Danish researchers have found that population migrations, both centuries ago and more recent ones, affect our current ability to synthesize vitamin D.
Our health is linked to the migrations of our ancestors. In Oxford Economic Papersresearchers show that the population flows of 500 years ago, from very sunny areas to places that are less, have consequences on our ability to synthesize vitamin D. The scientists have created a computer model allowing to to estimate the differences in UV exposure between a person and their ancestors, settled in a sunnier region.
The example of the great American migration
“Our results show that regions with lower UV levels, where people have settled from countries with higher UV levels, have a lower average life expectancy, and this would not have been the case in the absence of such immigration“, detail the researchers. According to them, the intensification of migratory flows from the South to the North could have consequences on life expectancy during the 21st century. They rely in particular on the example of the great migration to the United States in the 20th century: African-Americans left the territories of the South to join the North of the country, to escape racial discrimination.The Great Migration to the United States has significantly affected the health of African Americans”says Thomas Barnebeck Anderson, one of the co-authors at DailyMail. Leaving Georgia for New York represents a 43% drop in UV-R exposure from sunlight.
What are the consequences of vitamin D deficiency?
Taking into account all the factors that can have an impact on health, the researchers found that a decrease in UV-R exposure, compared to ancestors, was associated with a decrease in life expectancy. This observation is not surprising insofar as a lack of vitamin D increases the risk of death, and of diseases such as diabetes, cancer or hypertension.
Recently, researchers have found that deficient people are over-represented among patients with severe forms of Covid-19. Since October 2020, the National Academy of Medicine has recommended supplementing people who are deficient and suffering from Covid-19. It is not a question of treating or preventing the aggravation of the disease, but of supplementing the action of other drugs. Naturally present in oily fish and cod liver oil, vitamin D can be consumed in the form of food supplements. For Dr. Thomas Barnebeck Andersen, the results of this research highlight the “potential life expectancy benefits of vitamin D supplementation, especially during fall and winter“.
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