However, his comments have provoked protest from environmental groups.
Sir John's comments contradict research carried out by the organic farming pressure group the Soil Association, which found that organic crops contain more nutrients than conventionally grown plants.
Research carried out by doctors at Oxford University has found that olive oil has protective benefits.
They found that it reacts with acid in the stomach to prevent the onset of bowel and rectum cancers.
Bowel cancer is the second-most common cancer in the UK and kills nearly 20,000 people every year. However, if it is diagnosed early it is easily treatable.
Research carried out in Spain on rats last year also suggested that olive oil could protect against the disease.
Source BBC News
An ingredient of red wine could prevent the spread of herpes, according to scientists.
Research carried out in the US has found that the compound in red wine, when daubed on infectious sores, can stop a sufferer passing it on and could even lessen the chance of sores developing fully.
The scientists suggest this compound could also be used to treat facial cold sores if rubbed onto the affected area before the sores appear.Source BBC News