cron-web.org

[A1CR]

MR (November 2, 2004) posts surprising results of large study seeming to show fruit and vegetable consumption is only modestly associated with a reduced risk of cardiovascular disease, and provides virtually no benefits when it comes to cancer. Leafy green vegetables did a bit better than other fruits and veggies, but the benefit was still rather small. This is quite a counterintuitive finding, given the widely held belief that fruits and vegetables are the best thing since (and long before!) sliced bread. One could question these results based on the fact that it is only one study - but MR suggests it is large and well conducted. Of course,fruits and vegetables still represent a satiating low calorie source of required nutrient - so they've got that going for 'em.

The Harvard School of Public health have been suggesating for a while
that the anticancer effect of F&J are probably overblown. Most of the
data comes from case-control studies, and previos reports from their 2
Crown Jewels of Prospective Epidemiology -- the Nurses' Health study and
the Health Professionals' Follow-up Study -- have suggested, on a
piecemeal basis, that the anticancer effect is weak.

Now, pooling these 2 cohorts, they find that "participants in the
highest quintile of total fruit and vegetable intake had

- a relative risk for major chronic disease of 0.95 (95% confidence
interval [CI] = 0.89 to 1.01 [ie, not clear there was even a small
effect -MR]) times that of those in the lowest.

-Total fruit and vegetable intake [("for an increment of five servings
daily")] was inversely associated with risk of cardiovascular disease
... relative risk ... of 0.88 (95% CI = 0.81 to 0.95)

- but not with overall cancer incidence, with relative risk [of] ...
1.00 (95% CI = 0.95 to 1.05) for cancer.

Of the food groups analyzed, green leafy vegetable intake showed the
strongest inverse association with major chronic disease and
cardiovascular disease. For an increment of one serving per day of green
leafy vegetables, relative risks were 0.95 (95% CI = 0.92 to 0.99) for
major chronic disease and 0.89 (95% CI = 0.83 to 0.96) for
cardiovascular disease.

Conclusions: Increased fruit and vegetable consumption was associated
with a modest although not statistically significant reduction in the
development of major chronic disease. The benefits appeared to be
primarily for cardiovascular disease and not for cancer.

Yes, this COULD be a fluke -- but these are very large, prospective,
well-designed studies with large, homogenous populations and multiple
assessments of diet. This constitutes, IMO, a major blow against the
value of (at least) total vegetable & fruit intake against chronic disease.

The following link gives the full text of an accompanying editorial (2),
which I've not yet read:


http://jncicancerspectrum.oupjournals.org/cgi/content/full/jnci;96/21/1564

-MR