Vitamin D: Most of us are taking it for no reason. Are you one of them?
Vitamin D: Most of us are taking it for no reason. Are you one of them?
Hardly any supplement is swallowed as often. However, large-scale studies present a sobering picture, clearly separating those of you who are genuinely at risk from the clever marketing.
Hardly any supplement is swallowed as often. However, large-scale studies present a sobering picture, clearly separating those of you who are genuinely at risk from the clever marketing.
PVZ Editorial Team · 11 August 2026 · 4 min read
PVZ Editorial Team · 11 August 2026 · 4 min read
Vitamin D is the best-selling food supplement in German-speaking countries. It is said to strengthen bones, ward off infections, prevent cancer and boost your mood. According to surveys, up to two-thirds of people in Austria are undersupplied during the winter months because the geographical location from October to April barely allows the body to produce its own vitamin D via the skin.
Sounds like a clear case for a daily capsule, doesn't it? However, when researchers tested these big promises in randomised trials, surprisingly little of them stood up to scrutiny. The honest answer to the question of whether vitamin D supplements are useful is: it depends on who you are. And dramatically so!
What the large studies really show
The most significant study to date is the US VITAL study involving around 25,000 participants. Published in the New England Journal of Medicine in 2022, the findings showed that 2,000 International Units of vitamin D daily did not reduce the number of bone fractures in generally healthy adults, neither overall nor at the hip. [1] Prior to this, the same study had already demonstrated that the supplements had no measurable effect on cancer, cardiovascular disease, or overall mortality.
And this is not just an isolated study. The independent US Preventive Services Task Force (USPSTF) reached the same conclusion after reviewing the evidence: there is no robust benefit for preventing fractures in healthy, community-dwelling adults. [2] A large Cochrane review also found no convincing effect on mortality in the general population. [3]
Why the deficiency alarm is still justified
This is where many headlines get it wrong. "No benefit for healthy people" is completely different from "vitamin D is useless". The major studies mostly recruited people who already had adequate vitamin D levels. If you don't have a deficiency, you simply won't benefit from topping up your levels even further.
However, if you have a true deficiency, it is a completely different story. A severe vitamin D deficiency leads to rickets in children and osteomalacia (a painful softening of the bones) in adults. These conditions are very real, and supplementation reliably prevents them. So, the debate isn't about whether we need it, but rather who needs it.
These groups really should supplement
There are clearly defined risk groups for whom taking vitamin D is medically sensible and firmly established in guidelines:
Infants in their first year of life. Supplementation is standard practice in Austria to prevent rickets.
Older people in care homes who rarely get outdoors.
People with darker skin living in northern latitudes, as more melanin slows down your body's own vitamin D production.
People who cover their skin or rarely leave the house.
People with medical conditions that affect absorption, such as coeliac disease or inflammatory bowel disease, as well as those who have had certain gastrointestinal surgeries.
For everyone else, the federal public health portal explicitly does not recommend vitamin D supplements for general disease prevention in healthy adults without risk factors. [4]
How much is sensible, and when does it become too much?
The Austrian Nutrition Society suggests a guideline value of 800 International Units (20 micrograms) per day for adults, while the European Food Safety Authority sets the daily intake at 600 units. [5] The tolerable upper limit for long-term daily intake is 4,000 units.
Remember, more is not always better! Very high doses can cause calcium levels in your body to rise to dangerous levels, potentially leading to kidney stones, nausea, and in extreme cases, heart rhythm issues. High-dose monthly or annual injections, which used to be popular, are now generally advised against because some studies actually showed an increased rate of falls.
What the large studies really show
The most significant study to date is the US VITAL study involving around 25,000 participants. Published in the New England Journal of Medicine in 2022, the findings showed that 2,000 International Units of vitamin D daily did not reduce the number of bone fractures in generally healthy adults, neither overall nor at the hip. [1] Prior to this, the same study had already demonstrated that the supplements had no measurable effect on cancer, cardiovascular disease, or overall mortality.
And this is not just an isolated study. The independent US Preventive Services Task Force (USPSTF) reached the same conclusion after reviewing the evidence: there is no robust benefit for preventing fractures in healthy, community-dwelling adults. [2] A large Cochrane review also found no convincing effect on mortality in the general population. [3]
Why the deficiency alarm is still justified
This is where many headlines get it wrong. "No benefit for healthy people" is completely different from "vitamin D is useless". The major studies mostly recruited people who already had adequate vitamin D levels. If you don't have a deficiency, you simply won't benefit from topping up your levels even further.
However, if you have a true deficiency, it is a completely different story. A severe vitamin D deficiency leads to rickets in children and osteomalacia (a painful softening of the bones) in adults. These conditions are very real, and supplementation reliably prevents them. So, the debate isn't about whether we need it, but rather who needs it.
These groups really should supplement
There are clearly defined risk groups for whom taking vitamin D is medically sensible and firmly established in guidelines:
Infants in their first year of life. Supplementation is standard practice in Austria to prevent rickets.
Older people in care homes who rarely get outdoors.
People with darker skin living in northern latitudes, as more melanin slows down your body's own vitamin D production.
People who cover their skin or rarely leave the house.
People with medical conditions that affect absorption, such as coeliac disease or inflammatory bowel disease, as well as those who have had certain gastrointestinal surgeries.
For everyone else, the federal public health portal explicitly does not recommend vitamin D supplements for general disease prevention in healthy adults without risk factors. [4]
How much is sensible, and when does it become too much?
The Austrian Nutrition Society suggests a guideline value of 800 International Units (20 micrograms) per day for adults, while the European Food Safety Authority sets the daily intake at 600 units. [5] The tolerable upper limit for long-term daily intake is 4,000 units.
Remember, more is not always better! Very high doses can cause calcium levels in your body to rise to dangerous levels, potentially leading to kidney stones, nausea, and in extreme cases, heart rhythm issues. High-dose monthly or annual injections, which used to be popular, are now generally advised against because some studies actually showed an increased rate of falls.
"No benefit for healthy people doesn't mean it's useless!"
"No benefit for healthy people doesn't mean it's useless!"
"No benefit for healthy people doesn't mean it's useless!"
What does this mean for you?
Please don't take anything on suspicion, but don't rush into stopping anything either! The most sensible path forward involves three simple steps.
Be honest with yourself. Do you belong to one of the risk groups mentioned above?
A blanket blood test for everyone isn't necessary, but it certainly makes sense if you have symptoms, risk factors or feel unsure. This way, any actual deficiency can be targeted and corrected, rather than dosing in the dark.
If you do take supplements, stick to a moderate range, usually 800 to 2,000 units daily, rather than high, sudden doses.
We are delighted to help you clarify these kinds of questions at the PVZ Primärversorgungszentrum in Vienna's Josefstadt, for example during your preventive health check-up. We will look at your individual situation rather than just following a trend, and together we can decide whether a test or a supplement will genuinely make a difference to your well-being. You can easily book your appointment at Appointments and Contact.
Frequently Asked Questions
Are vitamin D supplements useful for healthy people?
For healthy adults without a deficiency and without risk factors, large-scale studies like VITAL have not shown any reliable benefit regarding bone fractures, cancer, or mortality. Taking supplements is primarily useful in cases of a proven deficiency or for defined risk groups.
Who in Austria has an increased risk of vitamin D deficiency?
Those particularly affected include infants, older people with limited sun exposure, people with darker skin tones, individuals who cover up their skin or rarely go outdoors, as well as people with intestinal absorption disorders. During the winter months, a large proportion of the population also has lower levels.
How much vitamin D per day is recommended?
As a general guide, 600 to 800 International Units (which is 15 to 20 micrograms) daily is recommended for adults. The tolerable upper limit for long-term intake is 4,000 units per day.
Can you take too much vitamin D?
Yes, you can. Taking very high doses over a long period can dangerously raise calcium levels in your blood, leading to kidney stones, nausea and, in severe cases, heart rhythm disorders. You should not consistently exceed the upper limit without consulting a doctor first.
Should I have my vitamin D levels checked?
A test for everyone isn't necessary. However, it is very useful if you have symptoms, belong to a risk group, or when a targeted treatment decision needs to be made. It is best to bring this up during your next preventive health check-up!
Sources
LeBoff MS et al. Supplemental Vitamin D and Incident Fractures in Midlife and Older Adults (VITAL). New England Journal of Medicine, 2022.
US Preventive Services Task Force. Vitamin D, Calcium, or Combined Supplementation for the Primary Prevention of Fractures. JAMA, 2018.
Bjelakovic G et al. Vitamin D supplementation for prevention of mortality in adults. Cochrane Database of Systematic Reviews, 2014.
Gesundheit.gv.at. Vitamin D: Bedarf, Quellen und Mangel. Public Health Portal of Austria, 2024.
EFSA. Dietary reference values for vitamin D. EFSA Journal, 2016.
This article is for general information only and does not replace individual medical advice. If you have any health-related questions, please consult your doctor – we would be delighted to welcome you to our PVZ clinic.
What does this mean for you?
Please don't take anything on suspicion, but don't rush into stopping anything either! The most sensible path forward involves three simple steps.
Be honest with yourself. Do you belong to one of the risk groups mentioned above?
A blanket blood test for everyone isn't necessary, but it certainly makes sense if you have symptoms, risk factors or feel unsure. This way, any actual deficiency can be targeted and corrected, rather than dosing in the dark.
If you do take supplements, stick to a moderate range, usually 800 to 2,000 units daily, rather than high, sudden doses.
We are delighted to help you clarify these kinds of questions at the PVZ Primärversorgungszentrum in Vienna's Josefstadt, for example during your preventive health check-up. We will look at your individual situation rather than just following a trend, and together we can decide whether a test or a supplement will genuinely make a difference to your well-being. You can easily book your appointment at Appointments and Contact.
Frequently Asked Questions
Are vitamin D supplements useful for healthy people?
For healthy adults without a deficiency and without risk factors, large-scale studies like VITAL have not shown any reliable benefit regarding bone fractures, cancer, or mortality. Taking supplements is primarily useful in cases of a proven deficiency or for defined risk groups.
Who in Austria has an increased risk of vitamin D deficiency?
Those particularly affected include infants, older people with limited sun exposure, people with darker skin tones, individuals who cover up their skin or rarely go outdoors, as well as people with intestinal absorption disorders. During the winter months, a large proportion of the population also has lower levels.
How much vitamin D per day is recommended?
As a general guide, 600 to 800 International Units (which is 15 to 20 micrograms) daily is recommended for adults. The tolerable upper limit for long-term intake is 4,000 units per day.
Can you take too much vitamin D?
Yes, you can. Taking very high doses over a long period can dangerously raise calcium levels in your blood, leading to kidney stones, nausea and, in severe cases, heart rhythm disorders. You should not consistently exceed the upper limit without consulting a doctor first.
Should I have my vitamin D levels checked?
A test for everyone isn't necessary. However, it is very useful if you have symptoms, belong to a risk group, or when a targeted treatment decision needs to be made. It is best to bring this up during your next preventive health check-up!
Sources
LeBoff MS et al. Supplemental Vitamin D and Incident Fractures in Midlife and Older Adults (VITAL). New England Journal of Medicine, 2022.
US Preventive Services Task Force. Vitamin D, Calcium, or Combined Supplementation for the Primary Prevention of Fractures. JAMA, 2018.
Bjelakovic G et al. Vitamin D supplementation for prevention of mortality in adults. Cochrane Database of Systematic Reviews, 2014.
Gesundheit.gv.at. Vitamin D: Bedarf, Quellen und Mangel. Public Health Portal of Austria, 2024.
EFSA. Dietary reference values for vitamin D. EFSA Journal, 2016.
This article is for general information only and does not replace individual medical advice. If you have any health-related questions, please consult your doctor – we would be delighted to welcome you to our PVZ clinic.
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If you enjoyed this article, you're probably feeling exactly the same as us: the urge to take action and really make a difference. But why stop at just reading? Come and join us, and be part of what we are building here.
