บทถอดความฉบับเต็มของ Organic Food

their own episode. Let's start with one 77 00:04:00.330 --> 00:04:05.030 of Mark's biggest gripes, that people think organic food tastes 78 00:04:05.129 --> 00:04:06.770 better than conventional food. 79 00:04:07.750 --> 00:04:09.680 Does it? We know what Mark thinks. 80 00:04:10.490 --> 00:04:12.849 OK, whatever. It doesn't taste any better. 81 00:04:13.270 --> 00:04:16.990 But hold on there. Mark hasn't done peer-reviewed studies. 82 00:04:17.329 --> 00:04:20.870 Lucky for us, researchers at the University of Uppsala in 83 00:04:20.990 --> 00:04:25.170 Sweden have. In a series of experiments, they gave people 84 00:04:25.230 --> 00:04:29.149 slices of tomatoes, presenting them as organic or conventional. 85 00:04:29.569 --> 00:04:31.389 And hey, good news for organic. 86 00:04:31.990 --> 00:04:34.769 People were more likely to say that the tomatoes presented 87 00:04:34.870 --> 00:04:36.769 as organic were tastier. 88 00:04:37.509 --> 00:04:40.360 But Uppsala... Here's the catch. 89 00:04:41.060 --> 00:04:46.199 Some of those tasty, seemingly organic tomatoes were actually conventional. 90 00:04:46.810 --> 00:04:50.670 The researchers at Uppsala University. 91 00:04:50.550 --> 00:04:52.269 Purposefully misled people. 92 00:04:52.870 --> 00:04:56.329 Other studies have similarly found that slapping an organic label 93 00:04:56.410 --> 00:04:59.540 over food, even if it's not organic, can make people 94 00:04:59.620 --> 00:05:00.779 think it tastes better. 95 00:05:01.360 --> 00:05:03.899 Generally speaking, though, researchers. 96 00:05:03.439 --> 00:05:08.439 Found that growing a crop organically or conventionally doesn't consistently 97 00:05:08.579 --> 00:05:14.120 affect its taste. But Mark did tell us about something 98 00:05:14.279 --> 00:05:17.649 that does consistently affect the taste of fruits. 99 00:05:18.089 --> 00:05:19.629 Say, strawberries. 100 00:05:20.509 --> 00:05:23.250 I take the Nutella. You know Nutella, I'm sure. 101 00:05:23.269 --> 00:05:23.870 Oh yeah, I know Nutella. 102 00:05:24.389 --> 00:05:26.329 I cut the stems off, spear it with a fork, 103 00:05:26.569 --> 00:05:28.680 shove it down in a Nutella bottle and swirl it 104 00:05:28.720 --> 00:05:29.540 about four times. 105 00:05:30.480 --> 00:05:30.980 Conclusion. 106 00:05:31.279 --> 00:05:36.279 When you cover something in Nutella, it tastes delicious. Put 107 00:05:36.319 --> 00:05:45.189 that Hazelnut spread over some pancakes, strawberries, just delightful. But yeah, 108 00:05:45.240 --> 00:05:48.220 when it comes to taste, whether it's conventional or organic, 109 00:05:48.240 --> 00:05:52.519 it doesn't make a difference. Okay, another big reason why 110 00:05:52.579 --> 00:05:55.980 people buy organic is because they think it's more nutritious. 111 00:05:56.220 --> 00:05:58.550 That is, they think it's packed with more vitamins and 112 00:05:58.620 --> 00:06:00.250 minerals than the conventional stuff. 113 00:06:01.410 --> 00:06:02.430 But is it? 114 00:06:03.310 --> 00:06:07.470 Dr Catherine Bradbury is a nutritional epidemiologist at Oxford University. 115 00:06:08.029 --> 00:06:09.230 If you review all of the. 116 00:06:09.170 --> 00:06:12.930 Studies, there's really not a lot of difference between organic 117 00:06:13.009 --> 00:06:16.269 and conventionally grown fruit and vegetables. You know, there's no 118 00:06:16.310 --> 00:06:20.110 difference in vitamin C content and potassium content and magnesium 119 00:06:20.170 --> 00:06:21.110 content overall. 120 00:06:21.660 --> 00:06:24.180 Catherine says that while there are many studies looking at 121 00:06:24.259 --> 00:06:27.060 whether or not there is more nutrition in organic foods, 122 00:06:27.500 --> 00:06:30.910 some studies say yes, others say no, when it comes 123 00:06:30.990 --> 00:06:33.769 to science, you have to look at the overall picture. 124 00:06:34.870 --> 00:06:38.810 And in 2012, researchers at Stanford did just that. They 125 00:06:38.829 --> 00:06:42.029 looked at scores of studies on the nutritional value of organics, 126 00:06:42.129 --> 00:06:48.189 analysing vitamin levels in tomatoes, eggplants, carrots, corn, plums, strawberries, peppers, wheat, kale. 127 00:06:48.350 --> 00:06:48.750 Yes! 128 00:06:49.810 --> 00:06:50.850 Even kale! 129 00:06:52.480 --> 00:07:03.430 And.... 130 00:06:57.730 --> 00:06:59.189 End quote. 131 00:07:00.050 --> 00:07:07.230 And any minor differences that were found wouldn't matter for 132 00:07:07.290 --> 00:07:11.610 most people. For example, organic produce tended to have more 133 00:07:11.709 --> 00:07:15.920 phosphorus in it, but the authors wrote that would only 134 00:07:15.980 --> 00:07:20.160 be important to someone facing near-total starvation. 135 00:07:21.040 --> 00:07:21.240 So. 136 00:07:22.389 --> 00:07:24.850 Probably not an issue for most people buying organic. 137 00:07:26.689 --> 00:07:27.180 Conclusion. 138 00:07:27.500 --> 00:07:29.920 The science is not there to support the claim that 139 00:07:29.980 --> 00:07:34.899 organic means it's more nutritious. It's pretty simple. So you 140 00:07:34.939 --> 00:07:37.860 can tick that off your list of reasons to buy organic. 141 00:07:38.620 --> 00:07:42.069 Next on that list, fear that conventional produce is covered 142 00:07:42.129 --> 00:07:46.230 in toxins that are going to make you sick. Perhaps 143 00:07:46.529 --> 00:07:49.230 when you think of an organic farm... You think of 144 00:07:49.290 --> 00:07:52.629 a serene farm with fruits and vegetables left to grow 145 00:07:52.709 --> 00:07:59.899 as nature intended, free from dangerous chemicals. And perhaps you 146 00:07:59.939 --> 00:08:03.220 think that because a lot of advertising is telling you that. 147 00:08:03.980 --> 00:08:16.540 Like this gem from the advocacy group Only Organic. And 148 00:08:16.639 --> 00:08:22.339 some organic farming techniques actually do fit this song and dance. Well, 149 00:08:22.399 --> 00:08:25.649 not exactly this song and

dance, but the Reeves brothers 150 00:08:25.790 --> 00:08:29.589 don't use chemicals in some processes. For example, they say 151 00:08:29.629 --> 00:08:33.970 goodbye to Weed Killer on their organic strawberries. Andy, Reeves' 152 00:08:34.009 --> 00:08:36.620 brother number two, told me all about it while he 153 00:08:36.629 --> 00:08:38.080 was working the strawberry fields. 154 00:08:39.240 --> 00:08:39.899 in a tractor. 155 00:08:42.059 --> 00:08:43.399 Andy? Hello. 156 00:08:43.620 --> 00:08:43.799 Hello. 157 00:08:43.820 --> 00:08:44.000 Hello. 158 00:08:46.299 --> 00:08:48.379 Ready? Ready. You want that on? 159 00:08:49.080 --> 00:08:49.879 Yeah, that'd be great. 160 00:08:50.899 --> 00:08:53.850 Without weed killer on their strawberries, the Reeves brothers use 161 00:08:53.870 --> 00:08:55.509 a real old school approach. 162 00:08:55.690 --> 00:08:59.370 We probably will hand weed the organic strawberries 10 times 163 00:08:59.610 --> 00:09:00.029 a season. 164 00:09:01.129 --> 00:09:02.129 Hand weed? 165 00:09:02.529 --> 00:09:04.620 Hand weed 10 times a season. 166 00:09:05.220 --> 00:09:06.860 Do you do the hand weeding personally? 167 00:09:07.899 --> 00:09:13.139 Are you kidding me? No. Did you ever? I'm 63 168 00:09:13.139 --> 00:09:16.629 years old. It's hard for me to even say the word. 169 00:09:19.389 --> 00:09:21.970 The Reeves farm doesn't hand weed because they think it's 170 00:09:22.029 --> 00:09:25.899 the right thing to do. Organic food regulations actually don't 171 00:09:26.059 --> 00:09:28.919 allow farmers to use the potent weed killers that they 172 00:09:28.980 --> 00:09:32.860 can on their conventional strawberries. But that doesn't mean the 173 00:09:32.919 --> 00:09:38.519 Reeves organic crops are chemical-free. Organic certification does allow farmers 174 00:09:38.580 --> 00:09:41.830 to use some synthetic chemicals to kill pests. 175 00:09:42.370 --> 00:09:44.590 Because while you can hand weed. 176 00:09:45.090 --> 00:09:48.899 You can't hand-pick out fungi and bacteria from a crop. 177 00:09:49.620 --> 00:09:53.259 So even organic crops sometimes need chemicals. 178 00:09:53.720 --> 00:09:55.259 Here's Mark, brother number one. 179 00:09:56.250 --> 00:09:56.970 So what is this? 180 00:09:56.990 --> 00:09:59.970 It says fungicide bacteria. 181 00:10:01.039 --> 00:10:03.519 This is copper hydroxide. 182 00:10:03.860 --> 00:10:04.460 Copper hydroxide. 183 00:10:04.480 --> 00:10:05.240 This is organic? 184 00:10:05.799 --> 00:10:06.240 Yes, it is. 185 00:10:06.720 --> 00:10:09.259 Mark handed me a heavy paper bag. Like a lot 186 00:10:09.279 --> 00:10:15.029 of pesticides, it had the word danger written across it. Caligro. 187 00:10:15.750 --> 00:10:16.830 Keep out of reach of children. 188 00:10:16.850 --> 00:10:19.720 Just going to stick my hand in it. It's like 189 00:10:19.759 --> 00:10:26.830 really fine powder, and it's kind of aquamarine-y. And now 190 00:10:26.909 --> 00:10:27.870 my hands are a bit blue. 191 00:10:28.529 --> 00:10:31.610 Copper oxide is, if you take a copper pipe and 192 00:10:31.649 --> 00:10:34.450 it gets corroded, it turns blue like that. When you're 193 00:10:34.470 --> 00:10:39.309 spraying that copper there, you really want to coat every 194 00:10:39.370 --> 00:10:41.690 leaf on the plant everywhere if you can. You want 195 00:10:41.710 --> 00:10:43.549 that coating all over the plant if you can. 196 00:10:44.149 --> 00:10:46.700 And that coating, whether it comes from an organic or 197 00:10:46.740 --> 00:10:49.919 a conventional pesticide, can remain on the food you take 198 00:10:49.960 --> 00:10:53.019 home from the store, even sometimes after you wash it, 199 00:10:53.600 --> 00:10:58.129 in very, very small amounts. But the important question for 200 00:10:58.230 --> 00:11:02.669 us is this. Are the tiny traces of pesticides sometimes 201 00:11:02.750 --> 00:11:06.590 found on organic food safer than those on conventional foods? 202 00:11:07.210 --> 00:11:09.750 The best study we have on this comes from Catherine Bradbury, 203 00:11:09.889 --> 00:11:12.080 you heard from her before, and her colleagues at the 204 00:11:12.139 --> 00:11:17.129 University of Oxford. So Catherine followed more than 620,000 women, 205 00:11:17.190 --> 00:11:20.120 some who ate organic food, others who ate conventional food, 206 00:11:20.240 --> 00:11:21.080 for nine years. 207 00:11:21.500 --> 00:11:25.039 She was looking for which women developed cancers. Here's Catherine. 208 00:11:25.840 --> 00:11:28.899 So we wanted to look at whether people who ate 209 00:11:29.590 --> 00:11:32.370 organic food were less likely to get cancer because that's 210 00:11:32.409 --> 00:11:33.789 one of the big beliefs out there. 211 00:11:34.250 --> 00:11:37.289 And Catherine found that women who said they usually or 212 00:11:37.450 --> 00:11:41.789 always ate organic food were less likely to get non-Hodgkin's lymphoma. 213 00:11:42.620 --> 00:11:46.110 That's good news for organic. But here's the catch. 214 00:11:46.870 --> 00:11:49.509 The study also found that those who said they ate 215 00:11:49.570 --> 00:11:53.639 organic food a lot were more likely to get breast 216 00:11:53.659 --> 00:11:56.980 cancer compared to those who said they never ate organic 217 00:11:57.039 --> 00:12:01.100 food at all. So less likely to get one type 218 00:12:01.139 --> 00:12:03.850 of cancer, more likely to get another type of cancer. 219 00:12:04.389 --> 00:12:05.169 What do we do with that? 220 00:12:06.080 --> 00:12:10.289 Well, Catherine says these specific correlations could just be chance findings, 221 00:12:10.570 --> 00:12:13.990 statistical blips that have nothing to do with diet. Because, 222 00:12:14.250 --> 00:12:17.730 you see, Catherine also looked at the overall cancer rate. 223 00:12:18.629 --> 00:12:18.809 And? 224 00:12:19.350 --> 00:12:21.389 It would have been amazing if you saw that, you know, 225 00:12:21.590 --> 00:12:24.429 they had a 50%

reduced risk of getting cancer overall. 226 00:12:24.789 --> 00:12:27.200 And then we saw the overall result and said, OK, yeah, 227 00:12:28.159 --> 00:12:28.899 there's nothing there. 228 00:12:29.860 --> 00:12:30.460 That's right. 229 00:12:30.720 --> 00:12:33.360 There was no overall difference in the cancer rate between 230 00:12:33.399 --> 00:12:36.879 women who ate organic and those who didn't. But Catherine 231 00:12:36.899 --> 00:12:39.740 wants more research because even though her study was big 232 00:12:39.860 --> 00:12:45.679 and comprehensive, it was still inconclusive. And Catherine's study, published 233 00:12:45.740 --> 00:12:49.820 in 2014, is the largest and longest of its kind. 234 00:12:50.419 --> 00:12:53.480 We have no other long-term research comparing the health of 235 00:12:53.539 --> 00:12:56.779 a lot of people who eat organic versus conventional. And 236 00:12:56.820 --> 00:13:00.019 that means we can't say more about whether or not 237 00:13:00.159 --> 00:13:03.950 eating small amounts of pesticides on your food might cause 238 00:13:04.039 --> 00:13:08.899 other diseases. Now, there have been studies looking into people 239 00:13:08.919 --> 00:13:12.340 who are exposed to high doses of conventional pesticides, like 240 00:13:12.440 --> 00:13:16.299 agricultural workers. So, for example, there is some research suggesting 241 00:13:16.320 --> 00:13:19.240 that agricultural workers have a high risk of certain kinds 242 00:13:19.279 --> 00:13:23.730 of cancers, like non-Hodgkin's lymphoma and breast cancer. There is 243 00:13:23.809 --> 00:13:27.269 also some preliminary work into pregnant women living in agricultural 244 00:13:27.309 --> 00:13:30.610 communities and the effect of pesticides on their unborn children. 245 00:13:31.590 --> 00:13:31.750 But. 246 00:13:32.629 --> 00:13:36.049 these studies can't be clearly translated to the average Joe 247 00:13:36.129 --> 00:13:39.470 at the supermarket. Because that average Joe is eating a 248 00:13:39.590 --> 00:13:43.490 steady diet of foods with tiny traces of pesticides, but 249 00:13:43.549 --> 00:13:44.789 is never exposed. 250 00:13:44.429 --> 00:13:45.529 To large amounts of them. 251 00:13:46.409 --> 00:13:49.500 Cynthia Curl is an assistant professor in environmental health at 252 00:13:49.539 --> 00:13:51.480 Boise State University in Idaho. 253 00:13:52.080 --> 00:13:54.360 And she says that when it comes to pesticides. 254 00:13:54.940 --> 00:13:59.240 We know that in high enough doses, they're toxic, otherwise 255 00:13:59.279 --> 00:14:03.549 they would be pretty poor pesticides. We really don't know 256 00:14:03.570 --> 00:14:08.049 at these low levels whether there are health effects. So 257 00:14:08.590 --> 00:14:10.549 if you're down to the levels that we're talking about 258 00:14:10.570 --> 00:14:12.870 in conventional food, is it below a threshold where there 259 00:14:12.889 --> 00:14:16.389 would be anything to worry about? That's the million-dollar question. 260 00:14:16.809 --> 00:14:20.259 With all this uncertainty, it's understandable why people are clamoring 261 00:14:20.299 --> 00:14:24.000 to get Cynthia to give speeches. Oh, yeah. 262 00:14:24.039 --> 00:14:26.860 I've had friends ask me to, you know, come talk 263 00:14:26.879 --> 00:14:29.500 to their preschools about the dangers of pesticides. 264 00:14:29.840 --> 00:14:30.019 Oh. 265 00:14:31.639 --> 00:14:35.139 I really try not to get into that. What would 266 00:14:35.179 --> 00:14:36.460 you tell a preschooler? 267 00:14:38.470 --> 00:14:40.129 To eat their fruits and vegetables. 268 00:14:40.190 --> 00:14:41.149 That's what I would tell them. 269 00:14:42.470 --> 00:14:47.570 I mean, we really have a hard time saying, even 270 00:14:47.629 --> 00:14:51.710 from very well-studied single pesticides, what level is safe, what 271 00:14:51.750 --> 00:14:55.230 level is unsafe, what do we mean by that? The 272 00:14:55.830 --> 00:14:58.750 unknowns on this topic just really outweigh what we know. 273 00:14:59.029 --> 00:15:00.289 I know that's probably not. 274 00:15:00.190 --> 00:15:03.580 Helpful for your podcast. But here's something you should know. 275 00:15:03.600 --> 00:15:07.840 When a pesticide scientist goes to the supermarket, does she 276 00:15:07.879 --> 00:15:08.559 buy organic? 277 00:15:11.100 --> 00:15:14.519 You know, I have a one-year-old and I do because 278 00:15:14.639 --> 00:15:17.559 I can. I recognize that it's a luxury. 279 00:15:17.740 --> 00:15:19.460 But you did say it because you've got a one-year-old. 280 00:15:19.700 --> 00:15:22.580 So there's like a, I guess it's just a risk-benefit 281 00:15:22.620 --> 00:15:24.580 analysis and you're like, we don't know, but. 282 00:15:24.850 --> 00:15:25.889 Yeah, pretty much. 283 00:15:27.080 --> 00:15:29.580 Cynthia told us that she also buys organic food for 284 00:15:29.700 --> 00:15:33.100 other reasons, like the potential health risks to agricultural workers. 285 00:15:34.639 --> 00:15:36.240 Conclusion. When it comes to. 286 00:15:36.220 --> 00:15:39.529 Understanding how traces of pesticides on our food affects our 287 00:15:39.629 --> 00:15:42.289 overall health, we don't know much. 288 00:15:43.029 --> 00:15:45.990 But the one big study we do have is on cancer. 289 00:15:46.450 --> 00:15:50.240 And overall, it found no link between eating conventional food... 290 00:15:50.580 --> 00:15:51.500 and getting cancer. 291 00:15:52.159 --> 00:15:55.059 And there is no other strong evidence that buying organic 292 00:15:55.120 --> 00:15:57.399 is in any other way better for your health than 293 00:15:57.440 --> 00:15:58.460 conventional produce. 294 00:15:59.679 --> 00:16:06.549 So that's health, but what about the environment? A quick break, 295 00:16:06.629 --> 00:16:06.990 and when. 296 00:16:06.909 --> 00:16:09.870 We get back, we're looking at the bigger picture. Is 297 00:16:10.009 --> 00:16:22.090 organic farming better for our planet?

Hey, it's Wendy from 298 00:16:22.149 --> 00:16:23.169 Science Versus, and I. 299 00:16:23.169 --> 00:16:25.629 Want to tell you about a podcast that I love, 300 00:16:25.870 --> 00:16:26.730 Science Friday. 301 00:16:26.909 --> 00:16:29.460 They cover all sorts of amazing things in the weird 302 00:16:29.500 --> 00:16:33.519 and wonderful world of science, from how concussions affect our 303 00:16:33.559 --> 00:16:36.639 brain to the inner secrets of a snake with a 304 00:16:36.720 --> 00:16:39.470 spider on its It's a lot of news that you 305 00:16:39.509 --> 00:16:41.889 can use and some that you can't, but you're going 306 00:16:41.909 --> 00:16:46.029 to love anyway. It's hosted by Ira Flato and Flora Lichtman, 307 00:16:46.190 --> 00:16:48.889 who is an old friend of the show and loves 308 00:16:48.970 --> 00:16:51.590 a pun as much as we do. Science Friday is 309 00:16:51.649 --> 00:16:54.210 on every day wherever you get your podcasts. 310 00:16:59.620 --> 00:17:03.139 Hi, and welcome back to Science Versus. So it's time 311 00:17:03.259 --> 00:17:04.720 to talk about the planet. 312 00:17:05.180 --> 00:17:05.720 Go Planet! 313 00:17:07.440 --> 00:17:10.220 Studies find that one of the big motivations for going 314 00:17:10.299 --> 00:17:13.910 organic is reducing our impact on the environment. And according 315 00:17:13.950 --> 00:17:18.630 to my organic coconut water bottle, organic farming methods means, quote, 316 00:17:19.130 --> 00:17:22.009 a better environment for the plants and a cleaner planet 317 00:17:22.089 --> 00:17:26.809 for all of us, end quote. But has my coconut 318 00:17:26.869 --> 00:17:31.250 water bottle just gone coconuts? I've got a lovely bunch 319 00:17:31.390 --> 00:17:35.529 of coconuts. When we talk about the environment, there are 320 00:17:35.630 --> 00:17:40.730 three main things to consider. One, soil health. Two, chemical contamination. 321 00:17:40.950 --> 00:17:47.599 And three, land use. Let's start with soil health. In 322 00:17:47.619 --> 00:17:49.460 the first half of the show, we covered some of 323 00:17:49.500 --> 00:17:52.559 the things you're not allowed to use on an organic farm. 324 00:17:52.859 --> 00:17:53.779 Certain pesticides. 325 00:17:54.569 --> 00:17:57.769 But you also have to do certain things to get 326 00:17:57.890 --> 00:18:02.130 organic certification. These are generally designed to keep the land, 327 00:18:02.289 --> 00:18:06.309 and particularly the soil, healthy. One example is that organic 328 00:18:06.369 --> 00:18:09.549 farmers have to rotate their crops. That is, you change 329 00:18:09.630 --> 00:18:12.430 where you grow plants each season. And when you do that, 330 00:18:12.529 --> 00:18:14.509 it means that the soil doesn't get sapped of the 331 00:18:14.549 --> 00:18:18.930 same set of nutrients year after year. Organic farmers also 332 00:18:19.049 --> 00:18:21.390 use manure instead of synthetic fertilisers. 333 00:18:21.970 --> 00:18:23.170 All for soil health.

334 00:18:25.259 --> 00:18:28.759 And research shows that these organic practices work. They trigger 335 00:18:28.799 --> 00:18:31.569 processes in the soil that make it more nutrient-rich and 336 00:18:31.660 --> 00:18:35.690 thrive with good bacteria, fungi and worms. And this can 337 00:18:35.730 --> 00:18:41.109 make some plants more resistant to pests and diseases. The 338 00:18:41.150 --> 00:18:44.029 healthy soil and diverse crop also bring more birds and 339 00:18:44.130 --> 00:18:46.789 insects to the yard. And the organic farmers are like, 340 00:18:47.549 --> 00:18:50.230 it's better than yours. Damn right it's better than yours. 341 00:18:50.269 --> 00:18:52.460 Now they can teach you, but they have to charge you. 342 00:18:54.539 --> 00:18:57.960 One review of 94 studies found that organic farms had 343 00:18:58.039 --> 00:19:01.559 on average 30% more biodiversity than conventional farms. 344 00:19:03.000 --> 00:19:03.480 Conclusion. 345 00:19:03.880 --> 00:19:08.319 Organic farming practices tend to create healthy soil and biodiverse farms, 346 00:19:08.740 --> 00:19:12.700 all good for the environment. But we're about to throw 347 00:19:12.720 --> 00:19:15.869 some manure at organic's green image. 348 00:19:16.470 --> 00:19:17.509 Next question. 349 00:19:18.309 --> 00:19:25.380 Does organic food prevent chemicals contaminating the environment? Conventional farmers 350 00:19:25.460 --> 00:19:29.160 often add synthetic fertilisers to help plants grow. And what 351 00:19:29.220 --> 00:19:32.700 makes fertilisers work and the plants grow big is this. 352 00:19:32.619 --> 00:19:34.349 Thing called nitrogen. 353 00:19:35.220 --> 00:19:38.130 Now, the problem is that when you pour nitrogen on 354 00:19:38.150 --> 00:19:40.630 the plants and they don't suck it up, the excess 355 00:19:40.670 --> 00:19:43.369 can run off into lakes, rivers and even the ocean. 356 00:19:43.930 --> 00:19:46.809 It can choke off the water's oxygen supply and eventually 357 00:19:46.849 --> 00:19:50.319 kill plants and animals. An extreme example of this can 358 00:19:50.359 --> 00:19:53.160 be found in the Gulf of Mexico, where nitrogen runoff 359 00:19:53.220 --> 00:19:56.380 from farms has drained into the Gulf, creating a 6,500 360 00:19:56.380 --> 00:19:57.119 square mile dead zone. 361 00:20:01.220 --> 00:20:05.220 On the pristine beaches of Mississippi, thousands of dead fish, stingrays, 362 00:20:05.299 --> 00:20:08.460 crabs and shrimp have washed ashore this month. They died 363 00:20:08.519 --> 00:20:10.960 from a lack of oxygen in the coastal waters of 364 00:20:11.000 --> 00:20:12.119 the Gulf of Mexico. 365 00:20:14.299 --> 00:20:17.900 To avoid things like this, organic farming rules don't allow 366 00:20:17.960 --> 00:20:23.049 the use of synthetic, highly concentrated nitrogen. But organic farmers 367 00:20:23.269 --> 00:20:27.630 still need a fertiliser because plants, organic or conventional, need 368 00:20:27.710 --> 00:20:30.769 a boost to get to market. Mark showed me a 369 00:20:30.819 --> 00:20:34.599 bag of the organically approved fertiliser, jam-packed with nitrogen. 370 00:20:34.819 --> 00:20:39.220 Look at this. Worm power, the engine of nature. And 371 00:20:40.700 --> 00:20:43.619 this is derived from earthworm castings. 372 00:20:43.720 --> 00:20:44.180 What's that? 373 00:20:45.000 --> 00:20:48.420 Come on, you know English, don't you? What's a casting? 374 00:20:48.700 --> 00:20:50.099 What does an earthworm cast off? 375 00:20:51.680 --> 00:20:55.160 I had no idea. We stood there for what felt 376 00:20:55.200 --> 00:20:56.779 like a very long time. 377 00:20:57.900 --> 00:21:00.180 It's shell. That's right. It's shell. No, it's s * 378 00:21:00.049 --> 00:21:00.180 * t. 379 00:21:00.759 --> 00:21:01.480 Oh, it's s * * t? 380 00:21:01.529 --> 00:21:01.740 Yeah. 381 00:21:03.450 --> 00:21:05.269 Oh, that's such a lovely euphemism. 382 00:21:06.069 --> 00:21:09.829 As well as using worm poo or castings for nitrogen, 383 00:21:10.230 --> 00:21:13.289 farmers use cow manure, or at the Reeves property, there's 384 00:21:13.329 --> 00:21:14.289 a nearby turkey farm. 385 00:21:14.990 --> 00:21:16.460 So we've got access to turkey manure. 386 00:21:17.119 --> 00:21:18.299 Are they organic turkeys? 387 00:21:19.359 --> 00:21:24.369 No, but manure, I guess, qualifies even better. even though 388 00:21:24.390 --> 00:21:26.809 the poop didn't come out of an organic crop, I guess. 389 00:21:26.829 --> 00:21:29.250 Nobody knows if it doesn't seem to have a problem 390 00:21:29.269 --> 00:21:29.549 with that. 391 00:21:30.009 --> 00:21:32.200 Gimlet producer Lynne Levy, who joined me at the farm, 392 00:21:32.279 --> 00:21:34.460 was pretty philosophical about this point. 393 00:21:34.660 --> 00:21:38.539 Organic shit, but not an organic asshole. Yeah, there you go. 394 00:21:39.220 --> 00:21:40.859 You've got to draw your line where you draw your line. 395 00:21:41.000 --> 00:21:41.500 And that's it. 396 00:21:41.599 --> 00:21:43.779 At the asshole. But here's the thing. 397 00:21:44.200 --> 00:21:47.769 It may be organic, but that turkey poo and worm casting, 398 00:21:48.130 --> 00:21:50.869 it's still full of nitrogen. And if you think it's 399 00:21:50.950 --> 00:21:54.589 special just because it's organically approved, you are drawing a 400 00:21:54.730 --> 00:21:58.740 line at the arsehole. Because that nitrogen, just like the 401 00:21:58.759 --> 00:22:02.220 synthetic stuff, it can wash into rivers and lakes. 402 00:22:02.559 --> 00:22:04.160 If we put 10 tonnes of manure on and we 403 00:22:04.220 --> 00:22:06.839 only need five, you're going to get some waste that's 404 00:22:06.859 --> 00:22:08.319 going to run off. That's all there is to it. 405 00:22:08.440 --> 00:22:10.289 Eventually the water is going to take it away if 406 00:22:10.329 --> 00:22:10.930 you don't use it. 407 00:22:12.130 --> 00:22:16.150 So yes, organic farming can leach nitrogen into the

environment. 408 00:22:16.950 --> 00:22:19.880 So then the next question, if you're worried about the environment, 409 00:22:20.259 --> 00:22:25.859 is this. Which type of farming leaches more, conventional or organic? 410 00:22:26.880 --> 00:22:30.079 Navin Ramankutty is a professor in global food security at 411 00:22:30.119 --> 00:22:32.220 the University of British Columbia in Canada. 412 00:22:32.799 --> 00:22:35.519 Yeah, a few studies that have been done of leaching 413 00:22:35.579 --> 00:22:38.039 seem to show that organic actually leaches more. 414 00:22:38.839 --> 00:22:39.660 Leeches more. 415 00:22:39.779 --> 00:22:41.700 Yeah, and so that's saying something. 416 00:22:42.420 --> 00:22:46.759 When you compare conventional and organic produce, say carrot for carrot... 417 00:22:46.960 --> 00:22:50.180 One review of 10 papers focusing on farming in Europe 418 00:22:50.559 --> 00:22:53.880 found that there was more nitrogen leaching from organic farms 419 00:22:54.279 --> 00:22:58.109 versus conventional. Navin pointed out that this is an average 420 00:22:58.410 --> 00:23:00.349 and there is a lot of variation in how different 421 00:23:00.390 --> 00:23:04.470 farms use nitrogen. Organic has the potential to leach more, 422 00:23:04.589 --> 00:23:09.299 partly because with manure, unlike precise lab-made fertilisers, it's difficult 423 00:23:09.339 --> 00:23:11.799 to give plants just the right amount of nitrogen that 424 00:23:11.839 --> 00:23:15.440 they need, potentially leaving more in the ground and more 425 00:23:15.519 --> 00:23:19.440 to leach. And that's because nitrogen in poo binds tightly 426 00:23:19.480 --> 00:23:22.460 to the soil and only releases slowly over time. 427 00:23:23.000 --> 00:23:23.799 So unlike with. 428 00:23:23.700 --> 00:23:26.660 Lab-made fertilisers, it's harder to give your crops a big 429 00:23:26.779 --> 00:23:30.140 jolt that you know they'll absorb. Instead, you just have 430 00:23:30.160 --> 00:23:31.980 to put a lot of manure on the soil and 431 00:23:32.059 --> 00:23:34.740 hope the plants take in as much nitrogen as possible. 432 00:23:34.769 --> 00:23:37.750 I'm not saying that we do it right all the time, 433 00:23:37.789 --> 00:23:40.150 but it's easier to do in conventional agriculture because you 434 00:23:40.170 --> 00:23:42.990 can apply it just when the plants need them and 435 00:23:43.029 --> 00:23:46.829 they're much more available to plants, the chemical fertilisers, And 436 00:23:46.849 --> 00:23:47.930 so plants can take them up. 437 00:23:49.569 --> 00:23:50.049 Conclusion. 438 00:23:50.869 --> 00:23:54.789 Even if you're using an organically approved fertiliser, nitrogen runoff 439 00:23:54.950 --> 00:23:59.269 can still be a problem. And there's one more environmental 440 00:23:59.329 --> 00:24:02.339 question related to organic farming that we have to talk about. 441 00:24:03.220 --> 00:24:03.640 Yield. 442 00:24:04.359 --> 00:24:07.220 That is, how much organic food can we

actually grow 443 00:24:07.319 --> 00:24:10.509 and how much space will it take? A review paper 444 00:24:10.609 --> 00:24:13.529 published by Navin found that on average, acre for acre, 445 00:24:13.750 --> 00:24:19.509 organic farms produce around 25% less food than conventional farms. 446 00:24:19.509 --> 00:24:23.190 25%. And that's because organic. 447 00:24:22.890 --> 00:24:26.690 Farmers can't use the most effective fertilisers, which can mean 448 00:24:26.869 --> 00:24:30.890 fewer crops for them and less food for us. So 449 00:24:31.049 --> 00:24:32.630 if we want to grow the same amount of food 450 00:24:32.650 --> 00:24:34.829 that we do now and we want to do it organically, 451 00:24:34.849 --> 00:24:38.799 we will need a lot more space. And we're already 452 00:24:38.920 --> 00:24:41.859 using a lot of our best agricultural land. So where 453 00:24:41.880 --> 00:24:43.900 would this new organic land come from? 454 00:24:44.480 --> 00:24:44.960 Forests? 455 00:24:45.480 --> 00:24:50.009 Native habitats? Land set aside for conservation? Your house? 456 00:24:51.250 --> 00:24:55.549 And organic farming suffers from another potential yield problem. Because 457 00:24:55.650 --> 00:24:59.369 while some organic practices help plants resist disease, if you 458 00:24:59.410 --> 00:25:03.269 can't use the most powerful pesticides to kill some particularly 459 00:25:03.470 --> 00:25:07.069 nasty pests, it can wipe out a farmer's crop. 460 00:25:07.779 --> 00:25:09.539 Here's the Third Reef's brother, Brian. 461 00:25:10.039 --> 00:25:12.589 Every year I put something organic in the ground, it's 462 00:25:12.700 --> 00:25:15.549 riskier than what I put in the ground conventionally. And 463 00:25:15.609 --> 00:25:17.450 sooner or later, that risk comes back to bite you. 464 00:25:17.470 --> 00:25:20.269 If you had five years of great conventional crops, but 465 00:25:20.289 --> 00:25:22.269 you had four years of organic and one year of 466 00:25:22.309 --> 00:25:25.529 a disaster, well, you've got to be watch out for that. 467 00:25:25.890 --> 00:25:28.789 His older brother, Mark, agreed, telling me about a feisty 468 00:25:28.869 --> 00:25:32.150 beetle battle with his organic acorn squash, where the organic 469 00:25:32.190 --> 00:25:34.589 pesticides just didn't work. 470 00:25:35.420 --> 00:25:38.319 Couldn't kill it i tried like three different organic sprays 471 00:25:38.400 --> 00:25:40.509 and they wouldn't touch there's a beetle and they wouldn't 472 00:25:40.529 --> 00:25:41.029 touch that. 473 00:25:40.930 --> 00:25:45.130 Thing do you remember um waking up in the morning 474 00:25:45.289 --> 00:25:48.289 after you tried one chemical and still seeing that friggin 475 00:25:48.329 --> 00:25:50.569 beetle there oh yeah. 476 00:25:50.529 --> 00:25:52.380 You know if you see an insect that's kind of 477 00:25:53.160 --> 00:25:55.039 drunken looking then you know well he might die it 478 00:25:55.579 --> 00:25:58.420 did something to him not these guys they were fine 479 00:25:58.839 --> 00:25:59.599 i think they liked. 480 00:25:59.480 --> 00:26:05.150 It i think they liked it you know More squash 481 00:26:05.170 --> 00:26:09.650 for the beetles means less squash for us. Now, this 482 00:26:09.710 --> 00:26:12.970 yield problem isn't black and white, so there is some 483 00:26:13.029 --> 00:26:16.269 scientific debate here. And some academics say that we would 484 00:26:16.289 --> 00:26:20.779 be fine producing 25% less food if we redesigned the 485 00:26:20.839 --> 00:26:25.660 food system to make sure that we wasted less food. Also, 486 00:26:26.200 --> 00:26:29.460 important to note, around a third of our croplands are 487 00:26:29.640 --> 00:26:31.140 used to feed livestock. 488 00:26:31.480 --> 00:26:34.140 So they feed cows and then we eat the cows. 489 00:26:34.880 --> 00:26:38.220 And given this, a paper published this year calculated that 490 00:26:38.299 --> 00:26:42.180 if the whole world went vegetarian or vegan, we could 491 00:26:42.259 --> 00:26:47.059 shift to an entirely organic system without encroaching into new space. 492 00:26:48.319 --> 00:26:50.819 Conclusion. Organic farming has, on. 493 00:26:50.819 --> 00:26:54.680 Average, lower yields than conventional farming. And unless we're planning 494 00:26:54.779 --> 00:26:58.359 on living in a tofurkey alternate reality, that could be 495 00:26:58.380 --> 00:27:00.480 a problem as the population grows. 496 00:27:01.579 --> 00:27:03.319 Also, not-so-fun fact here. 497 00:27:04.140 --> 00:27:07.859 At 2050, the population is expected to hit 9 billion. 498 00:27:08.319 --> 00:27:12.640 And food production, it's predicted, will need to rise by 70%. 499 00:27:12.640 --> 00:27:17.730 And organic food alone probably just can't get us there. 500 00:27:18.769 --> 00:27:22.309 So when it comes to science versus organic food, does 501 00:27:22.470 --> 00:27:23.230 it stack up? 502 00:27:24.930 --> 00:27:27.130 When it comes to taste, science says no. 503 00:27:28.269 --> 00:27:33.150 Organic food doesn't taste any better than the conventionally grown stuff. 504 00:27:34.039 --> 00:27:36.440 And nutrition? Science says.... 505 00:27:37.480 --> 00:27:37.660 No. 506 00:27:38.180 --> 00:27:41.960 Overall, organic food isn't more nutritious than conventional food. 507 00:27:42.759 --> 00:27:45.670 When it comes to the risks from chemicals on our food? 508 00:27:47.009 --> 00:27:50.450 Well, there's no conclusive evidence that organic food is safer 509 00:27:50.529 --> 00:27:54.670 than conventional food. But there is so little research directly 510 00:27:54.789 --> 00:27:57.269 on this that maybe it's just too early to tell. 511 00:27:58.980 --> 00:28:00.779 And then there is the effect on the environment. 512 00:28:01.180 --> 00:28:04.359 Some organic practices like rotating crops and planting cover crops 513 00:28:04.480 --> 00:28:07.200 are really good for the soil and increase biodiversity on 514 00:28:07.220 -->

00:28:11.869 the farm. But restricting the use of synthetic fertilisers means 515 00:28:11.950 --> 00:28:15.230 organic farming can leach more nitrogen into the environment. 516 00:28:16.009 --> 00:28:19.309 Plus, you need more land to grow organic produce. 517 00:28:21.130 --> 00:28:25.240 So things are looking pretty even for organic versus conventional. 518 00:28:26.119 --> 00:28:35.779 But here's something. To blow your mind. Too strong? Nah. 519 00:28:36.779 --> 00:28:43.460 Now, while supermarkets and some podcasts pit organic against conventional farming, 520 00:28:44.200 --> 00:28:48.269 in reality, it's often not like that. Take the Reeves farm. 521 00:28:49.029 --> 00:28:51.289 Mark Reeves may laugh at his organic customers. 522 00:28:51.410 --> 00:28:52.130 Okay, whatever. 523 00:28:52.150 --> 00:28:54.849 But that's because on his farm, he and his brothers 524 00:28:55.009 --> 00:28:59.130 use a lot of organic practices. on their organic and 525 00:28:59.289 --> 00:29:02.670 conventional crops. The Reeves brothers rotate their crop and don't 526 00:29:02.730 --> 00:29:05.710 use too much pesticide on any of their produce, conventional 527 00:29:05.849 --> 00:29:08.890 and organic, even though there are no rules telling them 528 00:29:08.950 --> 00:29:12.410 that they have to do that on their conventional crops. Plus, 529 00:29:12.509 --> 00:29:15.839 a recent study showed that the Reeves farm isn't exceptional. 530 00:29:16.400 --> 00:29:19.940 It is actually common for conventional farmers to adopt some 531 00:29:20.099 --> 00:29:21.160 organic practices. 532 00:29:22.099 --> 00:29:24.640 So why do the Reeves brothers go through all that trouble? 533 00:29:24.660 --> 00:29:26.519 We just know we get a heck of a crop. 534 00:29:26.950 --> 00:29:29.099 And in the long term, the soil on their farm 535 00:29:29.259 --> 00:29:29.960 is healthier. 536 00:29:29.980 --> 00:29:33.480 And it's because Mark does some of this organic stuff 537 00:29:33.579 --> 00:29:36.930 on his conventional crops that he doesn't totally get this 538 00:29:37.109 --> 00:29:39.109 allegiance that people have to organic. 539 00:29:39.710 --> 00:29:39.950 I don't. 540 00:29:40.000 --> 00:29:43.500 Believe in it because I see what goes on with conventional. 541 00:29:43.960 --> 00:29:47.160 On this farm, what happens here, we use so few 542 00:29:47.200 --> 00:29:47.839 chemicals here. 543 00:29:48.420 --> 00:29:50.940 But as a shopper, it's really hard to know what 544 00:29:51.000 --> 00:29:53.319 kind of farm that your produce is coming from. So 545 00:29:53.359 --> 00:29:55.799 it is understandable why people go for the food with 546 00:29:55.859 --> 00:29:57.559 some kind of seal of approval. 547 00:29:58.619 --> 00:29:59.039 Still, though. 548 00:29:59.849 --> 00:30:02.910 This kind of blended style of farming that Mark is doing? 549 00:30:03.710 --> 00:30:07.400 That's exactly what Navin Ramankutty and lots of other scientists 550 00:30:07.579 --> 00:30:11.380 think is the future. Using organic practices when they work, 551 00:30:11.880 --> 00:30:13.859 but synthetic chemicals when necessary. 552 00:30:14.339 --> 00:30:17.180 I think of a farm where, you know, we make 553 00:30:17.240 --> 00:30:19.369 use of compost and we make use of manure if 554 00:30:19.410 --> 00:30:22.849 we have it. But I will not shy from using 555 00:30:22.890 --> 00:30:26.130 a tiny amount of pesticide or a tiny amount of 556 00:30:26.210 --> 00:30:27.289 fertilizer when I need to. 557 00:30:27.980 --> 00:30:32.400 And Navin calls this a common-sense farm. Not traditionally conventional, 558 00:30:32.769 --> 00:30:38.630 not strictly organic, but just good science. That's science versus 559 00:30:38.769 --> 00:30:44.849 organic food. Next week is science versus the G-spot. Does 560 00:30:45.130 --> 00:30:48.789 it exist? So when you say you examined 400 women, 561 00:30:48.890 --> 00:30:52.579 what did you do? Can I have your vagina for 562 00:30:52.599 --> 00:30:56.500 a minute, please? And stick around for the ultimate orgasmic test. 563 00:30:56.980 --> 00:30:59.359 Organic test. It's about organic food. 564 00:30:59.380 --> 00:31:05.019 Jeez. This episode has been produced by Heather Rogers, Lynn Levy, 565 00:31:05.099 --> 00:31:08.799 Caitlin Kenney, Austin Mitchell and Caitlin Sori. Edited by Annie 566 00:31:08.819 --> 00:31:13.400 Rose Strasser and Alex Bloomberg. Fact-checking by Michelle Harris. Production 567 00:31:13.420 --> 00:31:17.849 assistance by Diane Wu and Shruti Ravindran. An extra big 568 00:31:18.069 --> 00:31:22.329 thanks to Stevie Lane, Joseph Lavelle Wilson and the Zuckerman family. 569 00:31:22.890 --> 00:31:24.289 Thank you for all your help. 570 00:31:25.269 --> 00:31:28.190 Sound design and music production by Matthew Boll, mixed by 571 00:31:28.250 --> 00:31:29.970 Martin Peralta and Hayley Shaw. 572 00:31:30.430 --> 00:31:33.890 Music written by Bobby Lord. Science Versus is a production 573 00:31:34.029 --> 00:31:34.910 of Gimlet Media. 574 00:31:43.880 --> 00:31:47.000 So, As a little treat for you all, we happened 575 00:31:47.099 --> 00:31:48.859 upon some organic cookies. 576 00:31:49.400 --> 00:31:51.480 They are for dogs. Yes. 577 00:31:52.720 --> 00:31:53.119 Dogs. 578 00:31:54.099 --> 00:31:59.460 Organic dog cookies. Our co-worker, PJ, works on the podcast, 579 00:31:59.500 --> 00:32:02.869 Reply All. He has a new dog. Can you describe 580 00:32:02.910 --> 00:32:03.869 what your dog looks like? 581 00:32:04.630 --> 00:32:08.789 My dog looks like a Build-A-Bear or an animatronic Disney 582 00:32:08.849 --> 00:32:09.509 teddy bear. 583 00:32:10.170 --> 00:32:12.799 So we did a taste test. This is not science, 584 00:32:12.859 --> 00:32:15.240 by the way. It's just one dog and two cookies, 585 00:32:15.480 --> 00:32:16.640 conventional and organic. 586 00:32:17.420 --> 00:32:18.930 I'm going to throw. 587 00:32:18.710 --> 00:32:19.349 Him over there. 588 00:32:19.910 --> 00:32:22.690 Okay, Ralphie, ready? You're going to get thrown, and then 589 00:32:22.730 --> 00:32:23.809 you're going to get cookies. Ready? Go. 590 00:32:26.009 --> 00:32:26.849 What's he going for first? 591 00:32:26.869 --> 00:32:27.769 What's he going for? He smells. 592 00:32:28.130 --> 00:32:30.559 Organic. Organic. 593 00:32:31.740 --> 00:32:37.440 One for organic. Well, that undermined the whole show. I'm 594 00:32:37.460 --> 00:32:39.339 Wendy Zuckerman. Back to you next time.