements can cause side effects, including:
People with food allergies should check labels to ensure that supplements and other products are free of allergens. Many omega-3 supplements contain fish or shellfish, for example.
Also, omega-3 supplements can interact with blood thinners, including warfarin (Coumadin) and similar medicines. It is important to consult a doctor before trying any supplement.
All fats contain 9 calories per gram. Consuming high amounts of any fat, including PUFAs, could lead to weight gain and related health conditions.
While PUFAs can be a beneficial part of a person’s diet, balance and moderation are key. Eating high levels of any type of fat could lead to health problems.
People should aim for a balance of omega-6 and omega-3 PUFAs and a similar amount of MUFAs. For most people, this will involve increasing the amounts of omega-3s and MUFAs in their diets.
It is also a good idea to avoid trans fats and limit the intake of saturated fats so that they represent less than 10% of the calories consumed each day, the Dietary Guidelines for Americans recommend.
Finally, anyone with a health condition should ask a doctor or dietitian about the right balance of fats and other nutrients.