Many opinions about [vitamin] D.
Text by Pauliina Romppanen at the Finnish daily newspaper Helsingin Sanomat, 11 December 2024. This is a non-professional translation from Finnish.
The recommended daily allowance of vitamin D is 10 micrograms but many seem to take more. Four experts tell us what they think about vitamin D. We also asked how much the doctors themselves take. The replies were surprising.
Specialist gynecologist and obstetrician Hannu Vierola, Terveystalo medical center, Iisalmi: “The current recommendation is much too low.”
“I have long been a proponent of vitamin D to be taken according to individual needs, there is no “one size fits all” vitamin D treatment.
The current recommended daily allowance of 10 micrograms per day is simply not sufficient. It may keep rickets away, but we lose out on all the other health benefits.
If everybody took one microgram of vitamin D per kilogram of body weight, the risk of developing many diseases would diminish. It would also be easy to remember: A person weighing 70 kg would take 70 and another person weighing 50 kg would take 50 micrograms.
For more than 20 years in my practice I have measured the vitamin D levels of women, including those who are pregnant, and have noticed that the current recommendation is not sufficient. For many, the vitamin D levels stay below 50 nanomoles per liter (nmol/l) even if they had followed the recommendation.
In my experience, for many people, energy levels rise and respiratory infections stay away, when the vitamin D deficiency is taken care of.
For pregnant women I recommend a daily dosage of at least 60 micrograms. A sufficient dosage of vitamin D reduces the risk of the mother developing pregnancy diabetes and of the child developing diabetes and asthma.
It is completely impossible to get enough vitamin D from food. It would also be good to take in consideration that vitamin D gets diluted in adipose tissue so overweight persons would need more of it than the recommended amount.
The ideal vitamin D level should be at least 75 nmol/l, but nutritional researchers disagree on this. According to the Finnish Food Authority a sufficient amount for one’s health is over 50 nmol/l, whereas we doctors find that, from a health perspective, the level should be higher.
According to the FinnRavinto study, for 27 percent of men and 15 percent of women the vitamin D levels where not sufficient during winter months, meaning over 50 nmol/l.
I don’t understand the precaution concerning the recommendation, the harmfulness of vitamin D is completely theoretical [translator’s comment: another person in this article says that 100 mcg is the safe upper limit for adults]. Vitamin D is clearly an easy and economical treatment.
I recommend for each Finn to, at least once in their lifetime, go and measure their levels of vitamin D during winter. And it would be a good idea for people suffering from depression to, in addition to vitamin D, go and measure their levels of ferritin and those relating to the thyroid gland.
For many in summer, the [vitamin D] level may be 100 [nmol/l], but in winter 40 [nmol/l], so it would make sense for the levels to be kept constant throughout the year. Which other laboratory value do we allow to fluctuate this much?
A special risk group are young immigrants and the elderly on whose skin only a fourth of the amount of vitamin D is produced compared to 30-year olds.
Since we know that a sufficient intake of vitamin D reduces the risk of up to 20 diseases, one must wonder about the current recommendation. It prevents the weakening of bones but also reduces the risk of getting an infection, developing diabetes and memory loss diseases.
Vitamin D is no wonder cure, but if our intake is not sufficient, it is like driving a car for years without changing the oil.
Myself I take vitamin D: 100 micrograms 5 days a week.
Assistant professor of dietary science and public health Jyrki Virtanen, University of Eastern Finland, Kuopio: There is not sufficient evidence for large vitamin D dosages.
“There hasn’t been strong evidence of the benefits of dosages of vitamin D which are clearly larger than the [official] recommendation. Considering expectations, the research results have been a quite big disappointment.
There have, however, been some signs of benefit. There seems to be a small positive effect concerning cancer deaths, as well as the alleviation of depression symptoms.
With daily dosages of 50-100 micrograms vitamin D would seem to prevent the development of prediabetes into type II diabetes. Even a correction of sugar metabolism disturbance has been seen.
A smaller dosage, 20 micrograms, would seem to prevent upper respiratory infections, but mostly in studies concerning children and teenagers. Concerning larger dosages, no additional benefits have been found.
We have ourselves studied the benefits of vitamin D supplementation in the Finnish Vitamin D Trial (FIND) study carried out 2012-2018.
We found that a 40 or 80 microgram daily dosage of vitamin D didn’t decrease the emergence of cancers or cardiovascular diseases. However the risk of atrial fibrillation was smaller for elderly persons.
The explanation for the modest research results might mainly be that the people being studied have already at the starting point of the study had their vitamin D at a good level, meaning at least 50 nmol/l, for most even a lot higher. People who participate in these studies are typically above average health conscious.
For the studies it is not possible to recruit only people with a vitamin D deficiency, because the placebo group can’t be held for several years in vitamin D deficiency, because it is an essential nutrient.
The persons studied have been allowed to use at the most 20 micrograms of vitamin D supplementation of their own. This way, large enough differences were not necessarily established between the people studied.
I don’t believe that the vitamin D recommendation will change on the public health level, because there is not sufficient evidence that there would be clear benefits from larger dosages. The recommendations always need to be founded in research.
Vitamin D is important specifically for bone health, and for this the current recommended vitamin D level of 50 nmol/l is sufficient. This level we generally attain well. The American Endocrine Association [literal translation of the name from the Finnish text] has also ended up recommending this level, having previously recommended higher vitamin D levels.
Our good level of vitamin D is above all due to the enriching of foods with vitamin D, such as milk, vegetarian milk, yogurt and margarine.
For example, according to research, in sunny southern European countries the vitamin D levels are on the average much lower.”
Myself I take vitamin D: 50 mcg per day, in the summer none.
This is how much doctors of medical centers take vitamin D:
“20 mcg per day. It is a sufficient amount.”
“60 mcg 2-3 times a week, because I forget to take it daily.”
“100 mcg per day, because then the level of vitamin D is sufficient.”
“50 mcg 3-4 times a week, because I forget to take it daily.”
“40-50 mcg per day because I engage in endurance training.”
“20 mcg per day because then vitamin D is at a good level, 60-70 nmol/l.”
“100 mcg per day because I’m older and because of the dark time of the year.
“40 mcg per day because I don’t eat fish weekly, nor do I spend much time in the sun.”
“10 mcg per day, according to the recommendation for my age group.”
Helsingin Sanomat approached three medical centers concerning how much vitamin D supplementation their doctors take themselves.
Specialist doctor in child neurology and researcher Mirjami Jolma, Päijät-Häme wellbeing services county: “There is too much precaution concerning the vitamin D recommendation.”
“Severe autism is especially common among children with an immigrant background and a suitable explanation for this is the vitamin D deficiency of the mother during early pregnancy.
I got interested in studying this subject when I noticed in my work at the autism day center of the New Children’s Hospital that most of the autistic children were from immigrant families around the world. The same phenomenon had been observed in Sweden already in the 1980s.
No genetic or cultural factor can explain this.
Many immigrant mothers in Finland don’t get enough vitamin D from food or from the sun, or they don’t take enough vitamin supplementation. Sufficient vitamin D during pregnancy is important for the development of the brain of the fetus.
In addition, there is a relationship between a vitamin D deficiency and a higher prevalence of pregnancy diabetes, pregnancy poisoning and the risk of a child being born prematurely or with a low body weight. A deficiency also increases the risk of multiple sclerosis (MS).
There is clearly insufficient guidance at maternity clinics and immigrant mothers don’t get guidance in their own language. It is a considerable problem and is also expensive for society.
I Finland we are perhaps too cautious in giving separate guidance for risk groups. These include, in addition to immigrants, vegans as well.
Vitamin D supplementation would be a very easy and inexpensive intervention considering how much human suffering a child’s severe autism causes these families. They may be in the country completely without a support network.
In vitamin D there is a vast range between the current recommendation and a safe upper limit. In my opinion we are exaggeratedly cautious about this. Myself I would recommend a daily dosage of 20 micrograms for risk groups all year around.
It would bring sheer savings also to health care expenditures, because vitamin D affects so many things within health.”
Myself I take vitamin D: 20 mcg per day from September to the beginning of May.
Professor of nutritional science Maijaliisa Erkkola, University of Helsinki: “We get enough vitamin D from food.”
“Vitamin D is often dreamed of as a savior for many things, but according to current research evidence there is no reason to raise the recommended amount or to recommend vitamin D supplementation to absolutely everybody.
There is no evidence that vitamin D levels of over 50 nmol/l would produces additional health benefits. There is, on an international level, relative agreement on this.
Such recommendations can’t be made where one would be encouraged to take some vitamin from a jar just in case. Food is its primary source and a safe one too.
Sure, if one in winter suspects that one doesn’t get enough vitamin D from one’s food, meaning that one uses little vitamin D enriched milk products and fatty bread spreads or fish, there is no harm from a supplement. For adults the safe upper limit is 100 micrograms per day.
Vegans, people with dark skin and those who don’t go outdoors much or who wear more covering clothing especially need to take vitamin D supplementation. They are part of the risk group.
I am also concerned about young people getting enough vitamin D, since they might do very radical food experiments.
It is still good to remember that for no nutrient is it [always] better with more.
If more than the recommended amount of a vitamin D supplement is taken for a long period of time, it can lead to hypercalcemia, meaning a higher level of calcium in the blood.
Often, those who take supplements are the ones who already have a good diet. If one takes a multivitamin and a vitamin D supplement there is already a very abundant intake.
I would ask stores to take responsibility concerning the sale of strong supplements. The client should always get proper guidance concerning the amounts contained in the supplements.
Doctors may recommend larger vitamin D dosages because they think of it more on an individual basis whereas nutritional recommendations are meant for the whole population.
Compared to other Nordic countries the average vitamin D situation of our population is on a much better level, because the food products which many use have been vitamin D enriched. The success of our vitamin D policy is admired elsewhere in the world.”
Myself I take vitamin D: I don’t take a supplement because I frequently eat fish and use vitamin D enriched fat free milk and fatty bread spread.