The surprising cause of stomach ulcers - Rusha Modi

3,687,417 views ・ 2017-09-28

TED-Ed


Please double-click on the English subtitles below to play the video.

00:06
In 1984, an enterprising Australian doctor named Barry Marshall
0
6885
5191
00:12
decided to take a risk.
1
12076
2110
00:14
Too many of his patients were complaining of severe abdominal pain
2
14186
4830
00:19
due to stomach ulcers,
3
19016
1740
00:20
which are sores in the lining of the upper intestinal tract.
4
20756
4201
00:24
At the time, few effective treatments for ulcers existed,
5
24957
3751
00:28
and many sufferers required hospitalization or even surgery.
6
28708
5049
00:33
Desperate for answers,
7
33757
1721
00:35
Dr. Marshall swallowed a cloudy broth of bacteria
8
35478
4028
00:39
collected from the stomach of one of his patients.
9
39506
3912
00:43
Soon, Dr. Marshall was experiencing the same abdominal pain,
10
43418
3869
00:47
bloating,
11
47287
811
00:48
and vomiting.
12
48098
1442
00:49
Ten days later, a camera called an endoscope
13
49540
3928
00:53
peered inside his insides.
14
53468
2511
00:55
Marshall's stomach was teeming with the same bacteria as his patient.
15
55979
5299
01:01
He'd also developed gastritis, or severe inflammation of the stomach,
16
61278
4750
01:06
the hallmark precursor of ulcers.
17
66028
4360
01:10
Dr. Marshall's idea challenged
18
70388
1842
01:12
a misconception that still persists to this day:
19
72230
3821
01:16
that ulcers are caused by stress,
20
76051
2599
01:18
food,
21
78650
999
01:19
or too much stomach acid.
22
79649
2531
01:22
Marshall thought the culprit was bacterial infections.
23
82180
3827
01:26
Initially, his idea was considered crazy
24
86007
2692
01:28
by the brightest medical minds on the planet.
25
88699
3180
01:31
But in 2005, he and Dr. Robin Warren received the ultimate validation
26
91879
5711
01:37
when they were awarded the Nobel Prize for medicine.
27
97590
5020
01:42
Our stomachs are J-shaped organs with surprisingly intricate ecosystems
28
102610
4991
01:47
awash in hormones and chemicals.
29
107601
3371
01:50
The stomach is under constant attack by digestive enzymes,
30
110972
3598
01:54
bile,
31
114570
851
01:55
proteins,
32
115421
991
01:56
microbes,
33
116412
969
01:57
and the stomach's own acid.
34
117381
2950
02:00
In response, it produces bicarbonate,
35
120331
2460
02:02
mucus,
36
122791
860
02:03
and phospholipids called prostaglandins
37
123651
3479
02:07
to maintain the integrity of its own lining.
38
127130
2982
02:10
This delicate balance is constantly regulated
39
130112
2850
02:12
and referred to as mucosal defense.
40
132962
3750
02:16
Since the mid-1800s, doctors thought stress alone caused most stomach ulcers.
41
136712
7210
02:23
Patients were given antidepressants or tranquilizers
42
143922
3060
02:26
and told to visit health spas.
43
146982
3080
02:30
This belief eventually shifted to the related notion of spicy foods
44
150062
4861
02:34
and stress as culprits.
45
154923
2938
02:37
Yet no convincing study has ever demonstrated that emotional upset,
46
157861
4394
02:42
psychological distress,
47
162255
1611
02:43
or spicy food
48
163866
1750
02:45
directly causes ulcer disease.
49
165616
4832
02:50
By the mid-20th century, it was widely accepted that excess hydrochloric acid
50
170448
4936
02:55
prompted the stomach to eat itself.
51
175384
3020
02:58
Fervent proponents of this idea were referred to as the acid mafia.
52
178404
5417
03:03
The biggest hole in this theory was that antiacids only provide
53
183821
3862
03:07
temporary relief.
54
187683
2373
03:10
We now know that some rare ulcers
55
190056
2138
03:12
are indeed caused by too much hydrochloric acid.
56
192194
3931
03:16
But they make up less than 1% of all cases.
57
196125
4069
03:20
Dr. Marshall and Dr. Warren pinpointed a spiral-shaped bacteria
58
200194
4292
03:24
called Helicobacter pylori, or H. pylori, as the real offender.
59
204486
6133
03:30
H. pylori is one of humanity's oldest and most frequent companions,
60
210619
4570
03:35
having joined us at least 50,000 years ago,
61
215189
3627
03:38
and now found in 50% of people.
62
218816
3169
03:41
Previously, we thought the stomach was sterile
63
221985
2380
03:44
on account of it being such an acidic, hostile environment.
64
224365
4545
03:48
Yet H. pylori survives the acidic turmoil of the stomach
65
228910
3376
03:52
with a variety of features that disrupt mucosal defense in its favor.
66
232286
5200
03:57
For example, it produces an enzyme called urease
67
237486
3690
04:01
that helps protect it from the surrounding gastric acid.
68
241176
3931
04:05
H. pylori can make over 1,500 proteins,
69
245107
3330
04:08
many of which are dedicated to maximizing its virulence.
70
248437
5010
04:13
We still have unanswered questions,
71
253447
2470
04:15
like why specific people develop ulcers at particular times.
72
255917
4869
04:20
However, we do know individual genetics,
73
260786
2881
04:23
other medical problems,
74
263667
1530
04:25
use of certain medications,
75
265197
1760
04:26
smoking,
76
266957
980
04:27
and the genetic diversity of Helicobacter strains all play a role.
77
267937
6122
04:34
In particular, certain pain medications used to reduce inflammation in joints
78
274059
5279
04:39
have been discovered to work with H. pylori
79
279338
2760
04:42
to create more severe stomach ulcers.
80
282098
3310
04:45
Dr. Marshall ended up being fine after his famous, albeit dangerous, experiment.
81
285408
6290
04:51
He ingested a course of antibiotics similar to the ones taken now for ulcers.
82
291698
5731
04:57
To be treated by simple antibiotics is a modern triumph
83
297429
3710
05:01
for a disease that previously needed surgery.
84
301139
3850
05:04
Marshall's work also reminded us that scientific progress is not always smooth.
85
304989
5552
05:10
But there's value in trusting your proverbial,
86
310541
2820
05:13
and sometimes literal, gut.
87
313361
2599
About this website

This site will introduce you to YouTube videos that are useful for learning English. You will see English lessons taught by top-notch teachers from around the world. Double-click on the English subtitles displayed on each video page to play the video from there. The subtitles scroll in sync with the video playback. If you have any comments or requests, please contact us using this contact form.

https://forms.gle/WvT1wiN1qDtmnspy7