Perhaps not everyone knows that vitamin D deficiency causes many problems for humans: damage to the bone metabolism, to the immune system, it can cause inflammatory intestinal and even neurological diseases. Still, the daily intake is not easy, even if it is contained in everyday foods, such as eggs, milk, salmon, cod liver oil. In vegetables, however, it is almost completely absent.
Precisely for this reason the Institute of Science of Food Production of the CNR, in collaboration with the John Innes Centre of Norwich, has designed a new line of tomatoes that can counteract vitamin D deficiency. The study was published in the journal Nature Plants.
Vitamin D: what it is, what it is for, who needs it (all)
by Cinzia Lucchelli
02 April 2022
About a billion people in the world suffer from this shortage, about 40% of the European population, 26% of the American and 20% of the Eastern population.
It happens for various reasons, starting with an inadequate food availability, or for special diets, such as vegan. “A lot also depends on the intestinal absorption of each individual person, very low especially in the elderly,” he explains Angelo Santinoone of the authors of the study, senior researcher CNR ISPA (Institute of Food Production Sciences).
Once taken, the conversion from pro-vitamin D2 or D3 found in foods to vitamin D occurs by exposing the skin to UV radiation, which however carries serious risks such as skin cancer.
Why the tomato?
The tomato represented that extra possibility of having another source of vitamin D. But why him? “Because unlike other vegetables – continues the researcher – the tomato has the biosynthetic machinery capable of producing provitamin D3, as it generates minimal quantities of cholesterol for the synthesis of some defense compounds. The provitamin is transformed into cholesterol by the enzyme 7-dehydrocholesterol reductase 2. We thought that silencing this enzyme could produce more provitamin D3. ” And so it was.
Vitamin D, when it is necessary to supplement it
by Simone Valesini
05 December 2021
Pro-vitamin D3 and genome editing
Thanks to CRISPR / Cas9 genome editing, the researchers introduced a small modification in the tomato gene that codes for the 7-dehydrocholesterol reductase 2 enzyme, involved in the conversion of provitamin D3 to cholesterol, without affecting the rest of the genome. By stopping the conversion, they achieved an accumulation of provitamin D 3 in the fruits and leaves, which was converted into vitamin D by treatment with UV-B light.
Two tomatoes a day
“We created five lines, made backcrosses to remove everything that was external to the tomato genome. Thus, in the second generation, there is no DNA extraneous to that of the plant”, continues Angelo Santino. Two bio-fortified tomatoes a day might be enough for a sufficient supply of vitamin D.
“Now we begin to observe the beneficial effects on health, especially on intestinal inflammation, then we should move on to clinical trials. The British colleagues have already had the approval for the production in the open field, which starts in June in Great Britain”.
And this is the sore point: perhaps, for the first time, Italy will have to import tomatoes from Great Britain, even if bio-fortified.