What is vitamin D?

A category of fat-soluble prohormones is known as vitamin D.(substances that have little hormonal activity on their own but can be converted into hormones by the body). Vitamin D aids the body's utilization of calcium and phosphorus in the formation of healthy bones and teeth. Vitamin D is produced by the skin when exposed to sunlight, and it can also be obtained through certain foods. Vitamin D insufficiency can induce rickets in children and osteomalacia in adults, which is the weakening of the bones.

Vitamin D2, also known as ergocalciferol, and vitamin D3, also known as cholecalciferol, are two significant forms of vitamin D for humans. Plants produce vitamin D2, and the body produces vitamin D3 when the skin is exposed to UV radiation from the sun. In the liver, both forms are converted to 25-hydroxyvitamin D. The blood then transports 25-hydroxyvitamin D to the kidneys, where it is converted to 1,25-dihydroxyvitamin D, or calcitriol, the body's active form of vitamin D. Calcitriol has been linked to lower the risk of cancer, according to research (National Cancer Institute, 2013).

The connection between vitamin D and cancer risk

The early epidemiologic study found that individuals living in southern latitudes, where levels of solar exposure are quite high, had lower incidence and death rates for specific malignancies than those living in northern latitudes. Because vitamin D is produced in response to UV radiation from sunlight, researchers speculated that variations in vitamin D levels could explain the link. A probable link between vitamin D and cancer risk has also been shown by experimental data. Vitamin D has been found to have numerous effects that may slow or prevent the development of cancer, including promoting cellular differentiation, limiting tumor blood vessel creation, and inducing cell death (apoptosis) (National Cancer Institute, 2013).

Vitamin D and its metabolites suppress tumor angiogenesis, stimulate cell mutual adhesion, and improve intercellular communication across gap junctions, so boosting the inhibition of proliferation that arises from close physical contact with neighboring cells within a tissue (contact inhibition). Vitamin D metabolites aid in the maintenance of a normal calcium gradient in the epithelial crypts of the colon and high serum levels of 25 (OH)D are linked to a significant reduction in the proliferation of noncancerous but high-risk epithelial cells in the colon. Mitosis in breast epithelial cells is inhibited by 1,25(OH)2D. Pulsatile calcium release from intracellular reserves, such as the endoplasmic reticulum, triggers terminal differentiation and death, and 1,25(OH)2D accelerates this release (Garland et al., 2006).

Connection between reduced cancer risk and topographical location

Vitamin D is also known as the sunshine vitamin since it is created naturally when exposed to ultraviolet-B (UVB) radiation from the sun. Individuals who live in colder climates and closer to northern latitudes have a higher risk of cancer than those who live in warmer climates and closer to southern latitudes.

This is due to the fact that people who live closer to the equator are exposed to more sunlight throughout their lives.

In the presence of Vitamin D, cancer cells' development was slowed. Vitamin D has been proven to trigger apoptosis (cell death) in cancer cells, limited development of tumor blood vessels, and stimulation of cellular differentiation in malignant cells, among other things.

Undifferentiated cancer cells multiply at a slower rate than well-differentiated cancer cells. The presence of Vitamin D has also been linked to the prevention of cancer cell formation (News Medical Life sciences, 2021).

Role of vitamin D in cancer

 Vitamin D has anti-cancer properties. Circulating vitamin D forms, as well as increasing concentrations of 25(OH)D3 and activity of 1,25(OH)2D3, regulate these vitamin D actions. Vitamin D stimulates cancer and normal cell growth, differentiation, and death via a regulatory system. According to these studies, inadequate vitamin D intake raises the risk of colorectal cancer. According to several types of research, vitamin D has anti-carcinogenic and growth-restraining effects on colorectal cancer. Vitamin D also influences growth factors, cell division regulation, cytokine generation, signaling, cell cycle control, and the apoptosis pathway (Kang et al., 2011).

Role Vitamin D in preventing breast cancer

Vitamin D-rich and fibrous-food-rich diets have been demonstrated to protect against breast cancer.

The calcitriol-steroid hormone is started by vitamin D. Calcitriol is a hormone that promotes the growth of cancer cells in the body. This hormone has anti-cancer characteristics through inducing apoptosis, promoting cell differentiation, and boosting anti-inflammatory and antiproliferative effects.

As a result, having a sufficient level of Vitamin D in our bodies has the potential to reduce our risk of breast cancer. Other variables, such as a sedentary lifestyle with little physical activity, smoking, being overweight, or living in colder climes, reduce the amount of circulating calcitriol.

Vitamin D in the bloodstream has the capacity to stop breast cells from proliferating. Vitamin D's activated form, 1,25 hydroxyvitamin D, is thought to have chemopreventive properties.

Not only does circulating 25 hydroxyvitamin D have chemopreventive properties, but it also inhibits the proliferation of malignant breast cells by promoting differentiation, apoptosis, and angiogenesis. Vitamin D receptor interference in healthy breast cells prevents cell proliferation and differentiation (VDR).

The expression of an enzyme termed CYP27B1 (1 hydroxylase) in mammary gland cells converts 25 hydroxyvitamin D (25(OH)D) to 1,25(OH)2D. During pregnancy and lactation, this enzyme is responsible for the formation of mammary cells. 2021) (News Medical Life Sciences).

Vitamin D is beneficial in the prevention of colorectal cancer

Vitamin D metabolites aid in the maintenance of a consistent calcium gradient in colon epithelial cells. Vitamin D levels in the bloodstream are high, which helps to keep non-cancerous cells from proliferating. Inducing the G1 phase of the cell cycle has an anti-proliferative impact.

Vitamin D helps to prevent cancer by boosting the production of growth factors and cytokines. Vitamin D also has a synergistic effect in triggering the differentiation of colon malignant cells (News Medical Life Sciences, 2021).

DAILY INTAKE OF VITAMIN D

The National Academies Institute of Medicine (IOM) has published the following vitamin D daily intake recommendations, assuming moderate sun exposure:

The recommended dietary allowance (RDA) for everyone aged 1 to 70 years old, including pregnant or lactating women, is 15 micrograms (g) per day. This RDA can alternatively be represented as 600 IU per day because 1 g equals 40 International Units (IU).

The RDA for people aged 71 and up is 20 g per day (800 IU per day).

Due to a paucity of evidence, the IOM was unable to calculate an RDA for babies. The IOM, on the other hand, determined an Adequate Intake threshold of 10 g per day (400 IU per day), which should be enough vitamin D.