Effect of selenium supplementation on changes in HbA1c: Results from a multiple-dose, randomized controlled trial

Area of Science:

• Nutritional Biochemistry
• Clinical Nutrition
• Gerontology

Background:

• Low selenium status is prevalent in certain elderly populations.
• Selenium plays a crucial role in various metabolic processes, including glucose regulation.
• Understanding the impact of selenium supplementation on glycemic control is important for public health.

Purpose of the Study:

• To evaluate the effect of varying doses of selenium supplementation on HbA1c levels.
• To assess changes in HbA1c after 6 months and 2 years in individuals with low selenium status.
• To explore the dose-response relationship of selenium supplementation on glycemic control.

Main Methods:

• A randomized, double-blind, placebo-controlled trial (Denmark PRECISE study) involving 491 participants aged 60-74 years.
• Participants received 100, 200, or 300 μg/day of selenium as yeast or placebo-yeast.
• HbA1c levels were measured at baseline, 6 months, and 2 years; intention-to-treat analyses were performed.

Main Results:

• After 6 months, a modest decrease in HbA1c was observed with 100 μg/day selenium, but not with higher doses, compared to placebo.
• After 2 years, HbA1c levels decreased significantly across all selenium treatment groups, with no significant difference compared to placebo.
• No significant dose-dependent effect of selenium supplementation on HbA1c was observed over the 2-year period.

Conclusions:

• Selenium supplementation did not significantly impact HbA1c levels in elderly Europeans with low selenium status after two years.
• The results support a potential U-shaped relationship between selenium supplementation and glucose metabolism.
• Further research is needed to elucidate the complex role of selenium in glucose homeostasis.