This may be a bit boring, as well as off-topic; but I was curious; so I looked up a bit more on how much to supplement vitamin D, so as to get the benefits and still be on the safe side.
What's recommended?
In the U.S., the NIH (National Institutes of Health) advises "consumers" to aim for 600 IU daily from childhood until age 70; and 800 IU from age 70 onwards. This amount can be gotten through diet or skin exposure, as well as through supplements. Beyond that, the safe upper limit for D intake is stated as 4,000 IU daily. The NIH "fact sheet" is here: ods.od.nih.gov/factsheets/V... I don't know about the U.K. but would guess similar recommendations.
As for Dr. David Grimes, the expert on Vitamin D who was interviewed in the YouTube video posted by Eryl: In a book he co-authored with Dr. David Anderson in 2020, "Vitamin D Deficiency and Covid-19", he differs from the U.S. guidelines in that he recommends somewhat higher daily intakes, but still not exceeding the equivalent of 4,000 IU/daily; the goal being to achieve "an ideal blood Vitamin D level of 40ng/ml." Toward this end, "a supplement of 2,000 to 4,000 units per day will usually achieve the target level. Alternatives are 20,000 units once week, or 100,000 units once a month."
What's too much?
Meanwhile, various experts say that taking Vitamin D above the recommended safe levels is not a good idea; e.g. a Harvard Health Publishing article titled "Taking too much vitamin D can cloud its benefits and create health risks", says that too many people are taking more than 4,000 IU per day; and many people (me among them, I will say!) have moved up to taking 1,000 IU per day, "which is beyond the dose of 600 to 800 IU recommended for most people".
That last caution seems sloppy to me, given that elderly persons above the age of 70 are in fact advised in the U.S. to take 1,000 IU per day anyway! Plus, we all have to consider how much D we are/aren't getting in your diet; and how much sun exposure we are/aren't getting.
I occasionally have gotten my doctor to send in a D3 blood test - that's how I found out one year that I was deficient & needed to supplement more. Unfortunately in the U.S., Medicare often refuses to pay for D3 testing . . . which seems a pretty stupid policy. Medicare has a lot of odd restrictions like that on what it will cover.
What about D3 and RLS?
Nothing new here. Which is to say, I still haven't found any study or other source that suggests bumping up your D3 to massive amounts would somehow cure or greatly reduce RLS. What is recommended is to make sure your D3 is not deficient, and if it is deficient, to supplement enough to get your D3 into a healthy normal range; this way, the severity of your RLS should be minimized, versus what it would be if you were still deficient in D3.
What about K2?
Right - we're still not finished, because there is also K2 to think about. My understanding has always been that K2 helps with D3 metabolism and thus has cardiovascular benefits; I have not seen a study that says it can help with RLS. Myself, I do make sure to take some K2 with D3 even so. On the other hand, a year ago Ajt0 posted about getting complete relief from RLS with "a supplement containing K2 as MK7+MK4, K1 and D3". This is in addition to Ajt0 cutting out sugar and switching to a vegetarian diet.
Myself, my K2 supplement has MK7 and MK4, but not K1. But K1 is supposed to be easily obtainable in your diet via leafy greens and vegetables; so I dunno.
The conclusion
Your mileage may vary.
- Randy
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