Share this
The world of dietary fats is fraught with confusion, contradictory advice, and simplified messaging that often misses crucial context. Few nutritional topics generate as much debate as industrial seed and vegetable oils—canola, soybean, corn, safflower, sunflower, and cottonseed oils, among others. These oils have become ubiquitous in our food supply, yet public understanding of their role in our diet remains murky at best.
This article is the first in a three-part series - written by our partner Synergy Health - exploring the complex relationship between industrial oils and health. Rather than adding to the chorus of voices simply labeling these oils as "good" or "bad," we aim to provide the context necessary for truly informed dietary choices.
The story of industrial seed oils isn't simply about biochemistry or nutritional composition—it's about food systems, processing methods, consumption patterns, and how nutrition science sometimes falls short in its reductionist approach to studying individual nutrients divorced from their food matrix and dietary context.
Understanding Industrial Seed and Vegetable Oils
What Are Industrial Seed and Vegetable Oils?
Industrial seed and vegetable oils are extracted from seeds, grains, and some fruits using mechanical and chemical processes that weren't possible until the 20th century. The most common include:
- Soybean oil – One of the most widely consumed oils
- Canola oil – Developed from rapeseed, marketed as heart-healthy
- Corn oil – A byproduct of corn processing
- Sunflower oil – Extracted from sunflower seeds
- Safflower oil – From the seeds of the safflower plant
- Cottonseed oil – Initially a waste product of cotton production
- Grapeseed oil – A byproduct of wine-making
What separates these from traditional cooking fats (like butter, lard, olive oil, and coconut oil) is not just their source, but the extensive processing required to produce them.
A Brief History: From Obscurity to Ubiquity
The story of industrial seed oils begins relatively recently in human history. While olive oil has been pressed for thousands of years and animal fats have been used throughout human existence, the extraction of oil from seeds and grains required industrial technology that didn't exist until the late 19th and early 20th centuries.
Cottonseed oil was one of the first seed oils to gain commercial importance in the United States. Initially a waste product of cotton production, it became marketable when Procter & Gamble developed a process to make it palatable, eventually creating Crisco (a solid cooking fat) in 1911. This represented a significant shift—for the first time, a laboratory-created fat was replacing traditional animal fats in American kitchens.
The mid-20th century saw further expansion of seed oil production, driven by:
- Agricultural policy that subsidized grain and seed production
- Emerging nutritional guidance in the 1950s-1970s that began to caution against saturated fats
- Food processing advances that required stable, shelf-stable, inexpensive oils
- Economics – seed oils were cheaper to produce at scale than traditional animal fats
By the 1990s, these once-obscure industrial oils had become the dominant source of dietary fat in many Western countries, particularly in processed and restaurant foods.
The Manufacturing Process: Not Your Grandmother's Kitchen
Understanding how industrial seed oils are produced helps explain why they differ fundamentally from traditional fats:
Extraction: Most seeds naturally contain relatively little oil and require extensive processing to extract it. This typically involves:
- Cleaning and grinding the seeds
- Pressing with tremendous force
- Solvent extraction (typically using hexane, a petroleum-derived chemical) to obtain the remaining oil
Refining: The crude oil then undergoes multiple refinement steps:
- Degumming to remove phospholipids
- Neutralization to remove free fatty acids
- Bleaching to remove pigments and remaining impurities
- Deodorization (heating to extremely high temperatures) to remove volatile compounds and odors
Modification: Some oils undergo additional processing:
- Hydrogenation (adding hydrogen atoms to create more solid fats)
- Interesterification (rearranging fatty acid positions)
- Fractionation (separating different types of fatty acids)
The result is a product far removed from its natural state—colourless, odorless, and flavourless oils that bear little resemblance to their source foods and contain few of the nutrients that would naturally accompany fats in whole foods.
This extensive processing stands in stark contrast to traditional fat production:
- Butter: cream separated from milk and churned
- Lard: rendered from animal fat with low heat
- Olive oil: cold-pressed from olives
- Coconut oil: extracted from coconut meat with minimal processing
Nutritional Composition: What's In (and What's Missing)
Industrial seed oils are primarily composed of polyunsaturated fatty acids (PUFAs), particularly linoleic acid (an omega-6 fatty acid). While these are essential fatty acids that our bodies need, the quantity and ratio in which we now consume them differs dramatically from historical patterns:
- Traditional diets: Estimated omega-6 to omega-3 ratio of 1:1 to 4:1
- Modern Western diets: Ratios often exceeding 15:1 to 20:1
Additionally, what's missing from industrial oils may be as important as what they contain:
- Missing fat-soluble vitamins that would naturally accompany fats in whole foods
- Absent polyphenols and antioxidants that protect natural oils from oxidation
- Removed sterols and other beneficial compounds during processing
This creates a nutritional profile that represents a significant departure from the fats humans consumed throughout evolutionary history.
Context Matters: How These Oils Are Actually Consumed
The Processed Food Connection
Perhaps the most crucial context missing from discussions about industrial seed oils is how they actually enter our diets. While nutrition advice often frames our choices as "use this oil instead of that one," the reality is more complex.
Most industrial seed oil consumption doesn't come from bottles of cooking oil deliberately selected at the supermarket. Instead, it comes from:
- Fried foods: Restaurant and fast-food establishments
- Baked goods: Commercial breads, cookies, crackers, pastries
- Snack foods: Chips, microwave popcorn, packaged snacks
- Condiments and sauces: Salad dressings, mayonnaise, dips
- Frozen and ready-to-eat meals: Frozen dinners, pizza, prepared foods
- Breakfast cereals: Many contain added oils for texture and shelf life
In these contexts, the oils serve multiple functions beyond simply providing fat:
- Extending shelf life: Preventing products from going stale
- Creating desired textures: Providing crispness, flakiness, or moistness
- Carrying flavors: Enhancing palatability
- Enabling processing techniques: Making mass production possible
As noted above, few people deliberately drizzle corn oil over their vegetables. Yet, industrial seed oils have become the predominant fat source in many diets through their ubiquity in processed foods.
Markers of Ultra-Processing
This leads to a critical insight: high consumption of industrial seed oils often serves as a marker for diets dominated by ultra-processed foods. When researchers observe health outcomes associated with high seed oil consumption, they're typically observing the effects of dietary patterns rich in ultra-processed foods—not simply the effects of the oils themselves.
This parallels the situation with sodium in modern diets. High sodium intake doesn't typically come from the salt shaker; it comes from processed and restaurant foods. Similarly, high industrial oil intake isn't typically from conscious cooking choices; it's from processed food consumption.
This distinction matters because it changes how we should interpret research and dietary advice. When studies link high vegetable oil consumption to certain health outcomes, we must ask: Is this about the oils themselves, or about the ultra-processed foods that deliver them?
The False Comparison Problem
- Simply eat less of the foods they previously buttered
- Replace those foods with different options
- Consume more processed foods that contain vegetable oils
The result is a dietary change far more complex than simply swapping one fat for another. This makes it extraordinarily difficult to attribute health outcomes to specific fats rather than to broader dietary pattern changes.
Real-World Examples: Learning from Population Studies
The New Zealand National Nutrition Survey Insight
The last New Zealand National Nutrition Survey provides a perfect illustration of how nutritional reductionism can lead us astray. The finding that the highest source of saturated fat in the New Zealand diet wasn't meat, eggs, or coconut oil, but baked goods, highlights a crucial reality: nutrients don't exist in isolation.
This insight challenges the common narrative that reducing saturated fat means cutting back on animal products. In reality, for many people, reducing saturated fat would primarily mean reducing consumption of cakes, cookies, pastries, and other baked goods—foods that also contribute refined carbohydrates, added sugars, and industrial oils to the diet.
Similarly, the finding that bread was the largest source of protein in the New Zealand diet reveals how focusing on individual nutrients misses the bigger picture of dietary patterns. This statistical reality challenges conventional nutritional thinking—someone trying to increase protein intake by eating more bread would also be increasing their intake of refined carbohydrates—a very different intervention than increasing protein through eggs, meat, or legumes.
Other Population Studies and Their Lessons
This pattern repeats in other population studies. For example:
- The famous Mediterranean diet is often credited for its olive oil content, but its benefits likely stem from the entire dietary pattern—abundant vegetables, fruits, legumes, seafood, and minimal ultra-processed foods.
- Traditional Asian diets have historically been low in total fat but show favorable health outcomes—not because fat is inherently problematic, but because these diets emphasized whole foods, vegetables, and minimal processing.
- The French Paradox (relatively good cardiovascular health despite higher saturated fat consumption) points to the importance of food quality, meal patterns, and cultural approaches to eating rather than specific nutrient quantities.
These examples suggest that dietary patterns and food quality matter more than specific amounts of individual fatty acids. When we reduce complex foods to their constituent nutrients, we lose the context that determines their health effects.
Conclusion: Setting the Stage for a Deeper Dive
This exploration of industrial seed oils in context raises important questions about how we study, discuss, and make recommendations about dietary fats. By understanding the history, processing, and actual consumption patterns of these oils, we begin to see why simplified "good fat/bad fat" narratives fall short.
In Part 2 of this series, we'll examine the scientific evidence regarding these oils in greater detail, exploring questions of fatty acid balance, oxidative stability, and conflicting research findings. We'll then conclude with Part 3, offering practical guidance for navigating this complex nutritional landscape in everyday food choices.
The key takeaway from this first installment is simple but profound: context matters. When thinking about industrial seed oils—or any food component—we must consider not just its chemical composition, but how, when, and alongside what it's typically consumed. Only then can we begin to make truly informed dietary choices.
Doing more for your wellbeing?
It's good for you
Leave a comment