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Newsletter # 17: Vitamin D

November 2023

Vitamin Focus: Vitamin D

Vitamin D deficiency is a global public health issue. About 1 billion people worldwide have vitamin D deficiency, while 50% of the population has vitamin D insufficiency. The prevalence of patients with vitamin D deficiency is highest in the elderly, the obese, nursing home residents, and hospitalized patients. Vitamin D deficiency is 35% higher in obese subjects irrespective of latitude and age. In the United States, about 50% to 60% of nursing home residents and hospitalized patients have vitamin D deficiency. Additionally, 47% of African American infants and 56% of Caucasian infants have vitamin D deficiency.


Common symptoms of vitamin D deficiency.

These include:


  • Muscle pain or cramping

  • Muscle weakness

  • Bone pain

  • Fatigue

  • Mood changes, like depression  


Benefits of Vitamin D.


Bone Health. Vitamin D has a critical role in maintaining bone health. It facilitates the absorption of calcium and phosphorus in the intestine, which are essential minerals for bone formation and maintenance. Insufficient vitamin D can lead to conditions like osteoporosis, rickets in children, and osteomalacia(soft bones) in adults. Adequate vitamin D levels are crucial for maintaining strong and healthy bones throughout life. Note: Vitamin D by itself is not an adequate treatment for existing osteoporosis.


Immune System Support. Vitamin D plays a vital role in modulating the immune system. It helps in the production of antimicrobial peptides and enhances the body's defense against infections. Research has shown that vitamin D deficiency is associated with an increased susceptibility to respiratory tract infections, autoimmune diseases, and other immune-related disorders.


Cardiovascular Health. Emerging evidence suggests that vitamin D may have a positive impact on cardiovascular health. Adequate vitamin D levels are associated with a reduced risk of hypertension, atherosclerosis, and heart disease. Vitamin D's role in regulating blood pressure and inflammation may contribute to its cardiovascular benefits.


Mood and Mental Health. Studies have linked low vitamin D levels to mood disorders such as depression and seasonal affective disorder (SAD). Vitamin D receptors are found in areas of the brain involved in mood regulation. Research suggests that vitamin D supplementation may help alleviate symptoms of depression and improve overall mental well-being.


Dementia. A recent study published by the Alzheimer Association showed a 40% reduction in Alzheimer's risk in those who supplemented with Vitamin D. The study assessed effects of Vitamin D on dementia incidence in 12,388 participants from the National Alzheimer's Coordinating Center dataset.


Cancer Prevention. One of the most intriguing areas of vitamin D research is its potential role in cancer prevention. Multiple epidemiological studies have indicated an inverse relationship between vitamin D levels and the risk of certain cancers, including breast, prostate, colorectal, and skin cancer. The mechanism behind this potential protective effect involves vitamin D's ability to regulate cell growth, inhibit angiogenesis (the formation of new blood vessels that tumors need to grow), and promote apoptosis (programmed cell death) in cancer cells.


Dietary Sources of Vitamin D. 


About 50% to 90% of vitamin D is absorbed through the skin via sunlight while the rest comes from the diet. While sunlight is a natural source of vitamin D, obtaining sufficient vitamin D from dietary sources is also important, especially for individuals with limited sun exposure or living in regions with reduced sunlight during certain seasons(like Michigan).


Common food sources of vitamin D include:


  • Fatty Fish: Salmon, mackerel, trout, and sardines

  • Cod Liver Oil

  • Egg Yolks: Egg yolks contain small amounts of vitamin D.

  • Fortified Foods: Many dairy products, breakfast cereals, and orange juice are fortified with vitamin D.

  • Mushrooms: Some types of mushrooms, such as shiitake and maitake, contain vitamin D when exposed to ultraviolet (UV) light during growth.


Measuring Vitamin D. The amount of Vitamin D supplement you need should be determined by blood levels. I would encourage patients to have their Vitamin D level(25-OH Vitamin D) checked each winter. Typically a winter level in Michigan would represent the low-point. If your doctor is unwilling to do this, you can have your level drawn without a doctor's order from several sources such as Labcorp and Quest Diagnostics. While doses averaging 2000iu/day are considered safe, many patients will require more(and some much less) to maintain a good level, especially in the winter.

Normal ranges of Vitamin D( measured as 25-OH Vitamin D) vary from lab to lab. I consider 50-75 nmol/l to be optimal. The dose required to maintain this level can vary greatly from person to person. As always, consult your Primary Care Doctor for correct dosing.


Dr Paz's Product Recommendations:




Holick, M. F. (2007). Vitamin D deficiency. New England Journal of Medicine, 357(3), 266-281.

Aranow, C. (2011). Vitamin D and the immune system. Journal of Investigative Medicine, 59(6), 881-886.

Wang, L., & Manson, J. E. (2012). Vitamin D intake and risk of cardiovascular disease in US men and women. American Journal of Clinical Nutrition, 95(2), 325-331.

Anglin, R. E., Samaan, Z., Walter, S. D., & McDonald, S. D. (2013). Vitamin D deficiency and depression in adults: systematic review and meta-analysis. The British Journal of Psychiatry, 202(2), 100-107.

Feldman, D., Krishnan, A. V., Swami, S., & Giovannucci, E. (2014). The role of vitamin D in reducing cancer risk and progression. Nature Reviews Cancer, 14(5), 342-357.

Song, M., & Giovannucci, E. (2016). Preventable incidence and mortality of carcinoma associated with lifestyle factors among white adults in the United States. JAMA Oncology, 2(9), 1154-1161.

Garland, C. F., Gorham, E. D., Mohr, S. B., Grant, W. B., Giovannucci, E. L., Lipkin, M., ... & Holick, M. F. (2007). Vitamin D and prevention of breast cancer: pooled analysis. The Journal of Steroid Biochemistry and Molecular Biology, 103(3-5), 708-711.


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