Zinc status following different bariatric procedures: systematic review and meta-analysis.

In 30 seconds

This systematic review and meta-analysis examined changes in serum zinc after bariatric surgery in people with obesity. Twelve studies involving 2,529 participants were included. Compared with baseline, pooled zinc levels fell significantly at 6 months (SMD -0.36, 95% CI: -0.58 to -0.14) and 1 year (SMD -0.35, 95% CI: -0.53 to -0.16), but not at 3 months or 2 years. Subgroup analyses found significant decreases at 6 and 12 months after Roux-en-Y gastric bypass and mini-gastric bypass, but not sleeve gastrectomy; evidence certainty was rated moderate.

Key findings

• At 6 months, serum zinc decreased from baseline (SMD -0.36, 95% CI: -0.58 to -0.14; p = 0.001).
• At 1 year, serum zinc decreased from baseline (SMD -0.35, 95% CI: -0.53 to -0.16; p = 0.001).
• Subgroup analyses found significant decreases at 6 and 12 months after RYGB and MGB, but not after sleeve gastrectomy.
• No significant pooled change was found at 3 months or 2 years.

Why it matters

Serum zinc may decline during the first postoperative year, with the pattern varying by procedure. Recognising this potential micronutrient change can inform postoperative nutritional assessment and help clinicians consider deficiency risk alongside other aspects of bariatric follow-up.

What to keep in mind

The pooled analyses showed substantial heterogeneity at 6 months, 1 year, and 2 years, limiting the consistency of estimates across studies.