Healthy fats can be sourced from both animal and plant-rich foods. Fats provide calories, help you absorb some vitamins, and render essential nutrients that your body needs to function properly.
Any foods that are rich in fat contain a mix of different fats, one of which is polyunsaturated fat. Polyunsaturated fats are normally liquid at room temperature and are referred to as “oils.” They’re mostly found in fatty fish, plant-based oils, seeds, and nuts.
What Are Polyunsaturated Fats?
There are two main kinds of fats (saturated and unsaturated).
Saturated fat has no double bonds in its chemical structure, whereas unsaturated fat has one or more double bonds. If a fat molecule has one double bond, it’s called “monounsaturated fat“, but if it has more than once, it’s called “polyunsaturated fat“.
Polyunsaturated fats along with monounsaturated fats are recognized as healthy fats, as they may decrease your risk of heart disease, mainly when substituted for saturated fats.
The two major sources of polyunsaturated fats are omega-3 and omega-6 fatty acids.
Both are necessary fatty acids that your body needs for brain function and cell growth. However, your body cannot make essential fatty acids, so you must get them from your diet.
Dietary fats are a compound of saturated, monounsaturated, and polyunsaturated fatty acids in various proportions.
For instance, most of the fat in butter is saturated, but it also includes some mono and polyunsaturated fats.
Some foods give a higher percentage of omega-3 and omega-6 polyunsaturated fats than others.
Here are several foods high in these essential fatty acids.
Omega-3 Fatty Acids
Omega-3s can be found in pine nuts, walnuts, flax, and sunflower seeds but these give a few active forms of the fat than fish do.
Fatty fish, such as salmon, boast the most omega-3s, whereas fish with a lower fat content, such as trout and bass, harbor lower levels.
The omega-3 content of 3 ounces (85 grams) of selected fish is:
- Salmon: 1.8 grams
- Bass: 0.7 grams
- Herring: 1.7 grams
- Shrimp: 0.2 grams
- Sardines: 1.2 grams
- Mackerel: 1 gram
- Trout: 0.8 grams
Additionally, fish don’t manufacture omega-3 fatty acids on their own. Rather, they store them by eating algae and small, microscopic organisms called plankton.
Omega-6 Fatty Acids
Plant-based oils are great in omega-6 fatty acids with the exception of coconut and palm oil, which contain a high portion of saturated fats and are solid at room temperature.
The oils highest in polyunsaturated fats include:
- Safflower oil: 74.6%
- Soybean oil: 58.9%
- Grapeseed oil: 69.9%
- Sunflower oil: 65.7%
- Flaxseed oil: 67.9%
- Poppyseed oil: 62.4%
These oils are liquid at room temperature because the double bonds allow the fat to bend and fold.
Oil-based condiments like mayonnaise and salad dressings, as well as kinds of margarine, are also high in omega-6 polyunsaturated fats.
As an indispensable component of your diet, polyunsaturated fats offer lots of impressive health benefits.
Much of these benefits are linked with the omega-3 fatty acids EPA and DHA.
1. May Reduce Age-Related Mental Decline
Omega-3 fatty acids are essential for brain development and function.
Studies link low blood levels of DHA with mental decline in older adults. More so, eating fish that is high in DHA may help prevent mental decline and related illnesses.
In five-year research in over 200 older men, fish-eating was linked with less mental decline.
Another study in over 5,000 people recorded that higher fish eating was tied to a 60% lower risk of dementia and a 70% lower risk of Alzheimer’s disease over an average of two years.
Dementia is the loss of brain function that reduces a person’s ability to think, remember, or reason. Alzheimer’s disease is the most common cause of dementia among older adults.
While some meta-analyses have evaluated how omega-3 fish oil supplements affect brain function in healthy older adults and those with Alzheimer’s disease, they have failed to find consistent results.
Some study recommends that omega-3s enhance memory function in older adults while other studies show no benefit.
2. May Improve Infant Development
Mothers who consume 8–12 ounces (227–340 grams) of fatty fish per week during pregnancy and breastfeeding may have healthier children.
In one research, the children of mothers who ate fish more than twice per week showed higher on language and visual motor skills tests than children whose mothers did not usually consume fish.
Another research noted that the children of mothers who ate 12 ounces (340 grams) of fish per week were less likely to have issues with behavioral, fine motor, and communication skills.
However, fish oil supplements do not appear to give the same results. Randomized control researches have failed to find regular benefits for infants whose mothers take omega-3 fish oil supplements.
For instance, taking omega-3 supplements during pregnancy seems to provide few or no advantages for preventing preterm births, allergies in early childhood, or children’s mental and visual development.
It’s suggested that pregnant or breastfeeding women eat weekly at least 8 but no more than 12 ounces (227 and 340 grams, respectively) of fish low in mercury, a heavy metal that can impair fetal development.
Pregnant women should limit or avoid fish with the highest mercury levels, including marlin, orange roughy, swordfish, tuna, king mackerel, and shark.
3. It May Promote Heart Health
Omega-3 polyunsaturated fats are renowned for their effects on heart health. Studies in the 1960s and ’70s recognized a decreased risk of dying from heart disease in populations that consumed fish.
Later researches linked higher fish consumption and higher blood levels of omega-3s with a lower risk of heart disease and heart-related death. Though, randomized control trials have discovered mixed results with omega-3 fish oil supplements.
For instance, in a study in over 12,500 people at risk of heart disease, supplementing with omega-3s for five years did not decrease their risk of either the disease or heart-related death.
Furthermore, a review of 10 studies in nearly 78,000 people prone to heart disease saw no benefit of omega-3 supplements on risk of heart attack, stroke, or any other related trauma.
Nevertheless, fish oil supplements have proved effective at lowering triglycerides, a type of fat which when raised raises your risk of heart disease and stroke.
Health Risks of Over-consumption and Improper Use
When it comes to nutrition, moderation is key. The same goes for polyunsaturated fats as consuming too much can pose health risks.
1. Increased Inflammation
Omega-3 and omega-6 polyunsaturated fatty acids play crucial roles in inflammation. In general, omega-3s are anti-inflammatory while omega-6s are pro-inflammatory.
Though inflammation can help you fight infections and heal injuries, chronic inflammation is at the root of several illnesses, such as obesity, diabetes, and heart disease.
Eating too many omega-6s in relation to omega-3s is thought to promote inflammation and add to poor health. As a result of excess omega-6-rich vegetable oils in the Western diet, specialists agree that people get plenty of omega-6 fatty acids and not enough omega-3s.
The Western diet’s high omega-6-to-omega-3 ratio is one reason it’s linked with many inflammatory conditions especially heart disease.
2. Concentrated Calories
All fats, including polyunsaturated fats, comprise 9 calories per gram — more than twice the calories found in carbs or protein. Therefore, the calories from polyunsaturated fats can add up fast. If you’re not careful, you might exceed your calorie needs.
As so, if you plan to consume more polyunsaturated-rich foods, it’s suggested that you remove other calories elsewhere rather than simply adding polyunsaturated fats to your diet.
For instance, if you wanted to replace some of your saturated fats with polyunsaturated fats, you could cook and bake with liquid oils rather than butter, lard, or shortening, which are high in saturated fats.
3. Improper Storage and Use in Cooking
Polyunsaturated fats spoil faster than other fats because of their multiple double bonds. Hence, you should store these oils in a cool, dark place before opening, after which you should keep them in the refrigerator.
Polyunsaturated fats also have a lower smoke point, which is the temperature at which an oil starts to smoke. When oil smokes, its fat breaks down and produces harmful substances, some of which have been linked to cancer and neurodegenerative diseases in animal studies.