LA Endocrine Blog

Efficacy of vitamin D supplementation on glycemic control in type 2 diabetes: An updated systematic review and meta-analysis of randomized controlled trials

Recent literature and case reports have highlighted a notable association between Vitamin D Supplementation and Blood Glucose Control Key points include:

• Study Overview:
  • The study enrolled 39 randomized controlled trials (RCTs) to evaluate the efficacy of vitamin D supplementation on glycaemic control in T2D patients.
  • Significant improvements were observed in serum 25(OH)D levels, fasting blood glucose (FBG), HbA1c, HOMA-IR, and fasting insulin levels.
• Mechanisms of Action:
  • Vitamin D regulates insulin synthesis and secretion by binding to the vitamin D receptor (VDR), enhancing glucose transport and insulin secretion.
  • It may improve glucose metabolism through effects on intracellular calcium and anti-inflammatory properties.
• Baseline Vitamin D and BMI:
  • Vitamin D supplementation was more effective in T2D patients with vitamin D deficiency.
  • An inverse relationship was noted between body weight and serum 25(OH)D levels, with lower baseline vitamin D levels in obese individuals.
• Dosage and Duration Insights:
  • Daily doses higher than 2000 IU showed marked improvements in glycaemic control.
  • Short-term supplementation (average dose 4700 IU/d) was effective in reducing FBG, HbA1c, and HOMA-IR.
  • Long-term interventions showed greater improvements in fasting insulin, suggesting delayed benefits in β-cell function.
• Clinical Implications:
  • Supports vitamin D as a potential adjunctive treatment for improving glycaemic control in T2D.
  • Highlights the importance of considering dosage and duration for optimal benefits.
• Additional Observations:
  • Vitamin D supplementation led to significant reductions in C-reactive protein (CRP) and triglyceride (TG) levels, indicating reduced systemic inflammation.

Citation:

Chen, & Liu. (2024). Efficacy of vitamin D supplementation on glycaemic control in type 2 diabetes: An updated systematic review and meta-analysis of randomized controlled trials. Diabetes, Obesity, and Metabolism Journal of Pharmacology and Therapeutics. https://doi.org/10.1111/dom.15941 

COVID-19 and Autoimmune Thyroid

Recent literature and case reports have highlighted a notable association between COVID-19 and the exacerbation of thyroid conditions. Key points include:

1. Thyroid Dysfunction: COVID-19 has been linked to various thyroid dysfunctions, including hypothyroidism, exacerbation of underlying autoimmune thyroid diseases, and both clinical and subclinical hyperthyroidism.
2. Autoimmune Thyroid Disorders: There have been several cases where COVID-19 has triggered or worsened autoimmune thyroid conditions such as Graves' disease. This includes instances of Graves' disease exacerbation and even impending thyroid storm post-COVID-19 infection.
3. Post-Vaccination Effects: Some reports suggest that mRNA COVID-19 vaccination can lead to the exacerbation of subclinical hyperthyroidism and other thyroid-related issues, although these cases appear to be less common.
4. Long-term Implications: Postacute COVID-19 syndrome, also known as long COVID, has been associated with persistent thyroid dysfunction in some patients, necessitating ongoing monitoring and management.
5. Autoimmune Risk: COVID-19 has been associated with an increased risk of developing autoimmune diseases, including those affecting the thyroid. However, vaccination appears to mitigate some of these risks.

Clinicians should be vigilant in monitoring thyroid function in patients with a history of COVID-19, especially those with pre-existing thyroid conditions or autoimmune disorders. Regular thyroid function tests and appropriate management strategies should be considered to address any exacerbations promptly.

Citation:

Sebastian, W. P., Parisa, A., Pandya, M., & Anees, A. (2024). Graves' Disease Exacerbation with Impending Thyroid Storm After SARS-CoV-2 Infection: A Case Report. The American journal of case reports, 25, e941311. https://doi.org/10.12659/AJCR.941311

Brazilian Nuts

Brazil nuts, due to their high selenium content, can be beneficial for both hyperthyroid and hypothyroid conditions, but their use and effects differ based on the specific thyroid disorder. Brazil nuts are a rich source of selenium, an essential micronutrient that plays a critical role in thyroid function. Selenium is a key component of enzymes involved in the synthesis and metabolism of thyroid hormones. Adequate selenium levels are necessary for the conversion of thyroxine (T4) to the more active triiodothyronine (T3), and for the protection of the thyroid gland from oxidative damage.

In clinical practice, recommending a moderate intake of Brazil nuts can be beneficial for patients with selenium deficiency or those needing support for thyroid health. However, it's important to monitor selenium levels, as excessive intake can lead to toxicity. Generally, one to three Brazil nuts per day can provide sufficient selenium without the risk of over-consumption.

• Dosage: Typically, one to two Brazil nuts per day can provide an adequate amount of selenium without risking toxicity.
• Monitoring: Regular monitoring of selenium levels and thyroid function tests is recommended to avoid over-supplementation and to tailor the approach based on individual patient needs.

In summary, while Brazil nuts can be beneficial for both hyperthyroid and hypothyroid conditions, their use should be carefully monitored and tailored to the specific needs of the patient.

Citation:

Barcza Stockler-Pinto, M., Carrero, J. J., De Carvalho Cardoso Weide,  L., Franciscato Cozzolino, S. M., & Mafra, D. (2015). EFFECT OF  SELENIUM SUPPLEMENTATION VIA BRAZIL NUT (BERTHOLLETIA EXCELSA, HBK) ON  THYROID HORMONES LEVELS IN HEMODIALYSIS PATIENTS: A PILOT STUDY. Nutricion hospitalaria, 32(4), 1808–1812. https://doi.org/10.3305/nh.2015.32.4.9384