Beginning of the chapterLactose intolerance and genetics (Lactose

Sensor)

47

SENSORS

LACTOSE SENSOR

Lactose intolerance

GENETICS

Lactose (in)tolerance

GALGAL

GLUGLU

LACTOSE

Lactase geneLactase gene

GLUGLU

GALGAL

Lactose cannot be directly Lactose cannot be directly absorbed in the intestineabsorbed in the intestine

The lactase enzyme breaks down The lactase enzyme breaks down lactose into smaller partslactose into smaller parts

GalactoseGalactose

GlucoseGlucose

GENETICS

GALGAL

GLUGLU

LACTOSE

Lactase geneLactase gene

GLUGLU

GALGAL

LACTOSE

Age++Age++

Lactose (in)tolerance

GENETICS

Moderate symptoms

Severe symptoms

Mild symptoms

Lact

ase

enzy

me

Lact

ase

enzy

me

Age (years)Age (years)10 20 30 40 50 60 7010 20 30 40 50 60 70

1 of 6 people: the lactase enzyme 1 of 6 people: the lactase enzyme is gradually switched offis gradually switched off

Lactose intoleranceLactose intolerance

Lactose (in)tolerance

GENETICS

GALGAL

GLUGLU

LACTOSE

Lactase geneLactase gene

GLUGLU

GALGAL

LACTOSE

Age++Age++

SNP

Lactose (in)tolerance

GENETICS

Moderate symptoms

Severe symptoms

Mild symptoms

Lact

ase

Lact

ase

enzy

me

enzy

me

Age (years)Age (years)10 20 30 40 50 60 7010 20 30 40 50 60 70

5 of 6 people: the lactase enzyme is constantly produced5 of 6 people: the lactase enzyme is constantly produced

1 of 6 people: the lactose enzyme 1 of 6 people: the lactose enzyme is gradually switched offis gradually switched off

Lactose intoleranceLactose intolerance

Lactose (in)tolerance

GENETICS

Lactose (in)tolerance

Genetic variation Genetic variation originated in an originated in an

EuropeanEuropean

GENETICS

Lactose (in)tolerance

Shortage of food Shortage of food caused the death caused the death of many peopleof many people

GENETICS

Lactose (in)tolerance

Milk as an Milk as an additional food additional food

source = source = survival survival advantageadvantage

GENETICS

Lactose (in)tolerance

Lactose tolerantLactose tolerant

Lactose Lactose intolerantintolerant

GENETICS

Lactose (in)tolerance

Lactose tolerantLactose tolerant

Lactose Lactose intolerantintolerant

LACTOSE SENSORVarious forms of

lactose intolerance

Lactase geneLactase geneAge++Age++

Primary lactose intolerance20% of people Occurs with increasing age

Secondary lactose intoleranceAcquired (non-genetic) Disease / intestinal damage

Congenital lactose intoleranceGenetic variation in the lactase geneVery rareOccurs in newborns

Milk protein allergy3% of babies

GLUGLU

GALGAL

Lactase geneLactase geneAge++Age++

LACTOSE SENSOR

What is the relationship between age and lactose intolerance?

0 1 5 16 30 50 80 0 1 5 16 30 50 80

PRIMARYPRIMARY

CongenitalCongenital

SECONDARY LACTOSE INTOLERANCESECONDARY LACTOSE INTOLERANCE

MILK ALLERGYMILK ALLERGY

BABY SensorBABY Sensor

LACTOSE SENSORLACTOSE SENSOR

ALLERGY SENSORALLERGY SENSOR

Standard lactose intolerance (breath) testStandard lactose intolerance (breath) test

End of the chapterLactose intolerance and genetics

(Lactose Sensor)

47