The effect of vinegar co-ingestion on postprandial glucose control in type 2 diabetes patients.

Diet is considered as one of the cornerstones of type 2 diabetes treatment,
next to pharmaceutical therapy and exercise. It has been shown that dietary
adjustments can strongly improve postprandial glycemia in type 2 diabetes
patients. Therefore, there is great interest in dietary modulation to improve
postprandial glucose metabolism. Over the last years, vinegar co-ingestion has
been shown to reduce postprandial glucose excursions in healthy subjects.
However, research on the glucoregulatory benefits of vinegar in type 2 diabetes
patients is currently lacking. Furthermore, it is not clear whether vinegar
co-ingestion has only sufficient therapeutic strength when ingested with a
mixed meal or also with mono-saccharides. Finally, it should be established
whether vinegar co-ingestion is an effective strategy to reduce postprandial
hyperglycemia under free-living conditions.

The main objective of this study is to assess the acute effect of co-ingested
vinegar on postprandial plasma glucose levels in type 2 diabetes patients.

Three studies will be performed in a single-blind, randomized, cross-over
design. Study 1 and 2 consist of 2 test days, separated by 1 week.
Study 3 consists of two 3-day test periods, separated by 1 week.

Study 1
During both test days, subjects will ingest a test drink or a placebo drink.
The test drink consists of 82,5 g glucose monohydrate dissolved in 225 ml water
and 25 ml vinegar. The placebo drink consists of 82,5 g glucose monohydrate
dissolved in 250 ml water. The drinks will be offered in a non-transparent
drinking bottle.

Study 2
During both test days, subjects will ingest a mixed meal combined with a test
drink or a placebo drink. The test drink consists 175 ml water and 25 ml
vinegar. The placebo drink consists of 200 ml water.

Study 3
During both test periods, subjects will ingest a standardized diet entirely
consisting of commercially available food products. The standardized diet
includes 3 meals and 3 snacks per day, which have to be ingested at
predetermined times (8:00, 10:30, 13:00, 15.30, 18,00, 20.30 h). Directly prior
to each main meal subjects have to ingest a test drink or placebo drink. The
test drink consists of 75 ml water and 25 ml vinegar. The placebo drink
consists of 100 ml water. Individual energy requirements will be calculated
with the Harris and Bennedict equation with appropriate adjustment for
subjects* activity level.

Study 1
Risks as the result of participation in this experiment are minimal. At the
insertion site of the of the intravenous catheter, a hematoma could occur.

Time investment:
screening: 1 hour
test days: 2 x 3 hours

Study 2
Risks as the result of participation in this experiment are minimal. At the
insertion site of the of the intravenous catheter, a hematoma could occur.

Time investment:
screening: 1 hour
test days: 2 x 5 hours

Study 3
Risks as the result of participation in this experiment are minimal. At the
insertion site of the of the intravenous catheter, a hematoma could occur.

Time investment
screening: 3 uur
test periods: 2 testperiods include 4 visits of 45 minutes

Risks as the result of participation in this experiment are minimal. At the
insertion site of the of the intravenous catheter, a hematoma could occur
Only the type 2 diabetes patients participating in study 3 will stop the use of
anti-diabetic medication during the last 2 days prior to the OGTT. After the
OGTT subjects will resume the use of their prescribed medication. This
temporary cessation of oral blood glucose lowering medication is included to
assess the *normal* glycemic and insulin responses without interference of oral
blood glucose lowering medication. This method of glucose tolerance testing has
been applied in our previous protocols (MEC 99-215, 02-077, 03-058, 04-218,
05-028, 06-3-081 & 09-3-028) without any adverse events.