An electronic capsule which, when taken orally, can sense the gases
oxygen, hydrogen and carbon dioxide in the digestive tract has been developed
- Electronic capsule
that can measure gases in the digestive tract can be used to estimate the
transit time, and changes in digestive health with dietary changes
- The approach can
help to individualize dietary changes to suit an individual
- The capsule could
also be useful as a non-invasive test to diagnose gastrointestinal
. The capsule has the
potential to be used to guide dietary changes or as a diagnostic tool for
digestive tract disorders. A pilot study carried out on the capsule was
published in Nature Electronics
The electronic capsule
is 26 mm length and 9.8 mm in diameter with a non-transparent shell and
contains sensors for carbon dioxide, hydrogen and oxygen, membranes with
embedded nanomaterials (to allow the fast diffusion of dissolved gases, and at
the same time block out liquid) beside a temperature sensor to measure the core
body temperature (when the temperature falls below 35°C, it indicates that the
capsule has been excreted out of the body), a microcontroller, a transmission
system, button-size silver oxide batteries. The information obtained by the
capsule is transmitted to a small receiver that the patient can carry in
his/her pocket, and is displayed on a mobile phone screen every 5 minutes
through Bluetooth communication. The scientists conducted a small pilot study
on the capsule in seven individuals on a normal fiber, low fiber and an
extremely high-fiber diet.
‘An electronic capsule has been developed, which when swallowed, can measure the hydrogen, oxygen and carbon dioxide levels in the gut, and changes associated with dietary alterations.’
The gases in the
digestive tract are due to swallowing of air, chemical and enzymatic changes,
and the action of the intestinal bacteria on the undigested foods.
The measurement of the
gases gives the following information:
- Since different
parts of the digestive
tract vary in the oxygen content, the measurement of the oxygen levels can indicate the position of
the capsule in the digestive tract. This was confirmed through
ultrasound done every 20 minutes during the study to locate the capsule.
- Since the
hydrogen levels are altered by the microbial activity in the colon, the measurement of the hydrogen levels
gives an indication of the health of the microbiota in the individual.
The carbon dioxide levels are also indicative of the fermentation in the
gut, though they may be altered by the carbon dioxide produce by
The electronic capsule
appears to have several advantages:
test done with the capsule is simple,
non-invasive and easy to perform, and continuous monitoring of the gas profiles
is possible. Earlier methods to measure gases in the digestive tract that
include flatus analysis, tube insertion, whole body calorimetry and breath test
are inconvenient for the patient and are often unreliable.
Though an occasional loss of data transmission
occurred, the capsules did not fail during the trials.
They were easy to swallow and were not damaged during their passage through the
The intake of the capsule was not associated
with any adverse effect. Abdominal discomfort
following a very high fiber diet and mild constipation following a low fiber
diet were noted, which were more likely to be due to the diet than the capsule
the pilot study, changes in the fiber content of the diet caused changes in small intestinal and colonic transit time and gut fermentation.
- A very high fiber
rich diet was associated with lack of fermentation, bacterial microbiota
associated with poor gut heath, and a failure of the colon to become
anerobic. This could be due to the inability of the microbiota to ferment
whole fiber possibly because of the trapping of oxygen in the fiber and
affecting the activity of anerobic bacteria. The diet was also associated
with discomfort, which could be due to the oxidative stress in the colon.
- A low fiber diet
was associated with reduced frequency of bowel movements. This was
followed by increased fermentation after introduction of fiber.
The findings of the
digestive tract revealed by the capsule are specific for a particular
individual can help to individualize dietary changes
In their study, the scientists also found
that the stomach may be releasing oxidizing chemicals to fight foreign bodies,
and the colon may also contain oxygen under certain situations.
The capsules can thus
help to study the function of the intestine, the bacterial flora and the
changes with diet. The scientists feel that the capsule has the potential to
study disorders of the digestive tract varying from malabsorption to colon cancer
They hope to see the capsule
in the market in the near future. Reference:
- Kalantar-Zadeh K et al. A human pilot trial of ingestible electronic capsules capable of sensing different gases in the gut. Nature Electronics 1, 79-87 (2018).Doi:10.1038/s41928-017-0004-x