Skip to 0 minutes and 12 secondsHELEN TRUBY: Today we're going to talk about the food matrix and how having food in its whole form is the way we usually ate food. But if we change the way that food is actually presented to us and we change the food matrix how that can actually alter its physiological properties and potentially its health properties. So we're going to look at, again, an example of an orange. We know that orange is a good source of vitamin C. And though they're not the only source of vitamin C in our diet, they are rich source of vitamin C. Now, vitamin C is a water soluble vitamin. That means that we don't store it in our bodies.

Skip to 0 minutes and 48 secondsAnd it's relatively easy to become depleted in vitamin C within sort of couple of months if you don't have any in your diet on a regular basis you become vitamin C deficient. And the deficiency disease is called scurvy. And scurvy was really described first in people who went on long sea voyages. So the mariners of old that perhaps sailed out across from Europe to find new countries often developed signs of vitamin C deficiency, which of course they didn't know was vitamin C deficiency at the time. But developed sores and sore mouths and were unwell and unable to effectively work. And that was remedied by giving people-- giving the sailor a very small amounts of lime juice or a citrus juice.

Skip to 1 minute and 35 secondsAnd that was just enough vitamin C to prevent them from becoming deficient during long sea voyages. So mariners were often called limeys at the time because that introduction of lime into their diet actually helped them stay nutritionally well. So large doses of vitamin C are not particularly useful in normal nutrition anyway because we can't store very much of it. So the amount of vitamin C we know-- the minimum amount to prevent scurvy is about 10 milligrams a day. And in Australia, our recommended daily intake a day is 45 milligrams. So that's already got a minimum amount, plus a bit for safety, plus a bit extra. So if you're having 45 milligrams a day, then you certainly shouldn't develop scurvy.

Skip to 2 minutes and 21 secondsSo if we think about food and what foods are going to provide us with that amount, if we look at a whole orange, and this is the majority of a small orange, and that will give you 45 milligrams of vitamin C. If we change the food structure or change the food matrix, and take that same amount of vitamin C and just juice it, that 100 mills is going to give us approximately the same amount of vitamin C-- more than enough that we need in a day. And obviously, we don't just get vitamin C from oranges, we get it from the range of fruit and vegetables. So the difference here though, is twofold.

Skip to 3 minutes and 1 secondOne, the whole orange is going to contain fiber. And in there is going to have about 2.3 milligrams of fiber a day. And this contains almost none, so 0.2 milligram of fiber. So just in terms of eating it, we know fiber keeps us feeling full. So in terms just satiety, we are able to eat that orange and that's probably enough for one serve. But probably if we poured ourself a glass of orange juice, we'd probably pour ourselves a whole glass or maybe at least half a glass of orange juice. We'd get a lot more energy from that.

Skip to 3 minutes and 33 secondsAnd this is a way that sometimes by changing the food matrix, we're actually making it very easy for us to over consume energy without a huge amount of benefit in terms of our nutrition. So it's better to have a food that's higher in fiber that you're going to remain fuller for longer, and it also has some benefits for gut health as well. So just in terms of thinking about our food as medicine-- on our medicine tablet of vitamin C, this is 1,000 milligrams of medicine-- pure vitamin C. How many oranges would we have to eat to get that amount of vitamin C?

Skip to 4 minutes and 8 secondsWe would have to eat about 23 whole oranges to get the same amount of vitamin C that's in this tablet. Clearly, you're really not going to sit down and have a whole meal of 23 oranges. And so if we need very high doses of vitamin C, then we'd obviously probably take a vitamin C supplement. But in all honesty, because our body doesn't store it, there's no big benefit for most people to take mega doses of vitamin C. Another example of where the food matrix is going to impact on its physiological benefit to us is oats. So here we have a few example of oat products and how it might appear in our diet. So oats comes in various forms.

Skip to 4 minutes and 49 secondsIt sort of most common form would be the rolled oats that we'd see in our muesli, or you'd make a flapjack or something like that from it. So that's its sort of roughest form that you're going to find oats in. But then you can get the bran out of oats, so bran. And also finally, a flour that also is made from oat. So the food matrix here is quite different, and clearly, you can make different products from these different types of-- different types of oat product. The question is, are they going to work differently? And the key thing about oat bran that makes it-- or oat products that makes it different to wheat-based products is that it contains soluble fiber.

Skip to 5 minutes and 33 secondsNow, soluble fiber is particularly important in gut health because it is metabolized or changed in our gut. And it produces short-chain fatty acids, which are beneficial to gut health. So we know that having soluble fiber in your diet is really important. In terms of the active compounds in here, we know that in oats it's actually beta-glucan. Having a dose of beta-glucan may well be helpful as part of a whole diet approach to reduce your cholesterol levels. How do we know though, that beta-glucan in whole oats is going to respond the same way as the beta-glucan in flour?

Skip to 6 minutes and 14 secondsSo for instance, will a bowl of muesli have the same beneficial effect as if we had for instance, a muffin made with flour? And the answer is no. Because the muffin is going to likely to contain much less beta-glucan than a bowl of oats. But obviously changing the food matrix and how it's provided to you is going to alter whether how much dose of that beta-glucan that you're getting and also how available it is. So government regulations help us understand what manufactures are putting into food products by food labeling.

Skip to 6 minutes and 52 secondsAnd the regulation around health claims of a product where the food matrix is being changed should inform us as to whether that's going to be a good product for you to buy or maybe not such a good product for you to buy. So it's really important to understand the food matrix and the impact that potentially has on how we're going to absorb that food and whether it does have a health benefit or not.

The food matrix

Watch Helen explore the food matrix and explain how a change to the food matrix can potentially impact the health properties of the food we eat.

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This video is from the free online course:

Food as Medicine

Monash University