How one of the most profound changes in our diet over the last century could be driving the chronic disease epidemic.
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THE TOPLINE
- Seed oils, like corn, canola, and soybean, are high in omega-6 fatty acids, contributing to an unhealthy omega-6 to omega-3 ratio in modern diets. This imbalance leads to chronic inflammation and is linked to heart disease and metabolic disorders.
- The production of seed oils involves chemical processes like bleaching, deodorizing, and the use of petroleum-based solvents, which remove nutrients and introduce inflammatory compounds like 4-HNE, a byproduct tied to vascular calcification.
- Reducing the intake of processed foods and seed oils while returning to natural fats (like olive oil, butter, and coconut oil) can improve health, reduce inflammation, and restore a balanced omega-3 to omega-6 ratio.
Emerging research is challenging the belief that highly refined seed oils, now found in copious amounts in highly or ultra-processed foods, are healthy alternatives to traditional fats. A recent study links a byproduct of seed oil metabolism—4-HNE (4-hydroxy-2-nonenal), derived from linoleic acid—to vascular calcification, a key factor in cardiovascular disease. This finding, along with a large body of work linked to the high omega-6 fatty acid content of these oils, highlights the need to reconsider our modern diets.
Seed oils – should I, shouldn’t I?
You may have noticed that ‘healthy eating’ social media feeds have been alive with mixed messages on seed oils. Nutrition experts have, for some time, been claiming they’re at the heart (excuse the pun) of the problem with the spiraling heart disease, obesity and type 2 diabetes problem afflicting US society. But there’s been recent push back from authorities such as Harvard T.H. Chan School of Public Health, saying it’s not the seed oils themselves that are harmful. They say it’s the junk, highly processed, and restaurant foods that they’re associated with that are the real problem.
For sure, highly- and ultra-processed foods, deep-fried, and other junk foods are a problem. All those sugars and other refined carbohydrates, the heat-damaged fats, the advanced glycation end-products, the cross-linked sugars, the polyaromatic hydrocarbons (PAH), the heterocyclic amines, not to mention chemical additives—these are among the very problematic ingredients and compounds that are hidden killers in the standard American diet (SAD).
But let’s separate out seed soils, the most common including corn, canola (rapeseed), soybean, sunflower and cottonseed.
There are three main issues, the latter being the least well known:
1. The high omega-6 content
2. The industrial manufacturing process of these highly refined oils
3. The presence of compounds like 4-HNE that cause calcification in the arteries.
Let’s look at each of these briefly.
Seed Oils and Their Omega-6 Problem
Seed oils are everywhere in our diets. They’re cheap, have long shelf lives, and are flavorless, making them a popular choice in processed foods, fast food, and restaurant dishes.
Historically, humans consumed omega-6 and omega-3 fats in a balanced ratio of 1:1 to 2:1. Today, this ratio has skewed drastically, reaching 20-30:1, causing chronic inflammation and contributing to heart disease. The new study further highlights how excessive omega-6 disrupts metabolism, crowding out omega-3s and pushing the body into a pro-inflammatory state. (Read more about how to balance your omega fatty acids here.)
Industrial Processing of Seed Oils
The process of producing seed oils is highly industrialized and involves a range of chemical treatments. Seeds are heated to high temperatures and treated with petroleum-based solvents, such as hexane, to extract the maximum amount of oil. This crude oil is then deodorized, bleached, and further treated with synthetic antioxidants to improve its shelf life. The result is a product that is devoid of essential nutrients and full of inflammatory fats.
Unfortunately, most consumers are unaware of this process and the potential health risks it poses. Seed oils are marketed as healthy alternatives to saturated fats, but the truth is that they are contributing to the chronic inflammation that underpins many of today’s most common diseases.
Vascular calcification by seed oils
This is where the recent study published in the journal Circulation by a group of 16 scientists from Shandong University, China, comes in.
The researchers investigated the role of 4-HNE, which is a product of lipid peroxidation formed during the industrial processing of seed oils, in vascular calcification. The study found that elevated 4-HNE levels were associated with increased vascular calcification in both human patients and animal models. The researchers revealed that 4-HNE promotes calcification by directly modifying a protein called Runx2, a key regulator of bone formation. They also found that the enzyme ALDH2, which metabolizes 4-HNE, was protective against vascular calcification.
On the back of these findings, don’t be surprised if we see ALDH2 drugs hitting the market in the future, no doubt being promoted to those who want to carry on eating junk foods.
So, what can we do about it?
Return to natural fats
The good news is that by reducing seed oils and opting for less processed, natural fats—like coconut oil, olive oil, butter, ghee, or animal fats—you can improve your health. Avoid processed foods and seek out restaurants that use healthier oils like avocado or olive oil. We have also written several educational articles on how to use natural medicines to improve heart health. Along with dietary changes, natural interventions like omega-3-rich foods, supplements, and regular exercise can support heart health.
Restore and rejuvenate through healthful eating
The ubiquity of highly refined seed oils in modern diets is contributing to chronic inflammation and heart disease. By returning to a diet of minimally processed or unprocessed natural fats and reducing our reliance on processed foods, we can greatly reduce our exposure to harmful components in oils and restore balance to our omega-3 and omega-6 ratios in order to protect our long-term health.
The new study linking seed oils to vascular calcification is a wake-up call to rethink our potential exposure to fats that have become ubiquitous in ultra-processed and restaurant foods.
Cooking at home, from scratch, is a skill and an art, that is being lost in our increasingly technologically-influenced lives. We owe it to the next generation to reignite the passion for conscientious home cooking with largely unprocessed foods and ingredients along with digital-free, mindful family dining, as these are indisputable pillars of long-term health and wellbeing.
