Vitamin D: The Prohormone – It is not Just for Bones and 400 IU is too little
The more I learn about vitamin D the more I am amazed:
1. Vitamin D is very important. What I learned in medical school only talked
about calcium and bone metabolism. Vitamin D does much more than this.
2. Most of us can easily get enough by spending time in the sun.
3. Almost all of those we test (even those who live in the South) have low vitamin D levels
First a little about how vitamin D works - The Vitamin D Endocrine System
7-Dehyrocholesterol (notice cholesterol is needed here) àPre-Vitamin D3 à (THIS IS WHERE SUNLIGHT COMES IN) Vitamin D3 àLIVER with 25-Hydroxylase à 25-OH-D3 à kidney, Breast, Prostate, Macrophages + other tissues with 1-alpha hydroxylase à 1,25 (OH)2-D3 a.k.a Hormone D because it is a Hormone
Terminology (just to show how confusing it can get)
Alfacalcidol: 1-alpha-hydroxycholecalciferol, 1 alpha (OH)D3.Calcifediol: 25-HCC, 25-hydroxycholecalciferol, 25-hydroxyvitamin D3, 25-OHCC, 25-OHD3.Calcipotriene: Calcipotriol. Calcitriol: 1,25-DHCC, 1,25-dihydroxycholecalciferol, 1,25-dihydroxyvitamin D3, 1,25-diOHC, 1,25(0H)2D3. Cholecalciferol: Activated 7-dehydrocholesterol, colecalciferol, Vitamin D3. Dihydrotachysterol: DHT, dihydrotachysterol 2, dichysterol.Ergocalciferol: Activated ergosterol, Calciferol, Ergocalciferolum, Irradiated ergosterol, Viosterol, Vitamin D2. Paricalcitol: 19-nor-1,25-dihydroxyvitamin D2, Paracalcin.
Physiologic Effects of Vitamin D
- Vitamin D enhances the efficiency of the intestinal absorption of calcium and phosphorus (think of low vitamin D if you see low phosphate level). Vitamin D can increase serum calcium
- Immunomodulation (activated T and B cells also have Vitamin D receptors)
How do we get vitamin D?
Sources of Vitamin D include:
Very few foods naturally contain vitamin D. Dietary sources include eggs from hens that have been fed vitamin D and fatty fish such as herrings, mackerel, sardines, and tuna. In the US, Canada, and many other countries the main source of dietary vitamin D is fortified milk and other foods. But these are relatively minor sources of vitamin D.
In the 1930s, rickets was a major public health problem in the United States. A milk fortification program was implemented to combat rickets, and it nearly eliminated this disorder in the U.S. About 98% to 99% of the milk supply in the U.S. is fortified with 10 micrograms (equal to 400 International Units or IU) of vitamin D per quart. Although milk is fortified with vitamin D, dairy products made from milk, such as cheese and ice creams, are generally not fortified with vitamin D and contain only small amounts. One cup of vitamin D fortified milk supplies one-half of the recommended daily intake for adults between the ages of 19 and 50, one-fourth of the recommended daily intake for adults between the ages of 51 and 70, and approximately 15% of the recommended daily intake for adults age 71 and over.
Brief exposure to sunlight (about 25% of the amount of time it would take to cause light pinkness to the skin) is the most efficient way to get vitamin D. Skin exposure to the sun provides as much as 80% to 90% of the body's vitamin D stores. Full-body sun exposure can lead to the synthesis of as much as 10,000 units of vitamin D per day. Vitamin D is stored in body fat for use during periods without sun exposure.
If vitamin D can easily be obtained from sunlight why would we be deficient? Several factors converge on us:
1. Sunscreens significantly reduce vitamin D synthesis in the body,
2. Lack of sun exposure - Those above 35 degrees latitude can only make Vitamin D from March- October. The elderly, who generally have less sun exposure and less dietary vitamin D intake, may be at the greatest risk for insufficient vitamin D. Factors such as lack of exposure to sunlight.
3. Skin factors
Dark-skinned people need increased exposure to sunlight to produce the same amount of vitamin D as fair-skinned people, because the skin pigment melanin competes with vitamin D precursors in the skin for photons from UV-B light. This also affects vitamin D in breast milk. The prevalence of hypovitaminosis D was 42.4% among African American women
Age related decline in: skin synthesis of vitamin D, dietary intake, impaired intestinal absorption, and reduced metabolism to active forms of vitamin D by the kidneys. Also, vitamin D receptors seem to decrease with age.
Fat Malabsorption also decreases Vit D
In children, vitamin D deficiency causes rickets. Rickets is a bone disease characterized by a failure to properly mineralize bone tissue. Rickets results in soft bones and skeletal deformities . Rickets has recently reemerged, in particular among African American infants and children. In 2003, a report from Memphis, Tennessee, described 21 cases of rickets among infants, 20 of whom were African-American. Prolonged exclusive breastfeeding without vitamin D supplementation is one of the most significant causes of the reemergence of rickets.
Vitamin D deficiency is common in adults as well. Most of us are suboptimal in our vitamin D status which can cause:
Osteoporosis (painless) or osteomalacia (very painful). Note: Vitamin K is also very important.40-60% of individuals with fibromyalgia are vitamin D deficient. A lack of Vitamin D results in the swelling of the bone matrix and this causes intense pain (the Jello effect). With osteomalacia muscle pain and proximal muscle weakness with symptoms such as sensation of heaviness in the legs, rapid fatigue, and problems with climbing stairs and getting up from a chair.
Your vitamin D level should NEVER be below 32 ng/ml. Any levels below 20 ng/ml are considered serious deficiency states and will increase your risk of breast and prostate cancer and autoimmune diseases like MS and rheumatoid arthritis.
This correlates with 1000-5000 IU Vitamin D3 levels of >75 nmol/liter
It is all about energy – the sun. . In models of autoimmune disease, vitamin D seems to act as an immunomodulator. This might explain why increased vitamin D intake is associated with a lower risk of rheumatoid arthritis.
Vitamin D is converted to 1,25 Dihidroxy- D3 which inhibits the proliferation of benign and malignant There is some epidemiological evidence that people with vitamin D deficiency might be at an increased risk of colon, breast, and prostate cancer.
One estimate is that 23,000 American lives could be saved yearly by adequate sunlight exposure and/or vitamin D supplementation.
Vitamin D for Cancer Treatment?
Vitamin D is converted to 1,25 Dihidroxy D3 which inhibits the proliferation of benign and malignant Prostate cells
Prevent steroid related bone loss (think of this when we are going up on Cortisol or Armour?)
Decreases Blood Pressure (UVB decreases BP by 6 mmHg)
High blood pressure and heart attacks are more common in winter months and in locations farther away from the equator (conditions where sunlight is less ample). People with higher blood levels of vitamin D had naturally lower blood pressures. Vitamin D is known to lower a blood pressure raising substance in the body called angiotensin II. If your blood 25-OH-vitamin D levels is lower than 34 ng/ml your risk of heart attack is doubled, compared to people whose levels are above 34.
Osteoarthritis - Studies showed knee and hip arthritis worsened faster in patients with 25-OH-vitamin D levels below 30 ng/ml.
Improves psoriasis and probably most inflammatory conditions
SAD Depression - Studies showed vitamin D supplementation is equally or more successful in treating Seasonal Affective Disorder compared with use of a lightbox.
Decreases the risk of type 1 diabetes 4 fold (important for infants)
Decreases the risk of MS by 40%
Migraines - Women with migraines who test as deficient in vitamin D often have improvement in their migraines if they begin taking vitamin D and calcium daily.
Musculoskeletal - Several studies showed that patients with persistent muscloskeletal pain and low back pain had vitamin D deficiency and their pain improved when they took vitamin D supplements.
Polycystic Ovary Syndrome and Infertility - Calcium and Vitamin D supplementation helped all the patients with PCOS and infertility after vitamin D deficiency in one small study.
Other conditionsDiabetes, insulin resistance, epilepsy, Graves disease, ankylosing spondylitis, systemic lupus erythematosis, obesity, and rheumatoid arthritis are some other conditions that have been associated with deficiency of vitamin D and/or improvement with vitamin D supplements.
- Raises Phosphate levels
- Decreases PTH level (think of Vitamin D with high calcium that could be increased PTH)
- Improves the treatment of TB
- Decreases CHF
-treat Osteogenesis imperfecta
Dosing Vitamin D
The correct form of vitamin D to take is vitamin D3 (not D2) – this is what we have in Physicians Preference, 1000 IU / cap. Most need 2000-5000 IU a day
While it is true that vitamin D has potential for overdose, researchers are now presenting evidence that it is actually required and safe at dosages of 4,000-5,000 IU per day for adults. Dosage of 100,000 IU daily for several months in adults and 40,000 IU daily in infants for 1-4 months are likely to be toxicity inducing. You may be susceptible to toxicity at lower dosages if you have excess blood calcium levels, hyperparathyroidism, hyperthyroidism, granulomatous diseases such as sarcoidosis, Crohn’s disease, tuberculosis and certain cancers.
Vitamin D toxicity
The symptoms of vitamin D toxicity are loss of appetite, nausea or vomiting, feeling nervous or weak, itching, excessive thirst, increased urination, and elevated blood calcium levels. However, if you are supplementing with vitamin D, you probably can avoid toxicity by having your doctor regularly monitor your blood calcium and vitamin D levels. To your health!
Donald P Ellsworth, M.D.
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