The results on melatonin and MS are interesting from my point of view, mainly because they show us how complex the interaction between environmental factors and the development or course of MS is – and how unrealistic it is to hope for simple answers here. I say this mainly with a view to the implementation of the findings on vitamin D – here the impression is sometimes given as if all unclear questions about the development of MS were solved, as long as vitamin D is substituted in large quantities.
So now melatonin. Melatonin is a hormone that controls the day-night rhythm of the human body. Its formation is inhibited in the brain by light, so the secretion of melatonin increases in darkness. The hormone therefore plays a role as a timekeeper in the human body. Due to the relationships between light and melatonin, there is also a seasonal change in melatonin levels – in autumn and winter, therefore, higher melatonin levels can be found during the day than in spring and summer.
Argentinian researchers presented a much-discussed paper in the prestigious scientific journal “Cell” in September 2015, in which they showed that the relapse rate of their MS study cohort correlates negatively with the measured melatonin levels – i.e., the relapse rate was lower the higher melatonin levels were measured, which is especially the case in the autumn and winter months. Accordingly, there was also lower disease activity in the autumn and winter months in the cohort examined.
This result is confusing against the background of the vitamin D hypothesis. Vitamin D is formed by sun exposure – high vitamin D levels are therefore found mainly in the summer months. In view of the importance currently attached to vitamin D, it is difficult to explain why the Argentine researchers were able to show increased disease activity precisely in these months.
The scientists justify this with the importance of melatonin for the immune system. With their work, they impressively show how the severity of the disease in the animal model of experimental autoimmune encephalomyelitis can be alleviated with melatonin treatment. In addition, they explain how melatonin blocks aggressive T cells (so-called Th17 cells) and instead regulatory immune cells, which lead to a mitigation of the immune reaction, (so-called Treg cells) are formed more frequently. All in all, a very impressive work that speaks for a role of melatonin in the development of MS.
What does this work teach us? This work is certainly no reason to now treat MS with melatonin – the authors of this important work also warn against this – because this topic still needs to be investigated much more intensively. But I am almost certain that this work – similar to vitamin D – will be over-interpreted by certain interest groups and one or the other “healer” will advocate the administration of melatonin. In fact, the work teaches us that the relationship between the environment and the development of disease is complex, that many factors play a role and there is no easy solution – and therefore no generally valid recommendations on how to behave towards environmental influences. So, stay relaxed …
