Vitamin D is a fat-soluble vitamin. Vitamin D has two primary forms:

• Vitamin D2, also known as Ergocalciferol
• Vitamin D3, also known as Cholecalciferol

Vitamin D2 is found in many human-made foods, whereas Vitamin D3 is present in animal-based foods and is synthesized in the skin from  7-dehydrocholesterol.

When activated, exhibit the same response, both forms of vitamin D exhibit the same answer, and a similar potency was seen in relation to the cure of rickets.

Vitamin D serves a variety of purposes. However, the regulation of calcium and phosphorus intake and the facilitation of regular immune system function are perhaps the most important. 

Vitamin D is necessary for regular bone and tooth growth and development and better resistance to some diseases.

Both of these vitamins are synthesized commercially and are used in dietary supplements and fortified foods.

But, do vitamin D supplements work?

Deficiency and toxicity

DEFICIENCY of vitamin D may occur from lack of intake, poor absorption (patients with IBD are at risk), and in case of increased demands.

Vitamin D deficiency results in:

• RICKETS: A condition that occurs in children and infants, causing skeletal deformity.
• OSTEOMALACIA: A condition that occurs in adults, causing weakening and softening of bones. 

TOXICITY of vitamin D most commonly occurs due to increased intake of supplements. It may present with Anorexia, weight loss, irregular heartbeat, and hardening of blood vessels leading to damage of the heart and kidney.

Vitamin D as a supplement

Vitamin D supplements are joint and are frequently been used in recent years. 

A reliable source of getting vitamin D is sunlight. Therefore, people who don’t get enough sunlight, especially in the USA (Northern half) and Canada, are at risk. 

Older people are also at risk of vitamin D deficiency.

Vitamin D supplements are therefore necessary for older people and people living in Northern latitudes.

A report in the Journal of the American Geriatrics Society demonstrated that senior women who took a vitamin D supplement alongside calcium for three months reduced their chance of falling by 49 percent compared with taking calcium alone. 

Those ladies who had fallen regularly in the past tended to obtain the most benefit from vitamin D.

Other benefits of vitamin D are also considered to use it as a supplement.

Autoimmune diseases

Increasing epidemiological evidence linking vitamin D deficiency and autoimmune diseases such as Multiple Sclerosis and Rheumatoid Arthritis was found.

According to a study published in the January 13, 2004 issue of Neurology, women who take vitamin D doses equivalent to those found in daily multivitamin supplements at least 400 international units are 40% less likely to develop multiple sclerosis than women who do not take over-the-counter supplements.

A study conducted by (Kassandra L. Munger, MSc; Lynn I. Levin, Ph.D., MPH; Bruce W. Hollis, Ph.D. al; in 2006) examined whether high levels of circulating vitamin D were associated with reduced risk of Multiple Sclerosis. 

The study suggested that high levels of circulating vitamin D are associated with a reduced risk of Multiple Sclerosis. 

Cardiovascular diseases

Recent studies have demonstrated a strong association between vitamin D insufficiency and risk of cardiovascular disease along with metabolic syndrome and Diabetes.

Studies on people with high blood pressure at Boston University studied after increasing their vitamin D levels. 

According to Holick, professor of medicine, physiology, and biophysics at Boston University, they were followed for nine months. As a result, their high blood pressure normalized, and their hypertension continued to be in remission. 

Anticancer

Michael F. Holick, Ph.D., MD, who heads the Vitamin D, Skin, and Bone Research Laboratory at Boston University School of Medicine, showed that “Activated vitamin D is one of the most potent inhibitors of cancer cell growth.”

In a study of more than 3,000 veterans (ages 50 to 75) at 13 Veterans Affairs medical centers published in the Journal of the American Medical Association in December 2003, those who consumed more than 645 IU of vitamin D per day along with more than 4 grams of cereal fiber per day had a 40% lower risk of developing precancerous colon polyps.

According to a research of 19000 males, those with 25(OH)D levels below 16 ng/mL had a 70% greater incidence rate of prostate cancer than those with levels over 16 ng/mL

According to a study, women regularly exposed to sunlight and consumers of above-average amounts of vitamin D had significantly lower incidence rates of breast cancer.

ANXIETY AND DEPRESSION

ACCORDING TO SOME STUDIES, Vitamin D supplements have been shown to benefit against anxiety and regulation of mood. For example, the study showed that persons with depression who took vitamin D supplements saw an improvement in their symptoms. 

On the other hand, according to another study, vitamin D deficiency was more common in persons with fibromyalgia who also had anxiety and depression. 

Clinical studies showed a reduced cognitive function, anxiety, and depression with low serum levels of 25-hydroxyvitamin D [25(OH) D], which is the storage form of vitamin D in the body.

Weight loss

A study suggested that people taking calcium and vitamin D supplements were able to lose more weight. In addition, extra calcium and vitamin D were said to have appetite-suppressing effects.

Overweight people who took a daily vitamin D supplement improved their heart disease risk factors in another trial.

Conclusion

Vitamin D is an essential vitamin that is necessary for overall health. Two forms of vitamin D having different sources are available. 

A variety of symptoms are observed in excess or deficiency of vitamin D. Vitamin D supplements are widely used nowadays. 

Many people are deficient in this vitamin; supplements are sometimes therefore needed to maintain optimal levels.

In addition to improving bone health by regulating the absorption of calcium and phosphorus, various other benefits like reduced risk of autoimmune diseases, depression, and cardiovascular disease were found.

Various food products that don’t naturally contain vitamin D are fortified with this nutrient. 

Regarding the use of vitamin D supplements, quality should be assured to avoid side effects. 

It’s essential to purchase high-quality supplements and choose supplements tested for purity and quality independently.