Press release, 2 October 2006
PURE FRUIT AND VEGETABLE JUICES AS GOOD AS WHOLE FRUIT & VEGETABLES IN PROTECTING AGAINST CHRONIC DISEASES

The commonly-held view that pure fruit and vegetable juices are nutritionally inferior to whole fruit and vegetables, in relation to chronic disease risk reduction, is unjustified according to a new report published in The International Journal of Food Sciences and Nutrition.

A diet rich in fruit and vegetables has long been associated with protection against cardiovascular diseases (CVD) and several common cancers. Although fruit and vegetables contain a range of vitamins, minerals and trace elements it has been the general belief that the preventative health benefits are down to soluble fibre and/or one or more antioxidants. However, a new comprehensive review of published studies conducted by Dr Carrie Ruxton an independent dietitian and Dr Drew Walker, Director of Public Health for Tayside, found that the impact of fruit and vegetables may relate more strongly to antioxidants than to fibre.

This is particularly the case for colo-rectal cancer where consumption of insoluble, rather than soluble, fibre seemed to be associated with risk reduction. Epidemiological data suggested at least similar associations between chronic disease risk and pure fruit and vegetable juices or whole fruit and vegetables. Meanwhile, clinical data appeared to give more weight to antioxidants and phenolic compounds, rather than soluble fibre, for cancer and CVD risk reduction.

Dr Ruxton comments “There is clear evidence to suggest pure fruit and vegetable juices impact favourably on a number of CVD risk factors, particularly platelet aggregation, LDL cholesterol oxidation and LDL cholesterol concentrations (in those with hypercholesterolaemia).

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“Initially, antioxidant vitamins were thought to explain the majority of health effects related to consumption of pure fruit and vegetable juices. However, other antioxidant nutrients, chiefly polyphenols, have been shown to be active juice constituents.”

Concord purple grape juice, which is rich in polyphenols, was found in several studies to significantly reduce on blood platelet aggregation. Three studies compared purple grape juice with other beverages e.g. orange juice, grapefruit juice, red wine and white wine, finding the strongest anti-platelet effects for purple grape juice, with red wine also showing significant effects. Further studies showed that tomato juice also decreased platelet aggregation.

In other studies, purple grape juice variously reduced blood pressure in hypertensive people, inhibited LDL oxidation and demonstrate an antioxidant effect. Studies on cranberry juice and apple juice also found inhibition of LDL oxidation. Citrus fruit juice was found in a large epidemiological study to be protective against the risk of ischaemic stroke.

The potential impact of pure fruit and vegetable juices on cancer is less clear. Dr Ruxton explains “It is evident that polyphenols and other antioxidant compounds found in pure juices exert cancer-protective effects via a decrease in oxidation and other damage to DNA. Whilst further long-term studies are needed, the weight of evidence for pure juices seems similar to that for whole fruit and vegetables since it is not clear than soluble fibre plays a key protective role in cancer prevention.”

Dr Walker concludes “When considering cancer and coronary heart disease prevention, there is no evidence that pure fruit and vegetable juices are less beneficial than whole fruit and vegetables. Thus, policies which maintain that pure fruit and vegetable juices are somehow nutritionally inferior are unjustified and should be re-examined.”

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