Review for 10.1186/1471-230X-7-46 (2007)

Reviewer's report
Title:Effect of apple cider vinegar on delayed gastric emptying in people with
type 1 diabetes mellitus
Version: 3Date:22 September 2007
Reviewer: Per M Hellström
Reviewer's report:
General
This is a nice but small study in humans. The presentation is really ultrashort and
there are some logic shortcomings that are difficult to get around. As it stands
right now, the MS is a description, no analysis. In order to make this intellectual
enough I would favour some comparison. Most of all comparisons should be
made to diabetics with normal gastric emptying, other wise it would be nice to
compare to prediabetic obese people, or evben try alkaline conditions in order to
evaluate if the reverse mechanisms apply. Finally a calculation of the contribution
of vinegar to the acidic milileu in the stomach should be of value. The reviewer is
interested to know whether gastroparesis includes also a stomach with no acid
production and neutral pH. under such circumstances 30 ml vinegar might have
some effect of pH, if full acid production, vinegar does nothing to pH. In other
words, was is the mechanism that brings about a change in gastric emptying.
Most ölikely acid since it is a well-known inhibitor of acid secretion and emptying
known from basic textbooks.
There is a logic mis interpretation of the MS. The measurements made obviously
do not measure gastric emptying of contents, but rather mural gastric dynamics,
which is another thing. On top of that comes the fact that at 15 min there is a
gastric receptive relaxation of the fundus (which might effect the antrum), which
is not present at 90 min. In short, there are two different mechanisms in operation
at the two different times when measurements were made. That makes
interpretation very difficult. Are we talking about a relaxation of the antrum or
contraction of the fundus? This is difficult to rule out without a spect analysis of
the stomach, or possibly a normal gastric emptying test in order to study the true
emptying process. I do regret that blood sugar was not measured along with the
emptying process. Even blood sugar may give a faint idea of the emptying
process, but would also say something about the metabolic homeostasis. Finally,
as the differences are rather small, it woulkd be an option to study the same
patients over again with greater vinegar load, just to validate the presented data
with a dose-response relationship.
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Major Compulsory Revisions (that the author must respond to before a decision
on publication can be reached)
More data needed: 1. Dose-response, 2. Other type of acid, 3.
Non-gastroparetics.
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Minor Essential Revisions (such as missing labels on figures, or the wrong use of
a term, which the author can be trusted to correct)
The MS is well written. More than one figure needed.
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Discretionary Revisions (which the author can choose to ignore)
None.
What next?: Reject because too small an advance to publish
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Acceptable
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests.