TEDGlobal 2010
Heribert Watzke: The brain in your gut
Filmed:
Readability: 4
1,704,961 views
Did you know you have functioning neurons in your intestines -- about a hundred million of them? Food scientist Heribert Watzke tells us about the "hidden brain" in our gut and the surprising things it makes us feel.
Heribert Watzke - Food scientist
Heribert Watzke studies the brain in our gut -- and works to develop new kinds of food that will satisfy our bodies and minds. Full bio
Heribert Watzke studies the brain in our gut -- and works to develop new kinds of food that will satisfy our bodies and minds. Full bio
Double-click the English transcript below to play the video.
00:16
This technology
0
1000
2000
00:18
made a very important impact on us.
1
3000
2000
00:20
It changed the way our history developed.
2
5000
3000
00:24
But it's a technology so pervasive,
3
9000
2000
00:26
so invisible,
4
11000
2000
00:28
that we, for a long time,
5
13000
2000
00:30
forgot to take it into account
6
15000
3000
00:33
when we talked about
7
18000
2000
00:35
human evolution.
8
20000
2000
00:37
But we see the results of this technology, still.
9
22000
3000
00:40
So let's make a little test.
10
25000
2000
00:42
So everyone of you turns to their neighbor please.
11
27000
3000
00:46
Turn and face your neighbors.
12
31000
2000
00:48
Please, also on the balcony.
13
33000
3000
00:51
Smile. Smile. Open the mouths.
14
36000
2000
00:53
Smile, friendly.
15
38000
2000
00:55
(Laughter)
16
40000
2000
00:57
Do you --
17
42000
2000
00:59
Do you see any Canine teeth?
18
44000
3000
01:02
(Laughter)
19
47000
2000
01:04
Count Dracula teeth
20
49000
3000
01:07
in the mouths of your neighbors?
21
52000
2000
01:09
Of course not.
22
54000
2000
01:11
Because our dental anatomy
23
56000
3000
01:14
is actually made,
24
59000
2000
01:16
not for tearing down raw meat from bones
25
61000
3000
01:19
or chewing fibrous leaves for hours.
26
64000
3000
01:24
It is made for a diet
27
69000
2000
01:26
which is soft, mushy,
28
71000
3000
01:29
which is reduced in fibers,
29
74000
3000
01:32
which is very easily chewable
30
77000
2000
01:34
and digestible.
31
79000
3000
01:37
Sounds like fast food, doesn't it.
32
82000
2000
01:39
(Laughter)
33
84000
2000
01:41
It's for cooked food.
34
86000
3000
01:44
We carry in our face the proof
35
89000
2000
01:47
that cooking,
36
92000
2000
01:49
food transformation,
37
94000
3000
01:52
made us what we are.
38
97000
2000
01:54
So I would suggest that we change how we classify ourselves.
39
99000
3000
01:57
We talk about ourselves as omnivores.
40
102000
3000
02:00
I would say, we should call ourselves coctivors --
41
105000
3000
02:03
(Laughter)
42
108000
2000
02:05
from coquere, to cook.
43
110000
3000
02:08
We are the animals
44
113000
2000
02:10
who eat cooked food.
45
115000
3000
02:13
No, no, no, no. Better --
46
118000
2000
02:15
to live of cooked food.
47
120000
2000
02:17
So cooking is a very important technology.
48
122000
2000
02:19
It's technology.
49
124000
2000
02:21
I don't know how you feel,
50
126000
2000
02:23
but I like to cook for entertainment.
51
128000
2000
02:25
And you need some design
52
130000
2000
02:27
to be successful.
53
132000
2000
02:29
So, cooking is a very important technology,
54
134000
3000
02:32
because it allowed us to acquire
55
137000
3000
02:35
what brought you all here:
56
140000
3000
02:38
the big brain,
57
143000
2000
02:40
this wonderful cerebral cortex we have.
58
145000
3000
02:43
Because brains are expensive.
59
148000
3000
02:46
Those have to pay tuition fees know.
60
151000
3000
02:49
(Laughter)
61
154000
2000
02:51
But it's also, metabolically speaking, expensive.
62
156000
3000
02:55
You now, our brain is two to three percent of the body mass,
63
160000
3000
02:58
but actually it uses 25 percent of the total energy we use.
64
163000
3000
03:01
It's very expensive.
65
166000
2000
03:03
Where does the energy come from. Of course, from food.
66
168000
3000
03:06
If we eat raw food,
67
171000
2000
03:08
we cannot release really the energy.
68
173000
3000
03:12
So this ingenuity of our ancestors,
69
177000
3000
03:15
to invent this most marvelous technology.
70
180000
3000
03:18
Invisible -- everyone of us does it every day, so to speak.
71
183000
4000
03:22
Cooking made it possible
72
187000
2000
03:24
that mutations,
73
189000
2000
03:26
natural selections, our environment,
74
191000
2000
03:28
could develop us.
75
193000
3000
03:32
So if we think about
76
197000
2000
03:34
this unleashing human potential,
77
199000
3000
03:37
which was possible by cooking and food,
78
202000
3000
03:40
why do we talk so badly about food?
79
205000
3000
03:43
Why is it always do and don'ts
80
208000
2000
03:45
and it's good for you, it's not good for you?
81
210000
2000
03:47
I think the good news for me
82
212000
2000
03:49
would be if we could go back
83
214000
3000
03:52
and talk about the unleashing,
84
217000
2000
03:54
the continuation of the unleashing of human potential.
85
219000
3000
03:57
Now, cooking allowed also
86
222000
2000
03:59
that we became a migrant species.
87
224000
3000
04:02
We walked out of Africa two times.
88
227000
3000
04:05
We populated all the ecologies.
89
230000
2000
04:07
If you can cook, nothing can happen to you,
90
232000
3000
04:10
because whatever you find,
91
235000
2000
04:12
you will try to transform it.
92
237000
2000
04:14
It keeps also your brain working.
93
239000
3000
04:17
Now the very easy and simple technology
94
242000
4000
04:21
which was developed
95
246000
2000
04:23
actually runs after this formula.
96
248000
2000
04:25
Take something which looks like food, transform it,
97
250000
3000
04:28
and it gives you a good, very easy, accessible energy.
98
253000
3000
04:31
This technology affected two organs,
99
256000
3000
04:34
the brain and the gut, which it actually affected.
100
259000
3000
04:37
The brain could grow, but the gut actually shrunk.
101
262000
3000
04:40
Okay, it's not obvious to be honest.
102
265000
2000
04:42
(Laughter)
103
267000
3000
04:45
But it shrunk to 60 percent
104
270000
2000
04:47
of primate gut
105
272000
2000
04:49
of my body mass.
106
274000
2000
04:51
So because of having cooked food,
107
276000
3000
04:54
it's easier to digest.
108
279000
3000
04:57
Now having a large brain, as you know,
109
282000
3000
05:00
is a big advantage,
110
285000
2000
05:02
because you can actually influence your environment.
111
287000
3000
05:05
You can influence your own technologies you have invented.
112
290000
2000
05:07
You can continue to innovate and invent.
113
292000
2000
05:09
Now the big brain did this also with cooking.
114
294000
3000
05:12
But how did it actually run this show?
115
297000
3000
05:15
How did it actually interfere?
116
300000
2000
05:17
What kind of criteria did it use?
117
302000
3000
05:20
And this is actually taste reward and energy.
118
305000
4000
05:24
You know we have up to five tastes,
119
309000
2000
05:26
three of them sustain us.
120
311000
3000
05:29
Sweet -- energy.
121
314000
2000
05:31
Umami -- this is a meaty taste.
122
316000
2000
05:33
You need proteins for muscles, recovery.
123
318000
3000
05:37
Salty,
124
322000
2000
05:39
because you need salt, otherwise your electric body will not work.
125
324000
3000
05:42
And two tastes which protect you --
126
327000
3000
05:45
bitter and sour,
127
330000
2000
05:47
which are against
128
332000
3000
05:50
poisonous and rotten material.
129
335000
3000
05:53
But of course, they are hard-wired
130
338000
2000
05:55
but we use them still in a sophisticated way.
131
340000
2000
05:57
Think about bittersweet chocolate;
132
342000
2000
05:59
or think about the acidity
133
344000
2000
06:01
of yogurt -- wonderful --
134
346000
2000
06:03
mixed with strawberry fruits.
135
348000
2000
06:05
So we can make mixtures of all this kind of thing
136
350000
3000
06:08
because we know
137
353000
3000
06:11
that, in cooking, we can transform it
138
356000
2000
06:13
to the form.
139
358000
2000
06:15
Reward: this is a more complex
140
360000
3000
06:18
and especially integrative
141
363000
3000
06:21
form of our brain
142
366000
2000
06:23
with various different elements --
143
368000
3000
06:26
the external states, our internal states,
144
371000
2000
06:28
how do we feel, and so on are put together.
145
373000
3000
06:31
And something which maybe you don't like
146
376000
2000
06:33
but you are so hungry that you really will be satisfied to eat.
147
378000
3000
06:36
So satisfaction was a very important part.
148
381000
3000
06:39
And as I say, energy was necessary.
149
384000
2000
06:41
Now how did the gut actually
150
386000
2000
06:43
participate in this development?
151
388000
3000
06:46
And the gut is a silent voice --
152
391000
3000
06:49
it's going more for feelings.
153
394000
2000
06:51
I use the euphemism digestive comfort --
154
396000
3000
06:55
actually -- it's a digestive discomfort,
155
400000
3000
06:58
which the gut is concerned with.
156
403000
3000
07:01
If you get a stomach ache, if you get a little bit bloated,
157
406000
3000
07:04
was not the right food, was not the right cooking manipulation
158
409000
3000
07:07
or maybe other things went wrong.
159
412000
2000
07:09
So my story is a tale of two brains,
160
414000
3000
07:12
because it might surprise you,
161
417000
2000
07:14
our gut has a full-fledged brain.
162
419000
3000
07:17
All the managers in the room say,
163
422000
2000
07:19
"You don't tell me something new, because we know, gut feeling.
164
424000
2000
07:21
This is what we are using."
165
426000
2000
07:23
(Laughter)
166
428000
2000
07:25
And actually you use it and it's actually useful.
167
430000
2000
07:27
Because our gut is connected to our emotional limbic system,
168
432000
3000
07:30
they do speak with each other
169
435000
2000
07:32
and make decisions.
170
437000
2000
07:35
But what it means
171
440000
2000
07:37
to have a brain there
172
442000
2000
07:39
is that, not only the big brain
173
444000
3000
07:42
has to talk with the food,
174
447000
3000
07:45
the food has to talk with the brain,
175
450000
3000
07:48
because we have to learn actually
176
453000
3000
07:51
how to talk to the brains.
177
456000
2000
07:53
Now if there's a gut brain,
178
458000
2000
07:55
we should also learn to talk with this brain.
179
460000
2000
07:57
Now 150 years ago,
180
462000
2000
07:59
anatomists described very, very carefully --
181
464000
3000
08:02
here is a model of a wall of a gut.
182
467000
3000
08:05
I took the three elements --
183
470000
2000
08:07
stomach, small intestine and colon.
184
472000
3000
08:10
And within this structure,
185
475000
2000
08:12
you see these two pinkish layers,
186
477000
2000
08:14
which are actually the muscle.
187
479000
2000
08:16
And between this muscle, they found nervous tissues,
188
481000
2000
08:18
a lot of nervous tissues,
189
483000
2000
08:20
which penetrate actually the muscle --
190
485000
2000
08:22
penetrate the submucosa,
191
487000
2000
08:24
where you have all the elements for the immune system.
192
489000
2000
08:26
The gut is actually the largest immune system,
193
491000
2000
08:28
defending your body.
194
493000
2000
08:30
It penetrates the mucosa.
195
495000
2000
08:32
This is the layer which actually touches the food you are swallowing
196
497000
3000
08:35
and you digest,
197
500000
2000
08:37
which is actually the lumen.
198
502000
2000
08:39
Now if you think about the gut,
199
504000
2000
08:41
the gut is -- if you could stretch it --
200
506000
2000
08:43
40 meters long,
201
508000
2000
08:45
the length of a tennis court.
202
510000
2000
08:47
If we could unroll it,
203
512000
2000
08:49
get out all the folds and so on,
204
514000
3000
08:52
it would have 400 sq. meters of surface.
205
517000
3000
08:55
And now this brain takes care over this,
206
520000
3000
08:58
to move it with the muscles and to do defend the surface
207
523000
3000
09:01
and, of course, digest our food we cook.
208
526000
3000
09:04
So if we give you a specification,
209
529000
3000
09:07
this brain, which is autonomous,
210
532000
2000
09:09
have 500 million nerve cells,
211
534000
2000
09:11
100 million neurons --
212
536000
2000
09:13
so around the size of a cat brain,
213
538000
3000
09:16
so there sleeps a little cat --
214
541000
3000
09:19
thinks for itself,
215
544000
2000
09:21
optimizes whatever it digests.
216
546000
3000
09:24
It has 20 different neuron types.
217
549000
3000
09:27
It's got the same diversity you find actually in a pig brain,
218
552000
2000
09:29
where you have 100 billion neurons.
219
554000
3000
09:32
It has autonomous organized microcircuits,
220
557000
3000
09:35
has these programs which run.
221
560000
2000
09:37
It senses the food; it knows exactly what to do.
222
562000
3000
09:40
It senses it by chemical means
223
565000
2000
09:42
and very importantly by mechanical means,
224
567000
3000
09:45
because it has to move the food --
225
570000
2000
09:47
it has to mix all the various elements
226
572000
2000
09:49
which we need for digestion.
227
574000
2000
09:51
This control of muscle is very, very important,
228
576000
3000
09:54
because, you know, there can be reflexes.
229
579000
2000
09:56
If you don't like a food, especially if you're a child, you gag.
230
581000
3000
09:59
It's this brain which makes this reflex.
231
584000
2000
10:01
And then finally,
232
586000
2000
10:03
it controls also the secretion of this molecular machinery,
233
588000
3000
10:06
which actually digests the food we cook.
234
591000
3000
10:09
Now how do the two brains work with each other?
235
594000
3000
10:12
I took here a model from robotics --
236
597000
3000
10:15
it's called the Subsumption Architecture.
237
600000
3000
10:18
What it means is that we have a layered control system.
238
603000
3000
10:21
The lower layer, our gut brain,
239
606000
2000
10:23
has its own goals -- digestion defense --
240
608000
3000
10:26
and we have the higher brain
241
611000
2000
10:28
with the goal of integration
242
613000
2000
10:30
and generating behaviors.
243
615000
2000
10:32
Now both look -- and this is the blue arrows --
244
617000
3000
10:35
both look to the same food, which is in the lumen
245
620000
3000
10:38
and in the area of your intestine.
246
623000
2000
10:40
The big brain integrates signals,
247
625000
2000
10:42
which come from the running programs
248
627000
2000
10:44
of the lower brain,
249
629000
2000
10:46
But subsumption means
250
631000
2000
10:48
that the higher brain can interfere with the lower.
251
633000
3000
10:51
It can replace,
252
636000
2000
10:53
or it can inhibit actually, signals.
253
638000
3000
10:56
So if we take two types of signals --
254
641000
2000
10:58
a hunger signal for example.
255
643000
2000
11:00
If you have an empty stomach,
256
645000
2000
11:02
your stomach produces a hormone called ghrelin.
257
647000
2000
11:04
It's a very big signal;
258
649000
2000
11:06
it's sent to the brain says,
259
651000
2000
11:08
"Go and eat."
260
653000
2000
11:10
You have stop signals --
261
655000
2000
11:12
we have up to eight stop signals.
262
657000
2000
11:14
At least in my case,
263
659000
2000
11:16
they are not listened to.
264
661000
2000
11:18
(Laughter)
265
663000
2000
11:20
So what happens
266
665000
2000
11:22
if the big brain in the integration
267
667000
3000
11:25
overrides the signal?
268
670000
2000
11:27
So if you override the hunger signal,
269
672000
2000
11:29
you can have a disorder, which is called anorexia.
270
674000
3000
11:32
Despite generating
271
677000
2000
11:34
a healthy hunger signal,
272
679000
2000
11:36
the big brain ignores it
273
681000
2000
11:38
and activates different programs in the gut.
274
683000
3000
11:41
The more usual case
275
686000
2000
11:43
is overeating.
276
688000
3000
11:46
It actually takes the signal
277
691000
3000
11:49
and changes it,
278
694000
2000
11:51
and we continue,
279
696000
2000
11:53
even [though] our eight signals would say, "Stop, enough.
280
698000
3000
11:56
We have transferred enough energy."
281
701000
2000
11:58
Now the interesting thing is that,
282
703000
2000
12:00
along this lower layer -- this gut --
283
705000
2000
12:02
the signal becomes stronger and stronger
284
707000
3000
12:05
if undigested, but digestible, material
285
710000
3000
12:08
could penetrate.
286
713000
2000
12:10
This we found from bariatric surgery.
287
715000
3000
12:14
That then the signal would be very, very high.
288
719000
3000
12:17
So now back to the cooking question
289
722000
3000
12:20
and back to the design.
290
725000
2000
12:22
We have learned to talk to the big brain --
291
727000
3000
12:25
taste and reward, as you know.
292
730000
2000
12:27
Now what would be the language
293
732000
2000
12:29
we have to talk to the gut brain
294
734000
2000
12:31
that its signals are so strong
295
736000
2000
12:33
that the big brain cannot ignore it?
296
738000
3000
12:36
Then we would generate something
297
741000
2000
12:38
all of us would like to have --
298
743000
2000
12:40
a balance between the hunger
299
745000
2000
12:42
and the satiation.
300
747000
3000
12:45
Now I give you, from our research, a very short claim.
301
750000
3000
12:48
This is fat digestion.
302
753000
2000
12:50
You have on your left
303
755000
2000
12:52
an olive oil droplet,
304
757000
2000
12:54
and this olive oil droplet gets attacked by enzymes.
305
759000
3000
12:57
This is an in vitro experiment.
306
762000
2000
12:59
It's very difficult to work in the intestine.
307
764000
3000
13:02
Now everyone would expect
308
767000
2000
13:04
that when the degradation of the oil happens,
309
769000
2000
13:06
when the constituents are liberated,
310
771000
2000
13:08
they disappear, they go away
311
773000
2000
13:10
because they [were] absorbed.
312
775000
2000
13:12
Actually, what happens is that a very intricate structure appears.
313
777000
3000
13:15
And I hope you can see
314
780000
2000
13:17
that there are some ring-like structures in the middle image,
315
782000
2000
13:19
which is water.
316
784000
2000
13:21
This whole system generates a huge surface
317
786000
3000
13:24
to allow more enzymes
318
789000
2000
13:26
to attack the remaining oil.
319
791000
2000
13:28
And finally, on your right side,
320
793000
2000
13:30
you see a bubbly,
321
795000
2000
13:32
cell-like structure appearing,
322
797000
2000
13:34
from which the body will absorb the fat.
323
799000
3000
13:38
Now if we could take this language --
324
803000
2000
13:40
and this is a language of structures --
325
805000
3000
13:43
and make it longer-lasting,
326
808000
3000
13:46
that it can go through
327
811000
2000
13:48
the passage of the intestine,
328
813000
3000
13:51
it would generate stronger signals.
329
816000
3000
13:55
So our research --
330
820000
2000
13:57
and I think the research also at the universities --
331
822000
2000
13:59
are now fixing on these points
332
824000
2000
14:01
to say: how can we actually --
333
826000
2000
14:03
and this might sound trivial now to you --
334
828000
2000
14:05
how can we change cooking?
335
830000
2000
14:07
How can we cook
336
832000
2000
14:09
that we have this language developed?
337
834000
3000
14:12
So what we have actually, it's not an omnivore's dilemma.
338
837000
3000
14:15
We have a coctivor's opportunity,
339
840000
3000
14:18
because we have learned over the last two million years
340
843000
3000
14:21
which taste and reward --
341
846000
3000
14:24
quite sophisticated to cook --
342
849000
2000
14:26
to please ourselves, to satisfy ourselves.
343
851000
2000
14:28
If we add the matrix,
344
853000
2000
14:30
if we add the structure language, which we have to learn,
345
855000
3000
14:33
when we learn it, then we can put it back;
346
858000
2000
14:35
and around energy,
347
860000
2000
14:37
we could generate a balance,
348
862000
2000
14:39
which comes out
349
864000
2000
14:41
from our really primordial operation: cooking.
350
866000
3000
14:45
So, to make cooking really
351
870000
3000
14:48
a very important element,
352
873000
2000
14:50
I would say even philosophers have to change
353
875000
2000
14:52
and have to finally recognize
354
877000
2000
14:54
that cooking is what made us.
355
879000
3000
14:57
So I would say, coquo ergo sum:
356
882000
3000
15:00
I cook, therefore I am.
357
885000
2000
15:02
Thank you very much.
358
887000
2000
15:04
(Applause)
359
889000
3000
ABOUT THE SPEAKER
Heribert Watzke - Food scientistHeribert Watzke studies the brain in our gut -- and works to develop new kinds of food that will satisfy our bodies and minds.
Why you should listen
Heribert Watzke set up the department of food material science at Nestlé in Switzerland, pulling together many disciplines, including chemistry, nutrition and neuroscience, in pursuit of ever better foods. Watzke's background is in chemistry -- in the mid-'80s, he was part of a groundbreaking team at Syracuse working on splitting water into hydrogen and oxygen to create alternative energy -- before moving to materials science.
At Nestlé's lab, Watzke focuses on the most basic form of human energy: the chemistry of food. Research on food has previously focused on its sensory qualities -- taste, aroma, texture. But there is much more to know. How does food's biological structure determine its quality, its digestibility, its nutritional qualities? What's the science of turning a biological structure (for instance, a kernel of grain) into something humans can make into pure energy (for instance, a slice of bread)? His team has been looking recently at the impact of food structure on fat digestion, in support of the fight against obesity. How much fat is needed to feel full? And how can we most effectively communicate with the 100 million neurons in our gut?
Heribert Watzke | Speaker | TED.com