The Danish Fitness and Nutrition Council has evaluated the basis for recommendations on the intake of antioxidants and has found limited basis for increasing the recommended intake levels for the antioxidants vitamin C and E. Evidence was insufficient to support recommendations for polyphenol or carotenoid supplementation. Supplementation with high doses of vitamin E and beta-carotene may present a health risk. A high intake of fruit and vegetables is associated with a reduced risk of lifestyle diseases, but there is no evidence that this association is due to an antioxidant effect.
Comment In: Ugeskr Laeger. 2006 Oct 9;168(41):3537; author reply 353717066533
INTRODUCTION: The aim of the present study was to quantify the impact of different dietary factors on the mortality from ischaemic heart disease in Denmark. METHODS: Relative risks and knowledge on the distribution of different dietary factors were used to estimate etiological fractions. RESULTS: It is estimated that an intake of fruit and vegetables and saturated fat as recommended would prevent 12 and 22%, respectively, of deaths from ischaemic heart disease in Denmark. An intake of fish among those at high risk for ischaemic heart disease, would lead to a 26% lower mortality, while alcohol intake among abstainers would have no significant quantitative effect. DISCUSSION: These results suggest that changes in dietary habits according to current recommendations would have an impact on public health in Denmark.
The incidence of urinary tract infections was compared in two geriatric units, where patients were offered cranberry juice and the usual mixed berry juice, respectively.
In all cases where urinary tract infection was suspected, the doctors noted symptoms and signs used as indication for urinary culture. The urine collected from men was the usual mid-flow specimen, whereas the specimens from women were taken from a bedpan and by catheter. End points were the prevalence of symptoms leading to urine culture, specimens with significant growth of bacteria, and the use of antibiotics.
Urine specimens were cultured in 140/338 cases. The reason for culture in 23% was general symptoms and in 62% urinary tract symptoms. A significant growth of bacteria was found in 54% and this information led to antibiotic treatment in 44%. In all cases (n = 55) where bedpan and catheter specimens were taken, the results were identical.
Cranberry juice in a geriatric department, where the mean stay was 4 weeks, did not influence the incidence of urinary tract infections.
In Denmark it is recommended to eat 600 g of fruit and vegetables daily. This recommendation has to a large extent been derived from the demonstrated inverse association with the risk of certain major cancer diseases, while the focus with respect to prevention of ischemic heart disease (IHD) has been directed primarily towards a reduced intake of ''hard'' fats. This systematic review includes prospective studies which have examined the association between the intake of fruit and vegetables, as well as specific fruits and vegetables (e.g., nuts and pulses, which are considered to be fruits and vegetables in the Danish recommendations), and the risk of developing IHD. Only one controlled intervention study has been performed. This study came out with a negative result because the advice to increase intake was unsuccessful. In the eight published cohort studies, the overall finding was that the risk of developing IHD was reduced, in the scientifically well-conducted studies, by about 20%. Studies have generally found a dose-response effect, from low intakes to high intakes, up to about 800 g daily. Large cohort studies have shown convincing evidence that increased intake of nuts reduces the risk of IHD. With respect to other groups of fruits and vegetables, there is good but not sufficient scientific evidence that particularly pulses, but also the group of carotenoid-rich fruit and vegetables (such as tomatoes, leafy green vegetables, carrots, broccoli, Brussels sprouts and many berries and fruits), reduces risk. In contrast, it is not possible to single out specific substances in fruit and vegetables as being beneficial. Based on the studies, it seems reasonable to recommend an increased intake of a mix of fruits and vegetables to reduce the risk of IHD. The maximum beneficial amount seems to be about 800 g per day.
Reactive free oxygen radicals are formed in the reactions involved in normal cell metabolism. This formation is closely regulated e.g. by dietary antioxidants. Present knowledge suggests that an imbalance, with surplus of free radicals, can play a role in the pathogenesis of certain types of cancer, atherosclerosis, and cataract. A number of epidemiological studies have demonstrated a reduced risk of developing these diseases in persons who consume a diet with a high content of vegetables and fruit, which contains large quantities of the antioxidants: beta-carotene, vitamins C and E. Intervention studies, using supplements of these antioxidants, have so far not been able to show a beneficial effect. The apparently protective effect of fruit and vegetables may be due to other active ingredients. In Denmark the average intake of vegetables and fruit is low, and it is estimated that an increased consumption of these foods could reduce the occurrence of certain cancer types and atherosclerosis. In contrast, there is no evidence that antioxidant supplements would provide protection against disease, and their safety remains to be established.