Do Seed Oils Like Groundnut Oil Cause Inflammation? A Food Technologist's POV

Seed oils cause inflammation.

You’ve probably heard this statement circulating widely. But as a food technologist working on oils by research for nearly 15 years, I believe we must ask a better question:

Is it the oil itself — or how it is processed and used — that matters?

Is it the PUFA–MUFA ratio?
Is it the extraction speed?
Is it the refining process?

Let’s separate chemistry from confusion.

What Is the Natural Fatty Acid Profile of Groundnut Oil?

Groundnut (peanut) oil naturally contains:

Monounsaturated fats (MUFA – Oleic acid): 45–55%

Polyunsaturated fats (PUFA – Linoleic acid): 25–35%

Saturated fats: 15–20%

This composition is determined by:

seed genetics, soil, climate, crop variety

Importantly:

This fatty acid profile is similar to several traditional cooking oils consumed for generations.

👉 The oil itself is not inherently inflammatory.
Linoleic acid (omega-6 PUFA) is an essential fatty acid required for:

Cell membrane structure, Skin barrier integrity, Immune signaling, Normal physiological function

The body cannot produce it — it must come from diet.

👉 Mechanical extraction speed does alter the PUFA : MUFA ratio.

So high-speed extraction does create an imbalance in fat composition.

---

🔥 What Actually Happens During High-Speed, High-Heat Extraction?

Here’s where the science becomes important.

Polyunsaturated fats (PUFAs) contain multiple double bonds.
These double bonds are chemically reactive and sensitive to heat and oxygen.

Industrial expeller or refined oil production often involves:

High friction speeds

Temperatures ranging from 70–120°C

Prolonged oxygen exposure

Metal surface contact

This environment promotes:

Lipid peroxidation

Formation of peroxide compounds

Breakdown into reactive aldehydes

Loss of natural antioxidants (like tocopherols)

The fatty acid ratio remains the same —
but some molecules become oxidatively damaged.

Why Refined Oils Often Show Higher Oxidative Markers

Refined oils undergo multiple processing stages:

Degumming

Neutralization

Bleaching

Deodorization (high heat, often 180–240°C)

During deodorization especially:

High temperatures strip volatile compounds

Natural antioxidants are destroyed

Minor lipid oxidation products form

Even if the oil looks clear and odorless, laboratory tests often show elevated:

Peroxide Value (PV)

Anisidine Value (AV)

TBA (Thiobarbituric Acid) values

Total Oxidation (TOTOX)

These markers indicate prior oxidative stress.

Additionally, refining removes protective compounds like:

Tocopherols (Vitamin E)

Polyphenols

Phytosterols

Without these natural antioxidants, the oil becomes more vulnerable to future oxidation, especially during storage and cooking.

So refined oils may show higher oxidative markers not because the fatty acid ratio changed —
but because their protective system was weakened.

---

🌾 What Happens at Slow 3 RPM Cold Pressing?

When oil is extracted slowly (e.g., 3 rpm):

Friction is minimal

Temperature remains below ~35–40°C

Oxygen exposure is lower

Natural antioxidants remain intact

This preserves:

Fatty acid structure

Tocopherols

Phenolic compounds

Oxidative stability

The PUFA–MUFA ratio stays the same.
And molecular integrity is maintained.

---

⚖️ So Do “Seed Oils Cause Inflammation”?

The phrase is oversimplified.

Linoleic acid (PUFA) is:

Essential

Required for cell membrane integrity

Needed for normal physiological signaling

It does not inherently cause inflammation.

However:

Oxidized PUFAs

Reactive aldehydes

Lipid peroxides

can contribute to oxidative stress and inflammatory signaling if consumed chronically.

The issue is not PUFA itself.
The issue is oxidative damage to PUFA.

 

Cold-Pressed vs Refined: The Real Difference

---

🌱 The Takeaway for Consumers

It is not about demonizing “seed oils.”
It is about understanding:

How the oil was extracted

How much heat it was exposed to

Whether natural antioxidants were preserved

Whether oxidation was minimized

Is it being reheated repeatedly?

Is your overall omega-6 to omega-3 balance reasonable?

Inflammation is rarely caused by a single food.
It is usually the result of dietary patterns, oxidative load, and lifestyle factors.

Final Word from a Food Technologist

The debate is not about speed changing fat ratios.
It is about speed and heat increasing oxidative damage.

Slow pressing doesn’t change the composition —
it protects it.

The problem is not the seed.

The problem is oxidation.

Groundnut oil — when minimally processed, gently extracted, and used appropriately — is not the inflammatory villain it is often portrayed to be.

It is chemistry, not mythology, that decides how food behaves in the body.

MJ