Introduction
The
purpose of this study was to see if dietary intakes of linolenic
acid, which is one of the two essential fatty acids, is associated
with reduced risk of hip fracture in older adults. Polyunsaturated
fatty acids are thought to infulence bone health via multiple
different mechanisms but studies on hip fracture risk are very
lacking and limited. The driving factor behind these claims is that
fatty acids have been shown to favorably affect intenstinal calcium
transport and calcium excretion. In previous adult human studies some
protective effects have been observed for omega-3 fatty acid intake
in relation to hip bone mineral density and for linolenic acid (ALA)
in relation to bone resorption.
Method
The
methods used to conduct the study started with participants who were
drawn from the Framingham Heart Study in which 5209 women and men
aged 28 through 62 years old were selected from a random sample of
2/3's of the househoulds in Framingham, MA to participate in the
study and were examined biennially for more than 50 years.
Eventually, 1164 of the 1402 surviving members had their BMD
measurements taken at the 20th biennial examination. The
study excluded multiple participants based on energy intakes less
than 2512 calories/day, with prior hip fractures, or participants
missing covariate information for BMI, smoking status, or physical
activity. The final study consisted of 904 participants with 552
women and 352 men. Usual dietary intake for the previous 12 months
was assessed with a self-administered 126-item FFQ for several
nutrients including total polyunsaturated fatty acids and linolenic
acid. In the study hip fractures were reported by participants at
each biennial exam or interview and then the occurrence of hip
fractures were further identified through systematic review of
medical records of hospitalizations and deaths which were then
confirmed by reviewing medical records and radio-graphic and operative
reports.
Results
The
results concluded that associations between polyunsaturated fatty
acids intakes and fracture risk were similar in analyses conducted separately in men and women in all models with the exception that
significant protective associations were observed between intakes of
AA and hip fracture risk in men, but not women. Higher ALA intake was
associated with lower hip fracture risk. Participants in the highest
quartile (Q4) of ALA intake had a 54% lower risk of hip fracture than
those in the lowest quartile (Q1), while participants in quartile 2
(Q2) had a 50% lower risk of hip fracture than those in the lowest
quartile (Q1).
Commentary
I
think that this study was very interesting and ground-breaking for
essential fatty acids with the focus being on linolenic acid and the
associated fatty acids. Prior to reading the entire study and
research I was a bit skeptical on any connection between essential
fatty acids and lower or reduced risk of hip fractures in older
adults. However, as the results clearly showed evidence that those
with the highest intake of alpha linolenic acid had a 54% lower risk
of hip fracture than those with the lowest intake of ALA, and
evidence even continued to support the hypothesis with the middle
quartile of ALA intake still showing a 50% lower risk than the lowest
quartile of ALA intake. This was a very important study as it proved
the hypothesis to be correct and opened doors to further research
regarding essential fatty acids and the potential benefits that we
have yet to discover.
Citations
Farina,
Emily, Douglas Kiel, Ronenn Roubenoff, Ernst Schaefer, Adrienne
Cupples, and Katherine Tucker. "Dietary Intakes of Arachidonic
Acid and α-Linolenic Acid Are Associated with Reduced Risk of Hip
Fracture in Older Adults ."Journal
of Nutrition.
American Society for Nutrition, n.d. Web. 27 Oct. 2012.
<http://jn.nutrition.org/content/141/6/11446.abstract>
