High fructose corn syrup and rat testis damage
What it found
In rats, long-term high fructose corn syrup in drinking water was linked to oxidative stress and lower sperm counts in the testis.
Melatonin treatment reduced some of these changes.
What they found
Animal and lab studies
Body and organ weights
Body weights rose significantly in both the syrup and syrup plus melatonin groups compared with controls. Right and left epididymis weights were significantly lower in the syrup plus melatonin group than in the control and syrup groups.
Oxidative stress markers
In the syrup group, MDA levels in the testis were significantly higher and SOD and CAT activities were significantly lower than in controls. Melatonin significantly raised SOD and CAT activities compared with the syrup group.
Sperm count and testis score
Sperm count and Johnsen's testicular biopsy score were significantly lower in the syrup group than in controls. Melatonin increased sperm count compared with the syrup group, but the score difference was not significant.
Testosterone levels
Total testosterone levels were not statistically different between the groups. The largest drop was seen in the syrup plus melatonin group.
Tissue changes
Testes from the syrup group showed slight hyperaemia and oedema in the stromal tissue, and slight to moderate degeneration. Melatonin improved these tissue findings.
Protein markers
HSP, iNOS, MDA, OPN and VEGF values were significantly increased in the syrup group. Melatonin reduced these increases.
What the authors conclude
“Our results showed that a long-term intake of HFCS caused testicular damage.”
Also in their conclusions
- They conclude that long-term intake of high fructose corn syrup caused testicular damage in rats.
- They say melatonin may be a promising pharmacological agent against testicular toxicity induced by high fructose corn syrup.
- They advise that the protective effects of melatonin on high fructose corn syrup induced damage should be extensively investigated in future studies.
How it was done
The authors wanted to see whether long-term high fructose corn syrup intake harms the male reproductive system, and whether melatonin could protect the testis.
Thirty-six male Sprague Dawley rats were split into three groups: control, high fructose corn syrup, and high fructose corn syrup plus melatonin. The syrup group drank a 20% fructose solution for 10 weeks, and the melatonin group also received melatonin (10 mg/kg per day) by gavage for the last 6 weeks.
What it can’t tell you
- These are animal studies. They can't show what happens in people.
- The study cannot prove that high fructose corn syrup causes the same effects in humans.
- It also cannot show whether melatonin would protect human testes.
Who paid
- Authors work at
- Suleyman Demirel University, Turkey; Mehmet Akif Ersoy University, Turkey
The paper
- Title
- The effects of high-fructose corn syrup consumption on testis physiopathology-The ameliorative role of melatonin
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Full text
- Cite
- Aslankoc R, Ozmen O (2019). The effects of high-fructose corn syrup consumption on testis physiopathology-The ameliorative role of melatonin. Andrologia. doi:10.1111/and.13327Free full textPubMed 31168831DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error