Vitamin D – Part I: Is Vitamin D really a vitamin? Why do we need it?

February 9, 2023

Vitamin D deficiency is a global health problem, for both developed and developing countries.

  • Approximately 50% of the global population has vitamin D insufficiency and 1 billion people have vitamin D deficiency
  • Approximately 29% of US adults >18 years have vitamin D deficiency and 41% insufficiency
  • 36% of young adults between 18-29 years had vitamin D deficiency at the end of winter
  • 1 in 10 US children have suboptimal vitamin D levels

Prohormone vs Vitamin

The current thought is vitamin D is not a vitamin after all and is actually a hormone or ‘prohormone’ as it has a chemical structure of a steroid molecule similar to the adrenal and sex hormones.  It is also derived from cholesterol just as other hormones, and circulates in the blood binding to receptors eliciting biological responses.  Vitamin D directly enhances the effects of the cardiovascular, endocrine, immune systems, and metabolic pathways.  Vitamin D is versatile and critical for health and longevity.

Many Roles of Vitamin D

Vitamin D receptors are found in almost all cells and tissues in the body and influences over 2500 genes!

Research shows many biological functions of vitamin D as well as a role in prevention and treatment of:

  • Type 1 and Type 2 diabetes
  • Multiple Sclerosis
  • Glucose intolerance
  • Hypertension
  • Alzheimer’s
  • Age-related macular degeneration
  • Autoimmune disease
  • Neuropsychiatric disorders including depression and schizophrenia
  • Chronic inflammatory disease states
  • Asthma
  • Respiratory and Lung infections
  • Cancer
  • Tumors
  • Cardiovascular disease
  • Aging as it Increases life expectancy at higher levels of normal
  • Fatigue

Studies Highlighting Vitamin D’s Role in Health and Disease

  • 82% lower risk of breast cancer in women with levels at or above 60 ng/mL compared to those with levels below 20 ng/mL
  • Women with most sun exposure between 10-19 years had a significantly reduced risk of development of breast cancer
  • 30-50% reduced risk of prostate, colorectal and other deadly cancers with optimal vitamin D status
  • Optimal levels may prevent and modify autoimmune diseases such as MS and IBD
  • Supplementation in pregnant women significantly decreases risk of preeclampsia, low birth body weight and preterm birth
  • 40% reduced risk of influenza A in school children taking 1,200 units of vitamin D per day
  • Individuals with vitamin D deficiency (<20 ng/mL) were 14 times more likely to have severe or critical COVID disease than patients with levels above 40 ng/mL
  • Vitamin D3 level of 50 ng/mL may prevent excess mortality from COVID
  • 25-33% lower odds of developing mild cognitive impairment or dementia with higher levels of vitamin D
  • Supplementation at or above 2,000 units per day may help reduce depressive symptoms
  • Upregulation of 291 genes that control 80 different metabolic processes involving DNA repair and immune function in those taking 2,000 units of vitamin D per day for several months
  • 50% increased risk of fatal stroke in those with vitamin D deficiency
  • Lower levels of D3 are associated with lower levels of estradiol and may decrease incidence of metabolic syndrome in postmenopausal women
  • Vitamin D deficiency is associated with depression
  • Normalization of D3 levels improves severity of fatigue

Vitamin D Deficiency in the Hospital

Vitamin D deficiency has been found to be the highest among the elderly and those hospitalized or institutionalized when optimal levels are needed the most!

  • Approximately 60% of nursing home residents had vitamin D deficiency
  • Approximately 57% of hospitalized patients had vitamin D deficiency

Though it is best to have optimal D3 levels prior to any hospital admission, it is imperative to request a vitamin D3 level upon admission and during any extended stay as it can predict disease course and outcomes. This is not readily ordered by doctors or healthcare providers!

Vitamin D and All-Cause Mortality

Vitamin D status and all-cause mortality has remained a controversial topic. A recently published article in the Chinese Longitudinal and Health Longevity study from 2012-2014, with mortality follow up in 2018, concluded:

  • 5% of participants were vitamin D deficient in 2012 and 68.4% in 2014
  • Deficient individuals had more than twice the mortality risk than those who had higher levels
  • Individuals with sufficient levels had a 30-53% lower risk of dying compared to deficient individuals
  • Females and the oldest old (80 years or older) showed the greatest benefit with improved vitamin D status

Conclusion:

Vitamin D has receptor sites in most cells in the body activating a myriad of chemical responses and functions in the body as evidenced by the presented research.  Vitamin D is essential in promoting a healthy body as well as decreasing morbidity and mortality.

The next blog will delve into what optimal Vitamin D levels are, how we can increase our vitamin D levels naturally, and the possibility of Vitamin D toxicity.

Have an awesome day!  Dr D

Posted in Vitamin D