From Food to Infertility: Disruption of the Male Reproductive Axis by Wheat Lectin in Rats

Wheat germ agglutinin at 250 mg/kg/day impaired sperm quality, cut testosterone, and damaged testicular tissue in prepubertal rats across 2–10 weeks

Journal: Reproductive Biology | Published: 2026-02-27 | Type: Animal study | PMID: 41762765 Authors: Okoko IE, Iwalokun BA, Duru FI, Osinubi AA, Ebuehi OA, Akang EN — University of Lagos and Nigeria Institute of Medical Research Funding/COI: Funding not disclosed; authors declare no competing interests

Summary

Wheat germ agglutinin (WGA), an anti-nutritional lectin in wheat, disrupted the hypothalamic-pituitary-gonadal axis and damaged testicular tissue in prepubertal male rats at all three assessed timepoints. Both pure WGA and a common wheat lectin extract (250 mg/kg/day, oral) reduced testosterone, elevated gonadotropins, oxidized testicular tissue, and degraded sperm across 2, 5, and 10 weeks of daily dosing. The study offers a plausible oxidative stress mechanism but uses a dose with no dietary analog.

Claims

• Testicular antioxidants — superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) — were significantly reduced (p < 0.05) in lectin-treated vs. control rats
• Serum and intratesticular testosterone decreased in both treatment groups
• LH, FSH, and prolactin were elevated, consistent with primary testicular dysfunction triggering feedback upregulation
• Malondialdehyde (MDA), a lipid peroxidation marker, was elevated — indicating oxidative stress as the likely mediator
• Sperm concentration, motility, and morphology were all significantly impaired
• Histology revealed seminiferous germinal epithelium damage, interstitial expansion consistent with edema, and basement membrane disintegration
• Damage was detectable at 2 weeks and progressed through 10 weeks

Study Quality

Forty-five prepubertal Sprague-Dawley rats (30 days old, 40–50 g) were randomized into three duration cohorts (2, 5, 10 weeks), each split into control, pure WGA, and wheat lectin extract groups — giving n=5 per group, which is barely enough to run statistics. The multi-timepoint design is a genuine strength, as it shows temporal progression rather than a single snapshot. Testing two lectin preparations (pure vs. extract) adds some construct validity, though it also complicates interpretation — the extract contains additional wheat components that could confound attribution.

The dose of 250 mg/kg/day is a pharmacological exposure, not a dietary one; no attempt is made to model what a realistic dietary intake would produce. The exclusive use of prepubertal animals is also a limitation: the developing reproductive axis may be substantially more sensitive than that of sexually mature males, making extrapolation to adult humans even more speculative. No dose-response curve is presented.

Red Flags

• n=5 per group — statistical significance in groups this small should be treated with skepticism; any single outlier rat can determine the result
• Dose has no dietary analog: 250 mg/kg/day is an experimental pharmacological dose; a 70 kg human equivalent would be 17.5 g of purified lectin daily, far beyond any realistic wheat consumption scenario
• Funding not disclosed — cannot assess independence
• Prepubertal animals only — developmental sensitivity likely exaggerates effects vs. sexually mature males; no adult comparator group
• Pure WGA vs. extract effects are not cleanly separated — extract results may reflect other wheat constituents
• No washout or reversibility data — unclear whether damage is reversible after cessation
• No mechanistic dose-response — it is unknown whether lower, more physiologically relevant doses produce any effect

Strengths

• Multiple timepoints reveal temporal progression of harm, not just a single endpoint
• Parallel biochemical and histological assessment provides convergent evidence
• Testing two lectin preparations increases construct validity modestly
• Oxidative stress mechanism is biologically plausible and internally consistent across endpoints
• Authors are transparent about limitations and explicitly caution against over-interpreting results

Verdict

Five rats per group cannot carry the weight the authors ask of this data. The dose is pharmacological, the animals are prepubertal, and the jump to human dietary relevance is enormous and unsupported by anything in the paper. What this study does offer is a mechanistic hypothesis — WGA → oxidative stress → testicular dysfunction — that is biologically coherent and worth exploring with better-powered, dose-calibrated, and adult-animal designs. As a proof-of-concept, it earns attention; as evidence that wheat harms male fertility, it earns none.