Vitamin D Fortification and Its Effect on Athletes' Physical Improvement: A Mini Review

Vitamin D in Melanoma: Potential Role of Cytochrome P450 Enzymes

Vitamin D is a promising anticancer agent for the prevention and treatment of several cancers, including melanoma. Low 25-hydroxyvitamin D levels, a routinely used marker for vitamin D, have been suggested as one of the factors in the development and progression of melanoma. The parent vitamin D needs activation by cytochrome P450 (CYP) enzymes to exert its actions via the vitamin D receptor (VDR). This review discusses the role of vitamin D in melanoma and how CYP-mediated metabolism can potentially affect the actions of vitamin D. Through interacting with the retinoid X receptor, VDR signaling leads to anti-inflammatory, antioxidative, and anticancer actions. Calcitriol, the dihydroxylated form of vitamin D3, is the most active and potent ligand of VDR. CYP27A1, CYP27B1, and CYP2R1 are involved in the activation of vitamin D, whereas CYP24A1 and CYP3A4 are responsible for the degradation of the active vitamin D. CYP24A1, the primary catabolic enzyme of calcitriol, is overexpressed in melanoma tissues and cells. Several drug classes and natural health products can modulate vitamin D-related CYP enzymes and eventually cause lower levels of vitamin D and its active metabolites in tissues. Although the role of vitamin D in the development of melanoma is yet to be fully elucidated, it has been proposed that melanoma prevention may be significantly aided by increased vitamin D signaling. Furthermore, selective targeting of the catabolic enzymes responsible for vitamin D degradation could be a plausible strategy in melanoma therapy. Vitamin D signaling can be improved by utilizing dietary supplements or by modulating CYP metabolism. A positive association exists between the intake of vitamin D supplements and improved prognosis for melanoma patients. Further investigation is required to determine the function of vitamin D supplementation and specific enzyme targeting in the prevention of melanoma.

The Relationship between Vitamin D Levels and Blood Glucose and Cholesterol Levels

BACKGROUND

Vitamin D deficiency has reached epidemic proportions globally. Observational data link low vitamin D status to diabetes, dyslipidemia, and metabolic syndrome, but interventional trials on the effects of supplementation are limited.

OBJECTIVE

We investigated associations between serum 25-hydroxyvitamin D (25(OH)D) levels and metabolic markers in Saudi adults.

METHODS

This retrospective cross-sectional study analyzed the clinical records of 476 patients from Saudi Arabia, aged 15-78 years. According to 25(OH)D levels, participants were stratified as vitamin D-sufficient (≥30 ng/mL), -insufficient (21-29 ng/mL), or -deficient (≤20 ng/mL). The outcomes were diabetic status (fasting glucose, HbA1c) and lipid panel results.

RESULTS

Higher diabetes prevalence was significantly associated with lower 25(OH)D levels (10.1% in the sufficient group, 11.6% in the insufficient group, and 18.3% in the deficient group). Similarly, worse lipid profiles were associated with more severe hypovitaminosis D, including a total cholesterol level of ≥240 mg/dL (5.3% in participants with normal vitamin D levels vs. 18.9% in those with deficient levels) and LDL ≥ 160 mg/dL (6.9% in participants with normal vitamin D levels vs. 13.2% in those with deficient levels). Vitamin D deficiency disproportionately affected women and adults > 45 years old.

CONCLUSIONS

Vitamin D deficiency is endemic in Saudi Arabia and strongly linked to worsened metabolic markers. Optimizing vitamin D status through screening and correcting the deficiency may provide a cost-effective approach to confronting the regional diabetes epidemic and reducing cardiovascular disease risk.