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Vinegar supplementation lowers glucose and insulin responses and increases satiety after a bread meal in healthy subjects

Authors:
  • Aventure AB

Abstract

To investigate the potential of acetic acid supplementation as a means of lowering the glycaemic index (GI) of a bread meal, and to evaluate the possible dose-response effect on postprandial glycaemia, insulinaemia and satiety. In all, 12 healthy volunteers participated and the tests were performed at Applied Nutrition and Food Chemistry, Lund University, Sweden. Three levels of vinegar (18, 23 and 28 mmol acetic acid) were served with a portion of white wheat bread containing 50 g available carbohydrates as breakfast in randomized order after an overnight fast. Bread served without vinegar was used as a reference meal. Blood samples were taken during 120 min for analysis of glucose and insulin. Satiety was measured with a subjective rating scale. A significant dose-response relation was seen at 30 min for blood glucose and serum insulin responses; the higher the acetic acid level, the lower the metabolic responses. Furthermore, the rating of satiety was directly related to the acetic acid level. Compared with the reference meal, the highest level of vinegar significantly lowered the blood glucose response at 30 and 45 min, the insulin response at 15 and 30 min as well as increased the satiety score at 30, 90 and 120 min postprandially. The low and intermediate levels of vinegar also lowered the 30 min glucose and the 15 min insulin responses significantly compared with the reference meal. When GI and II (insulinaemic indices) were calculated using the 90 min incremental area, a significant lowering was found for the highest amount of acetic acid, although the corresponding values calculated at 120 min did not differ from the reference meal. Supplementation of a meal based on white wheat bread with vinegar reduced postprandial responses of blood glucose and insulin, and increased the subjective rating of satiety. There was an inverse dose-response relation between the level of acetic acid and glucose and insulin responses and a linear dose-response relation between acetic acid and satiety rating. The results indicate an interesting potential of fermented and pickled products containing acetic acid.
ORIGINAL COMMUNICATION
Vinegar supplementation lowers glucose and insulin
responses and increases satiety after a bread meal in
healthy subjects
EO
¨
stman
1
*, Y Granfeldt
1
, L Persson
1
and I Bjo
¨
rck
1
1
Applied Nutrition and Food Chemistry, Department of Food Technology, Engineering and Nutrition, Lund University, Lund, Sweden
Objective: To investigate the potential of acetic acid supplementation as a means of lowering the glycaemic index (GI) of a
bread meal, and to evaluate the possible dose–response effect on postprandial glycaemia, insulinaemia and satiety.
Subjects and setting: In all, 12 healthy volunteers participated and the tests were performed at Applied Nutrition and Food
Chemistry, Lund University, Sweden.
Intervention: Three levels of vinegar (18, 23 and 28 mmol acetic acid) were served with a portion of white wheat bread
containing 50 g available carbohydrates as breakfast in randomized order after an overnight fast. Bread served without vinegar
was used as a reference meal. Blood samples were taken during 120 min for analysis of glucose and insulin. Satiety was measured
with a subjective rating scale.
Results: A significant dose–response relation was seen at 30 min for blood glucose and serum insulin responses; the higher the
acetic acid level, the lower the metabolic responses. Furthermore, the rating of satiety was directly related to the acetic acid
level. Compared with the reference meal, the highest level of vinegar significantly lowered the blood glucose response at 30 and
45 min, the insulin response at 15 and 30 min as well as increased the satiety score at 30, 90 and 120 min postprandially. The
low and intermediate levels of vinegar also lowered the 30 min glucose and the 15 min insulin responses significantly compared
with the reference meal. When GI and II (insulinaemic indices) were calculated using the 90 min incremental area, a significant
lowering was found for the highest amount of acetic acid, although the corresponding values calculated at 120 min did not
differ from the reference meal.
Conclusion: Supplementation of a meal based on white wheat bread with vinegar reduced postprandial responses of blood
glucose and insulin, and increased the subjective rating of satiety. There was an inverse dose–response relation between the level
of acetic acid and glucose and insulin responses and a linear dose–response relation between acetic acid and satiety rating. The
results indicate an interesting potential of fermented and pickled products containing acetic acid.
Sponsorships: Dr P Ha
˚
kansson’s foundation and Direkto¨r Albert Pa
˚
hlsson’s foundation for research and charity.
European Journal of Clinical Nutrition (2005) 59, 983–988. doi:10.1038/sj.ejcn.1602197; published online 29 June 2005
Keywords: acetic acid; vinegar; insulin; satiety; appetite; glycaemic index
Introduction
Today, we see a rapid increase in obesity and diseases related
to the insulin resistance syndrome (IRS). The health costs
will rise profoundly, and it is a great challenge for the future
to find means to counteract this development. The quality
of the diet has been shown to play an important role in the
combat of metabolic disorders and one quality parameter
of dietary carbohydrates relates to the glycaemic index
(GI), which is used to classify the glycaemic responses to
carbohydrate rich foods (Jenkins et al, 1981). At this time
point, there is a substantial amount of evidence that a diet
Received 22 April 2004; revised 30 December 2004; accepted 13 May
2005; published online 29 June 2005
*Correspondence: E O
¨
stman, Applied Nutrition and Food Chemistry,
Department of Food Technology, Engineering and Nutrition, Lund
University, PO Box 124, SE-221 00 Lund, Sweden.
E-mail: Elin.Ostman@inl.lth.se
Guarantor:EO
¨
stman.
Contributors: YG made the design of the experiment with assistance
from EO
¨
and IB. LP did the blood sampling and analysis. YG was in
charge of the collection and analysis of data. EO
¨
had the primary
responsibility for writing the manuscript, but YG and IB provided
comments on several drafts. None of the authors had any conflicts of
interest.
European Journal of Clinical Nutrition (2005) 59, 983988
&
2005 Nature Publishing Group All rights reserved 0954-3007/05 $
30.00
www.nature.com/ejcn
characterized by a low GI has benefits in both prevention
and treatment of several diseases linked to the IRS, such
as cardiovascular disease (CVD) (Liu et al, 2000) and
type II diabetes (Salmero
´
n et al, 1997a, b). New cross-
sectional data also indicate that such a diet is associated
with a lower prevalence of insulin resistance and meta-
bolic syndrome (McKeown et al, 2004). Furthermore,
evidences are at hand suggesting a beneficial role of
low-GI foods adjunct to appetite regulation. Consequently,
studies have demonstrated either increased satiety,
delayed return of hunger or decreased ad libitum food
intake after low-GI compared with high-GI foods (Ludwig,
2000). However, the role of dietary GI in relation to the
increasing prevalence of overweight and obesity remains
unclear. A shortcoming regarding the implementation
of the GI concept is the lack of low-GI products on the food
market.
A range of factors is known to affect the GI of carbohy-
drate-rich foods connected either to the characteristics of the
raw material (ratio of amylose/amylopectin (Granfeldt et al,
1995), soluble fibre content (Braaten et al, 1991), inclusion
of intact cereal kernels (Liljeberg & Bjo
¨
rck, 1994), etc.) or the
process (eg manufacturing process of pasta (Granfeldt et al,
1991), pumpernickel baking (A
˚
kerberg et al, 1998) and
fermentation (Liljeberg et al, 1995)). Previous results have
shown that the presence of lactic acid lowers the GI of bread
(Liljeberg et al, 1995) as well as improves the glucose
tolerance at a subsequent high-GI meal (second-meal effect)
(O
¨
stman et al, 2002a). The mechanism for the glucose-
lowering action of lactic acid has been suggested to be due
to a lowered rate of starch hydrolysis in the upper small
intestine (O
¨
stman et al, 2002b). Other organic acids that
have been investigated in relation to GI include acetic and
propionic acids. Both these acids have shown to lower the
glucose response to bread meals (Liljeberg & Bjo
¨
rck, 1998;
Darwiche et al, 2001), but in contrast to lactic acid, the
mechanism of action appears to be a lowered rate of gastric
emptying (Liljeberg & Bjo
¨
rck, 1998; Darwiche et al, 2001).
Propionic acid is present in certain types of cheese and
is also used in low amount as a preservative, for example,
in bread products. Acetic acid is found in a range of food
products such as vinegar, dressings and pickled products.
It is also formed upon fermentation processes, such as
sourdough fermentation, and can be considered a con-
stituent of a normal diet. The public interest for vinegar
has been increasing in the past few years, and new products
are currently being introduced in the market. In the
present study, the possible dose–response relationship
between the amount of acetic acid added to a bread meal
in the form of vinegar, and the glycaemic and insu-
linaemic responses were evaluated in healthy subjects. In
addition, the satiating effect of the different amounts of
vinegar as supplements to a white bread meal was evaluated.
The lower level of vinegar used in the present study is the
same as the one used in a former study by Liljeberg and
Bjo
¨
rck (1998).
Subjects and methods
Subjects and meals
A total of 12 healthy, nonsmoking volunteers, 10 women
and two men, aged 22.9 (s.e.m. ¼ 0.5) y, with normal body
mass indices (21.470.7 kg/m
2
) and without drug therapy
participated in the study. Besides a reference portion of white
wheat bread, three test meals containing an identical portion
of white wheat bread were served with 18, 23 or 28 g white
vinegar (6% acetic acid, Druvan, Eslo
¨
v, Sweden), which is
equivalent to 18, 23 and 28 mmol acetic acid in the
respective portions. The highest amount of acetic acid
corresponds with approximately 30 ml vinegar of this type.
The white wheat bread was baked according to Liljeberg
and Bjo
¨
rck (1994) and was identical to the reference bread
normally used in the GI determinations in our laboratory.
The bread was soaked in the portion of vinegar before
ingestion, and the intake of vinegar was thus distributed
over the meal. All meals contained 50 g available starch. The
subjects were served the meals in random order at four
separate occasions. The tests were performed approximately
1 week apart and commenced at the same time in the
morning. All meals were consumed steadily and finished
within 12–14 min. Water (150 ml) and 150 ml tea or coffee
was served with each meal. The test subjects were allowed to
choose between these drinks at the first occasion and then
the same drink was retained through all the test meals.
Sampling and analysis
The subjects arrived at the laboratory in the morning after
an overnight fast. A fasting blood sample was taken and the
subjects feeling of hunger/satiety was rated on a subjective
rating scale before the meal was served. The rating scale was
bipolar and graded from 10, to represent extreme hunger,
to þ 10, to explain extreme satiety (Liljeberg et al, 1995).
After the breakfast, blood samples were taken at 15, 30, 45,
60, 90 and 120 min for analysis of glucose and at 15, 30,
45, 90 and 120 min for analysis of insulin. The feeling of
hunger/satiety was rated at 15, 30, 45, 70, 90 and 120 min
postprandially. Blood glucose concentrations were deter-
mined with a glucose oxidase peroxidase reagent and serum
insulin concentrations were determined with an enzyme
immunoassay kit (Mercodia AB, Uppsala, Sweden).
The Ethics Committee of the Faculty of Medicine at Lund
University approved the study.
Statistical analysis
The areas under the curves (AUCs) were determined for the
blood glucose, serum insulin and satiety score (GraphPad
Prism ver. 3.0; GraphPad Software, San Diego, USA). GI and II
(insulinaemic indices) were determined by calculating the
difference between the AUCs for the test meal and the
reference meal in percent, with each subject being their own
reference. All areas below the baseline were excluded from
the calculations. Values are presented as mean7s.e.m.
Vinegar improves glucose tolerance and satiety
EO
¨
stman et al
984
European Journal of Clinical Nutrition
Subjects that rated their postprandial hunger lower than
the hunger at fasting, hence indicating no satiety after the
meal, were excluded from the calculations. All statistical
calculations were performed in MINITAB Statistical Software
(release 13 for Windows; Minitab Inc., State College, PA,
USA). Significances were evaluated with the general linear
model (analysis of variance) followed by Tukey
´
s multiple
comparisons test. Values of Po0.05 were considered signifi-
cant. The dose–response relation between the level of acetic
acid and glucose, insulin or satiety AUC was evaluated with
linear regression in GraphPad Prism (ver. 3.0).
Results
When vinegar was served with the white wheat bread, the
glycaemic responses were significantly lower at 30 min
postprandially (Po0.05), compared with the reference meal
without vinegar (Figure 1). No differences were noted in
between the test meals with acetic acid at this time point.
At 45 min, the highest amount of vinegar still lowered the
glucose level (P ¼ 0.0540), compared with the reference. The
GI of the test meal with the highest amount of vinegar
(GI ¼ 77) was significantly lower than that of the reference
meal, using the 90 min areas for calculation (Table 1). When
GI was calculated using the AUC at 120 min no significant
differences were found between any of the meals. A negative
linear relation was found between 30 min blood glucose
levels and vinegar content of the test meal (r ¼0.47,
P ¼ 0.001).
The insulin responses at 15 min were significantly lower
for the high and intermediate levels of vinegar compared
with the reference meal (Figure 2). At 30 min, only the
highest amount of vinegar lowered the insulin level
significantly compared with the reference. The II of the
meal with highest amount of vinegar (II ¼ 78) was signifi-
cantly lower than the reference, when using the 90 min
AUCs for calculation (Table 2). Calculating with the AUCs at
120 min, no significant differences in II were found between
any of the meals. When expressing the 30 min insulin
responses as a function of the vinegar content of the test
meal, a negative linear relation was found (r ¼0.44,
P ¼ 0.002).
The reference meal resulted in the lowest rating of satiety
(Figure 3). The satiety scores after the highest level of vinegar
were rated significantly higher than the reference at 30, 90
and 120 min after the meal. The score for the low and
intermediate levels of vinegar did not differ significantly
at any of the time points from either the reference or the
meal with a high amount of vinegar. The satiety AUC was
significantly larger for the meal with a high amount of
vinegar compared with that of the reference meal (Table 3). A
significant linear relation was found between the satiety
AUC and the acetic acid content of the test meals (r ¼ 0.41,
P ¼ 0.004). The satiety rating of the reference meal without
Figure 1 Mean blood glucose responses in 12 healthy subjects at a
breakfast with carbohydrate equivalent portions of white wheat
bread () served with 18 g(m), 23 g (.) and 28 g (E) of vinegar.
Values are presented as means (n ¼ 12) with bars indicating s.e.m.
Significant differences between glucose levels at certain time points
are indicated with letters (Po0.05).
Table 1 Blood glucose levels and glycaemic indices (GIs) at 90 and
120 min in 12 healthy subjects at a breakfast with carbohydrate
equivalent portions of white wheat bread served with various amounts
of vinegar
Meal GI 90 min GI 120 min
White wheat bread (WWB) 100
a
100
a
WWB þ 18 g vinegar 89.474.3
ab
96.275.6
a
WWB þ 23 g vinegar 104.7711.2
ab
117.0715.8
a
WWB þ 28 g vinegar 76.877.9
b
84.878.7
a
Values within a column not followed by the same letter are significantly
different.
Figure 2 Mean serum insulin responses in 12 healthy subjects at a
breakfast with carbohydrate equivalent portions of white wheat
bread () served with 18 g (m), 23 g (.) and 28 g (E) of vinegar.
Values are presented as means (n ¼ 12) with bars indicating s.e.m.
Significant differences between insulin levels at certain time points
are indicated with letters (Po0.05).
Vinegar improves glucose tolerance and satiety
EO
¨
stman et al
985
European Journal of Clinical Nutrition
acetic acid had returned to the rating at fasting after 90 min,
whereas the meals with acetic acid maintained positive
ratings over the entire experimental period of 120 min
(Figure 3).
Discussion
The most important finding in the present study was that
addition of acetic acid/vinegar improved not only the
postprandial blood glucose and insulin profiles, but also
the satiating effect of a meal based on white wheat bread.
With respect to satiety rating, the intake of acetic acid/
vinegar appeared not only to increase, but also to prolong
satiety. Furthermore, a significant dose–response relation
was found at 30 min postprandially for blood glucose and
serum insulin responses, indicating that the higher the acetic
acid level, the lower the metabolic response.
In previous work by Liljeberg and Bjo
¨
rck (1998) with meals
based on white wheat bread, a 35% lowering of GI and II was
seen with 18 mmol acetic acid (20 g vinegar) when served as
a vinaigrette sauce. In the present study, the same amount of
acetic acid (18 mmol) lowered mean GI by 11% but without
reaching statistical significance, and with no effect on II. In
the study by Liljeberg and Bjo
¨
rck (1998), the vinegar was
supplied as a vinaigrette sauce including water and olive oil
(8 g). Results from studies investigating the effect of fats with
various degrees of saturation on the blood glucose response
of a meal are conflicting (Gatti et al, 1992; MacIntosh et al,
2003). Consequently, it remains to be elucidated if the
combination of acetic acid and olive oil caused the more
potent lowering of the glycaemic response in the work by
Liljeberg and Bjo
¨
rck (1998). However, in a recent study, the
addition of 15 g sunflower oil (62% PUFA, 26% MUFA and
12% SFA) had no effect on the glycaemic excursions
following a potato meal in healthy subjects (Johnsson,
Andersson, Granfeldt and Bjo
¨
rck, unpublished data). Also,
in work by MacIntosh et al (2003) no differences in GI or II
were found for a meal with mashed potato and either butter
(SFA), sunola oil (MUFA) or sunflower oil (PUFA). Further-
more, Owen and Wolever (2003) concluded that a variation
of fat intake (nonhydrogenated-fat margarine: 41% PUFA,
41% MUFA and 14% SFA) across the normal range did not
significantly affect the glycaemic response to a white bread
meal.
The glucose-lowering effect of acetic acid/vinegar has also
been observed by other investigators. Johnston et al (2004)
reported that vinegar could significantly improve insulin
sensitivity in insulin resistant subjects. In a recent study by
Sugiyama et al (2003), the GI of a white rice meal was
lowered with 25–35% by adding either vinegar (11 g/portion)
or pickled cucumber (15 g vinegar/portion). Furthermore,
Brighenti et al (1995) found a 30% lowering of AUC for
glucose of 17 mmol acetic acid when served as a vinaigrette
together with sliced lettuce and white bread. In the latter
study, the suggested glucose-lowering effect was an inhibi-
tion of digestive amylases caused by the acid. However, in
vitro measurements of the rate of starch hydrolysis using a
simulated gastrointestinal model did not reveal any amylase
inhibition in the case of acetic acid containing bread
(Liljeberg et al, 1996). Moreover, as judged from studies in
healthy volunteers using paracetamol as a marker for the
gastric emptying rate, the presence of acetic acid appeared to
significantly reduce the gastric emptying rate, suggesting an
effect different from obstructed amylolysis (Liljeberg &
Bjo
¨
rck, 1998). In a study by Ebihara and Nakajima (1988)
Table 2 Serum insulin levels and insulinaemic indices (Is) at 90 and
120 min in 12 healthy subjects at a breakfast with carbohydrate
equivalent portions of white wheat bread served with various amounts
of vinegar
Meal II 90 min II 120 min
White wheat bread (WWB) 100
a
100
a
WWB þ 18 g vinegar 102.8712.0
ab
108.4711.4
a
WWB þ 23 g vinegar 87.3711.2
ab
94.2712.7
a
WWB þ 28 g vinegar 77.8710.4
b
84.6711.3
a
Values within a column not followed by the same letter are significantly
different.
Figure 3 Mean satiety scores in 11 healthy subjects at a breakfast
with carbohydrate equivalent portions of white wheat bread ()
served with 18 g (m), 23 g (.) and 28 g (E) of vinegar. Values are
presented as means (n ¼ 10 (reference and 18 g vinegar) or 11 (23
and 28 g vinegar)) with bars indicating s.e.m. Significant differences
between satiety scores at certain time points are indicated with
letters (Po0.05).
Table 3 Area under curve (0–120 min) for satiety scores in healthy
subjects after a breakfast with carbohydrate equivalent portions of white
wheat bread served with various amounts of vinegar
Meal n Area under curve for satiety score
White wheat bread (WWB) 10 210745
a
WWB þ 18 g vinegar 10 363738
ab
WWB þ 23 g vinegar 11 435775
ab
WWB þ 28 g vinegar 11 5127105
b
Values within a column not followed by the same letter are significantly
different.
Vinegar improves glucose tolerance and satiety
EO
¨
stman et al
986
European Journal of Clinical Nutrition
the administration of acetic acid improved the glycaemia in
rats and lowered the insulin response in humans signifi-
cantly. No lowering effect on the glucose response was seen
in humans, but a postponed glucose peak and prolonged
time to reach the fasting level postprandially were registered
with the acetic acid containing meal. Also, in the rat study,
the glucose response showed a slower decrease in the late
postprandial phase in the presence of the acid, which is in
line with a mechanism related to a lowered gastric emptying
rate (Ebihara & Nakajima, 1988).
In studies from the 1960s and 1970s, the influence of
organic acids on gastric emptying was evaluated in both
humans (Hunt & Knox, 1969, 1972) and animals (Blum et al,
1976). In one of these early reports, Hunt and Knox (1972)
stated that the higher the molecular weights of weak acids,
the lower the potential of slowing gastric emptying. This
finding suggests that acetic acid (M
w
¼ 60 g/mol) would be
more effective than lactic acid (M
w
¼ 90 g/mol) in lowering
the gastric emptying rate. This is in accordance with results
from Liljeberg and Bjo
¨
rck (1996, 1998) showing that the
presence of acetic acid but not lactic acid lowered the
postprandial appearance of paracetamol in the blood,
indicative of a delay in gastric emptying rate in the case of
acetic acid. In addition to organic acids, the rate of gastric
emptying can also be influenced by volume, caloric content,
viscosity, density and particle size of the gastric content
(Horowitz et al, 1994). Some peptides that are released in the
small intestine, such as cholecystokinin (CCK), amylin and
glucagon-like peptide-1 (GLP-1), have also been shown to
be involved in the regulation of the gastric emptying rate
(Hellstro
¨
m&Na
¨
slund, 2001; Feinle et al, 2002).
A difference between lactic- and acetic acid supplemented
bread meals, beyond their immediate glucose-lowering
effect, is that improved glucose tolerance at a subsequent
standardized meal (second meal effect) has only been
observed in meals with lactic acid (O
¨
stman et al, 2002a).
When acetic acid was served as a supplement to a white
bread breakfast meal, no effect on the glucose tolerance
was observed at the subsequent standardized lunch meal
(Liljeberg et al, 1999). In contrast, the presence of lactic acid
in a barley bread-based breakfast meal reduced glycaemia at a
subsequent standardized lunch meal by 25% (O
¨
stman et al,
2002a). The suggested mechanism for a second meal effect of
a low-GI food is that the prolonged digestive phase causes a
suppression of the plasma levels of free fatty acids (Wolever
et al, 1995). This may lead to improved insulin sensitivity at
the time of the next meal. The difference in the second meal
effect between low-GI foods may be related to the fact that
different gastrointestinal mechanisms may be responsible for
the slow release properties. Since a lowered gastric emptying,
and not a lowered starch digestion, causes the glucose-
lowering effect of acetic acid, it can be hypothesized that the
criteria for a second meal effect in the perspective from
breakfast to lunch depend mainly on a mechanism con-
nected to a prolonged digestive phase. In animal studies,
Fushimi et al (2001) showed that acetic acid could activate
gluconeogensis and induce glycogenesis in the liver after
a fasting state. Furthermore, when Caco-2 cells (human
colonic carcinoma cells) were cultivated with acetic acid for
15 days, Ogawa et al (2000) showed that acetic acid
suppresses the increase in disaccharidase activity (sucrase,
maltase, trehalase and lactase). These two latter studies add
pieces of evidence to the knowledge on how acetic acid
affects glucose absorption and metabolism, but more
research is needed to understand the importance of each
physiological phenomenon.
There is currently an ongoing discussion concerning the
need to standardize the GI methodology. One potentially
interesting issue for ranking of carbohydrate characteristics
relates to the time interval used for the calculation of GI. In
the present study, there are important differences between
glucose and insulin responses to the vinegar containing
meals and the reference meal in the early postprandial phase
(15–30 min). Despite these lowering effects of vinegar, a
difference in GI and II is only significant for the meal with
the highest amount of vinegar at 90 min and not at 120 min.
This suggests that the ranking of products may be slightly
different depending on the time period used. In fact,
products with an extended digestive phase and with low
but sustained increments in blood glucose may produce a
substantial late glycaemic area, thus evening out differences
in incremental areas compared with the rapidly digested
and absorbed starch in the wheat bread reference. This has
previously been shown to be the case with pasta (Granfeldt
et al, 1991).
In the present study, the meal with the highest amount
of vinegar also increased the late postprandial satiety more
than two-fold, compared with the reference meal. None of
the former articles on meal supplementation with vinegar
have evaluated satiety, so the current finding adds new
knowledge both to the specific effect of vinegar on satiety
and to the more general relation between GI and satiety,
suggesting that low-GI foods can produce not only a higher
satiety, with potential effects on food intake, but also
prolong the duration of satiety, which may influence the
voluntary intake at a subsequent meal.
Significant dose–response relations between the amount of
added vinegar and the glucose, insulin or satiety responses
were found based on the 30 min values in the present study.
The highest amount of acetic acid used in the present study
corresponds to approximately 30 ml of vinegar. This is a level
comparable with that of acetic acid in a portion of
pumpernickel bread (GI ¼ 68, II ¼ 63) previously tested in
our laboratory (Liljeberg & Bjo
¨
rck, 1994). However, a similar
amount of acetic acid served as a salad dressing, as pickled
vegetables may be difficult to ingest. The selection of pickled
and fermented products or meal additives, and the use of
vinegar-based drinks, which are currently introduced in the
market, may provide means to reach efficient levels of acetic
acid. Addition of vinegar to carbohydrate-rich meals of high-
GI character, or the use of, for example, homofermentative,
acetic acid producing starter cultures offers a potential to
Vinegar improves glucose tolerance and satiety
EO
¨
stman et al
987
European Journal of Clinical Nutrition
lower the GI and increase the postmeal satiety. The possible
long-term health benefits of including pickled products or
fermented products in the diet need to be examined.
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Vinegar improves glucose tolerance and satiety
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European Journal of Clinical Nutrition
... The seven ST studies were crossover, randomized controlled trials (RCT) investigating the effect of a single vinegar exposure on satiety or appetite as primary outcome (14)(15)(16)(17)(18)(19); sample sizes ranged from 12 to 27 healthy subjects (mean age, 22.2-27.5 yr; Table 1). Four studies reported a power of at least 80% (16,17), and one achieved 71% power (19), but the remaining two studies did not mention effect size or power (15,18). ...
... The seven ST studies were crossover, randomized controlled trials (RCT) investigating the effect of a single vinegar exposure on satiety or appetite as primary outcome (14)(15)(16)(17)(18)(19); sample sizes ranged from 12 to 27 healthy subjects (mean age, 22.2-27.5 yr; Table 1). Four studies reported a power of at least 80% (16,17), and one achieved 71% power (19), but the remaining two studies did not mention effect size or power (15,18). Four studies specified restricted disordered eating as an exclusion criterion (14)(15)(16). ...
... In five studies, either white or white wine vinegar was used (14,15,18,19). Mettler et al. (17) used AA dissolved in water with glucose. ...
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Research suggests that the active ingredient in vinegar, acetic acid, may reduce appetite, thereby reducing energy consumption. This article aims to assess the effect of vinegar or acetic acid on appetite measures and subsequent food intake in humans. This was conducted as a systematic literature review adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All participants were considered, regardless of age or health status. A search using MedLine (Ovid), PubMed, CINAHL Plus, Web of Science, and Cochrane Library between January and April 2021 resulted in 12 studies. Outcomes included appetite, measured using an appetite rating scale or visual analog scale; satiation, measured as food intake of intervention meal; and satiety, measured as the amount of food intake after vinegar or acetic acid consumption. Some short-term interventions indicate that vinegar containing at least 24.6 mmol acetic acid, when consumed alongside a meal containing solid foods, acutely suppresses appetite up to 120 min postprandially as well as ad libitum food intake 3 and 24 h after vinegar consumption. However, longer exposure vinegar interventions suggest that vinegar does not affect overall energy intake. Further research is needed to determine whether oral vinegar consumption may lead to long-term appetite reduction, decrease energy intake, and aid in weight loss.
... These 15 studies were metaanalyzed (29-31, 33, 34, 38-43) for PBG responses in healthy individuals, with 7 in metabolically compromised individuals (31,32,(43)(44)(45). Five of the healthy volunteer studies (30,40,42,43) and 6 of the nonhealthy volunteer studies (32,(43)(44)(45) were also meta-analyzed for the postprandial insulin response. ...
... When interpreting effect sizes, values <0. 40 = 117). A random-effects model was used to calculate standardized mean differences (squares), 95% CIs (horizontal lines), and summary effects (diamond). ...
... When interpreting effect sizes, values <0. 40 = 67). A random-effects model was used to calculate standardized mean differences (squares), 95% CIs (horizontal lines), and summary effects (diamond). ...
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Background Non-communicable disease development is related to impairments in glycaemic and insulinemic response, which can be modulated by fiber intake. Fiber's beneficial effect upon metabolic health can be partially attributed to the production of short-chain fatty acids (SCFAs) via microbial fermentation of fiber in the gastrointestinal tract. Objective We aimed to determine the effect of the SCFAs, acetate, propionate, and butyrate on glycemic control in humans. Methods CENTRAL, Embase, PubMed, Scopus and Web of Science databases were searched from inception to the 07/12/2021. Papers were included if they reported a randomized, controlled trial measuring glucose and/or insulin compared to a placebo in adults. Studies were categorized by the type of SCFA and intervention duration. Random effects meta-analyses were performed for glucose and insulin for those subject categories with ≥3 studies, or a narrative review was performed. Results We identified 43 eligible papers, with 46 studies within those records (n = 913), 44 studies were included in the meta-analysis. Vinegar intake decreased acute glucose response, standard mean difference (SMD) and (95% CI) –0.53 (–0.92, –0.14) (n = 67) in individuals with impaired glucose tolerance or type 2 diabetes and in healthy (SMD) –0.27 (–0.54, 0.00) (n = 186). The meta-analyses for acute acetate as well as acute and chronic propionate studies had no significant effect. Conclusions Vinegar decreased glucose response acutely in healthy and non-healthy. Acetate, propionate, butyrate, and mixed SCFAs had no effect on blood glucose and insulin in humans. Significant heterogeneity, risk of bias, and publication bias were identified in several study categories, including acute vinegar glucose response. As evidence was very uncertain, caution is urged when interpreting these results. Further high-quality research is required to determine the effect of SCFAs on glycemic control.
... There is a close link between the risk to develop diabetes type 2 and excess weight. The vinegar has proven to be interesting in the prevention and the treatment of diabetes, because it decreases the presence of glucose and insulin in blood (Johnson et al., 2011;Johnson, 2005;Leeman et al., 2005;Ostman et al., 2005). The acetic acid present in the vinegar is at the origin of the observed effects (Leeman et al., 2010). ...
... Moreover, the acetic acid increases the use of glucose by the human body (Johnson and Buller, 2005). Moreover, the vinegar increases satiety after the meal (Johnson et al., 2011;Johnson, 2005;Leeman et al., 2005;Ostman et al., 2005), and its daily consumption decreases blood pressure (Kondo et al., 2001). ...
... Most of trial data support beneficial effects of vinegar on postprandial glycemia and overall glycemic control. In healthy subjects, vinegar consumption with a meal (either as dressing on salad or as a drink) resulted in generally lower postprandial glycemia [386,[394][395][396] and in some studies reduced insulinemia [386] as well. In one study, a 55% reduction in post-meal glycemia was reported when a high GL meal was consumed [397]. ...
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As years progress, we are found more often in a postprandial than a postabsorptive state. Chrononutrition is an integral part of metabolism, pancreatic function, and hormone secretion. Eating most calories and carbohydrates at lunch time and early afternoon, avoiding late evening dinner, and keeping consistent number of daily meals and relative times of eating occasions seem to play a pivotal role for postprandial glycemia and insulin sensitivity. Sequence of meals and nutrients also play a significant role, as foods of low density such as vegetables, salads, or soups consumed first, followed by protein and then by starchy foods lead to ameliorated glycemic and insulin responses. There are several dietary schemes available, such as intermittent fasting regimes, which may improve glycemic and insulin responses. Weight loss is important for the treatment of insulin resistance, and it can be achieved by many approaches, such as low-fat, low-carbohydrate, Mediterranean-style diets, etc. Lifestyle interventions with small weight loss (7–10%), 150 min of weekly moderate intensity exercise and behavioral therapy approach can be highly effective in preventing and treating type 2 diabetes. Similarly, decreasing carbohydrates in meals also improves significantly glycemic and insulin responses, but the extent of this reduction should be individualized, patient-centered, and monitored. Alternative foods or ingredients, such as vinegar, yogurt, whey protein, peanuts and tree nuts should also be considered in ameliorating postprandial hyperglycemia and insulin resistance. This review aims to describe the available evidence about the effects of diet, chrononutrition, alternative dietary interventions and exercise on postprandial glycemia and insulin resistance.
... This observation agreed with the reports that processing methods like germination, fermentation, cooking, etc. influencing glycemic index of the foods [95][96][97]. For instance, it is well established that the low GI of fermented food is attributed to the short-chain organic acids produced during fermentation such as lactic acid, acetic acid, and propionic acid [98]. These short-chain acids have the potentials of inhibiting the activities of alphaamylase and alpha-glucosidase in starch hydrolysis in the upper small intestine [99,100]. ...
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Food processing either enhances or lowers nutritional parameters of agricultural products. Hence, this study investigated effects of some traditional processing methods on chemical, antioxidant, glycaemic index (GI) and load (GL) properties of groundnut kernel flours. The processed flours, i.e., cooked (CGN), germinated (GGN), fermented (FGN), co-germinated-cooked-fermented (GCF) and raw (RGN) flour samples were evaluated for chemical compositions, antioxidant activities, and glycaemic index/load. The crude protein, essential amino acids (+ histidine), aromatic amino acids, branched chain amino acids (g/100 g protein) and Arginine/Lysine ratios of groundnut flours were 10.95–27.0, 24.85–34.41, 43.32–56.5, 6.13–8.87, 11.58–17.33 and 1.33–2.20, respectively. The most abundant fatty acids were oleic acid (37.88–42.38%) and linoleic acid (34.38–39.64%), respectively, while polyunsaturated/saturated fatty acid ratios (1.45–1.82) were higher than recommended value (> 1.0). The minerals in GGN, FGN and GCF were significantly (p < 0.05) higher than CGN and RGN, while phytate- and oxalate-mineral molar ratio of groundnut samples were lower than critical levels. The GI (29–37.9%) and GL (4.4–13.1%) were lower than recommended value for low GI (< 55%) and GL (< 10%). The antioxidant activity, i.e., total phenol, iron chelation, DPPH, OH⁻ Free radicals and Ferric reducing antioxidant power were higher in GCF than other samples. The present study established some local processing methods (cooking, germination and fermentation) influenced chemical, antioxidant and glycaemic properties of groundnut. For instance, co-germination-cooking-fermentation increased protein content, antioxidant activity and lower glycaemic index/load (< 55%; < 10%) of groundnut samples.
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The aim of this study was to carry out a systematic review of clinical trials followed by meta-analysis, to evaluate the effect of sourdough bread on glycemic control and appetite and satiety regulators such as leptin, ghrelin, GLP-1 (glucagon-like peptide-1), GLP-2 (glucagon-like peptide-2), NPY (neuropeptide Y), AgRP (agouti-related protein), PYY (peptide YY), and GIP (glucose-dependent insulinotropic polypeptide). Clinical trials compared the intake of sourdough bread to that of an industrially fermented one or control glucose solution in adults over 18 years of age. This systematic review included all randomized, parallel, or crossover trials published up to June 2021 in the EMBASE, MEDLINE, Scopus, and Web of Science databases. After the selection process, 18 studies were included. The analysis of the final average difference of the change in serum glucose after 60 minutes for the intervention indicated that the consumption of sourdough bread has a lower impact on blood glucose compared to that of industrial bread or glucose (MD = -0.29, IC 95% = [-0.46; -0.12]; I2 = 0%). The evaluation of blood glucose 120 minutes after the consumption of the intervention also indicated a lower increment in blood glucose when compared to the consumption of other types of bread or the same amount of glucose (MD = -0.21, IC 95% = [-0.32; -0.09]; I2 = 0%). The certainty of evidence varied from low to very low. The results showed that sourdough is effective in reducing the increment of postprandial glycemia, especially when prepared with whole wheat flour, although it does not reduce fasting serum insulin, nor does it change plasma PYY.
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Background This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) is intended to provide clinicians an overview of the body weight effects of concomitant medications (i.e., pharmacotherapies not specifically for the treatment of obesity) and functional foods, as well as adverse side effects of common supplements sometimes used by patients with pre-obesity/obesity. Methods The scientific information for this CPS is based upon published scientific citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership. Results This CPS outlines clinically relevant aspects of concomitant medications, functional foods, and many of the more common supplements as they relate to pre-obesity and obesity. Topics include a discussion of medications that may be associated with weight gain or loss, functional foods as they relate to obesity, and side effects of supplements (i.e., with a focus on supplements taken for weight loss). Special attention is given to the warnings and lack of regulation surrounding weight loss supplements. Conclusions This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on concomitant medications, functional foods, and supplements is one of a series of OMA CPSs designed to assist clinicians in the care of patients with the disease of pre-obesity/obesity. Implementation of appropriate practices in these areas may improve the health of patients, especially those with adverse fat mass and adiposopathic metabolic consequences.
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In recent years, an unstoppable trend toward minimally processed foods has increased the popularity of fermented foods as a beneficial nutritional and functional strategy. Within food fermentations, complex microbial communities trigger different biochemical reactions that result in the release of multiple bioactive compounds with beneficial effect on human health. In the present review the latest studies on fermented foods are summarized. Special attention has been paid on the health benefits of main fermented foods available nowadays, the principal bioactive compounds responsible for such properties as well as the future trends of research studies regarding their potentialities. This review emphasizes the need of clinical evidence to ensure that fermented foods may entail a significant improvement on well-being. Fermented foods may represent a non-invasive strategy to face multiple disorders, as hypertension, diabetes, hyperlipidemia, oxidative stress and multiple cognitive disordes, among others. Release of bioactive compounds, microbial enzymatic conversions or probiotic activities are the main responsible for such interesting properties. However, the need of well-designed clinical trials is a must in order to obtain conclusive results. Bioavailability and biodisponibility of bioactive compounds as well as the design of precision probiotics are also another focus of interest in which it must be deepen.
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Objective: To examine prospectively the relationship between glycemic diets, low fiber intake, and risk of non-insulin-dependent diabetes mellitus. Design: Cohort study. Setting: In 1986, a total of 65173 US women 40 to 65 years of age and free from diagnosed cardiovascular disease, cancer, and diabetes completed a detailed dietary questionnaire from which we calculated usual intake of total and specific sources of dietary fiber, dietary glycemic index, and glycemic load. Main outcome measure: Non-insulin-dependent diabetes mellitus. Results: During 6 years of follow-up, 915 incident cases of diabetes were documented. The dietary glycemic index was positively associated with risk of diabetes after adjustment for age, body mass index, smoking, physical activity, family history of diabetes, alcohol and cereal fiber intake, and total energy intake. Comparing the highest with the lowest quintile, the relative risk (RR) of diabetes was 1.37 (95% confidence interval [CI], 1.09-1.71, P trend=.005). The glycemic load (an indicator of a global dietary insulin demand) was also positively associated with diabetes (RR= 1.47; 95% CI, 1.16-1.86, P trend=.003). Cereal fiber intake was inversely associated with risk of diabetes when comparing the extreme quintiles (RR=0.72, 95% CI, 0.58-0.90, P trend=.001). The combination of a high glycemic load and a low cereal fiber intake further increased the risk of diabetes (RR=2.50, 95% CI, 1.14-5.51) when compared with a low glycemic load and high cereal fiber intake. Conclusions: Our results support the hypothesis that diets with a high glycemic load and a low cereal fiber content increase risk of diabetes in women. Further, they suggest that grains should be consumed in a minimally refined form to reduce the incidence of diabetes.
Article
In the present study, we evaluated whether a low glycemic index (GI) breakfast with lactic acid bread had an effect on glucose tolerance and insulinemia at a subsequent high GI lunch meal. A barley bread containing lactic acid and a reference barley bread were consumed in the morning after an overnight fast in random order by 10 healthy men and women. Four hours after the breakfasts, the subjects ate a standardized high GI lunch, and the blood glucose and insulin responses were measured for the next 3 h. Significant lowerings of the incremental glycemic area (-23%, P = 0.033) and of the glucose response at 95 min were found after the lunch meal when the barley bread with lactic acid was given as a breakfast. At 45 min after the lunch meal, the insulin level was significantly lower (-21%, P = 0.045) after the lactic acid bread breakfast, compared with the barley bread breakfast without lactic acid. We concluded that barley bread containing lactic acid eaten at breakfast has the potential to improve second-meal glucose tolerance at a high GI lunch meal 4 h later.
Article
The possible effects of organic acids or an organic salt on the rate of gastric emptying was studied to identify the cause for reduced postmeal responses of blood glucose and insulin to foods containing such components, eg, sourdough bread. Paracetamol was included in bread products with added lactic acid or sodium propionate and used as a marker for the rate of gastric emptying in healthy subjects. In parallel, postprandial glycemia, insulinemia, and satiety were evaluated. The influence of lactic acid, propionic acid, and sodium propionate was also studied in rats after they were tube-fed with glucose solutions. The bread products with lactic acid or sodium propionate both lowered blood glucose and insulin responses. The bread with sodium propionate also prolonged satiety. The reason for the lowered metabolic responses with sodium propionate was probably a lowered gastric emptying rate, as judged from reduced blood paracetamol concentrations; there was no such effect observed with bread with added lactic acid. A similar amount of lactic acid in solution tube-fed to rats did not affect the disappearance of glucose from the stomach. In contrast with the finding in humans, sodium propionate had no effect on the rate of gastric emptying in rats whereas an equimolar solution of propionic acid reduced gastric emptying rate in rats. Possibly, less of this acid was produced in the gastric contents after a bolus load of a sodium propionate solution (in rats) than in an eating situation. Also, the pH and/or the osmolarity may be important, and when provided in excessive amounts, lactic acid reduced the gastric emptying rate in rats. A hydrochloric acid solution of similar pH was much less effective in this respect.
Article
Objective. —To examine prospectively the relationship between glycemic diets, low fiber intake, and risk of non—insulin-dependent diabetes mellitus.Desing. —Cohort study.Setting. —In 1986, a total of 65173 US women 40 to 65 years of age and free from diagnosed cardiovascular disease, cancer, and diabetes completed a detailed dietary questionnaire from which we calculated usual intake of total and specific sources of dietary fiber, dietary glycemic index, and glycemic load.Main Outcome Measure. —Non—insulin-dependent diabetes mellitus.Results. —During 6 years of follow-up, 915 incident cases of diabetes were documented. The dietary glycemic index was positively associated with risk of diabetes after adjustment for age, body mass index, smoking, physical activity, family history of diabetes, alcohol and cereal fiber intake, and total energy intake. Comparing the highest with the lowest quintile, the relative risk (RR) of diabetes was 1.37 (95% confidence interval [CI], 1.09-1.71, Ptrend=.005). The glycemic load (an indicator of a global dietary insulin demand) was also positively associated with diabetes (RR=1.47; 95% CI, 1.16-1.86, Ptrend=.003). Cereal fiber intake was inversely associated with risk of diabetes when comparing the extreme quintiles (RR=0.72,95% CI, 0.58-0.90, Ptrend=.001). The combination of a high glycemic load and a low cereal fiber intake further increased the risk of diabetes (RR=2.50, 95% CI, 1.14-5.51) when compared with a low glycemic load and high cereal fiber intake.Conclusions. —Our results support the hypothesis that diets with a high glycemic load and a low cereal fiber content increase risk of diabetes in women. Further, they suggest that grains should be consumed in a minimally refined form to reduce the incidence of diabetes.
Article
Adding large amounts of fat to carbohydrate reduces glycaemic responses, but the effect of varying fat across the normal range of intakes has not been studied. To test the hypothesis that fat would reduce glycaemic responses in a non-linear fashion, 12 overnight-fasted healthy subjects were studied on 5 separate days after consuming 50g available carbohydrate (white bread) plus 0, 5, 10, 20, or 40g fat (non-hydrogenated-fat margarine). Blood glucose peak rise (PR) and incremental area under the curve (iAUC) were reduced after 40g fat by 38 and 30%, respectively (p < 0.05). However, more than half these effects were seen after 5g fat. Grams fat correlated with both PR (r2 = 0.158, n = 60, p = 0.002) and iAUC (r2 = 0.080, p = 0.028), but an exponential model resulted in a better fit for iAUC (r2 = 0.084, p = 0.025) and a significantly better fit for PR (r2 = 0.244, p < 0.001). Thus, the results support the hypothesis that fat reduces glycaemic responses in a dose-dependent, but non-linear fashion. Variation of fat intake across the normal range of intakes (17–44% energy) did not significantly affect glycaemic responses.
Article
The formation of resistant starch (RS) in bread products was evaluated in vitro in relation to the processing conditions. The impact of the particular baking conditions applied to pumpernickel bread was investigated as well as the presence of malt and sourdough acids, commonly present in such bread. Also studied was the potential effect of including wholemeal barley from a high-amylose genotype. In some bread, the rate of hydrolysis of the potentially available starch fraction was evaluated by an in vitro procedure. A low-temperature, long-time baked product (20 h at 120 °C) contained significantly higher amounts of RS (5.4%, starch basis) than a corresponding ordinary baked bread (40min at 200 °C) (3.0%, starch basis). Addition of lactic acid increased RS recovery further (6.6% starch basis), whereas malt had no impact on RS yield. The highest level of RS was noted in a long-time baked bread based on high-amylose barley flour (7.7%, starch basis). In contrast to all other products, this bread also displayed a lowered rate of amylolysis of the non-RS fraction (hydrolysis rate index = 68). It is concluded that exchanging ordinary baking conditions for pumpernickel baking, particularly in the presence of certain organic acids, may substantially increase the RS content.
Article
The possible improvement of the nutritional properties of starch in barley flour-based bread by using barley genotypes varying in amylose content (3–44%) was evaluated. Breads were made from 70% whole-meal barley flour and 30% white wheat flour. Test breads were baked from waxy barley (WB), ordinary barley (OB), ordinary Glacier barley (OGB) and high-amylose barley (HAB). Each bread was baked either at conventional baking conditions (45 min, 200 °C) or at pumpernickel conditions (20 h, 120 °C). A white wheat bread (WWB) was used as reference. The resistant starch (RS) content and rate of starch hydrolysis were measuredin vitro. The glycaemic index (GI) and the insulinaemic index (II) of the high-amylose breads were determined in healthy subjects. The amount of RS (total starch basis) varied from <1% (WB) to approximately 4% (HAB) in conventionally baked bread, and from about 2% to 10% in the corresponding long-time/low-temperature baked products. The long-time/low-temperature baked HAB displayed a significantly lower rate of starch hydrolysisin vitrocompared with WWB and reduced the incremental blood-glucose response in healthy subjects (GI=71). In contrast, the GI of the conventionally baked HAB was similar to that for WWB. It is concluded that a barley flour-based bread of low GI and high RS content can be obtained by choosing high-amylose barley and appropriate baking conditions.
Article
It has been observed that bread containing lactic acid produced during the sourdough fermentation or added directly, has the ability to lower the postprandial glucose and insulin responses in humans. The main objective of the present work was to evaluate the possible mechanisms for a lowered glucose response to bread containing lactic acid, and to determine whether the same phenomenon also occurs when lactic acid is added to other cereal products. The rate of starch hydrolysis in bread and bread-like products was studied using an in vitro enzymatic approach. In addition, blood glucose and insulin responses to different lactic acid fermented barley gruels were evaluated in healthy subjects. It was concluded that the inclusion of lactic acid in bread reduces the rate of starch digestion by creating interactions between the gluten and starch. The presence of lactic acid during starch gelatinisation appeared to be a prerequisite for a reduced starch bioavailability. No effect of lactic acid was seen in gruels where the acid was formed after heat-treatment.
Article
Test meals of 300 ml. of six different organic acids were instilled into the stomach of six healthy mongrel dogs. Citric, acetic, propionic, lactic, tartaric and succinic acid were given in 50, 100, 150, and 200 mN concentrations. 2. During the emptying process, the gastric contents were aspirated and immediately re-instilled at 10 min intervals, and the following parameters were recorded: volume, concentration of the organic anion, pH, hydrogen ion concentration and osmolarity. 3. By multiple stepwise regression analysis, the combination of parameters which most effectively determines gastric emptying rate was found to be: concentration of the organic anion, followed by intragastric volume and number of previous test meals given on the same day. These three parameters appear in the equation for gastric emptying rate in which the individual characteristic of each acid is expressed by a constant. 4. Among the various acids, inhibition of emptying rate increases with rising number of carboxylic groups of the acid and its molecular weight. 5. After proximal gastric vagotomy, emptying rate of organic acids is independent of volume, and emptying approaches an exponential pattern. 6. A model for gastric emptying of organic acids with at least three different receptors is proposed: one for the structure of the organic acid, one for concentration and one for intragastric volume.