95.3 / 88.5 FM Grand Rapids and 95.3 FM Muskegon
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Ep. 67 – Vitamin D over-supplementation

Is a cautionary tale about vitamin D more hype than anything else? Maybe. Before you attribute a death to supplementation, it’s good to have all the facts. In this case, we don’t. I’ll let you know why we don’t on this edition of Straight Talk on Health

Welcome to Straight Talk on Health. I’m your host Dr. Chet Zelasko. Straight Talk on Health is a joint production with WGVU in Grand Rapids MI. I examine the world of health. Nutrition. Exercise. Diet. Supplementation. If there’s something new, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website drchet.com and sign up for my free emails.

Every once in a while, news about a dietary supplement “causing” a death makes headlines; such was the case when I my recently read my news feed. An assistant coroner in Surrey, U.K., declared that the cause of death for an 89-year-old man was excessive calcium build-up due to taking high levels of vitamin D supplements. He was hospitalized in May 2023 and died 10 days later. The coroner’s report, was just released 10 months later, cited the man’s vitamin D intake as a contributor to his death. That leaves us with a bunch of questions but first, a little refresher about vitamin D

Vitamin D is generally taken because, together with calcium, vitamin K, and other minerals, it contributes to bone health. In addition, the recent COVID epidemic demonstrate the benefit of vitamin D as a nutrient that is integral to boosting the immune system. While just 15 minutes exposure to sunlight per day can help us make all the vitamin D we need, we are more afraid of skin cancer than we are of weak bones. As a result, we slather up with sun block to protect our skin. The result is that we don’t get exposed to sunlight directly on our skin and don’t make enough vitamin D. In addition, those of us that live north of the Mason-Dixon Line live too far north to make vitamin D due to the angle of the sun which decreases the exposure to specific rays of the sun. As a result, many people, including yours truly, rely on vitamin D supplements to get enough vitamin D.

If we take more vitamin D than our body can process, the possibility exists that it can release calcium from the bones. The excess calcium can then settle in the coronary arteries and kidneys. As you might expect, that can seriously impact blood flow to those and all organs. In this case study, it was heart and kidney failure that were the actual causes of death.

But the coroner didn’t stop there. He criticized the labeling on the supplement bottles because it contained no warnings. More about that later. When queried by the author of the article, representatives of several U.S. medical schools talked about the “dangers” of exceeding the 4,000 IU (100 mcg) upper limit for vitamin D.

I think the man’s death was tragic, but I think everyone needs to take a deep breath. There are several issues related to this that were not talked about. Before we get into that, this is important to know.

You should know how much of every dietary supplement you take and why you take it. If you exceed the amounts recommended on the label, which are based on the country’s medical and nutrition experts, you should also know why you are taking vitamin D. But the case of the 89-year-old man who died because of an assumed excess vitamin D intake shouldn’t change a reasonable intake of vitamin D for anybody. Let’s take a look at what we don’t know.

How much vitamin D was he taking? The assistant coroner filed a complaint with the Food Standards Agency and the Department of Health and Social Care in the UK. In that report, he reported that the man’s serum levels of vitamin D was 380 but no units were given. The amounts considered to be adequate are 50 nmol/L or 20 ng/mL. It seems evident that the units reported were in nmol/L. If we use those units for vitamin D levels, 380 nmol/L would be three times higher than the amount indicating vitamin D toxicity at 125 nmol/L.

The problem is this: we don’t know how much vitamin D the man actually took. Not because they didn’t find out. It was redacted from the complaint. Why would they do that? The assumption was that he was taking a very high amount. Why hide that?

Why did the man decide to take more? Was he not feeling well? The autopsy stated that

the cause of death to be:

1(a) Congestive cardiac failure and acute on chronic kidney failure

(b) Hypercalacaemia

(c) Vitamin D toxicity

2. lschaemic Heart Disease

Someone with chronic heart disease and kidney disease might not feel all that great. He may have taken vitamin D in the hope it would relieve symptoms. That leads to another thing we don’t know.

What medications was he taking? Was he taking those at the right time in the proper quantities? I’ve dealt with in-laws and how they manage their medications the older that they got. Was someone overseeing his medications?

One more: How do we know how he processed vitamin D? The assumption was that he mega-dosed on vitamin D, but what if he simply couldn’t process it well at 89 years of age? What might have been a normal dose for another 89 year old might have triggered a negative response in this man.

Let’s talk about exceeding that upper limit of vitamin D. For adults, the Tolerable Upper Limit (TUL) is listed at 4,000 IU (100 mcg), but that includes a safety factor of 6,000 IU per day. There were no observable negative events in the literature even at 10,000 IU per day, but to be safe, it was set at 4,000 IU. What wasn’t mentioned by any of the experts for the news feed was that in some clinical trials, subjects have been given 500,000 IUs of vitamin D in a 2 day span with no associated deaths. Many trials use 50,000 IUs per week for months with no reported issues.

Also, I’ve never seen a vitamin D supplement without a recommended amount to take on the label. While true that there are no warnings on the Nutrition Facts labels in the US, they are not pharmaceuticals. Doesn’t mean they’re safe in any amount for sure but they are nutrients that should be taken responsibly. Do you read every word on the label of the supplements you take? I check the dose and the list of ingredients. It’s a given that a person would not exceed the daily dose. I hate to state the obvious but who was looking out for this man? Whether family or a facility, didn’t anyone know what he was doing? He was not in robust health to begin with and more than likely had numerous medications to control the heart and kidney disease.

I’ve never seen a warning about consuming excess medications on the prescription bottles either. Buried in the flyer that comes with the prescription, yes, but not on the label. Be honest, do you read every word on your prescription flyer? More than likely, just the side effects. That’s not an excuse but it is human nature.

Whether you’re 19 or 89, you should base your vitamin D intake on a vitamin D blood test. Vitamin D is not innocuous; take too much and it can be harmful. But there is nothing to fear in taking it in reasonable amounts to benefit your bones and your immune system. As cited earlier, physicians have prescribed 50,000 IU once a week for months to help people who need to raise their vitamin D levels. If it were not safe, it wouldn’t be used in that fashion. It also means you shouldn’t take it at a high level without guidance.

One more time, base your vitamin D intake on a vitamin D blood test and understand why you take the amount of vitamin D you take. There is no reason to get extreme; just be reasonable. I’m out of time so until next time, this is Dr. Chet Zelasko saying health is a choice. Choose wisely today and every day.


1. https://www.express.co.uk/life-style/health/1872500/supplements-vitamin-d-warning-man-dies-overdose

2. https://www.ncbi.nlm.nih.gov/books/NBK56058/

3. Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium; Washington (DC): National Academies Press (US); 2011.

Dr. Chet Zelasko is a scientist, speaker, and author. Dr. Chet has a Ph.D. and MA in Exercise Physiology and Health Education from Michigan State University and a BS in Physical Education from Canisius College. He’s certified by the American College of Sports Medicine as a Health and Fitness Specialist, belongs to the American Society of Nutrition, and has conducted research and been published in peer-reviewed journals. You can find him online at drchet.com.
Related Content