Peripheral arterial disease (PAD) is an atherosclerotic disease. Evidence suggests that
atherosclerosis is an inflammatory condition and long chain
n-3 fatty acids, found in oily fish and
fish oils, have been shown to reduce
inflammation. Genetic and lifestyle factors such as body mass index (BMI) also influence
inflammation. In this study we have examined the effect of
fish oil in patients with claudication secondary to PAD.
Fish oil supplementation, providing 1g EPA and 0.7 g DHA per day for 12 weeks, increased walking distance on a treadmill set at 3.2 km/h with
a 7% incline. Walking distance to first
pain increased from 76.2+/-8.5 m before
fish oil to 140.6+/-25.5 m after
fish oil (mean+/-SEM, p=0.004) and total distance walked increased from 160.0+/-21.5 m before
fish oil to 242.1+/-34.5 m after
fish oil (p=0.002).
Fish oil supplementation also improved ankle brachial pressure index (ABPI) from 0.599+/-0.017 before
fish oil to 0.776+/-0.030 after
fish oil (p<0.001). The increase in walking distance was dependent on both BMI and genotype for single nucleotide polymorphisms in the genes encoding the pro-inflammatory
cytokines tumour
necrosis factor-alpha and
interleukin (IL)-1beta and the anti-inflammatory
cytokine IL-10 (detected using amplification refractory mutation system polymerase chain reaction). Neither BMI nor any of the genotypes examined affected the ability of
fish oil to increase ABPI. The mechanisms by which
fish oil affects walking distance and ABPI do not appear to be the same.