The Importance of Vitamin D for immunity and Bone Health

Aug 17, 2024 | Teacher's Corner

Vitamin D is not strictly a vitamin because it is produced in the body. The sun turns a chemical in your skin into Vitamin D3 which is carried first to your liver and then your kidneys where it is transformed into active Vitamin D. It is also found in small amounts in fish and egg yolks but no other food except for fortified food.

During the years of the Covid pandemic there was a lot of discussion about the role Vitamin D plays in immunity. It was noticed that people who were dark skinned but lived in Northern climes were more prone to getting the Coronavirus. Dark skins prevent too much absorption of the sun. This is great if you live in an area where there is a lot of sun but not so good if you face days of cloud and slanted sunlight. Pigmentation can reduce Vit D production in the skin by 90%.

In the past little was known about the importance of Vitamin D in the role of the body’s immunity but today it is known to be a key factor in keeping certain conditions and illnesses at bay. Adequate vitamin D levels are essential for maintaining a balanced immune response and reducing the risk of infections, autoimmune diseases, chronic inflammatory conditions, and also certain cancers.

Vitamin D’s best-known role is to keep bones healthy by increasing the absorption of calcium. Severe deficiency causes rickets in children. Particularly concerning to older women is the link between Vitamin D deficiency and Osteoporosis. Without enough vitamin D, the body cannot efficiently absorb calcium. But because blood calcium is critical for neuromuscular and cardiac function, the body does not allow levels to fall. Instead, it pours out parathyroid hormone, which takes calcium from bone. Blood calcium levels remain normal, so your heart and nerves keep working nicely. But your bones bear the brunt: As bone calcium density falls, bones become weak and fracture-prone.

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American researchers have reported deficiencies in 41% of people aged 49 to 83, with a higher percentage among hospitalised patients. Young people are not excluded either – one study showed a quarter of people aged 18 to 29 were deficient. It would seem our indoor lifestyle and our fear of skin cancers is making us deficient. This is easily remedied by taking Vitamin D3 supplements. There is some disagreement about how much is enough but it would seem that we should be taking more than it was previously thought was enough. Also, to ensure proper transfer of calcium to the bones we also need to take Vitamin K2 as without it calcium would sit in our arteries. These days many vitamin brands sell a tablet that is a combination of the two.

(Terry Hodson )