24.09.2024 11:40
Research results
Daily vitamin D intake could reduce cancer mortality by twelve percent. But critics fear health side effects from the increased calcium levels in the blood associated with vitamin supplementation. Researchers from the German Cancer Research Center (DKFZ) recently showed that taking vitamin D or multivitamin preparations is associated with increased calcium levels. However, people with higher calcium levels were not more likely to develop atherosclerosis or kidney stones, the characteristic consequences of long-term increased serum calcium levels.
Taking vitamin D could reduce cancer mortality in the population by twelve percent – provided the vitamin is taken daily. This was recently shown by a summary of all meaningful clinical studies on this issue carried out at the DKFZ.
Vitamin D deficiency is widespread worldwide and is particularly common in cancer patients. Averaged over the year, the vitamin D blood levels of around 15 percent of German adults are below the threshold for a severe vitamin D deficiency*.
According to current studies, taking vitamin D does not protect against cancer, but it could reduce the likelihood of dying from cancer. The prerequisite for this is that the vitamin is taken daily in low doses.
Critics of vitamin D supplementation emphasize the potential risks of overdosing on the vitamin, especially if taken uncontrolled without a doctor’s prescription. Their concerns center around the vitamin’s best-known function, increasing the absorption of calcium from the intestines. Severely increased calcium levels (“hypercalcemia”) could result in kidney stones and atherosclerosis, also known colloquially as hardening of the arteries.
DKFZ scientists Sha Sha, Ben Schöttker and Hermann Brenner have now systematically investigated the dose-effect relationships between vitamin D serum levels and health-relevant aspects of calcium metabolism for the first time. The researchers were able to access the UK Biobank, which contains health data from around half a million Britons aged 40 to 69. Around 4 out of 100 biobank participants reported that they regularly take vitamin D supplements and around 20 out of 100 said they take daily multivitamin supplements containing low doses of vitamin D.
A high vitamin D serum status** in itself was not associated with increased blood calcium levels. However, when taking vitamin D or multivitamin supplements, the researchers observed a significantly increased likelihood of hypercalcemia (46 and 11 percent respectively). However, the people with increased calcium levels did not develop atherosclerosis or kidney stones more frequently.
To find out whether the hypercalcemia could have been caused by an overdose of vitamin D, the researchers compared the distribution of vitamin D levels among users of vitamin D supplements with and without the presence of hypercalcemia. No statistically significant connection with blood calcium levels was found. This means that the hypercalcemia was probably not triggered by taking the vitamin supplements, but that other causes, possibly hereditary factors, play a role.
“The study results show that taking vitamin D supplements can be considered safe in the British population. These results can be transferred to Germany. This is not surprising to us; an overdose of vitamin D only occurs when extremely high doses are taken over a long period of time. The usual vitamin D dosage in the EU is between 400 and 4,000 international units (IU) per day. In contrast, adverse effects of an overdose were only observed in clinical studies at a daily dose of 10,000 IU or more,” says Sha Sha.
“This is the largest study in the world to date in which dose-effect relationships between vitamin D concentrations in the blood, vitamin D supplementation and safety aspects of calcium metabolism were investigated. Fortunately, we were unable to establish any connection with diseases that can be traced back to an increased calcium concentration in the blood,” summarizes Ben Schöttker. “These results are highly relevant for weighing up the benefits and risks of vitamin D supplementation, because vitamin D supplementation tailored to needs in moderate doses could make an important and very cost-effective contribution to the prevention of cancer deaths and various diseases,” adds Hermann Brenner.
* The threshold value for a deficiency of 25-hydroxyvitamin D in the blood is 30 nmol/L (= 12 ng/ml). If one counts people with a less serious vitamin D deficiency (25-hydroxyvitamin D level in the blood
** A high vitamin D level is defined as a serum concentration of 25-hydroxyvitamin D of ≥100 nmol/L
Publication:
Sha Sha, Miriam Degen, Tomislav Vlaski, Ziwen Fan, Hermann Brenner and Ben Schöttker: The Safety Profile of Vitamin D Supplements Using Real-World Data from 445,493 Participants of the UK Biobank: Slightly Higher Hypercalcemia Prevalence but Neither Increased Risks of Kidney Stones nor Atherosclerosis
Nutrients 2024, DOI:
The German Cancer Research Center (DKFZ) is the largest biomedical research facility in Germany with more than 3,000 employees. Scientists at the DKFZ research how cancer develops, identify cancer risk factors and look for new strategies to prevent people from developing cancer. They develop new methods that can be used to diagnose tumors more precisely and treat cancer patients more successfully. The DKFZ Cancer Information Service (KID) provides those affected, interested parties and specialists with individual answers to all questions about cancer.
In order to transfer promising approaches from cancer research to the clinic and thus improve the chances of patients, the DKFZ operates translation centers together with excellent university hospitals and research institutions throughout Germany:
National Center for Tumor Diseases (NCT, 6 locations)
German Consortium for Translational Cancer Research (DKTK, 8 locations)
Hopp Children’s Tumor Center (KiTZ) Heidelberg
Helmholtz Institute for Translational Oncology (HI-TRON) Mainz – a Helmholtz Institute of the DKFZ
DKFZ-Hector Cancer Institute at the University Medical Center Mannheim
National Cancer Prevention Center (together with the German Cancer Aid)
The DKFZ is funded 90 percent by the Federal Ministry of Education and Research and 10 percent by the state of Baden-Württemberg and is a member of the Helmholtz Association of German Research Centers.
Contact for the press:
Dr. Sibylle Kohlstädt
Press Officer
Strategic communication and public relations
German Cancer Research Center
In Neuenheimer Feld 280
69120 Heidelberg
T: +49 6221 42 2843
E-Mail: S.Kohlstaedt@dkfz.de
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www.dkfz.de
