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The Study

Effect of marginal or severe dietary zinc deficiency on testicular development and functions of the rat.

In simple terms

This study looked at what happens to rat testicles when they don't get enough zinc in their food. It found that their hormones changed and their sperm production dropped, but it didn't prove that zinc deficiency caused those changes — maybe something else did.

11%

Analysis score

11/ 72

Maximum 72 for a cohort study.

Where the score came from

Reporting0
Methodology31
Publication100
Statistical23
Study type (basis of the score)
Cohort Study
Level 2b - Individual cohort study
What’s the bottom line?

Rats that didn't get enough zinc in their food had much lower hormone levels and fewer sperm.

Where does this study sit?

Reviews of RCTs (Meta-analyses)

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Cohort Studies
Level 2b
11

11 / 100

Quality score

Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.

Cannot establish causation

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Key takeaways

Summary

Based on the study abstract and findings.

  1. 1This suggests zinc is critical for making testosterone and sperm, and even a small lack can seriously hurt male reproductive function.
  2. 2Severe zinc deficiency: testosterone dropped 17.8x, no sperm.
  3. 3Marginal deficiency: testosterone down 62.6%, hCG-stimulated hormones down 72.4%, sperm count down 22.9%.

Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data

Publication

Journal

Archives of andrology

Year

1997

Authors

S. Hamdi, O. I. Nassif, M. Ardawi

89 citations
Analysis v5
Fit Body Science verdict — we translate health studies into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.