During the past decade research studies have found that annual doses of vitamin D do not provide much benefit.
There are far fewer studies publishing results with annual doses.
Mostly the studies being published since 2010 are ones which were started many years ago.
We are unaware of any new Clinical Trials using annual doses
Sometimes annual doses have actually ended up causing problems - such as more falls.
Imagine the consequences of taking a years worth of any food, supplement, or drug in a single day:
such as: salt, water, iodine, aspirin, sugar, wheat, vitamin A, etc, etc.
Vitamin D is perhaps the only item for which taking the annual amount in a single day will not cause a call to 911 or immediate death
- single high dose vitamin D not help bone loss - Feb 2012.pdf file
- Annual high-dose oral vitamin D and falls and fractures in older women: a randomized controlled trial. JAMA 2010
500,000 IU vitamin D once a year resulted in more falls
39% fewer falls with 2000 IU: example of good results when taken more frequently
- Yes, annual doses of vitamin D can be harmful – review Dec 2012 fractures
- Long time between large vitamin D injections resulted in 6X increase in health complaints – April 2014
Quarterly doses of vitamin D results in significant variation in blood levels of vitamin D - which stresses the body.
It appears, however, that the benefits of the vitamin D out-weigh the stresses of quarterly dosing.
- Quarterly vitamin D3 is too infrequent – it increases the occurrence of pneumonia – June 2012
- 50,000 IU vitamin D every 2 months for infants - 2010
- 120,000 IU vitamin D twice during pregnancy helped some – Jan 2012
- 300000 IU of vitamin D every 3 months may not have been enough – July 2010
- 200,000 every 3 months (= 2222 IU daily) to achieve 20-30 ng target
- 100000 IU of vitamin D every three months had problems – 2011
- 100,000 IU of vitamin D every 90 days was not frequent enough to prevent Diarrhea – Sept 2013
- Vitamin D dosing every three months is not often enough – found again – Jan 2016
The half-life for vitamin D for most people is approximately 1 month.
So, for most people, taking vitamin D monthly will result in a blood level of vitamin D which drops perhaps 30% by the end of the month
This variation results in some stress on the body.
Evolution has created bodies which typically experience even larger summer-winter changes in vitamin D levels
Note: there is some thought that the body needs to have variation in the vitamin D level - so should not keep it at a constant level all year long
Thus monthly doses of vitamin D appears to be NOT appropriate for people with vitamin D levels higher than 50ng/ml
- 30,0000 IU vitamin D monthly may treat MS – May 2011
- 50,000 IU monthly helped those lacking sun – Jan 2012
- Half of the seniors needed more than 50,000 IU vitamin D3 monthly – April 2011
- 100000 IU vitamin D monthly helped COPD patients – May 2011
- Vitamin D reduces pain of Menstrual Cramps – Feb 2012 taken monthly
- Giving an annual dose is an extremely poor way to discover if the person has a allergy to vitamin D
Virtually everyone can take vitamin D weekly, say on Saturday, without any problems.
Note: Should probably take vitamin D co-factors more frequently.
The body cannot take a whole weeks worth at a time and the body does not store some of the co-factors very well.
- Fraser Health in Canada is giving 20000 IU vitamin D weekly to reduce falls – Nov 2011
Monthly would have been OK, but Fraser officials were concerned that individuals might be away on the day of a monthly dose.
- Pregnant 70,000 IU loading dose then 35,000 IU weekly clinical trial
- 50,000 IU loading every 2 weeks – treatment of insufficiency clinical trial
- Adolescent Girls 50,000 IU weekly clinical trial
- Half-life of vitamin D varies with type (sun, D3, D2) and serum level
- Vitamin D dosing - weekly may be better than daily – video Aug 2018
Higher gradient (steeper slide) resulting from infrequent dosing results in more Vitamin D getting into the cells.
Note: Virtually all cells of the body can utilize/activate Vitamin D, no liver or kidney needed
Since most people take their pills on a daily basis (including co-factors) vitamin D will typically be taken daily.
Half-life = how long till half of the substance is gone (from the blood)
For people with a very low level of 10 nanograms, the response will fall by half in about 10 weeks
For people with a very high level of 50 nanograms, the response will fall by half in about 1 week
Note: Have not yet seen any study of vitamin D half-life. Would like to see one.
starting at 27 nanograms/ml, half life is about 50 days
short url = http://is.gd/D3weekly