Gene-edited tomatoes could be a new source of Vitamin D

Vitamin D plays a vital role in maintaining our health. It is manufactured by the body after the skin's exposure to sunlight, and another major source is food. Fish and dairy products provide the best dietary sources of Vitamin D, which means that it is often hard for people following a plant-based diet to get enough.

The leaves of tomatoes contain one of the building blocks of Vitamin D3, called provitamin D3 or 7-dehydrocholesterol (7-DHC), although only normally at very low levels. Furthermore, provitamin D3 does not occur in the tomato fruits themselves at all.

Coding tomatoes to contain vitamin D

Sources of vitamin DNow, researchers at the John Innes Centre in Norwich have used CRISPR-Cas9 gene editing to make revisions to the genetic code of tomato plants so that provitamin D3 accumulates in the tomato fruit. The leaves of the edited plants contained up to 600 ug of provitamin D3 per gram of dry weight. (The recommended daily intake of Vitamin D is 10 ug for adults.)

Forty percent of Europeans have vitamin D insufficiency

The researchers used gene editing to turn off a specific molecule in the plant’s genome which increased provitamin D3 in both the fruit and leaves of tomato plants. It was then converted to vitamin D3 through exposure to UVB light.

Biofortifying tomatoes

“We’ve shown that you can biofortify tomatoes with provitamin D3 using gene editing, which means tomatoes could be developed as a plant-based, sustainable source of vitamin D3,” said Professor Cathie Martin, corresponding author of the study which appears in Nature Plants.

“Forty percent of Europeans have vitamin D insufficiency and so do one billion people world-wide. We are not only addressing a huge health problem, but are helping producers, because tomato leaves which currently go to waste, could be used to make supplements from the gene-edited lines.”

Vitamin D insufficiency, is linked to higher risk of cancer, dementia, and many leading causes of mortality. Studies have also shown that vitamin D insufficiency is linked to increased severity of infection caused by SARS-CoV-2 / COVID-19.

great news for people adopting a plant-rich diet

First author of the study Dr Jie Li said: “The COVID-19 pandemic has helped to highlight the issue of vitamin D insufficiency and its impact on our immune function and general health. The provitamin D enriched tomatoes we have produced offer a much-needed plant-based source of the sunshine vitamin. That is great news for people adopting a plant-rich, vegetarian or vegan diet, and for the growing number of people worldwide suffering from the problem of vitamin D insufficiency.”

As Chief Scientist, John Cristofides explains, "About 90% of circulating vitamin D is derived from the action of the UVB component of sunlight on the skin. The remaining 10% of circulating Vitamin D is derived from dietary sources, which  include margarine, some breakfast cereals and liver but oily fish are particularly rich (mackerel, herring, sardines, salmon and fresh, not tinned tuna), whilst eggs, butter, beef and vegetable oils are a relatively poor source." 

The organ that stores urine. Full medical glossary
Abnormal, uncontrolled cell division resulting in a malignant tumour that may invade surrounding tissues or spread to distant parts of the body. Full medical glossary
A substance present in many tissues and an important constituent of cell membranes although high concentrations of a certain type of cholesterol in the blood are unhealthy. Full medical glossary
Decline in mental capacity, brain functioning and memory that affects day-to-day living. Full medical glossary
The basic unit of genetic material carried on chromosomes. Full medical glossary
Relating to the genes, the basic units of genetic material. Full medical glossary
Invasion by organisms that may be harmful, for example bacteria or parasites. Full medical glossary
A large abdominal organ that has many important roles including the production of bile and clotting factors, detoxification, and the metabolism of proteins, carbohydrates and fats. Full medical glossary
An outbreak of infection that affects numerous people in different countries. Full medical glossary
septic arthritis Full medical glossary
Essential substances that cannot be produced by the body and so must be acquired from the diet. Full medical glossary