6.2.2021vitamin d, covid-19, evidence based medicine, nutrition, communication, conflict of interest

Open letter to the NNR 2022 Committee

"It is unscien­ti­fic to advise people to eat healthier food, instead of taking vitamin  supple­ments, unless this method has been tested in RCT studies."

According to the principles of the ethical conduct of medicine, all parties that have an actual, potential or perceived conflict of interest should notify this conflict in scientific texts that are published in the field of medicine. The Nordic Nutrition Recommendation Comittee will produce scientific text concerning the health of people, and therefore conflicts of interest should be clearly documented.

In some countries like Finland, the national nutrition committee is nominated by the ministry of agriculture and works closely with the national food authority. The legal objective of national food authorities is normally to advance agriculture, implement agricultural policy and advance the health of animals. The health of people is not consistently included in the legal goals of food authorities.  A good example is given in the Finnish food and nutrition law, 34 a § . This means that there is a conflict of interest between agricultural policy and the health of people. A good example of this is vitamin D: According to agricultural policy, people should get their vitamin D from food and not from nutritional supplements. The supplements can be considered a threat to the economic welfare of the producers of dairy products. When this conflict of interest of the food authorities is combined with the case that ministry of agriculture nominates national nutrition committees, we have a conflict of interest, which should be documented to the nutrition recommendations, in case the writer has made his or her career in food administration or in the ministry of agriculture.

The work of the nutrition committee should start with a conceptual analysis and clarification of objectives in order to avoid an ideological bias. The committee should decide, whether its purpose is A) to make people eat healthy food or B) to make people healthy by assuring that the vitamin and micronutrient levels are good in their blood. If the committee selects objective A, this will lead to a bias against dietary supplements, and make the committee vulnerable to the pressures of agricultural policy. Nutritional committees in various countries have selected objective A as their primary goal. After decades of following this strategy, people still have unhealthy levels of vitamins in their blood. For example, in Finland 25% of the population have less than 50 mmol/l vitamin D in their blood and and 75% have less than 75 mmol/l  (Valsta et al 2018, 92) . According to common understanding, under 50 mmol/l is considered vitamin D deficiency and 75 mmol/l is considered as the requirement for a healthy immunological system. After such a failure in health policy, there might be a need to communicate more clearly to the population that sufficient vitamin D levels are hard to get from normal food - even in the case that one consumes dairy products to which vitamin D has been added. In this context, the "recommendations" given to the population are not purely a medical matter. They are a matter of communication strategy: Should we emphasize in press releases and materials that healthy food is a solution to most problems (hiding the fact that 75% of population does not get enough of vitamin D)? Or should we focus on the urgent need of the majority of the population to raise their vitamin levels, no matter what method they wish to use (not prioritizing healthy food over dietary supplements).

In order to know, which communication strategy is better, the nutrition committee should probably fund an RCT study on the topic. In this study, the 1st arm (group of test subjects) would receive a recommendation to eat more fish and dairy products to increase their vitamin D level. The 2nd arm would receive instructions to use vitamin D supplements. The 3rd arm would be a control arm, in which test subjects would continue as before. 

As we have not yet conducted such an RCT study yet, it is unscientific, and against the principles of evidence based medicine, to advise people to eat healthy food, instead of taking vitamin supplements (e.g. vitamin D). We do not yet know, which is a more effective way for improving vitamin levels in blood on the population level: Advising people to eat healthy food, or to advise people to take vitamin supplements. Please note that what needs to be tested in RCT studies is the effect of alternative communication strategies - not the effect of certain vitamins.

The need to test communication strategies in RCT studies shows vividly that decision making in health topics should not be left only to doctors of medicine, as they may not be the best professionals in the field of communication.

Dr. Pasi Malmi
Researcher of public administration and evidence based medicine


Harlin et al. (2021), chapters 5.5 - 5.7

Helsedirektoratet (2021) , call for comments to the Nordic Nutrition Recommendations 2022

Valsta et al (2018), page 92