Optimizing Vitamin D Synthesis
Jain receives a $1.52 million NIH grant
Dr. Sushil Jain, a professor in the Department of Pediatrics at LSU Health Shreveport, has been awarded a three-year, $1.52 million grant from the National Institutes of Health (NIH) for a project entitled Optimization of 25-hydroxy-vitamin D levels in African-Americans.
The project’s goal is to develop a safe, low-cost dietary supplement that can improve the body’s synthesis of vitamin D and reduce insulin resistance and inflammation. Advances in this research will especially provide significant benefits in preventing pre-diabetes and health disparities within the African- American population.
Vitamin D is an essential nutrient that promotes calcium absorption for the development of strong bones, glucose metabolism, providing immunity, the reduction of inflammation, and the regulation of over 200 genes in the human body. The fat-soluble vitamin naturally occurs in salmon, mushroom, egg yolks and enriched grains.
It is also produced in the human body when UV rays from sunlight trigger synthesis, but vitamin D in this raw state does not have any metabolic function and must undergo hydroxylation in the liver and kidney to transform the inert nutrients into physiologically active compounds.
The hydroxylation occurring in the liver results in 25-hydroxyvitamin D — 25(OH) VD — also known as calcidiol. The second hydroxylation, which occurs primarily in the kidney, results in 1.25-dihydroxy-vitamin D, also known as calcitriol.
The recommended daily dose for vitamin D is 600 IU, but many people take doses in the range of 2,000-4,000 IU daily, which is considered a high dose. The deficiency of 25-hydroxyvitamin D is a major public health issue worldwide. Two-thirds of the African- American population have a higher incidence of 25-hydroxy-vitamin D deficiency as well as associated health hazards.
Vitamin D deficiencies are known to be linked to rickets and higher incidences of diabetes, cancer and cardiovascular diseases. This clinical trial investigates whether the combined use of the micronutrients vitamin D and L-cysteine will exert measurable and beneficial effects on 25-hydroxyvitamin D levels and insulin resistance in African-American populations.
L-cysteine is needed to synthesize glutathione, which is essential for the regulation of vitamin D. Glutathione metabolizes enzymes that convert inert vitamin D that is consumed to 25-hydroxy-vitamin D and 1.25-dihroxyvitamin D in the body. Many obese and diabetic individuals, particularly African-Americans, have a deficiency of both glutathione and 25(OH) VD.
Therefore, if we provide or consume simultaneously both VD and L-cysteine (which is a precursor of glutathione), it will result in better efficacy or bioavailability of vitamin D in our body. The translation and validation of the novel approach will have a tremendous impact on medical practice, leading to the novel recommendation that supplementation that combines the use of vitamin D and L-cysteine is superior to the current practice of supplementation with high-dose vitamin D alone.
The long-term goal is to discover new approaches to ensure adequate 25(OH) VD status and to prevent the adverse effects of vitamin D deficiency on health conditions in the African-American population.
Sushil K. Jain, Ph.D., FACN, FICN; professor of pediatrics and biochemistry & molecular biology, Malcolm Feist Endowed Chair in Diabetes, and director of research of the Pediatrics Department at LSU Health Shreveport.