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When is the best time to take your vitamin D supplement?

A study at the Cleveland Clinic showed that if you take your vitamin D with the biggest meal each day, you can increase the level of vitamin D in the blood by an average of 50 percent.

Taking vitamin D once a day may be more reliable than taking seven times the dose once a week. You’ll probably remember it better on a daily basis. If you forget to take the pill one day, just take two the next day.

This study focused on a group of individuals who were taking 1000 – 50,000 IUs of vitamin D each day as part of the medical management advised at a bone clinic in the US. Mean levels of vitamin D at the start of the study were 30.5 ng/ml (76 nmol/l). This level of vitamin D would generally be considered ‘sub-optimal’.

In an effort to boost absorption of vitamin D, individuals were asked to take their vitamin D supplements with the largest meal of the day. After 2-3 months, vitamin D levels were checked again.

At the end of the study period, vitamin D levels had risen to an average of 47.2 ng/ml (118 nmol/l) – an average increase in vitamin D levels of about 57 percent.

This study is somewhat hampered by the fact that it lacked a control group – in this case a group of individuals who continued to take their vitamin D ‘normally’ (not, explicitly, at the biggest meal of the day). It’s possible, for instance, that the individuals in this study got, say, more sun exposure during the study and it is this that accounted for the rise in vitamin D levels.

Nevertheless, it seems sensible, I think, for individuals who are currently supplementing with vitamin D to take this with their largest evening meal. It doesn’t cost anything.


Cleveland Clinic Study here: http://www.ncbi.nlm.nih.gov/pubmed/20200983

Dr Briffa Article: http://www.drbriffa.com/2010/03/16/when ... upplement/

Interesting...The only thing that worries me about taking much later in the day is that your closer to
8 hours in the day where's there's no hydration.

How about splitting it up. once in the morning then again at dinner?

shadowfax wrote:How about splitting it up. once in the morning then again at dinner?

Probably there isn't any problem to split vitamin D intake as it takes time to be absorbed. I didn't find any specific study about it.

There are a lot of people following Coimbra's Protocol that split their intake throughout the day.

But, the majority of patients take it after lunch - all at once.

A related consideration is the dosing interval – one large bolus (frequency?) or continuously. Dr. Hollis is a recognized vitamin D expert.

Dr. Bruce Hollis – Vitamin D Dosing Interval (39 min.):


Sharon McDonnell, epidemiologist at GrassrootsHealth, introduces Bruce W. Hollis, PhD, Medical University of South Carolina, who speaks on the importance of daily vitamin D dosing and why our bodies need to maintain a steady amount of D3 to reduce the risk of many diseases like cancer.

@0:52 Hollis: I've personally thought about this for a long time being involved in vitamin D biochemistry and clinical trials, and in reading the literature of how all this fits together.
@3:49 Slide explains pathway for Vitamin D and Tissue Homeostasis


@16:37 You can get away with weekly doses, monthly doses, and even quarterly doses, if you are looking at skeletal problems. But if you're looking at other problems, such as cancer suppression, immune function, we feel that these doses… Weekly dose, you know, you might get away with it, but in these other doses absolutely not – monthly doses, quarterly doses, yearly dose. If you really want to have physiologic equivalence for all these studies, you would want to do a daily dose.

From the paper by Dr. Bruce Hollis:
"The Role of the Parent Compound Vitamin D with Respect to Metabolism and Function: Why Clinical Dose Intervals Can Affect Clinical Outcomes" in the Journal of Clinical Endocrinology and Metabolism

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3849670/