By Professor Dato Dr Ahmad Ibrahim
For decades, palm oil has been cast as a dietary villain. Its high saturated fat content — around 50% — led public health authorities to lump it together with butter, lard, and coconut oil. The message was simple: saturated fat raises LDL cholesterol, so palm oil must be bad for the heart. But science, as it often does, has turned out to be more complicated than the slogans.
A thoughtful review by Teh and colleagues revisits this question through a crucial but often overlooked lens: the sn‑2 hypothesis. And their conclusion nudges us toward a long‑overdue rethink of how we judge dietary fats. Not all saturated fats are created equal.
Palm oil is unique. Unlike animal fats, its saturated fatty acids — mainly palmitic acid — are not distributed randomly across the glycerol backbone. In palm oil, more than 80% of the palmitic acid sits at the sn‑1 and sn‑3 positions of the triglyceride molecule. The sn‑2 position is dominated instead by oleic acid, a monounsaturated fat.
Why does that matter? Because human digestion preferentially cleaves fatty acids from the sn‑1 and sn‑3 positions, leaving the sn‑2 fatty acid intact as a 2‑monoacylglycerol. That sn‑2 fatty acid — in this case, oleic acid — is absorbed differently. It does not form the insoluble calcium soaps that can increase faecal fat loss, and more importantly, it appears to influence lipoprotein metabolism in ways that simple saturation tables cannot predict.
What the lipid profiles actually show. Teh and colleagues review a range of controlled human studies. The headline finding: palm oil does raise LDL cholesterol compared to unsaturated oils like olive or canola — but significantly less than would be predicted from its palmitic acid content alone. And crucially, palm oil also raises HDL cholesterol, maintaining a more favourable total cholesterol‑to‑HDL ratio than many other saturated fats.
In direct head‑to‑head trials with partially hydrogenated vegetable oils — the old industrial trans‑fat source — palm oil consistently produced a superior lipid profile. That may be a low bar, but it underscores the point: demonising palm oil while ignoring the structural chemistry of its triglycerides is like judging a house solely by its brick count without looking at the architecture.
The missing piece: clinical outcomes. No op‑ed should overstate the case. The review acknowledges a major limitation: nearly all the evidence comes from intermediate biomarkers (LDL, HDL, triglycerides), not hard cardiovascular endpoints like heart attacks or strokes. The sn‑2 hypothesis is biochemically compelling, but definitive proof that palm oil’s unique structure translates into lower cardiovascular risk would require large, long‑term trials — which are expensive and unlikely to be funded by public health agencies that have already made up their minds.
There is also the question of context. Palm oil is rarely eaten in isolation. It appears in everything from margarines to instant noodles, often alongside refined sugars and low fibre. Blaming palm oil alone for the metabolic consequences of ultra‑processed foods is intellectually lazy.
A cautious reappraisal is therefore needed. The sn‑2 hypothesis does not turn palm oil into a health food. It does, however, dismantle the crude “saturates = bad” equation that has dominated dietary guidelines for forty years. This was exploited by competing oils for years. If the position of a fatty acid on the glycerol backbone changes its physiological effect, then our food labelling and dietary advice — which still treat all palmitic acid as identical — are woefully behind the science.
Teh and colleagues have done the field a service by pulling together a scattered literature. Their review suggests that for the average person replacing trans fats or butter, palm oil is a neutral to moderate choice — not as good as olive or canola for LDL lowering, but far less harmful than previously assumed. And in food systems where affordability and oxidative stability matter (most of the global South), that nuance could make a real difference.
The takeaway: let’s retire the food morality plays. Fats are not good or evil. They are molecules with structure, and structure determines function. The sn‑2 hypothesis invites us to grow up — from misplaced fat phobia to fat chemistry.
The author is affiliated with the Tan Sri Omar Centre for STI Policy Studies at UCSI University and is an Adjunct Professor at the Ungku Aziz Centre for Development Studies, Universiti Malaya.
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