The role of vitamin D in calcium absorption and bone health is well known. The overwhelming amount of research over the past twenty years has suggested that vitamin D has many other benefits. Research has also indicated that Vitamin D deficiency is not rare; on the contrary it has a very high prevalence and is even recognized as a major health problem for older adults. Presented below is a summary of the published scientific research findings on Vitamin D. For additional information and references, please refer to the Vitamin D article posted on our “Science” section.
Sunlight is the primary source of vitamin D.
A very small number of foods naturally contain vitamin D;
oily fish such as salmon, mackerel, and sardines
cod liver oil
Recent studies in humans have provided evidence that vitamin D3 (cholecalciferol from animal sources) is more efficient than vitamin D2 from plant sources.
41% of healthy adults, 49 to 83 years of age are found to be vitamin D deficient.
Students and young adults are also vitamin D deficient, especially those who work inside or who always wear sun protection.
Individuals who have darkly pigmented skin, those who are obese and the elderly have an increased risk of vitamin D deficiency.
In adults, vitamin D maintains bone mineral density and prevents osteoporosis.
The body’s largest source of calcium is found in bones, which are then used to maintain serum levels. When vitamin D is low, more bone is needed as a source of calcium to support balanced levels.
Vitamin D has a direct effect on muscle strength and is thought to maintain function of type II muscle fibers which could reduce risk of falling and fractures in the elderly.
Falls are the single most common cause of injury mortality in the elderly and account for 40% of all nursing home admissions.
Pregnant/Nursing mothers and Infants
Vitamin D regulates calcium/phosphorus absorption and metabolism for bone health.
This role becomes more important during pregnancy and lactation as bones are developing rapidly during this period.
Insufficient vitamin D intake during pregnancy can lead to low birth weight and/or result in the symptoms of rickets in infancy; biochemical disturbances, reduced bone mineralization, slower growth, bone deformities, increased risk of fracture
Protection from cancer
Studies have shown that vitamin D helps prevent breast, colorectal, ovarian and prostate cancers.
Clinical trials have suggested that vitamin D and calcium supplementation could have a role in the prevention of type 2 diabetes in populations at high risk.
A study which began in 1966 administered 2000 IU of vitamin D to children and revealed there was an 80% reduction in the development of type 1 diabetes though-out the following 30 years in those children.
Protection from inflammation and cold/flu
Vitamin D plays an important role in the regulation of immune system function and suppresses T-helper cell over-activity, and works to prevent autoimmune diseases such as type-1 diabetes, rheumatoid arthritis, scleroderma, and graft rejection.
A recent randomized controlled trial gave evidence that vitamin D provides a dramatic preventative effect against influenza and colds.
Vitamin D stimulates the expression of potent anti-microbial peptides and protects the lung from infection.
A low dose (800 IU/day) reduced reported incidence of cold or flu, and abolished the seasonality of cold and flu reports.
A higher dose (2000 IU/day), given during the last year of the trial, eliminated all reports of colds or flu.
Researchers now believe that vitamin D deficiency could contribute to congestive heart failure.
Calcium and vitamin D supplementation results in a 9.3% decrease in systolic blood pressure, a 5.4% decrease in heart rate and substantially reduces C-reactive protein levels in critically ill patients.
Disorders of the brain and cognition
Vitamin D receptors are present in the brain.
A review of older adults found a positive correlation between score on the mini-mental state examination and serum vitamin D levels.
Intake of Vitamin D is associated with a lower incidence of MS and vitamin D supplementation is often recommended in the early stages of MS to lower the risk of osteoporosis.
Mood and well-being
Vitamin D levels are related to positive mood and well-being People who suffer from unipolar and bipolar depression have significantly lower levels of vitamin D.
In a randomized study, eight subjects with seasonal affective disorder given vitamin D supplementation showed improvements in depression measures.