WEBVTT 00:00:00.000 --> 00:00:03.255 align:middle line:90% [MUSIC PLAYING] 00:00:11.900 --> 00:00:14.560 align:middle line:84% HELEN TRUBY: Today we're going to talk about the food matrix 00:00:14.560 --> 00:00:18.810 align:middle line:84% and how having food in its whole form is the way 00:00:18.810 --> 00:00:20.220 align:middle line:90% we usually eat food. 00:00:20.220 --> 00:00:22.100 align:middle line:84% But if we change the way that food 00:00:22.100 --> 00:00:25.790 align:middle line:84% is actually presented to us and we change the food matrix 00:00:25.790 --> 00:00:29.020 align:middle line:84% how that can actually alter its physiological properties 00:00:29.020 --> 00:00:31.250 align:middle line:84% and potentially its health properties. 00:00:31.250 --> 00:00:34.480 align:middle line:84% So we're going to look at, again, an example of an orange. 00:00:34.480 --> 00:00:37.219 align:middle line:84% We know that orange is a good source of vitamin C. 00:00:37.219 --> 00:00:39.260 align:middle line:84% And though they're not the only source of vitamin 00:00:39.260 --> 00:00:42.340 align:middle line:84% C in our diet, they are rich source of vitamin C. 00:00:42.340 --> 00:00:44.810 align:middle line:84% Now, vitamin C is a water soluble vitamin. 00:00:44.810 --> 00:00:47.460 align:middle line:84% That means that we don't store it in our bodies. 00:00:47.460 --> 00:00:50.060 align:middle line:84% And it's relatively easy to become depleted 00:00:50.060 --> 00:00:52.460 align:middle line:84% in vitamin C within sort of couple of months 00:00:52.460 --> 00:00:56.090 align:middle line:84% if you don't have any in your diet on a regular basis you 00:00:56.090 --> 00:00:58.400 align:middle line:90% become vitamin C deficient. 00:00:58.400 --> 00:01:00.960 align:middle line:84% And the deficiency disease is called scurvy. 00:01:00.960 --> 00:01:05.200 align:middle line:84% And scurvy was really described first 00:01:05.200 --> 00:01:08.330 align:middle line:84% in people who went on long sea voyages. 00:01:08.330 --> 00:01:10.730 align:middle line:84% So the mariners of old that perhaps sailed out 00:01:10.730 --> 00:01:14.980 align:middle line:84% across from Europe to find new countries often developed 00:01:14.980 --> 00:01:18.590 align:middle line:84% signs of vitamin C deficiency, which of course they 00:01:18.590 --> 00:01:21.520 align:middle line:84% didn't know was vitamin C deficiency at the time. 00:01:21.520 --> 00:01:24.320 align:middle line:84% But developed sores and sore mouths 00:01:24.320 --> 00:01:27.830 align:middle line:84% and were unwell and unable to effectively work. 00:01:27.830 --> 00:01:30.640 align:middle line:84% And that was remedied by giving people-- 00:01:30.640 --> 00:01:33.500 align:middle line:84% giving the sailor a very small amounts of lime juice 00:01:33.500 --> 00:01:35.050 align:middle line:90% or a citrus juice. 00:01:35.050 --> 00:01:38.020 align:middle line:84% And that was just enough vitamin C to prevent them 00:01:38.020 --> 00:01:41.210 align:middle line:84% from becoming deficient during long sea voyages. 00:01:41.210 --> 00:01:44.590 align:middle line:84% So mariners were often called limeys at the time 00:01:44.590 --> 00:01:47.830 align:middle line:84% because that introduction of lime into their diet 00:01:47.830 --> 00:01:51.210 align:middle line:84% actually helped them stay nutritionally well. 00:01:51.210 --> 00:01:53.510 align:middle line:84% So large doses of vitamin C are not 00:01:53.510 --> 00:01:56.840 align:middle line:84% particularly useful in normal nutrition 00:01:56.840 --> 00:02:00.170 align:middle line:84% anyway because we can't store very much of it. 00:02:00.170 --> 00:02:03.370 align:middle line:84% So the amount of vitamin C we know-- the minimum amount 00:02:03.370 --> 00:02:06.250 align:middle line:84% to prevent scurvy is about 10 milligrams a day. 00:02:06.250 --> 00:02:09.560 align:middle line:84% And in Australia, our recommended daily intake a day 00:02:09.560 --> 00:02:11.510 align:middle line:90% is 45 milligrams. 00:02:11.510 --> 00:02:15.020 align:middle line:84% So that's already got a minimum amount, plus a bit for safety, 00:02:15.020 --> 00:02:16.210 align:middle line:90% plus a bit extra. 00:02:16.210 --> 00:02:18.360 align:middle line:84% So if you're having 45 milligrams a day, 00:02:18.360 --> 00:02:21.010 align:middle line:84% then you certainly shouldn't develop scurvy. 00:02:21.010 --> 00:02:22.640 align:middle line:84% So if we think about food and what 00:02:22.640 --> 00:02:25.300 align:middle line:84% foods are going to provide us with that amount, if we look 00:02:25.300 --> 00:02:31.360 align:middle line:84% at a whole orange, and this is the majority of a small orange, 00:02:31.360 --> 00:02:35.730 align:middle line:84% and that will give you 45 milligrams of vitamin C. 00:02:35.730 --> 00:02:39.570 align:middle line:84% If we change the food structure or change the food matrix, 00:02:39.570 --> 00:02:43.440 align:middle line:84% and take that same amount of vitamin C and just juice it, 00:02:43.440 --> 00:02:45.230 align:middle line:84% that 100 is going to give us 00:02:45.230 --> 00:02:48.430 align:middle line:84% approximately the same amount of vitamin C-- 00:02:48.430 --> 00:02:50.100 align:middle line:84% more than enough that we need in a day. 00:02:50.100 --> 00:02:53.770 align:middle line:84% And obviously, we don't just get vitamin C from oranges, 00:02:53.770 --> 00:02:57.750 align:middle line:84% we get it from the range of fruit and vegetables. 00:02:57.750 --> 00:03:01.200 align:middle line:84% So the difference here though, is twofold. 00:03:01.200 --> 00:03:04.830 align:middle line:84% One, the whole orange is going to contain fibre. 00:03:04.830 --> 00:03:07.860 align:middle line:84% And in there is going to have about 2.3 grams 00:03:07.860 --> 00:03:09.320 align:middle line:90% of fibre a day. 00:03:09.320 --> 00:03:13.360 align:middle line:84% And this contains almost none, so 0.2 grams of fibre. 00:03:13.360 --> 00:03:15.170 align:middle line:84% So just in terms of eating it, we 00:03:15.170 --> 00:03:17.660 align:middle line:84% know fiber keeps us feeling full. 00:03:17.660 --> 00:03:21.570 align:middle line:84% So in terms just satiety, we are able to eat 00:03:21.570 --> 00:03:24.130 align:middle line:84% that orange and that's probably enough for one serve. 00:03:24.130 --> 00:03:25.590 align:middle line:84% But probably if we poured ourself 00:03:25.590 --> 00:03:27.240 align:middle line:84% a glass of orange juice, we'd probably 00:03:27.240 --> 00:03:30.270 align:middle line:84% pour ourselves a whole glass or maybe at least half 00:03:30.270 --> 00:03:31.280 align:middle line:90% a glass of orange juice. 00:03:31.280 --> 00:03:33.270 align:middle line:84% We'd get a lot more energy from that. 00:03:33.270 --> 00:03:36.630 align:middle line:84% And this is a way that sometimes by changing the food matrix, 00:03:36.630 --> 00:03:38.270 align:middle line:84% we're actually making it very easy 00:03:38.270 --> 00:03:41.540 align:middle line:84% for us to over consume energy without a huge amount 00:03:41.540 --> 00:03:43.750 align:middle line:84% of benefit in terms of our nutrition. 00:03:43.750 --> 00:03:46.930 align:middle line:84% So it's better to have a food that's higher in fiber 00:03:46.930 --> 00:03:49.530 align:middle line:84% that you're going to remain fuller for longer, 00:03:49.530 --> 00:03:53.880 align:middle line:84% and it also has some benefits for gut health as well. 00:03:53.880 --> 00:03:56.850 align:middle line:84% So just in terms of thinking about our food as medicine-- 00:03:56.850 --> 00:03:59.160 align:middle line:84% on our medicine tablet of vitamin C, 00:03:59.160 --> 00:04:02.900 align:middle line:84% this is 1,000 milligrams of medicine-- pure vitamin 00:04:02.900 --> 00:04:05.200 align:middle line:84% C. How many oranges would we have 00:04:05.200 --> 00:04:07.490 align:middle line:84% to eat to get that amount of vitamin C? 00:04:07.490 --> 00:04:10.430 align:middle line:84% We would have to eat about 23 whole oranges 00:04:10.430 --> 00:04:12.400 align:middle line:84% to get the same amount of vitamin C that's 00:04:12.400 --> 00:04:13.510 align:middle line:90% in this tablet. 00:04:13.510 --> 00:04:16.170 align:middle line:84% Clearly, you're really not going to sit down and have 00:04:16.170 --> 00:04:18.399 align:middle line:90% a whole meal of 23 oranges. 00:04:18.399 --> 00:04:23.010 align:middle line:84% And so if we need very high doses of vitamin C, 00:04:23.010 --> 00:04:26.800 align:middle line:84% then we'd obviously probably take a vitamin C supplement. 00:04:26.800 --> 00:04:29.720 align:middle line:84% But in all honesty, because our body doesn't store it, 00:04:29.720 --> 00:04:32.030 align:middle line:84% there's no big benefit for most people 00:04:32.030 --> 00:04:34.380 align:middle line:90% to take mega doses of vitamin C. 00:04:34.380 --> 00:04:37.010 align:middle line:84% Another example of where the food matrix 00:04:37.010 --> 00:04:40.440 align:middle line:84% is going to impact on its physiological benefit to us 00:04:40.440 --> 00:04:41.650 align:middle line:90% is oats. 00:04:41.650 --> 00:04:44.090 align:middle line:84% So here we have a few example of oat products 00:04:44.090 --> 00:04:46.580 align:middle line:84% and how it might appear in our diet. 00:04:46.580 --> 00:04:48.710 align:middle line:90% So oats comes in various forms. 00:04:48.710 --> 00:04:52.320 align:middle line:84% It sort of most common form would be the rolled oats 00:04:52.320 --> 00:04:56.670 align:middle line:84% that we'd see in our muesli, or you'd make a flapjack 00:04:56.670 --> 00:04:57.980 align:middle line:90% or something like that from it. 00:04:57.980 --> 00:05:00.070 align:middle line:84% So that's its sort of roughest form 00:05:00.070 --> 00:05:01.980 align:middle line:84% that you're going to find oats in. 00:05:01.980 --> 00:05:06.200 align:middle line:84% But then you can get the bran out of oats, so bran. 00:05:06.200 --> 00:05:11.200 align:middle line:84% And also finally, a flour that also is made from oat. 00:05:11.200 --> 00:05:13.540 align:middle line:84% So the food matrix here is quite different, 00:05:13.540 --> 00:05:15.450 align:middle line:84% and clearly, you can make different products 00:05:15.450 --> 00:05:19.390 align:middle line:84% from these different types of-- different types of oat product. 00:05:19.390 --> 00:05:22.550 align:middle line:84% The question is, are they going to work differently? 00:05:22.550 --> 00:05:25.640 align:middle line:84% And the key thing about oat bran that makes it-- 00:05:25.640 --> 00:05:28.730 align:middle line:84% or oat products that makes it different 00:05:28.730 --> 00:05:32.990 align:middle line:84% to wheat-based products is that it contains soluble fiber. 00:05:32.990 --> 00:05:34.950 align:middle line:84% Now, soluble fiber is particularly 00:05:34.950 --> 00:05:42.520 align:middle line:84% important in gut health because it is metabolised or changed 00:05:42.520 --> 00:05:43.550 align:middle line:90% in our gut. 00:05:43.550 --> 00:05:46.980 align:middle line:84% And it produces short-chain fatty acids, which 00:05:46.980 --> 00:05:48.630 align:middle line:90% are beneficial to gut health. 00:05:48.630 --> 00:05:51.370 align:middle line:84% So we know that having soluble fiber in your diet 00:05:51.370 --> 00:05:52.690 align:middle line:90% is really important. 00:05:52.690 --> 00:05:55.580 align:middle line:84% In terms of the active compounds in here, 00:05:55.580 --> 00:05:58.140 align:middle line:84% we know that in oats it's actually beta-glucan. 00:05:58.140 --> 00:06:01.630 align:middle line:84% Having a dose of beta-glucan may well 00:06:01.630 --> 00:06:04.490 align:middle line:84% be helpful as part of a whole diet approach 00:06:04.490 --> 00:06:06.290 align:middle line:84% to reduce your cholesterol levels. 00:06:06.290 --> 00:06:09.780 align:middle line:84% How do we know though, that beta-glucan in whole oats 00:06:09.780 --> 00:06:14.190 align:middle line:84% is going to respond the same way as the beta-glucan in flour? 00:06:14.190 --> 00:06:17.440 align:middle line:84% So for instance, will a bowl of muesli 00:06:17.440 --> 00:06:21.710 align:middle line:84% have the same beneficial effect as if we had for instance, 00:06:21.710 --> 00:06:23.900 align:middle line:90% a muffin made with flour? 00:06:23.900 --> 00:06:25.350 align:middle line:90% And the answer is no. 00:06:25.350 --> 00:06:27.760 align:middle line:84% Because the muffin is going to likely 00:06:27.760 --> 00:06:31.950 align:middle line:84% to contain much less beta-glucan than a bowl of oats. 00:06:31.950 --> 00:06:34.600 align:middle line:84% But obviously changing the food matrix 00:06:34.600 --> 00:06:36.800 align:middle line:84% and how it's provided to you is going 00:06:36.800 --> 00:06:39.920 align:middle line:84% to alter whether how much dose of that beta-glucan 00:06:39.920 --> 00:06:42.780 align:middle line:84% that you're getting and also how available it is. 00:06:42.780 --> 00:06:47.750 align:middle line:84% So government regulations help us understand 00:06:47.750 --> 00:06:50.270 align:middle line:84% what manufactures are putting into food products 00:06:50.270 --> 00:06:51.730 align:middle line:90% by food labeling. 00:06:51.730 --> 00:06:55.610 align:middle line:84% And the regulation around health claims 00:06:55.610 --> 00:06:59.330 align:middle line:84% of a product where the food matrix is being changed 00:06:59.330 --> 00:07:01.330 align:middle line:84% should inform us as to whether that's 00:07:01.330 --> 00:07:04.310 align:middle line:84% going to be a good product for you to buy or maybe not such 00:07:04.310 --> 00:07:05.800 align:middle line:90% a good product for you to buy. 00:07:05.800 --> 00:07:08.880 align:middle line:84% So it's really important to understand the food matrix 00:07:08.880 --> 00:07:11.040 align:middle line:84% and the impact that potentially has 00:07:11.040 --> 00:07:13.230 align:middle line:84% on how we're going to absorb that food 00:07:13.230 --> 00:07:16.630 align:middle line:84% and whether it does have a health benefit or not.