There is a vast body of science showing the many health benefits of vitamin D and D3. Vitamin D3, for example, is one of the most useful nutritional tools people have at their disposal for improving overall health. It has a strong influence over the body’s phosphorus controls, calcium, and bone metabolism and neuro-muscular function. Vitamin D3 is the only vitamin the body can manufacture from sunlight (UVB). Yet, with today’s indoor living and the extensive use of sunscreens due to concern about skin cancer, we are now a society with millions of individuals deficient in life-sustaining bone building and immune modulating, Vitamin D3.
Maintenance of blood calcium levels within a narrow range is vital for normal functioning of the nervous system, as well as for bone growth, and maintenance of bone density. Vitamin D is essential for the efficient utilization of calcium by the body.
Cellular differentiation results in the specialization of cells for specific functions in your body. In general, differentiation of cells leads to a decrease in proliferation. While cellular proliferation is essential for growth and wound healing, uncontrolled proliferation of cells with certain mutations may lead to diseases like cancer. The active form of vitamin D inhibits proliferation and stimulates the differentiation of cells.
Active vitamin D is a potent immune system modulator. There is plenty of scientific evidence that vitamin D has several different effects on immune system function that may enhance your immunity and inhibit the development of autoimmunity.
The active form of vitamin D plays a role in insulin secretion under conditions of increased insulin demand. Limited data in humans suggest that insufficient vitamin D levels may have an adverse effect on insulin secretion and glucose tolerance in type 2 diabetes.
Adequate vitamin D levels may be important for decreasing the risk of high blood pressure.
According to the National Institutes of Health, vitamin D may play a role in the following diseases:
Osteoporosis is most often associated with inadequate calcium intake. However, a deficiency of vitamin D also contributes to osteoporosis by reducing calcium absorption. While rickets and osteomalacia are extreme examples of vitamin D deficiency, osteoporosis is an example of a long-term effect of vitamin D insufficiency. Adequate storage levels of vitamin D help keep bones strong and may help prevent osteoporosis in older adults, in those who have difficulty walking and exercising, in post-menopausal women, and in individuals on chronic steroid therapy.
Vitamin D deficiency, which is often seen in post-menopausal women and older Americans, has been associated with greater incidence of hip fractures. In a review of women with osteoporosis hospitalized for hip fractures, 50 percent were found to have signs of vitamin D deficiency. Daily supplementation with 800 IU of vitamin D may reduce the risk of osteoporotic fractures in elderly populations with low blood levels of vitamin D.
Laboratory, animal, and some preliminary human studies suggest that vitamin D may be protective against some cancers. Several studies suggest that a higher dietary intake of calcium and vitamin D correlates with lower incidence of cancer. In fact, for over 60 years researchers have observed that greater sun exposure reduces cancer deaths. The inverse relationship between higher vitamin D levels in blood and lower cancer risk in humans is best documented for colon and colorectal cancers. Vitamin D emerged as a protective factor in a study of over 3,000 adults who underwent a colonoscopy to look for polyps or lesions in the colon. There was a significantly lower risk of advanced cancerous lesions among those with the highest vitamin D intake.
Alzheimer's disease is associated with an increased risk of hip fractures because many Alzheimer's patients are home-bound, frequently sunlight deprived, and older. With aging, less vitamin D is converted to its active form. One study of women with Alzheimer's disease found that decreased bone mineral density was associated with a low intake of vitamin D and inadequate sunlight exposure.
Diabetes mellitus, multiple sclerosis, and rheumatoid arthritis, are each examples of autoimmune disease. Autoimmune diseases occur when the body launches an immune response to its own tissue, rather than a foreign pathogen. Treatment with vitamin D has beneficial effects in animal models of all of the above mentioned diseases. The results of several studies suggest that adequate vitamin D intake may decrease the risk of autoimmune diseases. Evidence from animal models and human studies suggests that maintaining sufficient vitamin D levels may help decrease the risk of several autoimmune diseases.
The results of epidemiological and clinical studies suggest an inverse relationship between serum vitamin D levels and blood pressure. Data from epidemiological studies suggest that conditions that decrease vitamin D synthesis in the skin, such as having dark skin and living in temperate latitudes, are associated with increased prevalence of hypertension.
It is very rare to have a vitamin D overdose. Vitamin D toxicity induces abnormally high serum calcium levels (hypercalcemia), which could result in bone loss, kidney stones, and calcification of organs like the heart and kidneys if untreated over a long period of time.
Research published since 1997 suggests that the upper limit intake for adults is overly conservative and that vitamin D toxicity is very unlikely in healthy people at intake levels lower than 10,000 IU/day. Vitamin D toxicity has not been observed to result from sun exposure.
Infants 0-12 months- 1000 IU
Children 1-18 years- 2000 IU
Adults 19 years and older- 2000 IU
It is not always practical to get your vitamin D from sunshine, and quite difficult to get adequate amounts from your diet so for many people, a vitamin D supplement is a practical way to ensure adequate levels of this important protector are always available in your bloodstream.
Since a large body of science shows vitamin D works closely with calcium and magnesium, it is best to take your vitamin D in combination with calcium and magnesium to maintain a proper balance. Recent literature also shows most calcium supplements have too little vitamin D to be effective. And some of them use synthetic vitamin D2. A much better form is natural vitamin D3 which stays in your system longer and with more effect.
Vitamin D is found in many dietary sources such as fish, eggs, fortified milk, and cod liver oil. The sun also contributes significantly to the daily production of vitamin D, and as little as 10 minutes of exposure is thought to be enough to prevent deficiencies. The term "vitamin D" refers to several different forms of this vitamin. Two forms are important in humans: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is synthesized by plants. Vitamin D3 is synthesized by humans in the skin when it is exposed to ultraviolet-B (UVB) rays from sunlight. Foods may be fortified with vitamin D2 or D3.
The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. Recently, research also suggests vitamin D may provide protection from osteoporosis, hypertension (high blood pressure), cancer, and several autoimmune diseases.
It is becoming clear that a large percentage of individuals are deficient in this important nutrient, which has hormone-like activity. The fear of skin cancer has stopped many individuals from obtaining beneficial amounts of sunlight. The skin uses the energy of UVB to convert 7-dehydrocholesterol into Vitamin D3. Even individuals, who venture out into the sun often and use suntan lotion, may be deficient in Vitamin D3. Furthermore, as people age, we are less equipped to produce sufficient quantities of this vital nutrient. Additionally, the Recommended Daily Intake (RDI) of Vitamin D3 is set so low those mature individuals who consume this small amount (400 to 600 International Unites (I.U.’s)) are still likely to be deficient if they live north of the Tropic of Cancer or south of the Tropic of Capricorn.
Vitamin D3 deficiency is common in older adults and has been implicated in psychiatric and neurological disorders. It is also associated with low mood and with impairment on two of four measures of cognitive performance.
Musculoskeletal disorders have been linked to Vitamin D3 deficiency in a number of studies. One of the newest studies explored the role that low Vitamin D3 levels play in the development of chronic low back pain in women. The study revealed that patients with low back pain had significantly lower Vitamin D3 levels than the control group.
One of the best known and long-established benefits of Vitamin D3 is its ability to improve bone health and the health of the musculoskeletal system. It is well documented that Vitamin D3 deficiency causes osteopenia, precipitates and exacerbates osteoporosis, causes a painful bone disease known as osteomalacia, and exacerbates muscle weakness, which increases the risk of falls and fractures. Vitamin D3 insufficiency may alter the regulatory mechanisms of parathyroid hormone (PTH) and cause a secondary hyperparathyroidism that increases the risk of osteoporosis and fractures.
In a recent study, Vitamin D3 deficient subjects scored worse on mental function tests compared to individuals who had higher levels of the Vitamin.
A number of studies have strongly suggested that Vitamin D3 deficiency is associated with an increased risk of developing many forms of cancer including breast, ovarian, prostate and colon cancer. In one recent clinical trial, women who were taking large amounts of Vitamin D3 with calcium experienced a 60 percent or greater reduced risk of cancer than their peers in the placebo group, who were not consuming these supplements.
Vitamin D3 regulates T cells, which are important to the functioning of a strong immune system. Vitamin D3 acts as an immune system modulator, preventing excessive expression of inflammatory cytokines and increasing the killing efficiency of macrophages. In addition, it dramatically stimulates the expression of potent anti-microbial peptides, which plays a major role in protecting the lung from infection, and exists in immune system cells such as neutrophils, monocytes, natural killer cells, and in cells lining the respiratory tract.
Sources: The Mayo Clinic, American Association for Cancer Research, National Institue of Health & American Journal of Clinical Nutrition