Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and multiple other biological effects. In humans, the most important compounds in this group are vitamin D₃ and vitamin D₂.

Thank you so much Dr @Bhrigu Rajkhowa

I agree with Bhrigu Rajkhowa sir.

It helps to:

Prevent bone fractures

Prevent falls in older people and osteoporosis

Reduce the risk of cancer, especially colon cancer, prostate cancer, and breast cancer

Reduce the risk of diabetes, especially in young people and in those living in high altitude

Protect against heart disease, including high blood pressure and heart failure

Reduce your risk for multiple sclerosis

Improve you mood

Improve your lung function.

Thank you so much Dr @Sura Aldewachi

Vitamin D helps regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth and muscles healthy. A lack of vitamin Dcan lead to bone deformities such as rickets in children, and bone pain caused by a condition called osteomalacia in adults.

Thank you so much Madam @Sana Noreen

Promote healthy Bones and teeth. Regulating insulin level and supporting diabetes management

Thank you so much Madam @Theresa Uzor

Vitamin D is a prohormone, which means that its metabolites act as hormones, that affects many organ systems in the human body. It is metabolized by the liver to 25(OH)D, and the kidneys convert this to 1,25(OH)2D. In general, we need this vitamin to regulate our calcium and phosphorus metabolism and to keep the concentration of calcium in our bloodstream at a constant level. This is indispensable as dissolved calcium is required for nerves and muscles to work. Vitamin D also promotes normal bone formation and mineralization. Interestingly, vitamin D and related analogues have important immunomodulatory properties:

Article Vitamin D: Modulator of the immune system

Chapter Immunomodulatory Role of Vitamin D: A Review

I hope it helps.

I appreciate your answer Sir @Piotr Chmielewski

Vitamin D is a prohormone, which means it's metabolites act as hormones, that affects many organs in the body.

Thank you so much!!!

Hello @sujit Barman

I suggest this article about the evidences of Vit D in health: Article Vitamin D testing and treatment: A narrative review of curre...

In addition, this other paper where aspects related to its metabolism, molecular mechanism and pleitropic effects are addressed: https://pubmed.ncbi.nlm.nih.gov/26681795/

Regards.

Vitamin D as a fat soluble vitamin helps in the intestinal absorption of calcium and phosphorus

Thank you so much @Jorge Luis Petro & @Timothy Emmanuel Sir

Vitamin D is necessary for several physiological actions and for the robustness of the human skeleton. It allows (with menaquinone) the absorption of calcium by the intestine, the reabsorption of calcium and phosphorus by the kidneys (decreases calciuria) and bone resorption by osteoclasts.

Vitamin D works in bone and dental formation, interacting with calcium. It is a vitamin that can be assimilated through food, but also thanks to the rays of the sun when they penetrate the skin. Vitamin D is also essential for good muscle health. It also has virtues in the prevention of colorectal and breast cancer.

Indispensable for growth during infancy, it ensures the strength of the human skeleton and prevents osteoporosis. After a certain age, the body does not synthesize vitamin D as easily.

Vitamin D in human body is important as it helps regulates the immune system and neuromuscular system. It's main job is to keep right amount of calcium and phosphorus in our blood. It acts as an important tool for human growth. Our body produces vitamin d naturally when our body get directly exposed to sunlight. Most importantly vitamin D helps prevent our health from having certain diseases such as bone diseases, diabetes, hearth diseases ect.

Vitamin D is a fat soluble vitamin in the intestinal absorption of calcium and phosphorus. Vitamin D in the human body is important as it helps regulates the immune system and neuromuscular system.

Thank you so much @Ben Sir

and @Josephine H Matthew Sir

Thank you so much Madam @Theresa Uzor

Read this major review about vitD

Curr Opin Endocrinol Diabetes Obes 2019, 26:000–000

DOI:10.1097/MED.0000000000000508

or this one

Pleiotropic Actions of Vitamin D.

Front. Endocrinol. 10:341.

doi: 10.3389/fendo.2019.00341

I appreciate your answer Sir @Jos_Wielders

I think that vit D is much more.

Thank you so much Madam @Natalija Vukovic

I appreciate your answer Dr @Ambrose Emuobonuvie Akpovona

Thank you, vitamin-D plays a major role in calcium metabolism, hemoglobin production, fertility, skin, and immune function

Thank you so much Sir @Hyder Mirghani

Vitamin D is a fat-soluble vitamin that is naturally present in a few foods, is added to other foods, and is available in many nutritional supplements. Vitamin D has the properties of both a hormone and a vitamin and is necessary for mineral homeostasis and proper formation of bone. The major biological 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.

Studies report that it triggers the body’s immune cells to produce antibodies; therefore, vitamin D promotes an overall increase in the strength of the immune system. Some studies also reported that vitamin D assists in the maintenance of joint and muscle comfort, as well as the maintenance of a healthy mood, and supports breast, colon, and prostate health.

Totally agreed, in addition, some role in COVID-19 was reported

Vitamin D is a fat soluble vitamin that is naturally present in a few foods, is added to other foods and is available to many nutritional supplements. Vitamin D has the properties of both a hormone and a vitamin which is necessary for homeostasis and bone formation. The major biological function of vitamin D is to maintain normal blood vessels of calcium and phosphorus. Vitamin D also aids in the absorption of calcium, helping and maintaining strong bones.

Studies report that vitamin D triggered the body immune cells to produce antibodies, therefore it promotes the body immune system. Some studies also reported that vitamin D assist in the maintenance of joint and muscle comfort, as well as maintenance of of healthy mood and support breast, colon and prostate health.

Thank you so much Sir @Panna Chandra Nath

Thank you so much ma'am @Theresa Uzor

Please go through the following RG links.

Article The clinical importance of vitamin D (cholecalciferol): A pa...

Article Immunologic Effects of Vitamin D on Human Health and Disease

Thank you for sharing your knowledge

Vitamin D is important for the formation of calcium in the human body, so it is involved in the formation of bones and teeth, and we can increase its formation by exposure to sunlight.

It's important for boon formation .

Vitamin D is getting attention in different parts of medicine last 10 years. The role of Vit D in intensive care (ICU) is interesting for me. The role of Vit D in the prevention and treatment of acute respiratory infections and infections complete is of special interest in today's COVID-19 pandemic. Here is one very good study.

These review papers will give a good description of the present knowledge and questions remaining regarding the importance of vit D for the human body

1) The ongoing D-lemma of vitamin D supplementation for nonskeletal health and bone health Curr Opin Endocrinol Diabetes Obes 2019, 26:000–000

DOI:10.1097/MED.0000000000000508

2) Vitamin D in childhood and adolescence: an expert position statement Eur J Pediatr (2015) 174:565–576 DOI 10.1007/s00431-015-2524-6

3) Vitamin D supplementation: guidelines and evidence for subclinical deficiency Curr Opin Gastroenterol 2012, 28:139–150 DOI:10.1097/MOG.0b013e32835004dc

4) Skeletal and Extraskeletal Actions of Vitamin D: Current Evidence and Outstanding Questions (Endocrine Reviews 40: 1109 – 1151, 2019) doi: 10.1210/er.2018-00126

5) Vitamin D: Classic and Novel Actions Ann Nutr Metab 2018;72:87–95 DOI: 10.1159/000486536

6) Vitamin D signaling in immune-mediated disorders: Evolving insights

and therapeutic opportunities Molecular Aspects of Medicine 29 (2008) 376–387

Your skin is the largest organ of the body. Vitamin D contributes to keeping it healthy.

Please also see the following RG link.

Article Potential immunomodulatory effects of vitamin D in the preve...

Thank you so much all sir & madam.

Getting enough, but not too much, vitamin D is needed to keep your body functioning well. Vitamin D helps with strong bones and may help prevent some cancers. Symptoms of vitamin D deficiency can include muscle weakness, pain, fatigue and depression.

https://my.clevelandclinic.org/health/articles/15050-vitamin-d--vitamin-d-deficiency#:~:text=Getting%20enough%2C%20but%20not%20too,%2C%20pain%2C%20fatigue%20and%20depression.