Do so-called 'superfoods' REALLY boost your health?

They are hailed as the key to good health, requiring the minimum of effort. But do so-called superfoods actually have an added health benefit - or are they simply an easy way to part with cash?
From kale to chia seeds, blueberries to broccoli, these foods are credited with preventing and treating a host of diseases, from dementia to cancer. Research last year found that 61 per cent of people have bought a food or drink because it had been labelled as a superfood.  Indeed, figures show we're buying three times more quinoa, spending double the amount on kale and eating three times as many almonds as five years ago.
The theory behind superfoods is that they are particularly rich in antioxidant chemicals. These are said to mop up dangerous oxygen molecules called free radicals, thought to have a hand in everything from ageing to diabetes and cancer.

Source  - Daily Mail