Chopping up spinach and putting it in a smoothie is the healthiest way to eat it, research suggests.
Cooking the leafy vegetable breaks down its antioxidants, while mixing it raw with yoghurt or milk helps to release the powerful nutrient lutein.
Boiling or frying spinach are sure-fire ways of destroying lutein, a study found.
Lutein helps lower the risk of heart attacks and prevents eye damage, previous research suggests.
Reseachers from Linköping University in Sweden tested different ways of cooking supermarket-bought baby spinach to see how its nutritional content changed.
They measured the lutein levels regularly and concluded the leaves are best chopped up and consumed raw alongside dairy.
'Best is not to heat the spinach at all,' PhD researcher and study author Rosanna Chung said.
'And even better is to make a smoothie and add fat from dairy products, such as cream, milk or yoghurt.'
She explained: 'When the spinach is chopped into small pieces, more lutein is released from the leaves and the fat increases the solubility of the lutein in the fluid.'
The more lutein dissolved into a smoothie, the more it can be absorbed by the body, the scientists suggested.
Whereas cooking spinach for a long time at a high heat – such as in a lasagne or frying it – is the most damaging way to prepare the green vegetable.
A meal cooked at a lower heat, like a stew, retains more of the vitamin, with heating spinach in a microwave also potentially being a healthier option, the study suggests.
Study author Professor Lena Jonasson, from the department of medical and health sciences, said: 'What is unique about this study is that we have used preparation methods that are often used when cooking food at home.
'And we have compared several temperatures and heating times.
'We have also investigated methods of preparation in which the spinach is eaten cold, such as in salads and smoothies.'
The research was published in the journal Food Chemistry.
Lutein has been shown to help reduce chronic swelling in the blood vessels of people with coronary artery disease, which can lower their risk of a heart attack.
It is also referred to as the 'eye vitamin' because lutein it is thought to protect against damage from sunlight.
Many also take lutein supplements in a bid to reduce their risk of heart disease, colon or breast cancers, and type 2 diabetes, according to WebMD.
Source: The Daily Mail