20 LISTENER AUGUST 24 2019
THE IPCC DIET
Dietitian Jennifer Bowden says there
are important caveats among the micro-
nutrients. It is trickier to get two of the
essential omega 3 fatty acids, most plenti-
fully found in seafood: docosahexaenoic
acid (DHA) and eicosapentaenoic acid
(EPA). They can be found in algae, but
like moringa, eukaryotic photosynthetic
microalgae are yet to feature much in
lunch boxes, cafe cabinets or supermar-
ket aisles. Bowden says the best bet is to
eat plant oils such as flaxseed, walnut,
soy and canola. Although they don’t
contain DHA or EPA, either, they do have
alpha-Linolenic acid (ALA), which can be
converted into the other two fatty acids
in the body – but not efficiently.
The other elusive nutrient for vegans is
vitamin B12, which – less than ideally for
the committed clean eater – can only be
consumed within vegan rules as a dietary
supplement or through artificially forti-
fied processed foods such as plant milks,
yeast extracts or breakfast cereals.
Calcium isn’t as bioavailable through
many plant foods as it is through meat
and dairy, so vegans are usually advised
to consider supplementation; likewise
iodine.
Iron deficiency is less likely than previ-
ously thought in people cutting out meat,
but it’s a pronounced risk factor in the
young – especially young women – who
can take their vegan diets to extremes.
Meat is already well down the list of
iron sources in the New Zealand diet.
Bowden says the last nationwide nutri-
tional survey found the biggest sources
were bread (12%) and breakfast cereals
(10%), followed by vegetables, grains and
pasta, then beef.
Adding a vitamin C-rich food, such
as kiwifruit or citrus, to meals where the
source of iron is, say, lentils, beans and
nuts will make the iron more readily
absorbable. Bowden says vegans would
be wise to avoid drinking tea and coffee
or eating bran with meals as the polyphe-
nols and phytates present in them inhibit
iron absorption.
A
ticklish question is the stickability of
a vegan regime. US research organi-
sation Faunalytics found 84% ofvegetarians and vegans abandoned their
diet in 2014. A third of these did so within
three months of going meat-free, and
another 53% within a year. Many still ate
less meat afterwards, but those most likely
to “lapse” were those who were in it for
health rather than philosophical reasons.
Auckland dietitian Caryn Zinn has a
cohort of clients who describe feeling less
tired after giving up on their vegan diets.
She blames the lack of vitamin B12 and
iron, especially among teenage girls with
high iron needs as a result of menstrua-
tion. Missing out on easily absorbable
iron is a “potential disaster”.
Zinn says lauding plant-only diets as a
magic bullet for health is an oversimplifi-
cation. Researchers have often linked high
plant consumption to what have come to
be known as “blue zones” – populationpockets around the world that appear
to enjoy longer lives than their national
cohort. The most famous blue-zone take-
out message among nutritionists is the
healthiness of the Mediterranean diet,
which is typically low in meat protein and
high in vegetables and legumes.
“A lot of people have this view of
veganism with a bit of a halo around it,”
Zinn says. “It plays on people’s emotions
from an animal welfare and sustainabil-
ity perspective, but saying animal versus
plants and plants are better – it is just not
true. If you look at those living in the
world’s blue zones, they have a lot more
going on than just low meat consump-
tion. They eat non-processed wholefoods
cooked from scratch, they enjoy a strong
sense of community, they get out of doors
and stay on the move.”C
old water has been thrown on the
blue-zone theory by Australian
research that found data discrepan-
cies in studies of apparently long-lived
populations. Japanese in Okinawa have
been singled out as particularly long-
lived, but that appears to be down to
poor record-keeping and unfounded
assumptions, according to Saul Newman,
a researcher at the Australian National
University. He says, in fact, Okinawans
live fewer years than the average in other
Japanese provinces. Much wealthier
Tokyo, for example, appeared less healthy
because better records were kept of itscitizens.
An apparent blue zone in Icaria, Greece,
included 99% of men who were smokers.
The apparent health of that cohort could
have been down to “healthy volunteer”
bias, in which people most apt to co-oper-
ate with a survey are less likely to be sick.
Another blue zone in Sardinia appeared
to reflect not an unusual number of very
old people, but widespread old-age-bene-
fit fraud.
The US city of Loma Linda, California,
was yet another statistical marvel, but
Newman says it’s simply a richer popula-
tion than its surrounding cohort, and its
overall longevity is nothing special com-
pared with other similarly well-heeled
populations.
Though Newman’s efforts to
debunk the blue-zone theory have
been controversial, he says it may be
as meaningless to infer that smoking
prolongs one’s life as to attribute
longevity to specific food choices or
calorie restriction alone. Typically, he
says, the richer the population, the
healthier and longer-lived.
The scientific consensus stands, he says,
that a good diet, exercise, not smoking
and attendant advice remain sound.Z
inn says comparisons between the
healthiness of vegan and non-
vegan diets need to be made on an
equivalent footing. “If you are comparing
a vegan diet to a standard American diet,
then of course veganism will come out as
a dietary front runner. But if you compare
a good-quality vegan or vegetarian diet
with a good-quality meat diet, there is no
difference in terms of overall health and
longevity.
“Meat might be better because of
micronutrients that aren’t easy to get
from plants. To be vegan you have to be
creative with your food and take a lot of
supplements.”
Overall, says Katherine Black from
the University of Otago’s department of
human nutrition, a well-balanced vegan
or vegetarian diet can provide all the
necessary protein, fats, carbohydrates,
vitamins and minerals for optimal health
“but it depends on whether you put effort
into finding out what foods to replace
the food you do cut out. As with any diet,
you have to make sure it is a varied diet
and you are not substituting your animal
products with sweet treats or chips.” l“A lot of people have this
view of veganism with a
bit of a halo around it.”