Linolenic Acid Research

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 20^th 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>