High Doses of Vitamin D and Vitamin C and Their Effect on Thyroid Hormones and Body Mass in Male Domestic Rabbits

Vitamin D is essential for the normal functioning of many organs, including the thyroid gland. Therefore, vitamin D deficiency is a risk factor for many thyroid disorders, as well as autoimmune thyroid diseases and thyroid cancer. Many doctors recommend vitamin D supplementation to prevent these diseases. However, some people overuse it without considering its potential toxicity. For this reason, this study used male rabbits to investigate the effects of different doses of vitamin D3 on thyroid hormones. Male rabbits were injected with vitamin D3 for three months at doses of 200,000, 400,000, 600,000, and 800,000 IU monthly. The rabbits were then divided into five groups. The first group was a control group, while the second and third groups were injected with different doses of vitamin D only, while the third and fourth groups were injected with different doses of vitamin D + vitamin C (1000 mg). The results of this study showed a significant increase in the levels of thyroid hormones (T3 and T4) in the first and second groups only. With a change in body mass without any statistical significance.