That includes cabbage, spinach, kale, broccoli, spinach, beans, and peas.
The reason is that water-soluble vitamins dissolve in water - so if you boil vegetables containing these vitamins, you won't see much health benefit from them. As an alternative, don't cook them for too long if you must and use little water. She says: 'Minimise the cooking time and use small amounts of water with low heat to absorb the maximum amount of nutrients.'
'By cooking foods, especially boiling them, we lose some of these vitamins.
'The best way to keep as many of the water-soluble vitamins as possible is to steam or grill foods, rather than boil them, or to use the cooking water in soups or stews rather than pouring it away.' Lesht urged foodies not to get too worried about cooking technique.
'At the end of the day, your food needs to be palatable to you. It's more important to consume fruits and vegetables cooked and prepared the way you enjoy them than it is to be overly concerned with their bioavailability and nutrient loss due to cooking.
'In the grand scheme of things, eating a vegetable and only absorbing 50 per cent of its nutrients is still better than not eating the vegetable at all.'