As others have said, diet isn't a source of vitD *but* saturated fats are needed to make vitD bioavailable & that's why vegetarians have a hard time increasing their vitD.
Vitamin D3 deficiency has become an epidemic, probably because people are washing daily. If you wash skin exposed to the sun within 48 hours, you wash off the oils where the vitamin D production starts. In northern latitudes (above that of Atlanta, Georgia) the sun is at too low an angle for half the year to provide sufficient UV radiation. If even available, UVB rays are only accessible while the sun is directly overhead. Most people need to take vitamin D, especially seniors, as the ability to synthesize vitamin D in the skin declines with age.
With exposure to sunlight in the summer, the body can generate up to 20,000iu of vitamin D per hour with no ill effects. In addition, no adverse effects have been seen with supplemental vitamin D intakes up to 10,000 IU daily.
Vitamin D3 is not a vitamin at all but a necessary hormone that effects the immune system, bones & nearly every aspect of health. Having low Vitamin D levels greatly increases risk of cancer, heart disease, diabetes, MS & being deficient can create or greatly exacerbate health problems. Many researchers claim that optimized vitamin D levels are more effective than a flu shot in preventing viral infections.
Always take your vitamin D with a fat-containing meal to ensure absorption.
Some prescription vitamin D supplements are the wrong type (ergocalciferol - vitamin D2). As warned by the National Institute of Health -
Luckily you can buy vitamin D3 (cholecalciferol) over the counter and the upper limits are extremely high. U.S. RDA are much too low. Current recommendations from researchers are for 35iu per pound - a 143# person needs minimum of 5000iu per day (which is for minimal needs and does not replenish depleted stores) & the rda is 600iu.
Research published by Grassroots Health from the D*Action study shows that 97.5% of the adult population needs to take 14,100iu's of vitamin D per day in order to elevate their levels above 50ng/ml, which they believe is the best for disease prevention & Universal intake of up to 40,000 IU vitamin D per day is unlikely to result in vitamin D toxicity.
Your vitamin D level should never be below 32 ng/ml, and any levels below 20 ng/ml are considered serious deficiency states, increasing your risk of as many as 16 different cancers and autoimmune diseases like multiple sclerosis and rheumatoid arthritis, just to name a few.
They found that the body does not reliably begin storing cholecalciferol in fat and muscle tissue until 25(OH)D levels get above 50 ng/ml (125 nmol/L). That is, at levels below 50 ng/ml (125 nmol/L), the body uses up vitamin D as fast as you can make it, or take it, indicating chronic substrate starvation—not a good thing. 25(OH)D levels should be between 50–80 ng/ml (125–200 nmol/L), year-round.
The cheapest source I've found for vit D3 -
preferred recommendation - Country Life Vitamin D3 in MCT -- 5000 iu - 200 Softgels $8.62
2nd option - Vitacost Vitamin D Drops -- 2000 IU 900 servings - 1 fl oz = 365 days at 4960 iu $9.99
cheapest - 10,000 iu vit D for 365days $16.99 = $1.42 for a month's supply
Quick, free, self test of *severe* vitamin D deficiency -
Sternum and both tibia feeling pain when pressed probably represents vitamin D <20-25 ng/ml
If "yes" to both of these tests then you have a 93% chance of being Vit. D deficient.
Order the Correct Test. There are two vitamin D tests -- 1,25(OH)D and 25(OH)D.
25(OH)D also called 25 hydroxy is the better marker of overall D status.
Vitamin D, 25 Hydroxy regularly $59
Symptoms of acute vitD deficiency can include -
Weakness, Sadness, Listlessness, Tiredness, Muscle-Pain,
Twitching, (Eyelid, Arm, or Legs)
fingernails have small white spots,
Standing causes back, hip, groin, and/or leg pain.