Seed oils, such as pumpkin seed, canola (rapeseed), flaxseed, and other oils sourced from seeds, are commonly used in cooking and food production. While these seeds are highly nutrient-dense (many of them are considered superfoods), there is debate over whether or not seed oils are healthy.
This article answers the question: “What are seed oils?” and provides an overview of their potential health benefits based on scientific analyses.
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What Are Seed Oils?
Seed oils are versatile oils with various uses.
Definition and Sources
Seed oils are extracted from seeds and used in cooking and food processing. They include an array of refined or unrefined oils sourced from a plant's seed rather than its fruit.
Examples of seed oils include:
- Canola oil
- Soybean oil
- Sunflower oil
- Corn oil
- Grapeseed oil
- Pumpkin seed oil
- Cottonseed oil
- Soybean oil
- Safflower oil
- Peanut oil
- Rice bran oil
- Flaxseed oil
- Pomegranate seed oil
- Almond oil
- Perilla seed oil
- Papaya seed oil
- Custard-apple seed oil
- Jackfruit seed oil
- Cress seed oil
- Black seed oil
Many seed oils have long been used for baking and high-temperature cooking because of their natural taste and high smoke point.
Production Methods
Seed oils are generally extracted via chemical solvents or mechanical pressing. Such processes may involve refining, bleaching, deodorizing, or heating to transform the oil into a more versatile product. However, processing may remove many healthy phenols, vitamin E, and other antioxidants, making seed oils less healthy.
Unrefined oils are purer and less processed than refined oils, meaning they retain more of the original healthy nutrients without using chemicals during production.
Researchers found that virgin (unrefined) oils benefit gut microbiota, inflammation regulation, and important metabolic changes — and recommend virgin oils over refined oils.
Uses of Seed Oils
Seed oils are used in food manufacturing, home cooking, and restaurant food preparation. They are also common ingredients in processed foods, frying, and baking.
Are Seed Oils Unhealthy?
The following information explores whether or not seed oils are actually healthy.
Nutritional Profile of Seed Oils
The nutrition content of 1 tablespoon of common seed oils is as follows:
- Calories: 120
- Fat: 14 grams
- Carbohydrates: 0 grams
- Fiber: 0 grams
- Protein: 0 grams
Seed oils, particularly unrefined versions, are often rich in vitamins E, A, K, and D, and phenols.
Seed oils and other plant-based oils are also sources of polyunsaturated fatty acids (PUFAs), including omega-3 and omega-6 fatty acids and monounsaturated fats — which offer various health benefits.
Many seed oils are higher in omega-6 fats than omega-3 fatty acids. Omega-6 fats are essential fats that provide health benefits (when consumed in recommended amounts), such as a lower risk of high cholesterol and heart disease.
However, not all seed oils are higher in omega-6 fatty acids. Flaxseed oil, for example, contains much higher levels of omega-3s than omega-6s.
Scientific Evidence on Seed Oils and Health
Studies have explored the impact of seed oils and omega-6 fatty acids on heart health, inflammation, and cholesterol levels.
One review found that consuming pomegranate seed oil, flaxseed oil, almond oil, corn oil, rice bran oil, or canola oil may lessen the risk of heart disease. The researchers suggest that pomegranate seed oil, perilla seed oil, almond oil, flaxseed oil, and coconut oil may help prevent type 2 diabetes.
They recommend not consuming one seed oil over another but simply choosing a variety of plant-based oils that equal 22-44 grams per day for adults (depending on their caloric requirements). Doing so may reduce the risk of inflammation, high cholesterol, high blood sugar, cancer, obesity, heart disease, and kidney and liver problems.
The review also suggests that the following oils are beneficial because they contain WHO-suggested ratios of saturated fatty acids to mono- and polyunsaturated fats: rice bran oil, corn oil, olive oil, and cress oil.
Seed oils and other sources of dietary fat enhance the absorption of fat-soluble vitamins, protect the organs, provide satiety, boost energy, support hormone health, and regular body temperature.
Risks and Controversies
To lessen any potential risks associated with a high consumption of seed oils, it’s helpful to consume a variety of foods rich in both omega-3 and omega-6 fatty acids and aim for a ratio of 2:1 or 1:1 omega-6 to omega-3 fats.
Consuming too many omega-6 fatty acids at the expense of omega-3s may boost the risk of chronic inflammation, which is linked to arthritis, heart disease, and type 2 diabetes.
However, while omega-6 fatty acids have increased blood pressure and inflammation in lab studies, these studies may not accurately reflect effects on people — particularly because omega-6 byproducts linked to inflammation are not produced in large amounts in humans.
Another reason seed oils have gained a bad rap on social media is because they are often used to prepare highly processed foods, such as fast food fries and burgers. Repeatedly heating such fats to high temperatures during deep frying without frequently changing the oil is a health concern, but cooking at home with seed oils is not.
While potential risks and controversies exist, exaggerated social media claims and misconceptions that seed oils are harmful are not evidence-based claims.
Factors to Consider with Seed Oils
Factors to consider when choosing seed oils include:
Quality and Processing
It’s important to consider oil quality and its processing methods before consuming seed or other plant-based oils. Choose unrefined (virgin) varieties whenever possible to preserve essential nutrients and avoid chemical use during processing.
Balanced Consumption
Experts recommend consuming a balanced diet containing a variety of healthy fats. This includes combining seed oils with a mix of other plant-based fats (olive oil, fatty fish, avocados, nuts, seeds, etc.) as a nutritious way to maintain optimal health.
Incorporate healthy fats into the diet by:
- Add oils to dips, sauces, salad dressings, and marinades.
- Use oils to stir fry, grill, roast, saute, or bake.
- Lightly drizzle oils in foods and recipes to enhance flavor.
- Substitute oils for stick margarine, butter, lard, and other solid fats.
- Add avocadoes, nuts, or seeds to salads, soups, omelets, yogurt, oatmeal, or cottage cheese.
- Mix nut butter into protein shakes or fruit smoothies.
- Consume salmon, tuna, or other fatty fish rich in omega-3 fatty acids.
- Consider fish oil or vegan omega-3 supplements to balance omega-6s.
Consuming seed oils in moderation and combining them with other fats ensures a good mix of omega-3, omega-6, and other essential fatty acids.
Alternatives to Seed Oils
In addition to seed oils, other nutritious plant-based oils to consider include:
- Olive oil
- Avocado oil
- Coconut oil
These alternative oils provide a different composition and nutritional benefits, complementing seed oils.
However, you don’t have to avoid seed oils. In fact, the American Heart Association (AHA) suggests that canola, corn, peanut, safflower, sunflower, vegetable, and soybean oils are classified as heart-healthy.
Key Takeaways
What are seed oils? The key points regarding seed oils and their potential health impacts include:
- Seed oils are sourced from plant seeds and contain a mix of omega-3 fats, omega-6 fats, other fatty acids, vitamins, and antioxidants.
- Claims that seed oils are harmful aren’t backed by research.
- Choosing unrefined (virgin) oils rather than refined oils preserves the oil's nutritional content and avoids chemical use during processing.
- It’s best to consume a variety of plant-based oils, including seed oils, olive oil, avocado oil, coconut oil, and others — as well as fats present in nuts, seeds, avocados, and nut butter.
Consumers should rely on scientific evidence rather than social medical influencers for health advice. Many experts agree that there’s no reason to cut back on whole foods containing omega-6 fats, which are the dominant fatty acids in many seed oils.
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