Download ENZYME IN SALIVA SHAPES HOW WE SENSE FOOD TEXTURE

MONELL CHEMICAL SENSES CENTER
ADVANCING DISCOVERY IN TASTE AND SMELL
Media contact: Leslie Stein, 267.519.4707 or [email protected]
ENZYME IN SALIVA SHAPES HOW WE SENSE FOOD TEXTURE
Perception and digestion of starchy foods varies from person to person
PHILADELPHIA (October 13, 2010) – Creamy. Gritty. Crunchy. Slimy. Oral texture
perception is a major factor contributing to each person’s food preferences. Now, a new
study from the Monell Center reports that individuals’ perception of starch texture is
shaped by variability in the activity of an oral enzyme known as salivary amylase.
“Differences in starch perception likely affect people’s nutritional status by influencing
their liking for and intake of starchy and starch-thickened foods,” said study lead author
Abigail Mandel, a nutritional scientist at Monell.
Starch, such as from wheat, potatoes, corn, and rice, is a major component of the
modern diet, comprising 40 to 60 percent of our calories. Amylase enzymes secreted in
saliva help break down starches into simpler sugar molecules that are ultimately
absorbed into the bloodstream, thus influencing blood glucose levels.
In the study, reported in the journal PLoS ONE, analyses revealed that changes of
starch consistency in the mouth were directly related to salivary amylase activity.
Enzyme levels and activity were measured in several ways, using saliva collected from
73 subjects. First, each person’s saliva was mixed with a standardized starch sample
and a sensor measured the enzymatic break-down of the starch’s consistency. Next,
enzyme and protein assays directly measured the amount and activity of salivary
amylase in the saliva samples.
Finally, subjects completed continuous evaluations over a 60-second interval to rate the
perceived breakdown of a starch sample while in the mouth.
“Taken together, this means that foods with different starch levels will be perceived
very differently by people as a function of how much salivary amylase they produce.
What may seem like a thick and resistant pudding or starchy food to some may seem
noticeably thin in the mouths of others,” said senior author Paul A. S. Breslin, a Monell
sensory geneticist.
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Monell Chemical Senses Center
3500 Market St, Philadelphia, PA 19104
267.519.4700
www.monell.org
The findings may also extend to starch digestion and metabolism, ultimately lending
insight into why some people develop metabolic diseases while others don’t. Individuals
who have more salivary amylase may break starchy foods down more quickly, leading
to a more rapid increase of post-meal blood glucose levels.
“In today’s state of food excess and refined starch ingestion, it is possible that high
levels of salivary amylase contribute to the risk of insulin resistance and non-insulin
dependent diabetes,” said Mandel.
The study went on to demonstrate a genetic influence on salivary amylase activity.
Previous research had revealed that an individual can have anywhere from 2 to 15
copies of AMY1, the gene that codes for salivary amylase. Mandel and collaborators
analyzed DNA samples from 62 subjects and found that the number of AMY1 copies a
person has is directly related to the amount and activity of their salivary amylase.
Combining the findings, the study demonstrated a series of relationships extending from
variation in genes to individual differences in nutrient perception in the mouth. “A link
from genetic variation to enzymatic proteins to altered physiology to oral perception of
textures is quite novel and provides a complete story,” said Breslin.
Additional studies will explore relationships between the AMY1 gene copy number and
liking for and consumption of starchy foods, as well as whether salivary amylase levels
affect carbohydrate digestion and absorption.
Also contributing to the study were Catherine Peyrot des Gachons, Kim Plank, and
Suzie Alarcon, all from Monell. Breslin also holds an appointment as Professor in the
Department of Nutritional Sciences at Rutgers University. Funding was provided by the
National Institute on Deafness and Other Communication Disorders and National Starch
LLC.
The Monell Chemical Senses Center is an independent nonprofit basic research
institute based in Philadelphia, Pennsylvania. Monell advances scientific understanding
of the mechanisms and functions of taste and smell to benefit human health and wellbeing. Using an interdisciplinary approach, scientists collaborate in the programmatic
areas of sensation and perception; neuroscience and molecular biology; environmental
and occupational health; nutrition and appetite; health and well-being; development,
aging and regeneration; and chemical ecology and communication. For more
information about Monell, visit www.monell.org.
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Monell Chemical Senses Center
3500 Market St, Philadelphia, PA 19104
267.519.4700
www.monell.org