Vitamin D3 acts like a hormone, regulating mineral metabolism for bones and other organs. It increases intestinal absorption of magnesium, calcium and phosphate. It is important for healthy skeletal, bone, and teeth growth, increases bone density and prevents osteoporosis and fractures, prevents rickets and osteomalacia (softening of bones), may be required for brain cell growth, may reduce age related mental decline, stimulates production of insulin, helps prevent high blood pressure, may help prevent cancer and heart disease, helps regulate the inflammatory response and prevent autoimmune diseases like rheumatoid arthritis, type 1 diabetes, psoriasis and irritable bowel disease. Vitamin D is mainly made in skin exposed to sunlight, but is also found in cod liver oil, as well as egg yolk, salmon, mackerel, tuna, sardines, and crimini mushrooms exposed to UV light.
Quick Facts
-A group of related steroids, the most important of which are D3 and D2
-Acts like a hormone, regulating mineral metabolism for bones and other organs
-Increases intestinal absorption of magnesium, calcium and phosphate
-Helps maintain bone health, prevents cardiovascular disease, autoimmune disease, cancers and cardiovascular disease
-Not water soluble [58]
-”Main role is to maintain healthy calcium levels in the blood, helps maintain healthy levels of calcium and phosphorus
– Important for healthy skeletal, bone, and teeth growth, increases bone density and prevents osteoporosis and fractures, prevents rickets and osteomalacia (softening of bones), may be required for brain cell growth, may reduce age related mental decline, stimulates production of insulin, helps prevent high blood pressure, may help prevent cancer and heart disease, helps regulate the inflammatory response and prevent autoimmune diseases like rheumatoid arthritis, type 1 diabetes, psoriasis and irritable bowel disease, long term supplementation may reduce risk of multiple sclerosis [160]
-“Every fall, leading into winter, the sun sets further and further into the south. The days get shorter and the sun’s rays diminish in duration and intensity. This is when D3 (“The sunshine vitamin”) blood levels drop in mammals. That imperceptible signal results in profound behavioral changes that are easily observed in foxes, bears, and many other land roaming creatures: their activity slows while their foraging increases. They are fattening up their calorie stores for the long winter’s hibernation. With the advent of spring, the bright summer sun’s UVB rays once again bathe their skin and fur. This is where abundant D3 is synthesized from the photo-transformation of cholesterol. This hormone-like vitamin slowly absorbs into the bloodstream where it is delivered to the liver, then to the kidneys, where it is finally converted into the activated form of vitamin D. Rising levels of activated D signals renewed growth, heightened metabolic activity, better immunity, sharpened reproductive instincts, and accelerated tissue repair/regeneration. For millions of years, rising vitamin D levels were synonymous with health, healing and vitality in our mammalian relatives.” [174]
RDI
Males 19 – 30 yrs: 20 μg (800 IU)
Females 19 – 30 yrs: 20 μg (800 IU)
[128]
Deficiency
-May lead to type 2 diabetes because it is required for production of insulin from cells and some studies demonstrate a link between Vitamin D deficiency early in life and type 1 diabetes, rickets, muscle or bone pain (low back pain), frequent broken bones, osteoporosis, higher risk of periodontal disease (disease of tissues that support the teeth) in those over 50 years old, rheumatoid arthritis, increased risk of diabetes because of insufficient insulin, increased risk of high blood pressure, low calcium levels which are associated with muscle cramps, twitching nerves or muscles, numbness and tingling in fingers and toes, irregular heart contractions, and irritability. [160]
Toxicity
-A maximum daily dosage of 5,000 IU is recommended per day.
-188,000 IU per day in one case caused fatigue, forgetfulness, nausea, vomiting, slurred speech and other symptoms. Other cases are similar [175]
-Lethal doses in rats measured by LD50 (where half of the rats die at this dose) were 42 mg/kg (1.68 trillion IU / kg – so about 100 trillion IU say for the average person – pretty safe!) [176].
-Can elevate calcium absorption causing blood calcium to reach dangerous levels
Sources
Mainly made in the lower layers of the skin when exposed to UVB rays, which are in sunlight, also in high levels in cod liver oil, and lower levels in egg yolk, salmon, mackerel, tuna, sardines, and crimini mushrooms exposed to UV light [58]
*Bioavailability increases when consumed with fats
