They are the little blue fruits which put the ‘super’ in superfoods.
Blueberries are jam-packed with health-boosting compounds which have been linked to seemingly endless health benefits.
From the Holy Grail of slowing the ageing process to fighting devastating ailments like heart disease and Alzheimer’s, blueberries have been hailed in numerous studies.
A recent study placed them top of the list when it comes to antioxidant activity – compared to 40 other fresh fruits and vegetables.
Scientists at the US Department of Agriculture Human Nutrition Center put them top of the crops for mopping up harmful by-products of metabolism in the blood, known as free radicals.
They have been poked, prodded and ripped apart in a series of tests which have also detected other chemicals in the berries which reduce harmful cholesterol levels and even prevent bladder infections.
But while scientists continue to seek out the health boosting qualities, blueberries have even been used to treat the likes of cystitis since medieval times.
Now it seems the old wives knew what they were doing.
* Reduce signs of ageing
Blueberries, along with other colourful fruits and vegetables, contain high levels of antioxidants.
These compounds help to mop up damaging oxygen free radicals in the blood, which can damage cell membranes and DNA through a process known as oxidative stress.
Free radicals cause many of the physical signs of ageing.
Recent work indicates that blueberries contain compounds with anti-cancer properties.
They act to induce enzymes that protect against cancer and reduce rapid tumour growth.
Antioxidants also help to prevent or delay the onset of certain diseases, such as cancer.
*Ease the symptoms of Diarrhoea
In Sweden, dried blueberries are used to treat childhood diarrhoea.
Anthocyanoside compounds are believed to kill the E. Coli bacteria, which is sometimes linked to the infection.
Researchers at Tufts University in Boston found that ageing mice who were given blueberry extract improved their balance, coordination and short term memory.
Anthocyanin, which gives the blueberries their strong purple colour, appears to protect the neurons in the brain.
*Help treat bladder infections
Researchers at Rutgers University in New Jersey have identified a compound in blueberries that promotes urinary tract health and reduces the risk of infection.
It appears to work by preventing bacteria from adhering to the cells that line the walls of the urinary tract.
*Reduce the risk of heart disease
Blueberries may reduce the build up of so called ‘bad’ cholesterol, or LDL, that contributes to cardiovascular disease and stroke, according to scientists at the University of California at Davis.
Dr Agnes Rimando, of the US department of Agriculture team said: ‘We are excited to learn that blueberries, which are already known to be rich in healthy compounds, may also be a potent weapon in the battle against obesity and heart disease.’
*Help improve your eyes
Blueberries seem to be able to boost night vision.
One study showed that when Israeli fighter pilots were given regular doses of blueberry, their night vision significantly improved.
Scientists believe that this happens because compounds in the berries enhance capillary elasticity and permeability of the eye.
Blueberries are a rich source of folic acid, which may benefit the foetus during pregnancy.
The tiny fruit are also rich in potassium, which is essential for blood pressure control.
High blood pressure during pregnancy can contribute to the pregnancy complication preeclampsia so keeping good blood pressure control is important.
The berries also contain vitamin C, calcium, and other nutrients.
The fibre in blueberries can also stop common conditions in pregnancy including haemorrhoids and constipation
*Help your digestion
The more fibre in your diet, the better your digestive health. Blueberries are an excellent source of dietary fibre.
A handful of the berries contain around one tenth of the daily recommended intake of dietary fibre.