Vitamin D supplements may reduce risk of serious cardiovascular events in older people

Vitamin D supplements may reduce the risk of major cardiovascular events such as heart attacks among people aged over 60, finds a clinical trial published by The BMJ today.

The researchers stress that the absolute risk difference was small, but say this is the largest trial of its kind to date, and further evaluation is warranted, particularly in people taking statins or other cardiovascular disease drugs.

Cardiovascular disease (CVD) is a general term for conditions affecting the heart or blood vessels and is one of the main causes of death globally. CVD events such as heart attacks and strokes are set to increase as populations continue to age and chronic diseases become more common.

Observational studies have consistently shown a link between vitamin D levels and CVD risk, but randomised controlled trials have found no evidence that vitamin D supplements prevent cardiovascular events, possibly due to differences in trial design that can affect results.

To address this uncertainty, researchers in Australia set out to investigate whether supplementing older adults with monthly doses of vitamin D alters the rate of major cardiovascular events.

Their D-Health Trial was carried out from 2014 to 2020 and involved 21,315 Australians aged 60-84 who randomly received one capsule of either 60,000 IU vitamin D (10,662 participants) or placebo (10,653 participants) taken orally at the beginning of each month for up to 5 years.

Participants with a history of high calcium levels (hypercalcemia), overactive thyroid (hyperparathyroidism), kidney stones, soft bones (osteomalacia), sarcoidosis, an inflammatory disease, or those already taking more than 500 IU/day vitamin D were excluded.

Data on hospital admissions and deaths were then used to identify major cardiovascular events, including heart attacks, strokes, and coronary revascularisation (treatment to restore normal blood flow to the heart).

The average treatment duration was 5 years and more than 80% of participants reported taking at least 80% of the study tablets.

During the trial, 1,336 participants experienced a major cardiovascular event (6.6% in the placebo group and 6% in the vitamin D group).

The rate of major cardiovascular events was 9% lower in the vitamin D compared with the placebo group (equivalent to 5.8 fewer events per 1,000 participants).

The rate of heart attack was 19% lower and the rate of coronary revascularization was 11% lower in the vitamin D group, but there was no difference in the rate of stroke between the two groups.

There was some indication of a stronger effect in those who were using statins or other cardiovascular drugs at the start of the trial, but the researchers say these results were not statistically significant.

Overall, the researchers calculate that 172 people would need to take monthly vitamin D supplements to prevent one major cardiovascular event.

Research Paper:

Vitamin D supplementation and major cardiovascular events: D-Health randomised controlled trial


It seems to me that they could have learned MUCH more by testing all participants before and after supplementation. Considering the cost of doing these studies it seems like it would add very little cost.

Those very low would almost certainly benefit, but it’s nice to know for the purpose of figuring out what low actually is. I aim for 50.

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Yes, I really do think the benefits accrued to those who were vitamin D deficient as deficiency is increasingly prevalent globally.

Funny thing is though that Australia where the trial occurred has less vitamin D deficiency than most other countries.

Chalk one up for vitamin D.

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I just had my vitamin D tested. I take 5000 IU a day, and my value was still almost deficient. It’s crazy how everyone’s biology is different. I may bump up to 5000 IU twice daily.

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What was the value? D3 converts to 25OHD and there may be a limit to the rate at which you convert it (in the Liver). It is possible to buy 25OHD directly and that can increase D3 levels without putting a load on the liver.

You do, of course, have to be careful I find an iu of 25OHD is worth about 3-5 ius of D3.

It normally requires a prescription, but international pharmacies can often handle that if you send in a copy of your blood test.


My current value is 31 Ng/ml. Normal values are 30-100. So barely normal.

I heard Masterjohn say that Vitamins K, A & D influence each other’s status in the body. For what that’s worth.

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Are you taking a oil based capsule? I agree with keeping levels higher. I go for 80 ng/ml 200 nm/l

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Yes, I am taking an oil based capsule. It’s quite disconcerting.

Sunscreen kills vitamin D production. Michael Hollick talks about the other things that are produced in the skin by sunlight and he thinks on the whole it’s worth it. Try not to burn.

Since I’ve spent my entire life on the farm and the first half was on open topped tractors, trust me my skin has seen the sun. Also we used the farmer caps that don’t protect the ears. My ancestors came from northern Ireland. I’m white and get freckles instead of tan. I’ve never in my life put on sun screen.

When people on here talk about how important sunscreen is, I always cringe. The sun is your friend.

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I like to shoot for levels of 60 - 80. Since it is a fat soluble vitamin, taking with fat / food may help. I have seen some suggestions of adding probiotics to help absorption as well, but tend to just increase the dose. Most patients need 5,000 - 10,000 I/u per day of D3. On rare occasion, I have given IM injections of a compounded vitamin D if we can’t get the levels to come up.

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@Bicep I agree. I am finalizing a podcast episode with Professor Prue Hart on this exact topic. UV light provides more than Vit D. The risks of wrinkles and cancer can be managed via dose management and skin inspection. The benefits of UV light are more than skin deep, and come from regular but light dosing. Never burn but get a least a few minutes a day…more in winter. And wear a hat to protect the face and neck.


I was deficient in Vitamin D3 before I started taking supplements. I’m just surprised at the low absorption of 5000 IUs. Now I wonder if another supplement is interfering with it and if the same thing is happening to any of my other supplements.

Are you talking about patients that vit D deficient? Or just people in general?

Maybe try Cod liver oil, there is some vitamin D in those together with Vitamin E and A. Could be better absorption.
I have the same problem as you have, also supplemented with 5000IU for a while, I live in Thailand and do a lot of out door sport’s, still my levels was in the 30’s. After I tested I knew I had to do something different. So I added Cod liver oil, got a slight bump in my vitamin d levels after that. Now I am in the mid 40’s…still low but better still.
Maybe this is a genetic thing that is difficult to alter.

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Good point! In my area of the country I see mostly low and defiecient Vitamin D levels. To get my ‘ideal’ levels in the 60-80 range the most common doses are in the 5,000 - 10,000 I/u range. In general, if the level is below 30, I start with 10,000 for 3 months and then recheck levels. If just in low normal ranges (30’s,) usually 5,000 I/u.

To give some balance to the discussion, I did run across an article that showed a higher fall rate in elderly patients that were on vitamin D replacement. Its nice to see more studies coming out on vitamin D since 10 years ago most providers never checked levels and bench mark research was supportive of many positives in replacing vitamin D

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My N=1 experiments where I tracked the effect on my sleep of a largish dose (24,000/12,000) indicate it takes a few days to process a large dose and also that there is a mildly negative effect of cholecalciferol. Hence I have gone for 25OHD which simply puts up the 25OHD levels without a fuss. I still take cholecalciferol as well, but to keep at 80/200 I intermittently use 25OH (dedrogyl).

The numbers may vary with other people, but I think the idea has broader merit.


I remember there was some discussion of Vitamin-D having a U-shaped dosing benefit curve (perhaps by @John_Hemming ? — I apologize if I remembered incorrectly) perhaps from this thread (Cautions to Synthetic Vitamin D3 - #58 by John_Hemming). In it, whichever person suggested that 5,000 IU daily is too high for most normal people, and that D bioaccumulates in fat cells. I try not to venture too much out in the sun normally, and if it were up to me I’d visit beaches at night and during the winter.

For me, I had last tested in January 2023 at 32 levels and was taking 5,000 per day and, combined with heavy weights (for me) and hard “muscle-building” work at the gym, produced some nice likely hormonal changes which were clearly evident. I’ve since cut back to 5,000 every other day until I get my next reading. If I’m still at 32-ish I’ll likely push it back to 5,000 per day until it moves upward.

What is a serum level I should consider cutting back on my D intake?

There is not much good reasearch looking at serum levels of 25ohd, but i would stick to the “normal range” max 80/200 depending on units

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