Seed Oils: What They Are, a USDA Fat Chart and What Research Shows

Seed oils are cooking oils pressed or extracted from plant seeds, such as soybean, canola, corn, cottonseed, sunflower, safflower and grapeseed oil. Online they are often blamed for inflammation and chronic disease, mostly because many of them are rich in the omega-6 fat linoleic acid. The research picture is more reassuring than the headlines: controlled trials have not found that linoleic acid raises inflammation markers in healthy people, large cohort studies link higher linoleic acid levels with lower cardiovascular risk, and the American Heart Association supports liquid plant oils in place of saturated fat. Real questions remain, though, and this guide covers both sides with USDA data.

Peptide Labs does not sell seed oils or cooking oils. This article is general nutrition information, not medical advice.

What are seed oils? A seed oils list

There is no official definition, so the phrase usually means the inexpensive, neutral-tasting oils used in home kitchens, restaurants and packaged foods. A typical seed oils list includes:

• Soybean oil, often sold simply as vegetable oil.
• Canola oil, from a rapeseed variety bred for food use.
• Corn oil, pressed from the germ of the kernel.
• Cottonseed oil, used in frying and processed foods.
• Sunflower and safflower oils, sold in standard (high-linoleic) and high-oleic versions.
• Grapeseed oil and rice bran oil, the second technically from the bran rather than a seed.

Olive, avocado and coconut oils come from fruit flesh, not seeds, so they are usually left off the list. Seed oils also show up inside foods rather than only in the bottle: fried foods, chips, crackers, dressings and many packaged baked goods are made with them.

Seed oil fat profiles per tablespoon (USDA)

Every cooking oil has roughly the same calories, about 120 per tablespoon, so the real differences are in the type of fat. The table uses USDA FoodData Central SR Legacy entries (FDC IDs in brackets) and the FDA Daily Value of 20 grams for saturated fat. Linoleic acid is the main omega-6 fat; ALA is the plant omega-3.

Two patterns stand out. First, the seed oils are low in saturated fat compared with butter or tallow. Second, they are not one food: canola is mostly monounsaturated and carries the most plant omega-3 of the group, the high-oleic sunflower and safflower oils look more like olive oil than like corn oil, and grapeseed, standard sunflower, corn and soybean oils are dominated by linoleic acid. Lumping every seed oil together misses most of what matters.

Why are seed oils controversial?

Critics raise a handful of recurring arguments. Linoleic acid can be converted into arachidonic acid, a building block for some inflammatory signaling molecules, so a diet rich in it is said to be pro-inflammatory. Critics also note that Americans eat far more omega-6 than omega-3 and call that ratio unhealthy. Commodity oils are industrially extracted and refined. Polyunsaturated fats oxidize more readily than saturated fats, especially with heat. And seed oil use rose over the same decades as obesity and diabetes, although a shared timeline does not show cause and effect. Each argument contains a real fact; the question is whether it translates into harm when people actually eat these oils.

Are seed oils bad? What the research shows

Here are the main lines of evidence, from controlled trials, pooled cohort data and the recovered trials that critics cite most often.

• Inflammation (Johnson and Fritsche, 2012): a systematic review of 15 randomized trials in healthy people found that adding linoleic acid to the diet did not raise markers such as C-reactive protein, fibrinogen, cytokines or tumor necrosis factor. The authors concluded there was virtually no trial evidence that it increases inflammatory markers.
• AHA science advisory (2009): the American Heart Association reviewed omega-6 evidence and said it is incorrect to view these fats as pro-inflammatory, noting that eating less linoleic acid does not lower tissue arachidonic acid because the body tightly regulates that conversion.
• Pooled cohorts (Marklund and colleagues, 2019): 30 studies in 13 countries with 68,659 participants measured linoleic acid in blood or fat tissue. Higher levels were linked to lower risk of cardiovascular disease, cardiovascular death and ischemic stroke. This is observational, and two authors reported research support from Unilever, a food company.
• AHA presidential advisory (2017): trials that replaced saturated fat with polyunsaturated vegetable oil cut cardiovascular disease by about 30%, while swapping saturated fat for refined carbohydrates and sugar did not help.
• Recovered trials (Ramsden and colleagues, 2013 and 2016): reanalyzed data from the Sydney Diet Heart Study (458 men after a heart event, safflower oil) showed more deaths in the linoleic acid group, 17.6% versus 11.8%. The Minnesota Coronary Experiment (9,423 people in a nursing home and mental hospitals, corn oil) lowered cholesterol without reducing deaths. Both trials ran from the late 1960s to the early 1970s, with diets very different from today’s.
• Cochrane review (Hooper and colleagues, 2018): 19 trials with 6,461 people found low-quality evidence that eating more omega-6 fat makes little or no difference to deaths or cardiovascular events.

Put together, the evidence does not support the claim that seed oils are toxic, and replacing saturated fat with them lowers LDL cholesterol. It also does not prove large benefits, and the oldest trial data keep the debate alive. If you have heart disease or high cholesterol, talk with your clinician about your overall eating pattern rather than a single oil.

Linoleic acid and the omega balance question

Linoleic acid and the plant omega-3 ALA are both essential fatty acids, meaning the body cannot make them, according to the NIH Office of Dietary Supplements. That is worth remembering when seed oils are called unnatural. Rather than cutting omega-6, the practical lever for the ratio is adding omega-3: canola and soybean oils, flaxseed, chia seeds and walnuts supply ALA, while fatty fish supply the long-chain forms, because the body converts very little ALA into them. See our omega-3 guide and krill oil vs fish oil comparison for more.

What the Dietary Guidelines say

The 2020-2025 Dietary Guidelines for Americans told people to choose canola, corn, olive, peanut, safflower, soybean and sunflower oils rather than butter, shortening, or coconut or palm oils. The 2025-2030 edition, released in January 2026, shifted the tone: it says to prioritize oils with essential fatty acids, such as olive oil, and that other options can include butter or beef tallow. It keeps saturated fat below 10% of calories, says limiting highly processed foods helps meet that goal, and admits that more high-quality research is needed to know which fats support long-term health. Our guides to avocado oil, coconut oil and ghee compare those fats in detail.

Cooking, packaged foods and practical choices

Some concerns about seed oils are really concerns about how they are eaten. Seed oils are common in fried foods and packaged snacks, and the AHA’s 2021 dietary guidance favors liquid plant oils over tropical oils and partially hydrogenated fats while steering people toward minimally processed foods. A few practical points follow from the data above:

• High-oleic versions of sunflower and safflower oil are mostly monounsaturated, which makes them less prone to oxidation than high-linoleic oils.
• Store oils cool and dark: heat, light and air speed oxidation, so replace oil that smells stale.
• Look at the whole food: fried and ultra-processed foods bring salt, refined starch and sugar along with the oil, so swapping the oil alone changes little.
• Warfarin users: soybean oil has about 21% of the vitamin K Daily Value per tablespoon in USDA data, and MedlinePlus warns against large amounts of vegetable oils high in vitamin K, so keep intake consistent and ask your clinician before changing your diet.

For an eating pattern built around plant oils, see our Mediterranean diet guide and our guide to leafy greens, which pair naturally with an oil-based dressing.

Frequently Asked Questions

Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Last reviewed October 2026.

Related guides: Olive Oil Benefits: Research, Nutrition and Types of Olive Oil, Omega-3: Benefits, Foods, Side Effects and Heart Research, Avocado Oil: Nutrition, Benefits, Olive Oil Comparison and Quality.