Your Daily Vitamin D From Tomatoes? Gene Tweak could make it happen

News Photo: Your daily vitamin D intake from tomatoes?  Gene Tweak could make it happenBy Amy Norton HealthDay Reporter

TUESDAY, May 24, 2022 (HealthDay News)

A genetically modified tomato could one day rival salmon as a dietary source of vitamin D, if early research is successful.

British scientists have used gene ‘modification’ to produce the tomato, which is packed with provitamin D3, a precursor that the body can convert into Vitamin D.

The genetic tweak targeted an enzyme in tomatoes that normally converts provitamin D3 into cholesterol. With genetic modification, this process was disrupted, resulting in a precursor-rich tomato fruit.

The researchers said the tomato could potentially provide a similar amount of vitamin D to 28 grams of tuna or two eggs.

“We have produced a vegetable source of vitamin D3 adapted to vegans and vegetarianssaid lead researcher Cathie Martin. She is a professor at the John Innes Center, a plant science research center in Norwich, England.

That’s important, she says, because few foods naturally contain vitamin D, and they’re all animal products, including fatty fish (like tuna and salmon) and egg yolks. .

In the United States, vitamin D is also added to certain foods, such as cow’s milk and many non-dairy milks and breakfast cereals.

For this reason, vitamin D insufficiency and overt deficiency are less common in the United States than in many other places. This includes Europe, which has been “more reluctant” to add vitamin D to foods, Martin noted.

In fact, an estimated one billion people worldwide have insufficient levels of vitamin D, according to researchers.

And despite food fortification, about a quarter of Americans still have insufficient levels of vitamin D, the study authors noted. Certain groups, including the elderly and people with darker skin, are at increased risk: the body naturally synthesizes vitamin D when the skin is exposed to the sun, but this process is less effective in the elderly and those with darker skin.

Vitamin D deficiency is considered a major public health problem, as this nutrient plays a vital role in the body – maintaining strong bones, contributing to the normal functioning of nerves and muscles and supporting immune defences.

In short, says Martin, having more foods rich in vitamin D would be a good thing.

For the new work, described online May 23 in natural plants, Martin’s team turned to CRISPR technology. The tool allows researchers to precisely “cut” pieces of DNA from a gene, to modify its function.

Here, the researchers made a small modification to a tomato gene that regulates an enzyme – 7-dehydrocholesterol reductase – that converts provitamin D3 into cholesterol.

For those skeptical of “frankenfoods,” Martin pointed out that with gene editing, no foreign DNA is introduced into the plant. And the researchers found no unintended effects of the modification on other tomato genes.

Why not just take vitamin D supplements or eat fortified cereals?

“I have no problem taking a pill,” Martin said. “But it’s so much better to eat plant-based food.”

Tomatoes, she noted, provide additional nutrients like fiber, vitamin C and lycopene.

“To me, anything we can do to improve the nutritional content of our foods is positive,” said Amanda Palmer, assistant professor of international health at the Johns Hopkins School of Public Health in Baltimore.

Palmer, who was not involved in the research, studies “biofortification” – including the use of genetically modified rice to provide vitamin A and address the problem of vitamin A deficiency in low-income countries.

She called the new study “exciting” but also a first proof of concept. Many questions remain, Palmer said: How stable is provitamin D3 during storage and processing? How well is it absorbed by the body? And would it really change the vitamin D status of consumers?

Palmer noted that biofortification is typically done with staple crops that are part of a crop’s daily diet, such as rice and corn.


Vitamin D deficiency: how much vitamin D is enough?
See the slideshow

It’s unclear whether tomatoes could be consumed to a sufficient degree to have a “public health impact,” Palmer said.

The researchers believe their genetically modified tomato offers another potential benefit: Provitamin D3 levels were particularly high in the leaves of the tomato plants – which would normally be discarded. Instead, Martin said, producers could extract the vitamin from green vegetables for use in supplements.

This would not only provide an additional source of vitamin D suitable for vegans, she said, but could also give growers a financial incentive to produce the tomato.

“They could make money from the trash,” Martin said. In theory, this means that the tomatoes themselves could be sold for the same price as conventional tomatoes.

Researchers already have an answer to another crucial question about genetically modified tomatoes. “Yes,” Martin said, “they taste like tomato.”

More information

The US National Institutes of Health has more on Vitamin D.

SOURCES: Cathie Martin, PhD, professor, John Innes Center, Norwich, UK; Amanda Palmer, PhD, assistant professor, international health, Center for Human Nutrition, Johns Hopkins Bloomberg School of Public Health, Baltimore; natural plantsMay 23, 2022, online

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