Research Blog
Vitamin D (cholecalciferol) and cholesterol are both synthesized from 7-dehydrocholesterol (7-DHC). The enzyme 7-DHC reductase converts 7-DHC to cholesterol, while UVB radiation from sunlight converts it to cholecalciferol in the skin. Epidemiological research reveals that cholesterol levels increase as the distance from the Equator increases and decrease as distance decreases, highlighting an association with sunlight exposure. Cholesterol levels also tend to decline during the summer and increase in the winter (Patwardhan 2017).
Carlberg et al. 2022
An estimated 40% of U.S. residents have overt vitamin D deficiency, i.e., blood levels of 20 ng/mL (50 nmol/L) or below. Low serum vitamin D is closely associated with chronic diseases, e.g., diabetes, cardiovascular disease, and strokes. Deficiency risk increases with age and lack of sunlight exposure, and prevalence is generally higher for individuals with darker skin, which can block the UV light needed to produce vitamin D. Supplementation may help reduce elevated cholesterol and triglycerides and chronic disease risk. A systematic review and meta-analysis of 41 randomized, controlled trials involving adults over age 18 found that supplementation with vitamin D reduced triglycerides and total and LDL cholesterol levels (Dibaba 2019).
A prospective, randomized, six-month open-label trial of apparently healthy Indian men was conducted to evaluate the effect of sunlight and vitamin D supplementation on cholesterol and vitamin D levels. The control and intervention groups had serum vitamin D levels above or below 20 ng/mL (50 nmol/L), respectively. The intervention group was divided into increased sunlight exposure of 20 minutes to face and forearms (between 11 a.m. and 3 p.m.) over and above current exposure or a daily 1,000 IU vitamin D supplement.
Vitamin D levels increased significantly in the sunlight exposure and the supplementation groups. The sunlight exposure group significantly declined total cholesterol, LDL-C, and HDL-C levels. while the supplementation group had a significant increase in total cholesterol and HDL-C and a nonsignificant increase in LDL-C levels (Patwardhan 2017). Notably, LDL levels decreased in the sunlight exposure group from a mean of 106 mg/dL (2.74 mmol/L) to an optimal level of 98 mg/dL (2.55 mmol/L).
Patwardhan et al. 2017
Optimal Takeaways
- Cholesterol and vitamin D share common pathways for synthesis in the body.
- The association between cholesterol, sunlight, and vitamin D levels should be acknowledged and incorporated into therapeutic care plans.
- Sunlight exposure should be evaluated and addressed, especially in individuals with low vitamin D levels.
References
Carlberg, Carsten, and Eunike Velleuer. “Vitamin D and the risk for cancer: A molecular analysis.” Biochemical pharmacology vol. 196 (2022): 114735. doi:10.1016/j.bcp.2021.114735 This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Dibaba, Daniel T. “Effect of vitamin D supplementation on serum lipid profiles: a systematic review and meta-analysis.” Nutrition reviews vol. 77,12 (2019): 890-902. doi:10.1093/nutrit/nuz037
Patwardhan, Vivek G et al. “Randomized Control Trial Assessing Impact of Increased Sunlight Exposure versus Vitamin D Supplementation on Lipid Profile in Indian Vitamin D Deficient Men.” Indian journal of endocrinology and metabolism vol. 21,3 (2017): 393-398. doi:10.4103/ijem.IJEM_9_17 This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License,
