← ZOE Science & Nutrition
Loading summary
Transcript11 lines
- [00:01]
A
Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today, we're taking a closer look at one of the world's favourite breakfasts, oats. Depending on who you ask, oats are either a superfood or a source for concern. Either a great way to get fiber or a worrying blood sugar spiker. So what's the truth? Are oats a smart start to your day or something to be cautious about? Professor Sarah Berry joins me to dig into the science. What does it really say about oats? What are oats and, like, what happens to them before they arrived in my bowl?
- [00:44]
B
Yeah, so oats are a type of seed or a whole grain that comes from the oat grass, and this is called the avena sativa plant, and I hope I pronounced that correctly. They're very much like a wheat kind of plant. And the seed is encapsulated within this hull, which is like the kind of shell, and what happens is that is removed because you wouldn't be able to eat that shell. And what you're left behind is with the oat grain or the oat seed, and that consists of this outer bran layer, which is slightly brown, orangey, which is what you sometimes see in your oat flakes. You see a little specks, don't you, of this kind of brown and orange, and that's from this outer skin. And then within that outer skin is the main part of the oat, which we call the endosperm. And it's within that endosperm that contains all of the starch, so all of the carbohydrate, as well as some fibre and as well as some protein. And then in the outer layer, that skin, we often call it the bran, that contains a lot of fibre. And so an oat seed typically contains about 60 to 70% carbohydrates. It contains about 10% of protein, which is quite high for a whole grain. And it contains a very special type of fibre called beta glucan. It also contains lots of vitamins, so particularly B vitamins. And it contains lots of minerals, so magnesium, zinc, iron, manganese. And it contains some bioactives, which we call polyphenols. And it contains a particular type of bioactive. Is there evidence to show in populations that eating oats are even healthy for us? And there's some fantastic data that's come from what we call the epidemiological studies, which are studies in large populations where they've followed people for a long period of time and looked at, depending on whether people are oat eaters or not oat eaters, whether that affects their risk of disease. And in one such study, where they followed more than 500,000 individuals over many years, they found that people who were oat eaters versus those who didn't eat any oats actually had lower rates of type 2 diabetes by about 15% and lower all cause mortality, which basically means risk of dying, and that was by about 20%. Now, obviously, there's lots of other things that might explain some of this. You know, people who eat oats tend to smoke less, et cetera, but you can actually adjust for that in the analysis. You can never fully disentangle it. So it's not kind of the strongest evidence to pull on. But that gives us an idea that there's something going on there, that there's something about eating oats that might be beneficial for our health. And so the next thing we need to look at is clinical trials. And also, is there a mechanism, is there some kind of rationale why we might be seeing this? And what we know is that oats contain a very special fibre called beta glucan. And this fibre is well known to reduce circulating cholesterol levels, so to reduce total cholesterol, but also reduce ldl, which is our bad cholesterol that we know is linked to heart disease. And there's been lots of clinical trials that have been published showing that if you add oats to a meal or the beta glucan to a meal, that you can significantly reduce people's cholesterol levels. It needs to be about a certain dose. So we know that you need to be having about 3 grams of the beta glucan a day in order to lower your cholesterol. And so the FDA in the US and the efsa, the European Food Standards Agency in the uk, actually have an approved health claim that beta glucan, this fibre that's in oats at 3 grams a day, can reduce your cholesterol and hence is associated with improved heart health. And I think the evidence is quite consistent for that.
- [04:49]
A
If I understand it rightly, what you're saying is that it's the fiber in the oat that is giving you these health benefits. And there's some really good scientific evidence to support the health benefits. And it's not the starchy carbohydrate that you were talking about before, it's just a thing I feel like we come back to over and over again in this podcast. You know, it's sort of, sort of the fiber and the plant part of it, as it were, that's doing this.
- [05:16]
B
Yeah. You know, like with all food, there's often a double edged sword and there's components in foods that might be really, really great for us and there might be another component in the same food that isn't so healthy for us. But this is why we have to look at the food in its totality, which is what we do a lot at, Zoe, rather than looking at individual components. So we need to look at that oat in terms of also who you are. So if you're someone that has this big blood sugar response, that's not going to be the best food for you. For me, I have less of a blood sugar response. If I had slightly elevated cholesterol, then maybe I want to make it part of my daily routine, having some oats in there in order to reduce my cholesterol.
- [05:55]
A
And is the beta glucans the only thing about the oats that's contributing to that health effect?
- [06:01]
B
So we think that beta glucans is one of the main elements that makes oats healthy because of how it can reduce our cholesterol. We know, though, that in addition to how beta glucans impact our cholesterol levels, that they may also reduce our risk of type 2 diabetes. There's quite good evidence to show that if you consume oats, you have lower risk of type 2 diabetes and you have better insulin control.
- [06:28]
A
You're talking again about the impact of the beta glucan. Is there anything else in the oat that you think that's contributing to these health benefits?
- [06:33]
B
Yeah. So oats are also packed full of B vitamins, of also other minerals like the iron, the magnesium, et cetera. They also have polyphenols. There's a particular type of polyphenol and I can't remember the name, it's very long. It begins with A. And there is some evidence that this polyphenol has beneficial impacts on blood pressure, on pathways associated with inflammation, oxidative stress, and also has some beneficial impacts on blood vessel function. Now, it's difficult to tease apart where the benefits of oats on heart health is coming from. Is it often the beta glucans or is this polyphenol also impacting that as well? Again, I think it's kind of the whole grain and all of the different components that are having that beneficial effect.
- [07:20]
A
I wanted to come on to another question that we got from our listeners a lot, which is about pesticides in oats and I think one of the reasons I might have asked it is that we did a podcast a while ago about organic foods with Professor Tim Spector, who we both know well, and oats was one of the foods that he talked about in terms of pesticides. So what's the situation and how worried do you think we should be?
- [07:47]
B
So there's a particular pesticide that is used to dry out oats before harvesting so they can be harvested more quickly. It's a chemical called glyphosate. It's also found in common pesticides that you can go and get in your DIY store, like Roundup, for example. And what it does is it dries out the grain so you can harvest it more quickly and so you can produce it more quickly. Now, you've got to remember the grain has this outer hull, this kind of shell, so should be a little bit protected from it. But there is some evidence that oats will still absorb some of this pesticide. Oats seem to absorb it more than some of the other whole grains, like wheat, for example. And so there are small levels found in many oats. Now, organic oats rarely contain this because them being organic, this pesticide isn't sprayed. But occasionally you'll find some organic oats that might have tiny, tiny amounts because you know you're getting stuff leached from soil from neighbouring fields, for example. There are very strict regulations about the level of glyphosates that are found in food and in oats because there has been a link with cancer. Most of the evidence, though, linking it to cancer comes from kind of cell, sort of lab experiments or from animals. The evidence in humans is quite weak, but there is sufficient evidence to set tolerable limits above which we know there is potentially an increased risk of cancer. So there's regulations internationally in the us, in the uk, in Europe, for example, of safe, tolerable upper limits, above which there is a probable association with cancer. So there's some carcinogens. So cancer causing agents that we have great confidence that cause cancer. So alcohol is one of those. So alcohol is classed as a type 1 carcinogen that we know is linked to an increased risk of cancer. Glyphosate is classed as a probable carcinogenic. The levels that are found in most foods are actually quite low. I think unless you are eating oats all day long, day after day, it is almost impossible to reach that safe upper limit. Now, obviously it's going to vary from one to, you know, farm to the next farm. And so it's difficult to kind of blanket say that they are all safe, but I think that the levels are generally found in food. Based on the evidence that I've seen, based on the random sampling that is published, I don't think it's something we should worry too much about at all. However, if you can buy organic oats, if they're affordable and accessible for you, I would recommend that you choose organic over non organic. But if that's not accessible for you, I think you can still enjoy your porridge or oatmeal without worrying about that too much.
- [10:49]
A
As you can imagine hosting this podcast, running Zoe, juggling Family Life. It all keeps me pretty busy. So I try as best I can to stay energized and show up well in all those parts of my life by fueling my body with the right food, by exercising, and by adding a scoop of daily 30 to my meals every day. If you haven't heard of Daily 30 yet, it's the gut supplement designed by our gut health scientists here at Zoe. It's made of over 30 high quality hand picked plants including seaweed, fungi and different types of fiber. Better yet, it contains ingredients that support gut health, digestion and energy, which is ideal for packed calendars and busy lives. Simply add one scoop a day to any meal for an extra boost of fiber and plant diversity. And because it tastes delicious on just about anything and adds a satisfying crunch, it quite quickly slots into your life, becoming a daily healthy habit you'll always have time for. By the way, whenever we talk about Daily 30 as a good source of fiber, we're required to say that it contains 4 grams of total fat per serving. Obviously that's all amazing healthy fats from plants, so order yours today@zoe.com Daily30 thanks for listening and see you next time.