Superfoods
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Hello, and welcome to Zoë Shorts, the Bite Size podcast where we discuss one topic around science and nutrition. I'm Jonathan Wolf, and as always, I'm joined by Dr. Sarah Berry. And today's subject is superfoods.

Yeah, that's right, Jonathan. From blueberries to salmon to kale, it seems like anything and everything can be classed as a superfood these days. Supposedly, they can prevent everything. Cancer, reduce inflammation, help you live longer and make you look 20 years younger as well. Which you definitely don't need, Sarah. And I think the question today is, are some foods really more super than others? Or is this just another clever marketing point? I have quite a clear answer on this one. Brilliant.

Maybe let's start with where the term superfoods originated. And we did a little research on this. The world's first so-called superfood was the humble banana. In 1918, the Scientific Monthly published an article called The Banana, a Food of Exceptional Value. Sure enough, food manufacturers got excited and the United Fruit Company ran with this, putting out a massive marketing campaign around the time of World War I.

They said bananas are practical, cheap and nutritious and should be added to every meal.

Superfoods really took off in the 1990s, when the US government endorsed blueberries as being little antioxidant-rich disease fighters. The Department of Agriculture retracted this research 20 years ago, but it didn't matter. Blueberry production doubled and superfood mania took off. These days, it seems like there's a new superfood every week: garlic, cinnamon, ginger, green tea. And so, Sarah, what actually are superfoods?

So there is actually a dictionary definition for a superfood and the dictionary says it's a food that's rich in compounds that are beneficial to health. But there's actually no scientific definition of a superfood.

Between the period of 2011 and 2015, there was about a 200% increase in the number of new foods and drink products launched around the world that had the term superfood branded all over them. And so what do they do? Well, they're thought to contain all of these healthy nutrients and bioactives, so antioxidants, minerals, vitamins, as well as fiber and healthy sources of fat.

And so claims of superfoods and their supernatural ability have included everything from aiding our digestion, preventing cancer, improving our brain function, reducing symptoms of autism, and so, so much more. And one of the reasons why superfoods have been such a big deal is because it allows them to talk about being really big in individual nutrients. So the question is like, why are we so obsessed by this idea of single nutrients? It turns out that this really comes from the history of nutrition and nutritional science.

Many of us probably remember at school, studying about scurvy happening to British sailors who were stuck on a boat for too long and suddenly realizing that they needed limes, which is why I understand I'm a limey. But actually it went much further than that.

And so a lot of nutritional science research in the 19th century was understanding a whole series of different nutrients that we require. But this really became a big deal with governments in World War I. Different governments discovered that they had all these soldiers that they couldn't conscript

because of nutritional deficiency. And so suddenly that really focused this idea that they might be getting enough calories at this point, but they were really missing single nutrients. And Sarah, I think that sort of continued through then into things like guidelines and labels, hasn't it? Yeah, absolutely. So historically we've had nutrient-based guidelines, but we don't eat nutrients. We eat foods. We don't even eat single foods. We consume dietary patterns.

And are we in a world still where most people in the West have to worry about nutrient deficiency?

So nutrient deficiency is now really rare. There are a certain proportion of the population where iron deficiency anemia is a problem, but for the majority of people, nutritional deficiencies are just not a problem. So we've come from this world of single nutrients. Now we're talking about superfoods. What do the research studies actually show? So there's lots of research looking at single foods and single nutrients in relation to cancer, heart disease, and other conditions.

So, for example, a recent review of cancer studies found that people who include mushrooms in their daily diet had lower risk of cancer. And this was thought to be because mushrooms contain ergothionine, which is an antioxidant rich chemical to protect cells. There's been research into nuts showing that people that consume more nuts have 15% lower risk of cancer. Research in tomatoes because they contain cancer fighting lycopene.

All of these studies though are either using supplements or using mega doses of these amounts of plants. So how they translate in real life is questionable. I can see that the American Institute for Cancer Research says that the evidence is too limited to draw any real conclusions. Cancer Research UK says there is no good evidence that any one food prevents cancer, including superfoods.

It's true that a healthy balanced diet can help to reduce the risk of cancer, but is unlikely that any single food will make much of a difference on its own. Yeah, and foods work in unison and how one nutrient in one food impacts another nutrient is really important. So that's again why we have to be cautious making interpretations from some of these either supplement studies or mega dose food studies in relation to their health qualities.

And I think the other thing we have to do is really look at the details of the research, right? So in general, there's a big claim out of a particular paper, it gets blown up in the media, and it's not necessarily backed up really by the evidence. So if you look at many of these studies, right, they're on very small numbers of people, they're done for a few months, some of them are not even done on human beings. There are one or two examples, aren't there, Sarah, of single food studies that actually go on for many years and enough time to actually see whether it has any impact

on these health outcomes? Yeah, there are. There are only a couple of these kind of studies because they're so challenging to run. For example, there's a study called the COSMOS trial that was looking at how polyphenols impact a whole host of outcomes using a supplement. But generally, they all suffer from the limitations that you've just listed. So we're left saying, you know, can there be a superfood? What's the bottom line from where we are today, Sarah?

So in my opinion, there is no superfood, that there is a super diet and this is a diet that's diverse, that's packed full of fruits, vegetables, legumes, so very plant-based and also a highly unprocessed diet as well.

Now I think we can say that there are some foods that have super healthy effects on us but I still wouldn't class them as superfoods. And by these I mean berries, fish, leafy greens, nuts, olive oil, live yogurt and legumes. And if we can get a decent amount of those into our diet then I think we're on to a super healthful diet.

And is that because the big challenge with the idea of superfood is it suggests that you can keep your current diet and just add this superfood sort of like a drug, right? We're used to this idea that you can get some sort of magic drug that solves your infection or whatever it is. And is that why you're so against the idea of a superfood? Yeah, I think it's a really reductionist approach, just like the reductionist approach that you mentioned earlier with us focusing on single nutrients.

And I think it's because it's our whole dietary pattern that actually determines the healthiness of our diet rather than a single food. Often we have to consume huge amounts of these so-called superfoods to reap the health benefits.

And we also have to consider the food that it's displacing and replacing. So by adding a large amount of one particular food into our diet, what are we actually displacing from our diet? Are we still getting a balanced amount of other nutrients and other foods? And are we still having that most important component of our diet, which is diversity?

And what about olive oil? If there's anything that could be a superfood, surely it's olive oil. There's a real long-term randomized control trial, right, with Predimed, Cordoprev over seven years. There was genuine impact on heart disease. Doesn't that get to be a superfood, Sarah? So olive oil is one of those I just listed as being a super healthy food.

But it's more that terminology that we can focus on a single food to elicit good health in us. So this is like you can't eat McDonald's and then have olive oil and somehow be healthy. And this is what's standing in the way of it getting the Sarah Berry superfood stamp. Absolutely.

That's brilliant. What about, I thought about this also, I think there's one other potential sort of superfood, because I think one of the biggest challenges is, you know, how do you take all of that advice into real life, particularly if you have a family? And so, you know, I definitely see this, you know, with my kids in particular, trying to get them to eat a healthier diet. And so my other thought about a superfood is, well, sometimes a superfood is something where you can do a swap. You've

you've made it significantly healthier for your family. And actually, they're very happy to have that. Quinoa is a good example of something which was described as a superfood. I know you hate the idea of a superfood, but definitely we know that if you're swapping out rice, for example, for quinoa, you've significantly improved the properties because of its whole grain, it's got more protein, less refined starch, or indeed, I've managed to get the whole family to swap out regular pasta for whole wheat pasta and they're completely happy.

So are we allowed to think of those as a sort of minor superfood or am I pushing too far?

I think we can think of them as a super swap and I think that super swaps is a great dietary strategy to modify your diet and make it healthier because we know that how we eat is really ingrained in our culture, in our social setting and so asking people to totally modify their diets really hard and super swaps is a great way that we say hey you can still eat in your typical way but like you say have olive oil instead of another seed oil or instead of butter or you know

in your case, Jonathan, I'll allow that quinoa instead of your potatoes, for example. And I think that's a great way. It's all the kind of nuances around the term superfood that you can have a cure-all in one food regardless of the rest of your diet. That's what I think many nutritionists have the issue with because it's disregarding the rest of your diet and emphasizing that one single food will have this wonderful miracle effect on your health.

So the final conclusion on this one is thumbs down for superfoods. Thumbs down for superfoods, thumbs up for super swaps and super healthy components of your diet. Brilliant. Sarah, thank you. And thank you to our listeners for listening to this episode of Zoe Shorts. We'll post links to all of the papers that we talked about on the website, which is joinzoe.com slash podcast.

And if you'd like to try Zoe's personalized nutrition program to improve your health and manage your weight, you can also get 10% off from that link. I'm Jonathan Wolfe. I'm Sarah Berry. Join us next week for another Zoe podcast.