What’s the problem with seed oils?

You might’ve noticed a flurry of interest in these in the media lately. So why is there concern about them, and are those concerns valid?

First, let’s step back to last month when I listed 7 tips for better eating from UK nutrition professors Tim Spector and Sarah Berry.

In addition to the nutrition company they run, both are employed by King’s College London.

Sarah Berry has been a key figure in the recent seed oils discussion. She’s come out strongly in defense of them and dismissed concerns as ‘nutri-nonsense’.

However… Unilever has also been funding King’s College London for around 20 years.

Unilever makes a huge range of processed foods, including sauces, gravy and sauce mixes, soup mixes (Continental soup), mayonnaise, and desserts.

They’re a giant in the food industry, and they use a ton of seed oils in their products. As all processed food companies do.

But let’s not be cynical. Maybe Professor Berry genuinely believes seed oils are good for heart health.

Closer to home, a well-known dietitian writing in a major Australian newspaper about seed oils this month also believes that the disquiet about them is a bit over the top.

In response to the claim that they contribute to inflammation in the body, she argued that it’s dietary patterns over time that affect inflammation, not one food or ingredient.

Moreover, she said, the problem isn’t seed oils. It’s that we eat too much processed food. If we used olive oil instead and ate three or four serves of oily fish each week, plus a handful of nuts and seeds, we wouldn’t have anything to worry about.

So yes, nothing the matter with these oils as long as you eat something else instead. Pardon?

She also pointed out that there are worse things we can eat, like vegetable oils. Only the manufacturers know what’s in vegetable oil, but presumably it’s a blend of seed oils. And telling us that there are worse options is hardly making the case for seed oils.

By now, she’d gone around the mulberry bush so many times I had to look at her website. It’s a pitch to prospective employers, i.e. food manufacturing companies.

It explains the advantages to the food industry of working with a dietitian. In a nutshell, dietitians will become brand ambassadors for a company’s product. They’ll communicate with other ‘influencers’ and develop a ‘nutrition story’ (for the company) that will resonate with customers.

Too bad if we poor customers (or readers) are deluded enough to think they’re committed to our health. They’re working for the industry. (I hasten to add that all dietitians aren’t aligned with big food companies; only some are.)

But let’s set aside what she and Sarah Berry have to say in support of seed oils, to see why people might be bothered by them.

The main ones used commercially are sunflower, safflower, corn, soy, cottonseed, and canola, though grapeseed, rice bran, sesame, and peanut oils come under this umbrella too. They’re polyunsaturates (yes, ‘poly’ means many), and if we look at their molecular makeup, they have a lot of double bonds.

Olive oil though is monounsaturated, and has only one double bond. Saturated fats (from meat, dairy, and coconut oil) have no double bonds.

Why are double bonds relevant? Because when you heat oil the double bonds come apart and oxidise. So seed oils, with their polyunsaturated makeup, oxidise fast if you cook with them.

Oxidised oils easily become rancid, and oxidation brings about inflammation which is linked with a raft of diseases.

So polyunsaturates, including vegetable oils, are too unstable to be healthy everyday cooking oils.

Former MasterChef winner, Adam Liaw, says he mostly uses vegetable oil because of the neutral flavour, versatility, and high performance in cooking. As ridiculously talented as he seems to be, and as well-behaved as vegetable oil must be in his kitchen, we can do better health-wise.

Olive oil is more stable and a good compromise for a lot of people. Saturated fat is the most stable of them all. Duck or goose fat and tallow can be found on shelves in delis or supermarkets.

Butter works at lower temperatures, but it will burn. Ghee doesn’t, so for that reason it’s a better option. Refined coconut oil is also considered good for cooking because it’s tasteless and odourless and more stable than the unrefined version. In future we might also see more use of MCT oil which is a byproduct of the coconut and palm oil industries.

An obvious question might be why sunflower seeds (which contain the oil) are considered healthy, but the oil itself is a problem. That’s because nuts and seeds contain vitamin E, which is anti-inflammatory. We lose vitamin E when we cook.

Oils such as sesame or nut oils are good for dressings, because they’re not being heated (but keep them in the fridge). Macadamia oil is an exception. It can be used as a dressing or for cooking because, like olive oil, it’s monounsaturated.

Sesame and peanut oils are used in some Asian cooking. Sesame oil doesn’t take much heat, and the toasted sort is best used to add flavour rather than to cook with. Using sesame and peanut oils occasionally won’t cause too much grief, but they’re not ideal for regular use.

A lot of commercial products such as dips and spreads use canola or sunflower oil, and while these aren’t being used to cook with, we don’t know about the distribution process and how much heat they’ve been exposed to. So it’s probably wise to limit the amount of foods we eat that contain them.

Let’s finish with an explanation of how the idea that polyunsaturates would be the answer to heart disease came about. An American journalist called Nina Teicholz became fascinated with the story and dug through old files and reports to piece it together.

It started in the 1960s when the American Heart Association (AHA) adopted a policy that saturated fats should be replaced with polyunsaturates to prevent heart disease.

In reality, no one knew what caused heart disease, and there was no evidence that polyunsaturates would lower the risk of it.

But the AHA felt they needed to come up with something, and this new policy might’ve had something to do with the fact that Proctor and Gamble, makers of Crisco (a hardened form of cottonseed oil developed to replace lard), had poured millions into the AHA since 1948.

In response to this policy with no evidence, there was a flurry of research around the world as teams of scientists tried to find some.

About 25 studies — long, large, high-quality trials involving around 76,000 participants — were unable to find any proof that switching from saturated fats to polyunsaturates would lower the risk of heart disease.

What they did find was that the people who ate the most seed oil had a higher risk of cancer.

Throughout the 80s there were high-level meetings to try to make sense of that, but in the end it was decided that the need to lower cholesterol to reduce the risk of heart disease was so great that the cancer findings would be set aside.

Polyunsaturates will lower cholesterol because there are compounds in plants called sterols, and these have a similar structure to cholesterol. When we consume polyunsaturated fats, the sterols replace cholesterol in the walls of our cells.

But, as has been shown over and over and over, lowering cholesterol with sterols doesn’t reduce the risk of heart disease or stroke.

Seed oils are unlikely to be the whole story when it comes to inflammation and chronic disease, but they’re at least part of it. And given that menopause and ageing already encourage inflammation, the last thing we need is to increase it unnecessarily.

Professor Berry didn’t offer any real evidence for her ‘nutri-nonsense’ claims, and she probably won’t. She doesn’t need to.

Because this idea of polyunsaturates being heart healthy still hangs on, despite the weight of findings against it.

Entrenched ideas combined with vested interests are mighty hard to shift.

Photo Source: Centra Foods