Scientists at the German Cancer Research Center support the systematic enrichment of foods with vitamin D. Their calculation models show that the addition could prevent around 130,000 cancer deaths in Europe.
Vitamin D is considered to be a booster for the immune system. In a new study, scientists from the German Center for Cancer Research (DKFZ) now show that the vitamin helps reduce cancer mortality. Researchers have determined that foods in 34 European countries are fortified with vitamin D, thus preventing around 27,000 cancer deaths each year. According to the model’s calculations, if all countries enriched foods with adequate amounts of vitamin D, around 130,000 cancer deaths in Europe could be prevented. That would be about nine percent. Cancer researchers are therefore calling for foods to be systematically enriched with vitamin D.
However, the vitamin D supplement probably wouldn’t prevent cancer by itself, says Tobias Niedermaier, a member of the study, but only cancer deaths. In an interview, the cancer researcher explains what’s behind this difference.
What do we know about the connection between vitamin D intake and cancer? How does Vitamin D counteract this?
Niedermaier: Vitamin D does not reduce the risk of cancer, but it does reduce the risk of dying from cancer. It has a variety of effects on the immune system and basically has an immunomodulatory effect. It suppresses the factors that favor cancer, the so-called oncogenes and chronic inflammatory reactions. The assumption is that the multiple effects of vitamin D on the entire immune system and especially on cancer cells increase the chances of cancer survival. Always in addition to established therapies, not in any way substitute.
The immune system also plays a crucial role when it comes to eliminating the cancer cells that occur in our body every day. Does vitamin D not support the immune system in this daily struggle and in this sense does it have a preventive effect?
Niedermaier: This cannot be ruled out, but there are insufficient data to suggest that vitamin D supplementation reduces the risk of cancer. However, there are plausible reasons to assume that a reduction in cancer risk, even if it exists, has not been found by previous studies. This includes, for example, that comparison groups often also took vitamin D or that vitamin D was given in the wrong form, for example in insufficient doses or in very high monthly doses instead of small daily doses.
What was the basis of your investigation?
Niedermaier: The cornerstone was a meta-analysis of randomized trials, according to which administration of vitamin D tablets in a dosage of 400 international units per day reduces cancer mortality by 11%.
But surely not all studies have reached this eleven percent?
Niedermaier: No For example, it was 15% in the 800 units per day study and 17% in the 2,000 units per day study. Cancer mortality therefore tended to decline more markedly in studies with higher daily doses. 400 units is the size that could realistically be reached with the food fortification.
Preparations have been provided in the studies, why do you advocate fortifying foods with vitamin D?
Niedermaier: I had recently published a study with colleagues for which we had reviewed the literature on accumulation and serum levels. The question was, when you eat fortified foods, how much does your serum vitamin D level increase? We found that the range of serum elevations was virtually identical to the serum elevations in studies administering 400 units per day in tablet form. Our conclusion: If food is adequately fortified with vitamin D, serum increases similar to those obtained with vitamin supplements can be achieved.
But is fortifying food then the best way?
Niedermaier: Only a minority of the population takes vitamin D tablets. Fortifying foods would get people out of their vitamin D deficiency almost automatically. Just like iodized table salt has long been commonplace and has greatly curbed the previously widespread iodine deficiency and its consequences. It would be a simpler, cheaper and more effective way to improve vitamin D levels in the population.
Adding something to a finished product is easy. But if I consciously eat healthy, I don’t sprinkle vitamin D on my broccoli.
Niedermaier: Right. But you can fortify a series of foods that are absolutely fundamental that everyone consumes or should consume: orange juice, bread, milk, yogurt, oat milk, cereals … It is not that you can fortify everything, because even through processing and vitamin D preparation is lost. But the range of suitable foods is wide enough to reach everyone.
The press release cites the United States, Canada and Finland as example countries where this has already been done. Are “the” three or how common is enrichment?
Niedermaier: It is not particularly widespread in Europe. The only countries that are significantly enriching are Finland and the United Kingdom and, to a lesser extent, Iceland and Sweden. Other than that, there is no country that would systematically get rich.
What conclusions could you draw from where vitamin D was added to food?
Niedermaier: There is a study that compared serum levels in Finland in 2000 and 2011. Of the 6,000 Finns involved in the study, only 44% had an adequate intake of vitamin D with serum levels above 50 nanomoles per liter in 2000. Milk , dairy products, margarine, orange juice and cereals have been systematically enriched with vitamin D since 2003. And in 2011, more than 90 percent were sufficiently supplied with vitamin D. This shows that even in a country with long, dark winters, food Fortifying with vitamin D can greatly reduce the spread of a deficiency. It is well known that fortification is effective.
Do you also have corresponding values for Germany?
Niedermaier: There is a study by the Robert Koch Institute with a representative group of the population through the seasons. About 30% were poorly cared for and another 31% had suboptimal care. 38 per cent were adequately supplied, in any case on an annual average. Of course, this varies, in the winter around 50 percent are inadequately supplied and less than 20 percent are adequately supplied. There is still a lot of room for improvement in Germany when it comes to vitamin D intake.
For humans, sunlight is the main source of vitamin D production, not so much from food …
Niedermaier: Exactly. The problem is that most of the population in Germany has a vitamin D deficiency throughout the year or at least a suboptimal supply. Because the sun’s rays are not intense enough in the winter and you should protect yourself from the sun’s rays even in the summer. The golden mean is right. If you are attempting to expose yourself to the sun, as many parts of your body as possible should be exposed to the sun, but not too long to avoid sunburn. The duration varies according to the type of skin and the season, which cannot be said in general terms.
They say the more vitamin D is given, the better the results will be …
Niedermaier: I assume that with 400 units per day the potential is not yet exhausted. If someone takes 400 units per day from food, including systematically fortified ones, there is still the potential for a few percentage points of further reduction in mortality if, for example, they take another 1000 units per day via pills.
Is there a risk of overdose?
Niedermaier: Of course, you shouldn’t overdo it. Up to 4000 units per day are considered safe. You cannot overdose on sunlight, the body shuts down production in good time if exposed to high levels. An overdose from food supplements is theoretically possible. In practice, this happens perhaps a handful of times a year. There are very highly fortified preparations, 20,000 units in one capsule. The recommendation is therefore to take one of these capsules every 20 days. If you take one of these capsules – or even more – per day, it is entirely possible that you have problems. Too much vitamin D leads to high levels of calcium in the blood, which can also be very dangerous. It is important to note that if the food is fortified in the usual quantities, there is no risk of overdose.