A joint
Australian-Vietnamese meta-analysis of
9 observational studies of 2,749 people found that
vegetarians had bones five percent less dense than
meat-eaters and vegans were six percent weaker. However,
the results were of such little significance that the
authors ended their paper by saying: “In conclusion, the
results of this meta-analysis suggest that there is a modest
effect of vegetarian diets, particularly a vegan diet, on
BMD, but the effect size is unlikely to result in a
clinically important increase in fracture risk.”
This
article, released ahead of scheduled publication, which
gives the public the perception that the news was so
important that it could not wait, in the American
Journal of Clinical Nutrition was
by the same authors as the vegan-osteoporosis article I
discussed in my June 2009 newsletter. The article I
reported on received little press worldwide and showed
results very favorable for a vegan diet and bone health.
Published in the April 2009 issue of the journal Osteoporosis
International, the
same researchers directly examined 105 postmenopausal
Mahayana Buddhist nuns, and compared them to 105 omnivorous
women and found, “…although vegans have much lower intakes
of dietary calcium and protein than omnivores, veganism does
not have (an) adverse effect on bone mineral density (BMD)
and does not alter body composition.”
The
highly publicized study showing negative effects of a vegan
diet was a meta-analysis—a selected compilation of similar
studies. This kind of analysis is notorious for showing bias
and is easily manipulated by the choice of studies included
or excluded in the research paper. Because of the ease of
exploitation, meta-analysis has been referred to as an
exercise in “mega-silliness.”
Their original research found 922 studies, but after
applying exclusion criteria there were only 9 studies left,
which included 2749 individuals; 5 studies were of Asians,
populations where osteoporosis-related fractures are much
lower because of their healthier diet and greater physical
activity, than Westerners.
This
analysis found no correlation between dietary calcium intake
or protein intake and BMD. The results comparing diets of
vegetarians and omnivores with BMD were considered
clinically insignificant by the authors. Furthermore, BMD
is a poor predictor of
future fracture risk. The criticisms could go on, making
this one of the worst studies ever published in a respected
journal. So why did this article condemning eating a vegan
diet get so much attention?
This
flawed research telling people worldwide that vegan diets
are bad for the bones was funded by the AMBeR alliance
incorporated in Malaysia, which owns Amber F&B Nutrition Sdn
Bhd, a dairy products producer and wholesaler. This
company’s business is
the “manufacturing of sweetened condensed milk, evaporated
milk and dairy products.” Once a study is published then
the public relations department of the industry takes over
and sends “Press Releases” to the media worldwide. Because
people love to hear “good news about their bad habits
(eating beefsteaks, fried chicken, cheese, and ice cream),”
the press and the public revel in this good news, even when
the conclusions are untrue as in this case. You might think
there would be at least one curious reporter who would read
the research before spreading the lie.
You can
write the authors at: tuan.nguyen@unsw.edu.au and
ask your questions about the two studies and why the one
funded by a dairy industry showing no relevance to a
person’s choice of a vegan diet and the risk of fracture
received so much worldwide attention.
