What are the benefits of Vitamin D (Vitamin D)?

From the Guidelines

Vitamin D is essential for maintaining strong bone health, immune function, and may help prevent chronic diseases, with a recommended daily intake of 600-800 IU for most adults. The benefits of vitamin D are numerous, including enhancing calcium absorption, promoting proper bone mineralization, reducing inflammation, and potentially preventing certain chronic diseases such as heart disease and some cancers 1. Vitamin D also plays a role in mood regulation, potentially reducing depression risk.

Sources of Vitamin D

Vitamin D can be obtained from:

• Natural production when skin is exposed to sunlight (15-30 minutes several times weekly)
• Foods like fatty fish, fortified dairy products, and egg yolks
• Supplements available as vitamin D2 (ergocalciferol) or D3 (cholecalciferol), with D3 generally considered more effective at raising blood levels 1

Recommendations

• A daily intake of 600-800 IU is recommended for most adults, with higher doses (1,000-2,000 IU) often suggested for those with deficiency
• A serum vitamin D level of 20 ng per mL (50 nmol per L) is recommended for good bone health 1
• If supplementing, take with meals containing fat to improve absorption
• Excessive vitamin D can cause toxicity, so blood level monitoring is recommended when taking higher doses

Key Considerations

• Randomized trial data are needed to determine whether long-term supplementation with vitamin D has a favorable impact on the development or clinical course of non-skeletal diseases 1
• The current recommendations address vitamin D supplementation, testing, and monitoring in individuals with or at risk for diseases such as osteoporosis, chronic kidney disease, and endocrinopathies 1

From the FDA Drug Label

Man’s natural supply of vitamin D depends mainly on exposure to the ultraviolet rays of the sun for conversion of 7-dehydrocholesterol in the skin to vitamin D3 (cholecalciferol). The two known sites of action of calcitriol are intestine and bone. Calcitriol is the most active known form of vitamin D3 in stimulating intestinal calcium transport The beneficial effect of calcitriol in renal osteodystrophy appears to result from correction of hypocalcemia and secondary hyperparathyroidism.

The benefits of vitamin D include:

• Stimulation of intestinal calcium transport
• Regulation of calcium and phosphorus metabolism
• Correction of hypocalcemia and secondary hyperparathyroidism in renal osteodystrophy 2 3 The main sites of action of vitamin D are the intestine and bone.

From the Research

Benefits of Vitamin D

• Vitamin D plays an essential role in regulating calcium and phosphate metabolism and maintaining a healthy mineralized skeleton 4
• It is also associated with chronic musculoskeletal pain, muscle weakness, and an increased risk of falling 4
• Several observational studies observed the association between robust levels of serum 25(OH)D in the range of 40-60 ng/mL with decreased mortality and risk of development of several types of chronic diseases 4
• Vitamin D has been implicated in the regulation of neuromuscular function and in reducing the risk of falls, a major cause of bone fractures 5
• The active metabolite of vitamin D, 1,25-dihydroxyvitamin D [1,25(OH)2D], behaves as a hormone and binds to the vitamin D receptor (VDR) present in nearly all tissues of the human body, exerting biological effects via paracrine/autocrine actions related to cardiovascular disease, diabetes, cancer, and the immune system 5

Role of Vitamin D in Bone Health

• Vitamin D is essential for calcium absorption and bone mineralization, and is positively associated with bone mineral density [BMD] 6
• Prolonged and severe vitamin D deficiency leads to rickets in children and osteomalacia in adults 6
• Sub-optimal vitamin D status has been reported in many populations, but it is a particular concern in older people 6
• Vitamin D supplementation can improve muscle strength, which in turn contributes to a decrease in incidence of falls, one of the largest contributors to fracture incidence 6
• Vitamin D may influence fracture risk via a number of different mechanisms, including its mediating effects on muscle function and inflammation 6

Prevention and Treatment of Osteoporosis

• Severe vitamin D deficiency is a common cause of rickets in children and osteomalacia in adults 7
• Vitamin D must be hydroxylated in the liver and then finally in the kidney to become 1alpha,25-dihydroxy-cholecalciferol, a biologically highly active renal hormone 7
• Vitamin D, alfacalcidol, and calcitriol therapy regimens are used to treat different forms of osteoporosis 7
• An increase in calcium intake to 1000-1500 mg/d along with an adequate source of vitamin D of at least 400 IU/d is important for maintaining good bone health 8