Ability of a Tea Leaf Extracts Preparation to Slow Down Carbohydrate and Fat Absorption
Status:
Completed
Trial end date:
2005-11-01
Target enrollment:
Participant gender:
Summary
Objective - A variety of herbal, over-the-counter preparations of tea leaves are said to
reduce the rate of absorption of fat ( allegedly via inhibition of pancreatic lipase) and
carbohydrate (via inhibition of carbohydrate digestion and blocking of glucose transport by
the intestinal mucosa). There has been some study of the ability of these products to reduce
the blood glucose increase observed after a carbohydrate meal and to reduce blood cholesterol
levels in chronic studies. The purpose of the present study is to objectively determine if
one cup of "tea" made from a combination of three types of tea leaves (mulberry, black and
green tea) can cause malabsorption of carbohydrate and fat taken in conjunction with the tea.
Research Design - The study will consist of a double blind, placebo controlled crossover
study in 20 healthy subjects. On one of two days (one week apart) the subjects will ingest a
standard meal consisting of 30 g of sucrose (in the tea) and 30 g of starch in the form of
white rice plus 10 g of fat as butter. To measure triglyceride absorption, each meal will
also contain 250 mg of 13-C labeled triolein. Triolein is a commonly ingested fat consisting
of glycerol bound to three oleic acids. 13-C is a stable (non-radioactive) isotope of carbon.
On one of the test days the subjects (randomly) will concurrently consume the active
preparation, a tea containing extracts of the three types of tea leave described above plus
the meal, and on the other test day they will consume the meal with a liquid placebo
preparation (warm water, sugar and food coloring). Subjects will provide a breath sample
before and at hourly intervals for 8 hours after ingestion of the meal. Carbohydrate
malabsorption will be determined by the hydrogen concentration in the breath samples and fat
malabsorption by the concentration of 13-CO2 in the breath samples.
Clinical Significance - An increase in breath hydrogen indicates carbohydrate malabsoption
and a low 13-CO2 indicates lipid malabsorption. Objective evidence that the tea leaf extract
actually induces carbohydrate and/or fat malabsorption could provide the basis for further
studies.