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lundi 8 octobre 2012

For stroke prevention go raw on fruits and veggies

Raw and processed fruit and vegetable consumption and 10-year stroke incidence in a population-based cohort study in the Netherlands

LM Oude GriepW M M VerschurenD KromhoutM C Ocké and J M Geleijnse
Prospective cohort studies have shown that high fruit and vegetable consumption is related to a lower risk of stroke. Whether food processing affects this association is unknown. We evaluated the associations of raw and processed fruit and vegetable consumption independently from each other with 10-year stroke incidence and stroke subtypes in a prospective population-based cohort study in the Netherlands.
We used data of 20069 men and women aged 20–65 years and free of cardiovascular diseases at baseline who were enrolled from 1993 to 1997. Diet was assessed using a validated 178-item food frequency questionnaire. Hazard ratios (HRs) were calculated for total, ischemic and hemorrhagic stroke incidence using multivariable Cox proportional hazards models.
During a mean follow-up time of 10.3 years, 233 incident stroke cases were documented. Total and processed fruit and vegetable intake were not related to incident stroke. Total stroke incidence was 30% lower for participants with a high intake of raw fruit and vegetables (Q4: >262g/day; HR: 0.70; 95% confidence intervals (95% CIs): 0.47–1.03) compared with those with a low intake (Q1: less than or equal to92g/day) and the trend was borderline significant (P for trend=0.07). Raw vegetable intake was significantly inversely associated with ischemic stroke (>27 vs less than or equal to27g/day; HR: 0.50; 95% CI: 0.34–0.73), and raw fruit borderline significantly with hemorrhagic stroke (>120 vs less than or equal to120g/day; HR: 0.53; 95% CI: 0.28–1.01).
High intake of raw fruit and vegetables may protect against stroke. No association was found between processed fruit and vegetable consumption and incident stroke.

European Journal of Clinical Nutrition 65, 791-799 (July 2011) | doi:10.1038/ejcn.2011.36

Results are not so striking for CHD but look at this figure and you will decide by yourself!
" Processing of fruit and vegetables alters their structure and induces significant changes in chemical composition, nutritional value, and bioavailability of bioactive compounds, which may induce different effects on CHD risk. Fruit juices, for example, have a lower content of fiber than raw fruit, but they may be a good source of phytochemicals [9]. Prospective studies that examined intake of citrus fruit juice in relation to risk of CHD [10], and cardiovascular diseases (CVD) [11], respectively, found no association. Vegetables are often cooked before consumption, which induces loss of water-soluble and heat-sensitive bioactive compounds [12][13]. On the contrary, processing can enhance the availability of bioactive compounds [14]. It has been shown that heat treatment improves the bioavailability of lycopene from tomatoes [15][16] and carotenoids from carrots [17]. Furthermore, processing could convert folate polyglutamate in vegetables into monoglutamate, which has better bioavailability as well [18][19]. "
BTW I would like to add that raw F&V are far more efficient than processed ones because processing CONCENTRATE the non hydric fraction of F&V and as you will see above the quantities are similar in weignt... So processing F&V is very deleterious even for the prevention of CHD.