Mothers do know best. We should eat our vegetables. Research work at UCC into the health benefits of consuming more fruit and vegetables suggests there is evidence to show dietary factors may lie behind the dramatic increase in mortality from heart disease, related disorders and cancers.
This is not to rule out lifestyle factors such as smoking, obesity and hypertension, says Dr Nora O'Brien, senior lecturer in nutritional sciences, but the benefits of eating more vegetables and fruit cannot be over-emphasised.
Dr O'Brien's research team is examining how bioactive micronutrients (phytochemicals) contained in fruit and vegetables affect cell culture models in the laboratory so that the mechanism by which the interaction occurs can be better understood. There may also be commercial applications in the functional foods sector, i.e. foods designed to confer some health benefits to the consumer. Such foods, she adds, would become available only when fully supported by scientific evidence.
Heart disease and forms of cancer are the primary causes of mortality in Western countries like Ireland, Dr O'Brien says. "When one compares the principal causes of death in Western societies in 1900 to current times, some dramatic changes are apparent."
She says the primary causes of mortality in 1900 were pneumonia and influenza, tuberculosis, diarrhoea and enteritis, which together accounted for over 30 per cent of deaths. Mortality due to heart disease and cancer accounted for only 12 per cent of all deaths.
Currently, the picture is very different. "Infectious diseases account for a negligible level of total mortality, while the chronic diseases are responsible for approximately 60 per cent of all deaths," she says.
"The genetic make-up of Western societies clearly has not altered significantly in the interim. Hence, other factors are related to these dramatic changes," says Dr O'Brien.
The cost of treating chronic diseases is becoming a major burden on health services worldwide, according to Dr O'Brien, and there is increasing recognition that prevention is a better approach.
By prevention is meant the reduction of the age-specific incidence of such diseases, particularly below the 70-year-old threshold. "A very large body of evidence supports the hypothesis that increased intake of fruits and vegetables is protective against chronic disease.
"Very many expert reports published worldwide, including Ireland, over the last 30 years, have recommended increased intakes of fruit and vegetables as part of an overall strategy to prevent chronic diseases", says Dr O'Brien. For example, the World Health Organisation report, Diet, Nutrition and the Prevention of Chronic Diseases, recommended an intake of least 400 grammes of fruit and vegetables daily (in addition to potatoes) including, within that amount, at least 30 grammes of legumes, nuts and seeds.
"This represents approximately double the current average Irish intake," says Dr O'Brien.