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HbA1c

HbA1c (Glycated hemoglobin) is a biomarker of glucose metabolism, and higher HbA1c is associated with more disease progression and comorbidities in states of insulin resistance or diabetes.

Research analysis led by Kamal Patel.
All content reviewed by the Examine.com Team. Published: Jul 5, 2013
Last Updated:

Human Effect Matrix

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what supplements affect hba1c
Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-a - Very High See all 18 studies
Although sporadic evidence suggest improvements in HbA1c in diabetics, the entirety of the evidence does not support a reliable and significant improvement in diabetic persons.
grade-a - Moderate See all 10 studies
Although the majority of evidence suggests absolutely no influence on HbA1c, reductions have been reported and a lone case has noted a clinically irrelevant increase of HbA1c (secondary to the increase in glucose). Practically, there is unlikely to be any large changes
grade-b Strong Very High See all 3 studies
The reduction of HbA1c associated with berberine, according to a meta-analysis of diabetics using 1,000-1,500mg berberine daily, was −0.72% (95% CI −0.97 to −0.47) more than placebo. This reduction appears to be one of the more significant reductions associated with dietary supplements.
grade-b Minor Low See all 3 studies
There may be an effect on HbA1c, but it appears unreliable and not overly potent.
grade-b Minor Low See all 3 studies
More evidence than not suggest no significant effect on HbA1c levels, but one study suggests a decent decrease with the other two studies trending towards a decrease. There may be a role for magnesium in reducing HbA1c levels to a minor degree
grade-b Minor Very High See 2 studies
Reduction seen in HbA1c was not overly remarkable
grade-b - Very High See all 3 studies
No significant reduction (or increase) in HbA1c levels following CLA supplementation
grade-b - Very High See all 10 studies
No significant influence of Vitamin C supplementation on HbA1c levels
grade-c Notable Very High See 2 studies
Preliminary evidence in diabetics suggest potent HbA1c reducing effects (6g of the root reducing HbA1c by 2% over a few months)
grade-c Notable Moderate See 2 studies
Lone study noted a decrease from 9% to 8% with 2g spirulina, which is somewhat notable but requires more evidence to establish this.
grade-c Minor Moderate See all 3 studies
There appears to be a slight reducing effect on HbA1c
grade-c Minor - See study
May be able to mildly decrease HbA1c, although the research supporting this claim is very preliminary at this time.
grade-c Minor - See study
A minor decrease in HbA1c has been noted with olive leaf consumption
grade-c Minor Moderate See 2 studies
A possible reduction in HbA1c, but small in magnitude and unreliably seen
grade-c Minor - See study
A decrease in HbA1c has been noted in diabetics given a tea of Salacia for months, but the decrease was minor in magnitude and outperformed by Glibenclamide
grade-c - Very High See 2 studies
No significant influence on HbA1c concentrations in persons with impaired glucose tolerance, even when endothelial function is improved
grade-c - - See 2 studies
grade-c - Very High See 2 studies
Two studies in diabetics have failed to find an influence of benfotiamine on HbA1c
grade-c - - See study
HbA1c does not appear to be altered in response to cocoa flavanol ingestion.
grade-c - Moderate See all 11 studies
Some studies have found reductions but, even in type 2 diabetics, evidence is inconsistent.
grade-c - - See study
Alongside a failure to improve insulin sensitivity or to reduce glucose was a failure to reduce HbA1c concentrations in the plasma of those with metabolic syndrome given 500mg hesperidin.
grade-c - - See 2 studies
grade-c - - See study
No significant changes in HbA1c seen with supplementation of red clover in diabetics.
grade-c - - See study
No significant influence of rose hip on HbA1c concentrations in the blood of non-diabetic yet obese persons relative to placebo
grade-c - - See study
No significant alterations in HbA1c levels following Royal Jelly ingestion for 6 months
grade-c - - See study
No significant influence on HbA1c serum levels has been detected
grade-c - Very High See 2 studies
The decrease in HbA1c is statistically insignificant and very small in magnitude, likely not a concern.
grade-c - Very High See 2 studies
HbA1c does not appear to be influenced in type II diabetics given supplementation of vitamin E.
grade-d Notable - See study
The decrease in HbA1c noted in this pilot study (15.6%) was fairly marked and requires replication.
grade-d Minor - See study
Requires more studies before conclusions can be made, appears to simply be exerting anti-oxidant effects.
grade-d Minor - See study
The reduction of HbA1c noted is minor, from 7.8% down to 7.4% with 90 days supplementation of the leaf extracts
grade-d Minor - See study
A mild decrease in HbA1c has been noted in diabetics given the seeds as an adjuvant to standard therapy
grade-d Minor - See study
A slight decrease in HbA1c has been noted with safflower despite no alterations in any other diabetic biomarker
grade-d Minor - See study
One randomized, controlled trial found a modest reduction, accompanied by reduced fasting and postprandial glucose levels.
grade-d Minor Very High See 2 studies
A decrease in HbA1c has been noted with vanadium supplementation
grade-d Minor - See study
A decrease in HbA1c levels has been detected in type II diabetics consuming Mate tea, although not to a remarkable degree
grade-d - - See study
Currently no studies noting changes in HbA1c, as it appears to be unaffected by supplementation.
grade-d - - See study
grade-d - - See study
No significant influence on HbA1c levels of diabetics given chia seeds
grade-d - - See study
No significant influence of sulbutiamine on HbA1c
grade-d - Very High See 2 studies
No significant alterations in HbA1c concentrations