Vegetable and Seed Oils: Healthy or Not?

August 6, 2024

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Image of a hand pouring a miscellaneous seed or vegetable oil over a tray of carrots. — Are vegetable oil and seed oil bad for you? It depends. Credit: Anna Pyshniuk Pexels

When you start searching for information on seed oils, one key question comes up over and over again: are vegetable oil and seed oil bad for you?

A quick scroll on social media and you’ll run into opinions from both sides. Many comments are likely to deem these oils “poison” or “toxic” — but you’re just as likely to see responses from others saying seed oils are heart-healthy.

So, what’s the truth? Read below to learn what vegetable and seed oils are all about, what foods you can find them in, and a deeper look into both sides of the argument through the lens of evidence-based research.

What Are Vegetable and Seed Oils?

Seed oils come from the extracted seeds of plants.

Examples of seed oils include:

corn
sunflower
canola (rapeseed)
soybean
grapeseed
peanut
cottonseed
pumpkin seed
chia seed
rice bran
sesame

Seed Oils Are Made from One of Two Methods

Seed oils are typically made by one of two common methods: oil extraction or cold pressing.

Oil extraction involves exposing the plant seeds to high temperatures and pressures to extract the oil.

Cold pressing involves crushing seeds to extract their oils.

Research reports that oil extraction produces more yield, but also more impurities, which is why oils made with this method must be refined before use¹. In contrast, cold-pressed oils do not require refining.

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What Food Products Contain Seed and Vegetable Oils?

Seed and vegetable oils are in a variety of food products, so you’re probably consuming at least some of these oils without even realizing it. Part of the reason why these oils get a bad reputation is because most of the food products that contain seed and vegetable oils are heavily processed.

Image of a large bowl of pink salt, two halves of an avocado covered in seeds, and a bottle of seed or vegetable oil on a marble countertop. — *You may be consuming seed and vegetable oils in a number of food products without even realizing it.* – Credit: Ready Made Pexels

16 Processed Food Products That Contain Vegetable or Seed Oils²:

salad dressings
mayonnaise
cooking oils
shortening
chips
candy
fried foods
prepackaged frozen meals
baked goods
margarine
microwave popcorn
certain baby formulas
certain prepared protein drinks or meal replacement drinks
coffee creamers
prepackaged cake frosting
dairy-free cheese products

However, it’s also important to note that there are some “natural” or minimally processed foods that contain seed or vegetable oils.

Natural Food Products That Contain Vegetable or Seed Oils

seasoned frozen vegetables
granola and granola bars (try a homemade bar recipe to avoid added sugars and artificial ingredients!)
roasted nuts
nut butters (and if you’re having trouble choosing, consider picking one from this nutritionist-approved list of the seven healthiest nut butters)

Are Seed Oils Bad for You? The Arguments on Both Sides of the Debate

“Seed Oils Are Bad”

For people on this side of the debate, the first question we need to address is: why are seed oils bad for you? The major concern of those who believe seed oils are bad is that the omega-6 and omega-3 ratio in the human body is higher when you consume such oils. According to a 2018 study, intake of omega-6 fatty acids (also known as linolenic acid) promotes oxidative stress, which may increase the risk of heart disease³.

When a person consumes a healthy ratio of such fatty acids (anywhere between 2:1 and 6:1 omega-3 to omega-6 fatty acids⁴), these fats can work together to help store energy in cells and play a role in cell division and growth. But when the ratio of omega-6 fatty acids is higher than the omega-3 fatty acid ratio, the risk for heart disease can increase³. Examples of oils containing omega-6 fatty acids include soybean, canola, sunflower, and peanut oils, while flaxseed, walnut, and olive oils are high in omega-3 fatty acids.

Does Refining Seed Oils Strip Them of Nutrients?

The other response you might hear when you ask why seed oils are bad is that they undergo refining, which strips the oils of nutrients. Research shows that this is in fact true — but not always. Refining is necessary for certain vegetable oils to increase shelf life and eliminate undesirable compounds⁵. And it’s true that this process can also strip the oils of compounds like tocopherols, polyphenols, and carotenoids, which are antioxidants that can reduce oxidative stress in cells.

Not Every Seed Oil Loses Its Nutrients Through Refining

A 2024 study shows that pomegranate seed oil has a higher resistance to losing antioxidants through thermal processing than other seed oils like sesame oil⁶. A 2023 study also shows that heating certain seed oils like coconut, grapeseed, and rapeseed oil does not compromise their safety or fatty acid profile⁷. Therefore, it’s safe to say that not all seed oils lose nutrient value through refining.

“Seed Oils Are Healthy”

Is vegetable oil bad for you or is vegetable oil healthy? Are seed oils good for you or are seed oils bad for you? Those on the “seed oils are healthy” side of the debate argue that although the omega-6 fatty acids in vegetable oils could increase the risk of heart disease, they are better than other fat alternatives.

A 2021 study reports that replacing butter or margarine intake with vegetable oils like canola, corn, or olive oils can actually reduce the risk of heart disease⁸. Furthermore, a 2023 study shows that olive oil, corn oil, cress oil, and rice bran oil feature an abundant number of nutritious compounds⁹.

Despite the fact that some seed oils may have health benefits, it’s worth prioritizing balance when it comes to your health. In order to offset any potential drawbacks of the omega-6 fatty acids in vegetable oils, it’s important to incorporate more than one type of vegetable oil into your diet.

Are Vegetable Oil and Seed Oil Bad for You? Not Always

The key thing for people on both sides of the debate to remember is that not all seed and vegetable oils are the same. Health experts suggest that seed oils do not need to be cut from your diet completely. In moderation, certain oils can actually be beneficial to your health and may have anticancer properties.

In fact, a 2024 animal study reports that chia seed oil extracted by cold pressing is rich in omega-3 fatty acids and may help prevent risk factors for heart disease¹⁰ (not to mention some surprising benefits for your skin!) Human studies need to be done to confirm these findings, but they are promising.

Every Seed Oil Is Different

Studies done on other specific seed oils help illustrate the point that every seed oil is different. A 2023 study shows there is sufficient evidence that seed oils such as pomegranate seed oil, flaxseed oil, and rice bran oil can reduce risk of heart disease, while coconut oil or perilla seed oil may benefit those with diabetes due to their higher phenolic content¹¹.

A 2024 study also reports that pumpkin seed oil is a healthy vegetable oil known to have anti-inflammatory and antioxidant properties, which in turn may help reduce risk of certain cancers and cardiovascular diseases¹². Not to mention that seed oil mixtures such as those containing apricot, date, grapeseed, broccoli seed, and black seeds have potent antibacterial qualities that could have promising medical applications¹³^,¹⁴.

Should I Add Seed and Vegetable Oils to My Diet?

After reading the above, you might ask: “Why are seed oils bad?” There certainly seems to be enough research saying otherwise. The reason this common misconception has spread is because some health and wellness reporters are not taking the time to stay up to date with the latest research (or interpret it with the nuance it deserves).

Consider Limiting Your Intake of Processed, Fried, and Fast Foods

Research shows that it is not so much the seed and vegetable oils themselves that cause oxidative stress, or cell damage, in the body. In most cases, it’s the types of food that these oils are often found in, such as highly processed, fried, or fast foods that lead to chronic disease¹⁵. Another factor that influences the impact of seed and vegetable oils on health outcomes is the portion size of these oils that are consumed on a regular basis, as well as the variety of oils (or lack thereof).

Studies show that consumers can reduce their risk of potential heart disease by consuming oils that do not undergo refining, such as those that are cold pressed¹⁶. One 2023 study goes as far as to argue that many consumers can reap health benefits from vegetable oils because they can provide an important energy source at a low cost¹⁷. Experts simply recommend that consumers avoid heating these oils for long periods of time (so avoid deep-frying!), which releases potentially harmful compounds¹⁸.

Where Does Olive Oil Land in All of This?

Olive oil is a type of vegetable oil that is a large part of the well-known Mediterranean diet. Its omega-3 fatty acid content has the potential to improve gut health, and its phytonutrient content can lower cholesterol¹⁹.

Image of a small glass bowl on a countertop being filled with olive oil, alongside a few olives and metal tools. — *Olive oil is one of the most popular vegetable oils — and luckily, it has a number of health benefits.* – Credit: Pixabay Pexels

A 2023 study also reports that virgin oils like certain olive oils, especially those that are cold pressed, can have significant positive impacts on brain health²⁰. The omega-3 fatty acids in olive oil even show promise to reduce risk of certain cancers like breast cancer²¹. In other words, while it’s still good to be mindful of how much you use, there’s no need to throw away that new bottle of EVOO (and here’s our favorite Italian olive oil, while we’re at it)!

The Takeaway: My Top 3 Recommendations As a Registered Dietitian

1. Stop Following Uneducated Influencers for Science and Nutrition Advice

As a registered dietitian, my first piece of advice is to stop looking to social media for guidance. When in doubt, look to food science and nutrition experts for recommendations on making choices related to your diet.

2. Choose the Right Oil for the Right Job

My second piece of advice is to choose appropriate oils for the way you are going to use them. For example, olive oil has a medium smoke point, which makes it perfect for tasting or for lower temperature recipes like slow-roasting vegetables or fish²².

You should only use lower smoke point oils like flaxseed, pumpkin seed, or walnut oil, for recipes that don’t require heat, like salad dressings. For recipes that involve pan-frying, deep-frying, or sautéing, use oils with a higher smoke point such as avocado, corn, canola, or peanut oils.

Image of a pan on a four-burner stove, with a chef drizzling a vegetable or seed oil into the pan. — *To cook with seed and vegetable oils in the healthiest way possible, be sure you’re using the right oil based on its smoke point.* – Credit: RDNE Stock Project Pexels

And if you’re still not sure which oil to use with your dinner tonight, check out this handy list to find out where your preferred cooking oil stacks up.

3. Reduce or Eliminate Highly Processed, Fried, and Fast Foods from Your Diet

My third and final piece of advice is to limit your intake of highly processed foods, also known as ultra processed foods, which contain seed or vegetable oils for texture or flavoring. A 2020 study shows that the fats and sugars in these foods increase inflammation in the body, which can lead to disease states like diabetes and heart disease²³.

P.S. Did you know? Organic Authority has its own nutrition and wellness shop to meet your needs and help you take control of your health. Shop clean supplements for energy, sleep, inner beauty for skin support, protein, workouts, pantry items and more. Shop The Organic Authority Shop now.

Note! The opinions and views expressed by the authors at Organic Authority in blogs and on social media and more, are theirs alone and do not necessarily reflect the views, opinions or position of Organic Authority, Inc and do not necessarily represent the views of Organic Authority sponsors and/or partners. Organic Authority content is for informational and entertainment purposes, and any views expressed should not be accepted as a substitute for qualified expertise. Any highlighted alternative studies are intended to spark conversation and are for information purposes only. We are not here to diagnose or treat any health or medical conditions, nor should this be relied upon as a substitute for professional medical advice, diagnosis or treatment, even if it features the advice of medical practitioners and physicians. When making any lifestyle or health changes, consult your primary care physician.

Sources:

Staci has been a registered dietitian since 2010 and has treated hundreds of patients for nutrition-related issues ranging from… More about Staci Gulbin, Registered Dietitian

Tags:cooking oils heart healthy olive oil refined oil Registered Dietitian seed oils vegetable oils