BBC SCIENCE FOCUS MAGAZINE COLLECTION 71Chromium in Brewer’s
yeast is beneficial for
some diabeticsXi Yang Shen may lower
blood sugar and boost
the immune systemGETTY, ALAMY
W
IS FOR
WHEATGRASS
Wheatgrass is simply t he leaves of t he
young wheat plant. It contains roughly
the same nutrient content as the same
weight of spinach or broccoli. As a
food, it’s fine, if a little unpleasant
tasting. As a medicine, the evidence
is very weak. Some small studies have
found that it reduces the symptoms of
ulcerative colitis and the side effects of
chemotherapy, but most of the claims
that it oxygenates the blood or rids
the body of toxins are not supported
by science.RATING
X
IS FOR
XI YANG SHEN
Also known as American ginseng,
both this and Asian ginseng contain
chemicals called ginsenosides and
gintonin. Despite a long history of
use in Traditional Chinese Medicine,
the evidence for the health benefits
of ginseng is fairly weak. A few small
trials have found that it lowers blood
sugar and also boosts the immune
system. But claims that it improves
‘wellness’, reduces stress or acts as
an aphrodisiac are not backed by
well-designed studies.RATING
Y
IS FOR
YEAST
Saccharomyces cerevisiae (Brewer’s
yeast) is a good source of selenium,
chromium and B-complex vitamins
(but not B12 – that’s a myth). The most
important micronutrient is chromium.
Numerous studies have shown that
it helps type 2 diabetes sufferers by
increasing their tolerance to blood
glucose and reducing the amount of
insulin they need. There is also some
limited evidence that it lowers the
LDL ‘bad’ cholesterol and raises HDL
‘good’ cholesterol.RATING
by LUIS VILLAZON
Luis is a science and tech writer, and
author of How Cows Reach the Ground.Z
IS FOR
ZINC
Over 300 enzymes in your body require
zinc to function. Dietary deficiency is
more com mon i n vegeta r ia ns, because
phytates present in whole grains and
legumes inhibit zinc absorption. Zinc
supplements seem to help protect
against AMD (age-related macular
degeneration) and conflicting evidence
suggests it may reduce the symptoms
of the common cold. But zinc can be
very toxic at high doses and interferes
with antibiotic medication, so use
supplements with caution.RATING