Assessment of Vitamin D Supplementation and Immune Function

Specific Aim 1:

Determine if high dose vitamin D supplements decrease the production of proinflammatory and increase the production of regulatory cytokines and chemokines by innate immune cells stimulated ex vivo.

Specific Aim 2:

Determine if high dose vitamin D supplements decrease serum markers of inflammation and increase serum and cellular levels of defensive molecules (e.g., cathelicidin).

Specific Aim 3:

Determine if high dose vitamin D supplements decrease blood levels of proinflammatory T-helper type 1 (Th1) and Th17 cells and increase levels of anti-inflammatory T-regulatory (Treg) and Th2 cells.

Specific Aim 4:

Determine if high dose vitamin D supplements increase antigen specific T cell and B cell responses after tetanus vaccination.

Inclusion criteria

• Age 20-49 (men) and 20-45 (women)
• BMI 18.5-30
• Serum 25OH Vitamin D 25-50 nmol/L

Exclusion criteria

• Pregnant or nursing women
• Daily smoker
• Anemia (Hgb<12 mg/dL for women and <13 mg/dL for men) determined at initial visit
• Any report or diagnosis of disease or chronic condition that may affect vitamin D absorption such as cystic fibrosis, celiac disease, surgical removal of part of the stomach or intestines, and some forms of liver disease
• Diagnosis of hyper parathyroidism and chronic granulomatous disease, which increases risk of hypercalcemia.
• Planned to travel to a location at which either altitude or latitude would result in significant vitamin D synthesis during the study period.
• Not previously vaccinated with TT, or vaccinated within five years
• Use of steroids or antibiotics within the past 4 weeks
• Current use of nutritional supplements that may alter immune function such as omega 3 fatty acid supplements
• Current use of anti-inflammatory or anti-convulsion medications
• Self reported history of significant adverse response to previous vaccinations