One of yesterday's headline read "Lutein, zeaxanthin could increase heart attack risk." Once
again, an overly zealous health reporter has chosen to go for dramatic
headlines instead of scientific accuracy by overstating the risk
involved in a carotenoid study published in the July 2005 issue of The Journal of Nutrition.
The subjects in this study were Hispanic Americans of Mestizo background who lived in the central valley of Costa Rica
between 1995 and 2004 and who were diagnosed
of a first acute MI by 2 independent cardiologists from the 6
recruiting hospitals in the catchment area. The control subjects came
from the same population, but had no history of previous MI.
More study cases
than controls were current smokers and more of the study cases had a
previous history of diabetes and hypertension. Compared with controls,
study cases also had greater waist-to-hip ratios (abdominal obesity);
lower incomes; higher intakes of saturated fat, lutein and zeaxanthin;
and lower intakes of polyunsaturated fat, and tocopherols. A lower
proportion of study cases consumed alcohol at the time of the study
compared with controls. Adipose tissue concentrations of the
full-spectrum of carotenoids were initially lower in study cases than
study found that beta carotene in adipose tissue, but not in the diet
is associated with a decreased risk of nonfatal acute MI, whereas these
researchers suggest lutein + zeaxanthin may be positively associated
with a slightly increased risk of MI.
It's important to
note that the major sources of dietary lutein and zeaxanthin were
identified as celery; eggs, broccoli, salsa, peppers, spinach, oranges,
yellow squash, avocado and cilantro; all of which are considered
excellent sources of dietary carotenoids. Surprisingly, cooked spinach
and yellow squash were associated with the highest risk of MI in this
study. One possible explanation is that these two foods could be
associated with undesirable chemical substances such as agricultural
pesticides, which have been found in these two vegetables, as well as
in sweet potatoes in the United States and Costa Rica, but why this is
not the case in other dietary carotenoids is difficult to explain.
study suggests that inverse associations between dietary antioxidants
and intermediate cardiovascular end points, as well as markers of
inflammation, may indicate that if dietary carotenoids and tocopherols
are protective, their effect may be small and probably more important
at the beginning of the disease process.
Ellen Troyer, MT, MA - Biosyntrx Chief Research Officer
Spencer Thornton, MD - Biosyntrx President