Many of your patients will be consuming all the news they can get about the United States and the policies and views of President Trump and his allies. Anecdotally we’re hearing from practices that patients are asking questions based on what they hear from people like the podcaster Joe Rogan’s guests or the nominee (at the time of writing) for Health Secretary Robert F Kennedy Jr.
RFK, as he’s called, has quite rightly been railing against the consumption in the US of ultra processed foods and the epidemic of chronic disease, not to mention the nation’s low life expectancy compared to countries like Australia and Japan.
That’s not controversial.
Where he and others who share his views differ from the experts, is when it comes to the role of seed oils. Now just because he differs with experts doesn’t mean he’s wrong but in this case his arguments are misleading and wrong.
What’s the gripe?
What we’re talking about here are seed oils such as grape, sesame, canola, sunflower and flax. They’re usually used for frying because they tolerate high temperatures before they smoke. Seed oils are also used, because of their heat stability and other properties, in ultra processed foods.
To explain the gripe, you need a bit of technical detail. Fatty acids are the building blocks of fats and are described by how their carbon atoms bind to hydrogen. They can be linked by just one bond or two. Saturated fats have no double bonds. They’re bad for you, especially when they come in meat. They tend to increase LDL cholesterol, inflammation and oxidative stress. Monounsaturated fatty acids are best known in olive oil. They tend to be neutral when it comes to heart disease and their main benefit comes from replacing saturated fat in your diet and the bioactive compounds in extra virgin olive oil. The seed oils contain polyunsaturated fatty acids and depending on where on the molecule the double bond is, they can be called omega 6 or omega 3 fatty acids. You’ve no doubt heard of omega 3 fatty acids in fish and fish oil.
Well, the debate about seed oils is about omega 6 fatty acids because they dominate over omega 3’s. RFK and others argue that omega 6 fatty acids are bad for you because they say they promote inflammation and oxidative stress and increase the risk of diabetes and heart disease. The critics also make a lot of the ratio between omega 6 and omega 3 fatty acids in these oils. One of these omega 6 fatty acids is linoleic acid which is an essential fatty acid, meaning we can only get it from food and not having enough can cause deficiency symptoms such as dry, scaly skin. One reason RFK and others say that linoleic acid is bad for you is that the body converts it into an inflammatory substance called arachidonic acid.
Seed oils like grapeseed have a lot of omega 6, while canola and sunflower and peanut oil, less but still more than, say, olive oil.
Okay…. That’s the argument.
Here are the facts. Omega 6 fatty acids reduce inflammation, oxidative stress and toxic forms of cholesterol and in so doing reduce the risks of heart disease and probably type 2 diabetes. There is nothing scientific about the omega 6 to omega 3 ratio. They don’t fight with each other. Study after study shows this. See the reference at the foot of this article
And the arachidonic acid story? Well in fact only 0.2 per cent of linoleic acid is converted to arachidonic acid. Barely measurable.
So, the bottom line? Seed oils aren’t the problem. In fact, they can be part of the solution, not that you want to be eating fried foods a lot. The argument about these oils distracts us from what we need to eat for optimum health which is a largely unprocessed diet which is high in vegetables, low in red meat and where cooking is slow – at a moderate heat.
That’s where science meets RFK.
Reference
Petersen KS, Maki KC, Calder PC, Belury MA, Messina M, Kirkpatrick CF, Harris WS. Perspective on the health effects of unsaturated fatty acids and commonly consumed plant oils high in unsaturated fat. Br J Nutr. 2024 Oct 28;132(8):1039-1050. doi: 10.1017/S0007114524002459. Epub 2024 Oct 30. PMID: 39475012; PMCID: PMC11600290.
