Vitamin D Overview Current Research and Recommendations Across the Life Span

Posted by e-Medical PPT Wednesday, September 26, 2012
Vitamin D Overview
It is a fat soluble vitamin.
Not just a vitamin it is a prehormone
Found in some food and made in the body after exposure to UV rays
Major biological function is to maintain normal blood levels of Ca and Po4
Other tissues like macrophages, prostrate tissue also have vit D receptor

Mean  vitaminD, Calcium and multivitamin use was higher in white girls than in black
Both races had mean dietary vitamin D intake above adequate levels
Race and season strongest predictor of vit D status
Black girls had lower mean vit D value
Vitamin D value were significantly higher in summer than in winter
Living at low latitude does not entirely prevent poor vitamin D status

Vitamin D & Cancer
Environmental:  sunlight & diet
Calcitriol (hormonal form of vitamin D) controls the differentiation of many cells that possess vitamin D receptors (VDR)
Induce cell differentiation and apoptosis of cancer cells while inhibiting cell proliferation, angiogenesis, and metastasis
Genetic:  VDR polymorphisms

Women who regularly took vitamin D3 and calcium had a 60% reduction in all-cancer incidence compared with a group taking placebo and a 77% reduction when the analysis was confined to cancers diagnosed after the first 12 months.

Lung cancer
inhibits proliferation and induces differentiation of lung cancer cell lines (Higashimoto, et al., 1996, Guzey, et al., 1998)
inhibits metastatic growth and locoregional recurrence of lung cancer cells in mice (Wiers, et al., 2000)

Breast cancer
inhibits cell proliferation, induces differentiation & apoptosis, and inhibits angiogenesis in normal and breast cancer cells (Colston, et al, 1989, Saez, et al, 1993, Mantell, et al., 2000)
suppresses high-fat diet-induced mammary tumorigenesis in rats (Jacobson, et al., 1989, Xue, 1999)
Inverse association between vitamin D & calcium intake and breast density
Inconclusive results in studies looking at VDR genetic polymorphisms and breast cancer
Inverse association between high sunlight exposure and breast cancer risk
Association may be stronger for premenopausal than postmenopausal women due to interactions between vitamin D, the VDR, estrogen and insulin-like growth factor-I (IGF-I)
More frequent sun exposure during adolescence was associated with a 35% reduction in breast cancer risk later in life
Lower risk also linked to cod liver oil and milk intake > 10 glasses / week
Milder protection seen for people age 20 – 29
No protection for people over age 45
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