The 2010 Dietary Guidelines for Americans recommend that individuals consume 4.5 to 5 cups
fruits and vegetables daily. However, at current intake levels, fruit consumption will have
to improve by more than 100% and vegetable intake by 50% to meet this recommendation.
Importantly, intake of brightly colored fruits and vegetables is even lower when potatoes are
not considered. It is possible that improved fruit and vegetable intake will have beneficial
health effects. For example, higher intakes of fruits and vegetables, and particularly
cruciferous vegetables (e.g., broccoli, Brussels sprouts, cauliflower, etc.), are associated
with lower rates of many degenerative diseases, including some cancers, yet this group of
vegetables may continue to be under-consumed due to their strong flavors. A supplement made
from these vegetables (Cruciferous CompleteTM made by Standard Process Inc. Palmyra, WI)
contains a group of phytochemicals called glucosinolates that can shift estrogen metabolism
in a favorable way. One proposed biomarker of chemoprotection from breast cancer is the
urinary estrogen metabolite ratio of 2- to 16α-hydroxyestrogens (2:16). In the main study,
the effects of cruciferous vegetables (broccoli or Brussels sprouts), Cruciferous CompleteTM
whole food supplements, or placebos on this ratio of urinary estrogen metabolites in healthy
premenopausal women will be compared over an eight-week period. The investigators hypothesize
that treatment with daily supplements will increase the 2:16 ratio as compared to daily
consumption of a combination of Brussels sprouts and broccoli or a placebo, suggesting
reduced breast cancer risk.
In a sub-study, the relationships between serum α-carotene, β-carotene, β-cryptoxanthin,
lutein and lycopene with dietary carotenoid intake as measured by a food frequency
questionnaire and body composition will be evaluated in healthy premenopausal women.
Carotenoids are a family of lipophilic compounds found primarily in colorful plant tissues
and their concentration in human blood reflects dietary intake of carotenoid-rich foods.
Carotenoid levels in the blood of healthy women do not appear to be influenced by menstrual
status, but are inversely associated with body fatness. Thus, serum carotenoid concentrations
may serve as a functional marker for chronic disease risk associated with excess body fat.