Reproductive Endocrinology · Thyroid and Metabolic Function
RRM Academy Synopsis
Women with PCOS had lower blood zinc than women without PCOS
Women with PCOS had lower blood zinc levels than women without PCOS. This comparison in India included 50 women per group, matched for body mass index (BMI). Zinc was also lower when fasting insulin was higher, in both groups. PCOS, now renamed polyendocrine metabolic ovarian syndrome (PMOS), was diagnosed by Rotterdam criteria.
Key Findings
- Serum zinc was lower in the 50 women with PCOS than in the 50 women without PCOS (P = 0.012).
- Five of the 50 women with PCOS (10%) had serum zinc below the study's deficiency cutoff. No woman without PCOS fell below it.
- Fasting insulin was higher in the PCOS group than in the non-PCOS group (P = 0.001).
- Higher fasting insulin went with lower zinc in women with PCOS (r = −0.332, P = 0.019). Women without PCOS showed the same direction.
- Higher BMI went with lower zinc too: r = −0.378 (P = 0.007) with PCOS, and r = −0.7452 without.
Interpretation
The study compared two groups at one point in time, with blood drawn on days 2 to 5 of the cycle. The result is an association. The design cannot show that low zinc contributes to PCOS or that supplements change insulin. The women were aged 18 to 35, and the comparison group came from an outpatient clinic for minor ailments. Serum zinc may not reflect zinc inside cells, and the authors could not measure that. The zinc and insulin link appeared in both groups. The authors call for larger studies.
RRM Context
Restorative reproductive medicine asks what drives PCOS in each woman, and insulin resistance is a central candidate. This paper adds a nutrient marker that tracked with insulin levels in the same women. The authors propose a follow-up study of zinc supplements with diet and weight loss.
Abstract
Background
Zinc is an essential micronutrient, a vital stabiliser and a cofactor in many enzymes such as superoxide dismutase and phospholipase C and also acts as an antioxidant by protecting the sulfhydryl groups of different proteins and enzymes against free radicals. It is unclear if serum zinc levels are correlated with polycystic ovary syndrome (PCOS) and its pathophysiology, although relation between diabetes and insulin resistance has been established.
Aims
This study aimed to investigate circulating serum zinc levels in PCOS subjects compared with non-PCOS subjects.
Design and Setting
In this cohort study, PCOS subjects were compared with normal subjects aged between 18 and 35.
Materials and Methods
All the included subjects underwent measurement of anthropometric parameters, fasting insulin, luteinising hormone, follicle-stimulating hormone, thyroid-stimulating hormone, prolactin, progesterone, oestrogen and serum zinc levels. These values were taken on days 2-5 of the menstrual cycle.
Statistical Analysis
Univariate analysis and linear regression were performed for serum zinc levels and fasting insulin levels in PCOS subjects and non-PCOS subjects using SPSS (version 21) and Microsoft Excel (2019).
Results
Serum zinc levels in the PCOS group were lower than in the control group (P = 0.012). Fasting insulin levels in the PCOS group were higher than in non-PCOS subjects (P = 0.001). We found a negative correlation between zinc and fasting insulin (r = -0.580, P < 0.0001) in the normal group and (r = -0.332, P = 0.019) in the PCOS group. A positive correlation was found between body mass index (BMI) and fasting insulin levels in both the PCOS group (r = 0.227, P = 0.112) and normals (r = 0.612, P < 0.0001). A negative statistically significant correlation between BMI and zinc in both the PCOS group (r = -0.378, P = 0.007) and the non-PCOS group (r = -0.7452, P < 0.0001) was seen.
Conclusion
The data suggest that serum zinc levels were found to be lower in PCOS subjects as compared to normal controls and evaluation of these levels may indicate that zinc has a vital role in PCOS pathophysiology.
Topics
Keywords
Fasting insulin, polycystic ovarian syndrome, serum zinc
