Do seed oils reduce CVD?

Summary

* This is the last of six notes in the seed oils mini-series. It started with a review of claims made by the chief scientist of the ZOE company, Professor Sarah Berry, that seed oils are not toxic and that they reduce cardiovascular disease (CVD): "There's also many, many randomized control trials that showed that if you increase your polyunsaturated fatty acid intake, you reduce your LDL cholesterol significantly, and it results in a 32% reduction in cardiovascular disease."

* I have had several exchanges with Professor Berry and the ZOE company seeking a reference for this statement. Nothing has been forthcoming. I am open to evidence being provided at any time in the future, but until/unless this happens I must assume that this is a baseless claim.

* This note looks at whether seeds oils reduce CVD, in the absence of evidence from those claiming this. It looks at i) the association between seed oil intake and CVD ii) the evidence from all randomised controlled trials (which we comprehensively reviewed in the seed oils mini-series) and iii) what I suspect Berry and ZOE think the mechanism is – cholesterol lowering.

* On (iii), seed oils are rich in plant sterols and consumption of plant sterols lowers human cholesterol (‘replaces’ might be a more accurate term). However, one of the papers published during my PhD looked at the evidence in this field – does 'replacing' human cholesterol with plant cholesterol improve health outcomes? Looking particularly at heart disease (as this was Berry's claim), the answer is a clear no.

* There is evidence that if you increase your polyunsaturated fatty acid intake with anything that contains plant sterols you reduce your total cholesterol (and hence probably LDL-Cholesterol). However, we must assume that there is no evidence that this "results in a 32% reduction in cardiovascular disease." Anytime Berry/ZOE want to provide the evidence, I'll review it.