HOW TO live longer: A healthy, balanced diet is key to looking after the body and maintaining good health. Everyone knows they should be eating more fruit and veg, but citrus fruits in particular have essential health benefits.
Citrus fruits, like oranges, lemons, limes and grapefruits, are well-known for their high vitamin C content.
Vitamin C supports the immune system, helping fight off infections.
However, citrus fruits are also linked with protection against diseases such as heart disease, cancer and dementia.
"Various studies link higher intakes of vitamin C and the phytochemicals found in fruit with a reduced risk of heart disease," said the nutritionists.
According to Brewer and Kellow, one study of almost 115,000 adults found people who had the highest amounts of citrus fruits in their diet had a 28 per cent reduced risk of stroke.
For those with the highest levels of citrus juices, the risk decreased by 35 per cent.
Studies have also shown components of citrus fruits may help lower cholesterol, although much of the hesperidin, which is thought to lower cholesterol, is found in the white pith and peel.
In 2017, one study also found the risk of dementia over six years was reduced by 23 per cent in those who ate citrus fruit most days.
"More research is needed, but citrus fruits contain vitamin C and phytochemical that may help brain cells to stay healthy," said Brewer and Kellow.
Citrus fruits may also help reduce the risk of cancer of the oesophagus, mouth, larynx, pharynx and stomach by 40-50 per cent.
So which citrus fruits should be eaten in particular?
According to the nutritionists, oranges, mandarines and satsumas contain over 170 phytochemicals with anti-inflammatory, anti-tumour and antioxidant functions.
They are also rich in hesperidin, which may lower cholesterol levels, and are a good source of beta-cryptoxanthin, which is good for lung health.
Grapefruits, meanwhile, help to lower cholesterol levels. Pink and red grapefruits are also rich in lycopene, which is an antioxidant.
Lemons and limes can benefit the heart, as they enhance flavours of food without having to add salt.
Brewer and Kellow recommend choosing unwaxed citrus fruits, which should be eaten raw.
Eating the whole fruit is more beneficial than just drinking the juice, so you get more fibre.
The peel also contains considerably more antioxidants than the juice, so use the grated zest to add flavour to your dishes.
"Citrus fruits are especially rich in vitamin C, which is vital for strong immunity. This vitamin has been found to stimulate the functions of white blood cells, while as an antioxidant it protects immune cells from the damaging effects of free radicals," said Brewer and Kellow.