Seed Oils

Podcast Transcript

Whether or not you are aware of it, in the last day, if you are anywhere near average, there is a very good chance that you have consumed seed oils.

Seed oils are everywhere in the modern diet. They are contained in almost every processed food and a great many foods prepared at home and in restaurants.

For one of the biggest components of the modern diet, surprisingly, it was completely absent from human diets just a little over a century ago.

Learn more about seed oils, what they are, and how they are made on this episode of Everything Everywhere Daily.

Before I get into the discussion of seed oils and their surprising history, I should explain what it is I’m talking about when I refer to seed oils and what I’m not referring to.

Seed oils are commonly known as vegetable oils. However, the term vegetable oil is really a misnomer and a marketing term because there are no vegetables in vegetable oil.

They are made out of seeds and grain, and hence, for the rest of this episode I will be referring to them as seed oils.

The most common seed oils are cottonseed, soybean, corn, sunflower, safflower, and canola. These are also sometimes referred to as industrial seed oils to separate them from other oils.

What I am not talking about when I refer to seed oils are oils such as olive oil, coconut oil, avocado oil, and sesame oil. These are often referred to as cold pressed oils.

Cold pressed oils have been around for thousands of years and they are produced by a very simple process. You take the olives or coconuts and you press them under a heavy weight to get the oil out.

I remember watching a man in Kerala, India making coconut oil. He took hunks of coconut and fed them into a machine with two rollers that compressed the coconut and then oil drained out into a jug. The oil ran through a simple filter to remove the impurities, but that was it.

Olive oil and other cold pressed oils are all made in a similar way which is why they are thousands of years old.

Cold pressed oils are made from seeds or fruits which are heavily laden in oil. Seed oils, as they are normally defined, are not.

Before industrialization, seed oils were not a major part of human diets. Traditional societies used animal fats like lard, tallow, and butter, and in some regions, cold-pressed oils from olives, coconuts, or sesame.

The seeds of plants such as flax aka linseed, hemp, and castor were occasionally used to produce oil for lamps, paints, and medicinal purposes rather than for food.

The development of mechanical presses in the 19th century allowed the extraction of oil from seeds that had been previously impractical to press by hand.

In the early 1800s, mechanical screw presses were developed that could extract more oil than traditional methods.

By the mid-1800s, the development of hydraulic presses allowed for much greater pressure to be applied to seeds, significantly increasing oil yields.

The first widely used industrial seed oil in the U.S. was cottonseed oil. In the late 1800s, cottonseed was a waste byproduct of the cotton industry. With the invention of more efficient presses, entrepreneurs realized it could be refined and marketed as an oil.

Cottonseeds were long considered a waste byproduct of cotton fiber production, particularly in the American South, where cotton was a dominant crop throughout the 18th and 19th centuries. For much of that time, cottonseeds were discarded or used sparingly as livestock feed and fertilizer.

But by the mid-19th century, the advances in mechanical pressing made it possible to extract oil from the seeds, leading to new industrial applications. Initially used in the production of soap, candles, and lubricants,

Cottonseed oil was not used for human consumption at this time because it had a very bitter taste and often had impurities.

In the early 20th century, two key chemical breakthroughs laid the foundation for the industrial use of seed oils: the Sabatier process and Wilhelm Normann’s hydrogenation technique.

The Sabatier process, developed by French chemist Paul Sabatier, involved reacting hydrogen with carbon dioxide over a nickel catalyst to produce methane and water, demonstrating the powerful catalytic properties of nickel in facilitating hydrogenation reactions. Building on this catalytic principle, Wilhelm Normann, a German chemist, applied it to organic fats and oils.

In 1903, Normann patented a process for the hydrogenation of liquid unsaturated fatty acids, using hydrogen gas and a nickel catalyst to convert them into more saturated, solid fats.

Both Sabatier and Normann shared the 1912 Nobel Prize for Chemistry for their work.

Normann’s patent was purchased by Joseph Crosfield and Sons, who intended to use it for making soap. However, another soap manufacturer, Procter and Gamble, hired their chief chemist and filed their own patents, which refined the technique for its use on cottonseeds and for storage at room temperature.

Their idea was to use this solid crystallized cottonseed oil as a food product. The name they came up for this crystalized cottonseed oil was…..Crisco.

Crisco, introduced in 1911, had a similar texture and color as lard as was sold as a lard replacement. It was marketed as a modern way to cook.

They gave away cookbooks to housewives where every recipe used Crisco as an ingredient.

Sales of Crisco skyrocketed over the next several decades.

They also funded a very small organization 1948 with a $1.5 million donation called the American Heart Association.

World War I and World War II accelerated the development and production of seed oils, both for industrial uses and as cheap food substitutes. Animal fats were diverted to the military or in short supply, and seed oils—especially soybean oil—began to replace them.

The rise of industrial agriculture in the mid-20th century, especially in the United States, led to an explosion in production of corn, soybeans, and other oilseed crops. These were subsidized, grown in vast monocultures, and heavily processed into oils.

Soybean oil, in particular, became dominant. By the 1950s, it had overtaken butter in the American diet. It was promoted as a healthier, plant-based alternative to saturated fats, coinciding with the growing influence of the lipid hypothesis that associated saturated fats with heart disease. Soybeans also provided a double yield—protein for animal feed and oil for human consumption—making them an economically efficient crop.

Corn oil followed a similar path. As the corn surplus mounted in the U.S., manufacturers developed new uses for it. Corn oil, extracted from the germ of corn kernels, was marketed as a “heart-healthy” oil in the mid-20th century.

Likewise, canola, sunflower, safflower and other seed oils grew in popularity as more techniques were developed which allowed them to be sold.

If you have ever been to a farmers market, the one thing you are highly unlikely to ever find is artisanal or hand made seed oils. That is because it is a highly industrial process that can’t be easily replicated at a small scale.

Modern industrial processing of seed oils involves a sophisticated multi-stage process designed to maximize yield and create a shelf-stable, neutral-tasting product.

After seeds are cleaned, dehulled and crushed into flakes, oil is extracted through mechanical pressing and/or chemical solvent extraction using hexane.

The raw oil then undergoes a series of refinement steps: degumming removes phospholipids using water or acid; neutralization eliminates free fatty acids with alkaline solutions; bleaching with activated clay removes pigments and remaining impurities; and deodorization—where high-temperature steam distillation of up to 500°F/260°C strips away volatile compounds that create odor and flavor.

Optional further processing may include winterization, which is chilling and filtering to remove waxes and the addition of antioxidants to prevent it from becoming rancid.

This highly mechanized, chemical-intensive process transforms seeds with relatively modest oil content into the clear, tasteless, oxidation-resistant cooking oils that have become ubiquitous in modern food manufacturing and kitchens worldwide.

Because it is an industrial process which can be done at scale, and because the inputs are often grains which are subsidized and grown on an industrial scale, seed oils have become extremely cheap.

In the second half of the 20th century, the processed food industry exploded, and seed oils became a cornerstone of mass production due to their neutral flavor, stability, and low cost. They were used in everything from baked goods and salad dressings to margarine, snack foods, and fast food fryers.

This led to a staggering increase in seed oil consumption. Globally, seed oils became the dominant source of dietary fat by the late 20th century, shaping modern eating habits and sparking ongoing debates about their long-term health effects.

According to the Food and Agriculture Organization, the FAO, and data, from the Organisation for Economic Co-operation and Development, the global average seed oil consumption is around 27 kg per person per year or roughly 60 pounds. This equates to about 74 grams per day, or more than 6 tablespoons of oil daily.

Americans consume closer to 35–40 kg or 77–88 pounds per year, with most of this coming from the likes of soybean and canola oil.

By some estimates, Americans consumed almost zero industrial seed oils in 1900, but now they make up over 20% of daily caloric intake, primarily via processed foods and restaurant cooking.

The substitution of seed oils for traditional fats represents the most significant dietary change in human history.

This isn’t just the United States or other developed countries. Everywhere I traveled around the world I saw seed oils, often in very large plastic jugs, on sale in markets and in use.

Given what an enormous part of the average human diet seed oil has become, it should come as no surprise that it is a very big business.

In terms of market value, the global oilseed market was estimated to be $260 billion in 2024. It is projected to grow at a compound annual growth rate of approximately 4%, reaching approximately $387 billion by 2034.

Soybeans dominate this market, accounting for over 59% of the total revenue share in 2024. I’ll probably do an episode on soybeans in the future.

What has been the implication of this surge in seed oil consumption in such a historically short period of time?

Initially, many of the seed oils created by hydrogenation were high in trans fats.

In the early 2000s, after decades of research, trans fats were declared hazardous, prompting reformulations of many seed oil products. The FDA banned artificial trans fats in the U.S. food supply in 2015, leading companies to use alternative processes such as interesterification or switch to non-hydrogenated oils.

Another possible health concern is omega-6 polyunsaturated fatty acids. Most seed oils are high in omega-6 polyunsaturated fatty acids.

Omega-6 occurs naturally and it is has been consumed by humans since the dawn of time.

However, they were consumed alongside Omega-3 fatty acids.

Traditional diets had omega-6 to omega-3 ratios estimated at 1-to-1 to 4-to-1.

The ratio was dependent on where people lived and the local foods they ate.

Modern diets, partially due to seed oil consumption, often have ratios of 15:1 to 20:1

Some research suggests this imbalance may promote inflammation.

The rise in seed oil production has also resulted in large amounts of land devoted to crops for its creation.

I should also note that seed oils aren’t just used for food, although that is the biggest part of the market. It’s a major ingredient in cosmetics, soaps, shampoos, detergents, and biofuels.

I’ve covered many technologies that have changed the world, especially during the 20th century. Many of these such as electricity, the automobile, and the internet are very obvious to see how it has impacted our daily lives.

Seed oils are arguably just as important. They have gone from not being consumed by humans at all to becoming an enormous part of the daily diet of people all over the world in just a century.

Unlike other technologies, most people aren’t even aware of the massive change that have taken place. Check out the ingredients of almost any processed food product today and you’ll find seed oils somewhere in the ingredients list.

It all started with a technique developed in the early 20th century which made a machine lubricant into an edible food product.