Is Sunflower Oil Healthy?

There are four types of sunflower oil available in the United States, all of which are made from sunflower seeds that are bred to produce different fatty acid compositions.

These include high linoleic (68% linoleic acid), mid-oleic (NuSun, 65% oleic acid), high oleic (82% oleic acid), and high stearic/high oleic (Nutrisun, 72% oleic acid, 18% stearic acid) (1).

As their names suggest, some sunflower oils are higher in either linoleic or oleic acid.

Linoleic acid, commonly known as omega-6, is a polyunsaturated fatty acid that has two double bonds in its carbon chain. Meanwhile, oleic acid, or omega-9, is a monounsaturated fatty acid with one double bond. These properties make them liquid at room temperature (2).

Linoleic and oleic acid are both sources of energy for the body and contribute to cell and tissue strength (3, 4).

However, they react in different ways to heat during cooking and therefore may have varying effects on your health (5).

High stearic/high oleic sunflower oil (Nutrisun) also contains stearic acid, a saturated fatty acid that’s solid at room temperature and has different culinary applications (6).

This type of sunflower oil is not meant for home cooking and instead may be used in packaged foods, ice creams, chocolate, and industrial frying (7).

Summary

There are four types of sunflower oil available in the United States, all of which differ in their contents of linoleic and oleic acid.

All sunflower oils are 100% fat and contain vitamin E, a fat-soluble nutrient that protects cells from age-related damage (8, 9).

Sunflower oils do not contain protein, carbs, cholesterol, or sodium (8).

The chart below summaries the main differences in fatty acid composition between 1-tablespoon (15-mL) servings of the three sunflower oils used in home cooking (8, 10, 11):

Summary

Sunflower oils with more oleic acid are higher in monounsaturated fat and lower in polyunsaturated fat.

All of the purported benefits of sunflower oil are associated with high oleic varieties, particularly those that comprise 80% or more oleic acid (12, 13).

Some research suggests that a diet rich in monounsaturated fatty acids like oleic acid may help reduce high cholesterol levels and thus your risk of heart disease.

A study in 15 healthy adults found that those who ate a diet rich in high oleic sunflower oil for 10 weeks had significantly lower blood levels of LDL (bad) cholesterol and triglycerides, compared with those who ate a diet containing a similar amount of saturated fat (13).

Another study in 24 people with high blood lipid levels observed that consuming a diet with high oleic sunflower oil for 8 weeks led to significant increases in HDL (good) cholesterol, compared with a diet without sunflower oil (12).

Other studies suggest similar results, which has led the Food and Drug Administration (FDA) to approve a qualified health claim for high oleic sunflower oil and products with a similar fatty acid composition (14).

This allows high oleic sunflower oil to be labeled as a food that may help reduce the risk of heart disease when used in place of saturated fats.

Still, evidence supporting the possible heart health benefits of sunflower oil is inconclusive, and more research is warranted.

Summary

Some studies suggest that consuming high oleic sunflower oil, especially in place of saturated fats, may help reduce your risk of heart disease by lowering LDL (bad) cholesterol and raising HDL (good) cholesterol.

Despite some evidence suggesting that sunflower oil offers health benefits, there’s concern that it may be linked to negative health outcomes.

High omega-6 content

Varieties of sunflower oil that are not high oleic contain more linoleic acid, also known as omega-6.

Mid-oleic (NuSun) sunflower oil, one of the most commonly used varieties in the United States, comprises 15–35% linoleic acid.

Even though omega-6 is an essential fatty acid that humans need to obtain from their diet, there are concerns that consuming too much of it can lead to inflammation in the body and related health issues (15).

This is because linoleic acid is converted into arachidonic acid, which can produce inflammatory compounds (15).

The overconsumption of linoleic acid from vegetable oils coupled with a decreased intake of anti-inflammatory omega-3 fatty acids — an imbalance commonly seen in the American diet — may lead to negative health effects (16).

In particular, animal studies suggest that the arachidonic acid produced from omega-6 in the body may increase inflammatory markers and signal compounds that promote weight gain and obesity (17, 18, 19).

Oxidation and aldehydes

Another negative aspect of sunflower oil is its release of potentially toxic compounds upon being heated to temperatures of 356°F (180°C) repeatedly, such as in deep-frying applications (20).

Sunflower oil is often used in high heat cooking, as it has a high smoke point, which is the temperature at which it starts to smoke and break down.

However, studies show that a high smoke point does not correspond with an oil’s stability under heat.

One study found that sunflower oil released the highest amount of aldehydes into cooking fumes, compared with other plant-based oils in three types of frying techniques (21).

Aldehydes are toxic compounds that can damage DNA and cells and thus contribute to conditions like heart disease and Alzheimer’s (22).

The longer that sunflower oil is exposed to heat, the more aldehydes it emits. Therefore, gentle, low heat cooking methods such as stir-frying may be a safer use of sunflower oil (20).

What’s more, of the different types, high oleic sunflower oil is likely the most stable variety when used in high heat frying and cooking (5).

Summary

Sunflower oils that are not high oleic contain more omega-6, which may harm your health. Research also suggests that sunflower oil emits high levels of toxic aldehyde fumes when exposed to high heat over extended periods, compared with other oils.

Based on existing research, consuming small amounts of high oleic sunflower oil may provide marginal benefits for heart health.

High linoleic or mid-oleic (NuSun) sunflower oils likely do not have the same benefits and may also produce dangerous compounds during deep frying at high temperatures (5).

On the other hand, olive and avocado oils are also rich in monounsaturated oleic acid but less toxic when heated (23, 24).

Additionally, oils that are low in polyunsaturated fatty acids, such as high oleic sunflower, canola, and palm oils, are more stable during cooking, compared with high linoleic sunflower oil (21).

Therefore, while sunflower oil may be alright in small amounts, several other oils may provide greater benefits and perform better during higher heat cooking.

Summary

Other common oils, such as olive, avocado, palm, and rapeseed, may be more stable during cooking than high linoleic sunflower oil.

High oleic sunflower oil is thought to provide some benefits for heart health.

However, sunflower oil has been shown to release toxic compounds when heated to higher temperatures over time. Some varieties are also high in omega-6 and may contribute to inflammation in the body when consumed in excess.

Overall, using sunflower oil in lower heat applications is probably fine. Avocado and olive oils may also be good options that may be more stable during cooking.

Ultimately, using a variety of oils for different applications may result in a better balance of the types of fat in your overall diet.