Two tomatoes a day could keep the doctor away, if British scientists have their way.
A research team led by scientists at the John Innes Centre in Norwich have changed the genetic* makeup of tomatoes to become a strong source of vitamin D, which regulates nutrients* like calcium* that are crucial for keeping bones, teeth and muscles healthy.
Although vitamin D is created in our bodies after exposure* to sunlight, its major source is food, largely in dairy and meat.
Low vitamin D levels – associated with a huge range of conditions, from cancer to heart disease – affect roughly one billion people globally, the researchers said.
Co-author of the study, Professor Cathie Martin, told Australia’s 3AW radio that people in the northern hemisphere often got less sun, but they were not the only ones who were vitamin D deficient*.
“There’s a big, strong genetic component, meaning that a lot of people in Asia, particularly Southeast Asia, also suffer deficiency in vitamin D,” she said. “Plants don’t normally produce provitamin D, which is what we’ve done.
“They’re purple, the ones that we’ve engineered*. Those are genetically modified* organisms and there we introduced a couple of genes … pigments* in plants that are also supposed to have health benefits, a bit like super fruits, like blackberries and cranberries – the same compounds as in those.”
Tomato leaves naturally contain one of the building blocks of vitamin D3, called 7-DHC. Vitamin D3 is considered best at raising vitamin D levels in the body. The scientists used a tool called Crispr that worked like a pair of genetic scissors to edit the plant’s genome*, so that 7-DHC substantially built up in the tomato fruit and leaves. When leaves and the sliced fruit were exposed to ultraviolet* light for an hour, one tomato contained the equivalent vitamin D levels as two medium-sized eggs or 28g of tuna.
The researchers’ results were published in the journal Nature Plants. They are now assessing whether sunshine, instead of ultraviolet light, can effectively convert 7-DHC to vitamin D3, and it could be some time before the modified tomatoes are ready for the supermarket.
But two medium, gene-adjusted tomatoes should be enough to fill the gap in vitamin D from dietary sources, said the study’s lead author, postdoctoral researcher Dr Jie Li, who added that it was hard to tell a modified tomato from a wild one.
“They taste like tomatoes,” Professor Martin said.
What’s the deal with vitamin D?
- Vitamin D is really important for healthy bodies
- It is a fat-soluble* vitamin, both a nutrient we eat and a hormone our bodies make
- Children need vitamin D for bone growth and development and it helps us absorb calcium
Vitamin D and sunlight
- Kids need sunlight on their skin for their bodies to make vitamin D and they get about 80 per cent of their vitamin D this way
- Scientists aren’t exactly sure how much sun Australian kids need for good levels of vitamin D, but they do know it depends on where you live and the time of year
- Exercise helps your body make vitamin D, so do some daily physical activity while you’re outside in the sun
Vitamin D and food
- Most children won’t get enough vitamin D from food alone, but food with lots of vitamin D adds to the vitamin D you get from sunshine
- Foods naturally containing vitamin D include fresh fatty fish (salmon, herring, mackerel and sardines), liver, mushrooms and egg yolks
- Some low-fat dairy products, breakfast cereals and margarine have vitamin D added to them and all infant formula contains vitamin D
What happens when we don’t get enough vitamin D?
- Serious vitamin D deficiency in children can cause weak bones and joints, delayed motor development, muscle weakness, aches, pains and fractures
- Vitamin D deficiency in adults has been linked to osteoporosis*, some cancers, heart disease and diabetes
Source: Raising Children Network
- genetic: relating to genes and the origin and variation of organisms via their DNA
- nutrients: chemical compounds in food that the body uses to function properly
- calcium: most common mineral in the body, needed for healthy teeth, bones and other tissue
- exposure: experiencing or being affected by something in a particular situation or place
- deficient: lacking, incomplete, defective, inadequate in quantity or supply
- engineered: designed and created using scientific principles
- modified: changed, altered, adjusted
- pigments: plant molecules that absorb light for growth and energy
- genome: complete set of genetic information in an organism
- ultraviolet (UV): high frequency, electromagnetic radiation that can damage tissue
- fat-soluble: vitamin that can dissolve in fats and oils
- osteoporosis: condition causing bones to become thin, weak and fragile
- How many people globally are vitamin D deficient?
- What colour are the genetically modified tomatoes?
- What is the name of one of the building blocks of vitamin D, found in tomato leaves?
- After ultraviolet exposure, one tomato had the equivalent vitamin D of how many eggs and how much tuna?
- What is the name of the tool that acted like a pair of genetic scissors to edit the genome?
LISTEN TO THIS STORY
1. Eat tomatoes
Work with a partner to come up with an advertising headline and slogan to convince people to eat these genetically modified tomatoes to increase their vitamin D levels.
In your advertisement, explain the need for vitamin D in your diet and why we all need it.
Sketch your advertisement and slogan to present to the class.
Time: allow 30 minutes to complete this activity
Curriculum Links: English; Health and Physical Education; Personal and Social
How do we ensure children are getting exposed to enough vitamin D to keep their growing bodies strong and healthy? Come up with three suggestions for how to increase their exposure to sunlight.
Time: allow 15 minutes to complete this activity
Curriculum Links: English, Health and Physical Education; Critical and Creative Thinking
What happens next?
Imagine this story becomes part of an animated series made up of three cartoons. The three cartoons tell the complete story and this article is only Part 1. Think about what the rest of the story could be and draw the next two cartoons that tell the story.
Time: allow 30 minutes to complete this activity
Curriculum Links: English; Visual Arts; Visual Communication Design; Critical and Creative Thinking