Are there any common supplements that can alone or in combination with other supplements increase one's Hemoglobin A1c (HbA1c) values?

Supplements That May Increase HbA1c Values

No common supplements have been definitively proven to increase HbA1c values, but certain supplements may mask abnormal glucose levels or interfere with HbA1c testing, potentially affecting diabetes diagnosis and management.

Supplements That May Affect Glucose Control and HbA1c

Supplements That May Lower HbA1c (Potentially Masking True Values)

1. Cinnamon

   • May subtly improve glycemic control in some patients
   • In one small study, 2g daily for 12 days showed reduction in HbA1c from 8.22% to 7.86% compared to placebo 1
   • However, meta-analyses show inconsistent results with no significant changes in HbA1c or fasting blood glucose in many studies 1

2. Chromium

   • Has shown beneficial effects on glycemia in some populations, particularly those with marginal baseline chromium status 1
   • Two randomized, placebo-controlled studies in Chinese diabetic subjects showed improvements in glycemic control 1
   • Dosage and formulation significantly influence outcomes 1

3. American Ginseng

   • One of the best-studied herbal supplements for diabetes 1
   • Has shown modest short-term beneficial effects on glycemia 2

Factors That May Artificially Affect HbA1c Measurements

1. Vitamin B12 Deficiency

   • Long-term metformin users may develop vitamin B12 deficiency 1
   • B12 deficiency can affect red blood cell production and potentially influence HbA1c values 1

2. Iron Supplementation

   • Iron supplementation can lead to a modest fall of 0.5-0.7% in HbA1c along with a rise in total hemoglobin in patients with advanced CKD 1
   • This effect is likely due to the formation of new red cells and alterations in hemoglobin glycation rates 1

3. Erythropoietin Administration

   • Similar to iron, can affect HbA1c by altering red blood cell production 1

Clinical Implications and Recommendations

Assessment of HbA1c Accuracy

• HbA1c measurements may be inaccurate in certain conditions:

  • Reduced red blood cell lifespan
  • Recent blood transfusions
  • Hemolysis
  • Carbamylation of hemoglobin
  • Acidosis 1

• When HbA1c values are unexpectedly low:

  • Review patient's supplement use, particularly cinnamon, chromium, and ginseng
  • Consider screening for conditions that might artificially lower HbA1c, such as anemia or hemoglobinopathies 3
  • Review blood glucose logs or CGM data to correlate with HbA1c values 3

Recommendations for Supplement Use

• The American Diabetes Association states: "There is no clear evidence of benefit from vitamin or mineral supplementation in people with diabetes who do not have underlying deficiencies." 1
• Routine supplementation with antioxidants such as vitamins E and C and carotene is not advised due to lack of efficacy evidence and concerns about long-term safety 1
• Patients should be advised that dietary supplements are not subject to the same manufacturing regulatory standards as approved medications 1

Clinical Monitoring

• For patients taking supplements that may affect glucose control:
  • Monitor HbA1c more frequently
  • Consider using alternative measures of glycemic control such as fructosamine or glycated albumin in certain cases 1
  • Consider asking patients to temporarily discontinue supplements before diagnostic testing for diabetes 1

Common Pitfalls

• Assuming "natural" products are always safe and effective 4
• Failing to ask patients about supplement use during medication reconciliation
• Overlooking potential supplement-drug interactions
• Relying solely on HbA1c without considering factors that may influence its accuracy
• Not recognizing that supplements may mask underlying diabetes or prediabetes, potentially delaying proper diagnosis and treatment 1

While many supplements claim to improve glycemic control, the evidence for most is limited, inconsistent, or of poor quality 2. Healthcare providers should maintain open communication with patients about supplement use and emphasize the importance of proven medical therapies for diabetes management.