Seed oils Health

Vegetable (Seed) Oils: The Misleading 'Healthy' Choice?

The potential negative health effects of high omega-6 industrially produced oils like canola, soy, corn, grape-seed, sunflower and cottonseed:

Gut Health

Gastrointestinal Inflammation:

Industrial seed oils, which are high in omega-6 fatty acids, may contribute to gastrointestinal conditions like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Studies in mice have shown that diets high in omega-6 fatty acids from corn oil increase pro-inflammatory gut bacteria, fostering gastrointestinal pathologies.

Altered Gut Microbiota:

Human studies indicate a correlation between industrial seed oils and GI conditions. Women with IBS have elevated levels of arachidonic acid (an omega-6 fatty acid) and pro-inflammatory PUFA metabolites compared to healthy controls.

Heart and Arterial Effects

Cardiovascular Disease:

Oxidised fatty acids from industrial seed oils play a pivotal role in developing cardiovascular diseases. The consumption of linoleic acid-rich oils is linked to the formation of oxidised lipoproteins, which in turn, contribute to atherosclerosis and heart disease.

Increased Omega-6-to-Omega-3 Ratio:

This imbalance, caused by high consumption of industrial seed oils, is a risk factor for cardiovascular diseases due to the pro-inflammatory and prothrombotic effects of excess omega-6.

Brain Effects

Cognitive Decline and Mental Health:

A high omega-6-to-omega-3 fatty acid ratio predisposes individuals to depression, anxiety, cognitive decline, and dementia. Canola oil consumption has been linked to worsened memory and impaired learning ability in Alzheimer’s disease.

Trans Fatty Acids:

Trans fatty acids (TFAs) in industrially produced oils are associated with cognitive decline. They result from hydrogenation and thermal processes like frying and refining of vegetable oils.

Metabolic and Mitochondrial Problems

Insulin Resistance and Diabetes:

Research indicates that high levels of linoleic acid (the primary fatty acid in industrial seed oils) alter neurotransmitter signalling, increasing food consumption and fat mass. Diets high in soybean oil have been linked to obesity, insulin resistance, diabetes, and fatty liver disease.

Obesity:

The repeated heating of industrial seed oils depletes vitamin E and induces the formation of free radicals that cause oxidative stress, potentially leading to high blood pressure, heart disease, and liver damage.

Other Potential Health Problems

Inflammation:

Industrial seed oils raise C-reactive protein, TNF-alpha, and interleukin-6 levels, biomarkers of systemic inflammation.

Macular Degeneration:

A high intake of omega-6 fatty acids increases the risk of age-related macular degeneration, a leading cause of blindness.

Osteoarthritis:

There’s an association between omega-6 fatty acids and the presence of synovitis in osteoarthritis. Conversely, omega-3 fatty acid consumption shows an inverse relationship with cartilage loss in the knee.

Industrial Processing Concerns

Hexane and Bleach Processing:

Hexane, a volatile solvent used in oilseed extraction, is categorised as a hazardous air pollutant by the EPA. Inhalation can damage the nervous system, and ingestion may produce symptoms like abdominal pain, nausea, weakness, and even paralysis.

Additives and Free Radicals:

Processing of these oils creates free radicals and requires the addition of synthetic antioxidants like BHT, BHA, and TBHQ, which have been linked to cancer, liver and kidney toxicity, and thyroid function depression.

List of Foods and Products that Typically Contain Industrially Produced Oils:

• Processed Snacks: Chips, crackers, and microwave popcorn

• Fast Food: Fried chicken, fries, and other fried items

• Prepackaged Baked Goods: Cakes, cookies, pastries, and bread

• Salad Dressings and Mayonnaise: Many commercial varieties

• Frozen Meals: Ready-to-eat frozen dishes

• Margarine: Commonly made with these oils

• Non-Dairy Creamers: Often contain these oils

• Canned Soups: Some brands use these oils

• Sauces and Gravies: Pre-made varieties

• Vegetable Shortening: Often made with these oils

• Protein Bars or Shakes: Many brands include these oils

• Chocolate: Some types contain these oils

• Candy Bars and Candy: Various brands use these oils

• Oat Milk, Almond Milk, and Other Plant-Based Milks

• Cosmetics and Personal Care Products

• Cooking Oils: Such as corn oil, cottonseed oil, palm kernel oil, safflower oil, soybean oil, sunflower seed oil

Why Are These Oils and Fats Promoted?

1. Economic Interests: Derived from heavily subsidised crops; cost-effective for manufacturers

2. Shift from Saturated to Unsaturated Fats: Early public health recommendations demonised saturated fats

3. Marketing and Lobbying Efforts: Industry-funded studies and marketing campaigns promoting these oils as healthy

4. Nutritional Misunderstanding and Simplification: Early oversimplification led to all unsaturated fats being deemed good

5. Food Industry Influence: Longer shelf life and versatility made these oils attractive to food producers

6. Shift in Dietary Patterns: Rise of convenience foods post-WWII suited these oils

7. Incomplete or Evolving Science: Nutrition science continues to develop a more nuanced understanding of fats

Action Points

1. Prioritise Unprocessed, Natural Fats: Use extra virgin olive oil, coconut oil, butter, ghee, lard, tallow, avocado oil, and fats from fatty fish

2. Limit Intake of Industrially Processed Vegetable Oils: Reduce consumption of soybean, sunflower, canola, corn, and cottonseed oils

3. Balance Omega-3 and Omega-6 Fatty Acids: Increase omega-3s (fatty fish), decrease omega-6s (processed/fried foods)

4. Avoid Trans Fats: Steer clear of partially hydrogenated oils found in many processed foods

5. Cook at Appropriate Temperatures: Use heat-stable oils like avocado oil, coconut oil, lard, ghee, and tallow