Complementary Alternative Cardiovascular Medicine

32 Alternative Cardiovascular Medicine
review that can allow one to determine the diuretic strength of the herb.
Although not completely understood, the purported diuretic activity is
believed to be associated with the sesquiterpene lactones found in the
plant, along with high potassium levels. Because the leaf contains approx
4% potassium, the potassium depletion often associated with diuretics is
generally not a problem with this botanical. The German Commission E
recognizes the root and leaf for the stimulation of diuresis (19).
The dose is generally 3 g/d. Dandelion has a low risk of toxicity when
used appropriately. Even though dandelion leaf is a rich source of potassium,
practitioners should monitor patients who take the herb for prolonged
periods for possible hypokalemia.
GARLIC (ALLIUM SATIVUM)
Class 2 for Dyslipidemia, Class 3 for Hypertension
Garlic is the best known of the lipid-lowering herbs among the lay
public. The lipid-lowering effects of garlic have been demonstrated in
both animal studies and human clinical trials. Several meta-analyses have
been performed during the years, demonstrating a reduction in total cholesterol
of 5–12% (21–24). The lipid-lowering effects of garlic are believed to
result from inhibition of HMG-CoA reductase (25) and increased catabolism
of fatty acid containing lipids, particularly triglycerides (26).
Although the evidence does support a small but statistically significant
decrease in lipid levels at 3-mo follow-up, pooled analyses of placebocontrolled
trials failed to demonstrate significant reductions of total cholesterol
at 6 mo. Contradictory results are likely the result of
methodological shortcomings and the use of different garlic formulations
and different time scales used in the studies (27). A recent report by the
Agency for Healthcare Research and Quality (AHRQ) concluded “it is not
clear if statistically significant positive short-term effects—but negative
longer term effects—are due to: systematic differences in studies that
have longer or shorter follow-up durations; fewer longer term studies; or
time-dependent effects of garlic” (28).
Most garlic supplements are standardized to allicin potential and are
enteric coated to prevent gastric acid inactivation of the allicin-producing
enzyme, alliinase. A recent evaluation of garlic powder tablets used in
clinical trials (1989–1997) found that the there was great variation in the
amount of allicin released when subjected to the USP acid disintegration
test (724A). Older batches were more resistant to acid disintegration and
released three times more allicin (44% vs 15% of their potential,
p < 0.001) than newer lots. Conflicting trial results may be the result of
lower amounts of bioavailable allicin in some products. A recent evalu-