Are Seed Oils Bad For You? – NewYork-Presbyterian – Health Matters

An integrative health specialist breaks down what to know about seed oils, including if they are healthy and how to choose the best oil to use.

Published May 29, 2025

Written by Camille Bautista-Fryer

Seed oils are a pantry staple used in everything from sauteed vegetables and salad dressings to French fries and potato chips. They’ve also been making headlines as social media users debate if seed oils are bad for our health. So what’s the truth about seed oils? Are they toxic or do they have health benefits?

“There is no reason to be afraid of seed oils,” explains Dr. Michelle Loy, an integrative health specialist at NewYork-Presbyterian/Weill Cornell Medical Center. “Minimally processed seed oils, like flaxseed oil or sesame oil, can be added in small amounts to dishes like cooked vegetables to help improve taste and increase your vegetable intake while providing essential fatty acids.

“But rather than demonizing seed oils or putting one type of fat over another on a pedestal, we should focus our attention on eating whole, unprocessed foods naturally rich in fiber.”

Dr. Loy shared more with Health Matters on the difference between vegetable oils and seed oils, and how to choose the right one for your diet.

What are seed oils?

Dr. Loy: Seed oils are a type of oil made from a plant’s seeds rather than its fruit. The oils are extracted from the seed through a mechanical or chemical process that may include bleaching, refining, and heating.

Common types include:

• Canola oil
• Corn oil
• Flaxseed oil
• Grapeseed oil
• Peanut oil
• Safflower oil
• Sesame oil
• Sunflower oil
• Palm Kernel oil

Is vegetable oil a seed oil? What’s the difference?
All seed oils are vegetable oils, but not all vegetable oils are seed oils.

Technically, oils that are derived from the vegetable or fruit itself (and not the seed) are not seed oils. Examples would be olive oil, avocado oil, coconut oil, or palm oil.

Vegetable oils, including seed oils, tend to be high in unsaturated fats, meaning they are liquid at room temperature, compared to trans-fats or saturated fats, which are solid at room temperature. Saturated fats can contribute to higher levels of cholesterol.

Seed oils have more polyunsaturated fats, or “healthy fats,” and have been associated with lowering risk of cardiovascular disease and cancer.

Why do people think seed oils are bad for you?
This is what people are saying about potential risks of seed oils and what people should know and consider.

Increased calories: Calories can add up in any high-fat diet, regardless of whether it’s saturated or unsaturated. It’s easier to overconsume calories in oil form than in food form.

The Bottom Line: Think about how easy it is to drench salads with dressing versus how many olives you can consume in one sitting. Choosing whole foods is always healthier. But seed oils can be sources of heart-healthy fats when used in moderation.

Chemical processing: To some extent, seed oils are processed and may be extracted by hexane, a solvent. Cold-pressed oils tend to be preferential to hexane-extracted oils.

The Bottom Line: The main problem with some seed oils and vegetable oils is that they’re typically found in processed, packaged foods. The oil isn’t the main concern. Rather, it’s the foods that seed oils associate with — what I call the “friend group.” These foods tend to be high in sugar, high in sodium, low in protein, and low in fiber (such as chips, crackers, and baked goods).

Inflammation: Seed oils can be high in omega-6 fatty acids, which are a type of unsaturated fat. Too much omega-6 in our diet can contribute to inflammation.  

The Bottom Line: The body doesn’t produce omega-6 on its own, so it’s necessary to get it from foods. Including more foods with omega-3, such as flax and chia seeds; nuts like almonds, pecans, walnuts; fatty fish, like salmon and mackerel; can help balance omega-6 fatty acids since omega-3 has more anti-inflammatory benefits.

Are there any benefits to seed oils?
Seed oils contain both omega-3 and omega-6 unsaturated fats, which in moderation, are important for functions like hormonal regulation, brain health, and fat-soluble vitamin absorption. Omega-3 fatty acids are also linked to reduced risk of heart disease.

What should people consider when shopping for a cooking oil?
From a health perspective, most seed oils are comparable. Choose the one that fits the flavor profile of your dish, is minimally processed, and fits your budget. And think of using it as a finishing touch rather than as the main cooking liquid.

Remember that it’s probably more important what you’re cooking the oil with, rather than which oil you use. For example, steamed vegetables with a splash of olive oil and lemon juice are healthier than deep fried French fries with palm kernel oil or beef tallow.

Additional considerations include:

• Environmental factors: Those who are environmentally conscious may want to limit palm kernel oil. In addition to the high saturated fat content, it negatively contributes to environmental deforestation.
• Smoke points: Because most seed oils are high in unsaturated fats, they have lower smoke points and are less stable at high heats. For sauteeing or roasting foods at temperatures higher than 400°F, try to choose seed oils with a higher smoke point, such as canola, sesame, safflower or peanut. Oils with lower smoke points, such as walnut or flaxseed, can be reserved for dressings and marinades or used as a finish over cooked foods. Vegetable oils like avocado oil, coconut oil, palm oil can be heated to higher temperatures.
• Health conditions: For patients at risk for cardiovascular conditions and are choosing between types of fat, I recommend seed oils or vegetable oils over solid, saturated fats like coconut oil, lard, tallow, or bacon fat. For patients who need to follow a calorie-restricted diet or limited fat diet for medical reasons, they can opt for air frying or cooking with alternatives like water, broth, citrus juice, vinegar, or pureed beans or tofu.

What do you tell patients about seed oils?
As a physician, I urge my patients, colleagues, and the public to focus on eating nutrient-dense, whole foods rather than getting caught up in the latest dietary fads. Whole foods are not only healthier but also more practical and often less expensive than processed alternatives.

We don’t need more “healthy snacks” made with various types of oils/fats or “clean sugars.” We need to focus our efforts on increasing access to whole foods like apples, nuts, hummus, carrots, and edamame. Nutrient-rich, vitamin and mineral-rich, antioxidant, fiber-rich, and anti-inflammatory foods provide the nutrients needed to feed our minds, bodies, and microbiomes while minimizing our exposure to the excess fat, sugar, salt, artificial flavorings, additives, and colorings in processed foods.