Omega-3 fatty acid supplementation improves vascular function and reduces inflammation in obese adolescents
Introduction
The prevalence of overweight and obese children and adolescents is increasing worldwide and is likely to have a great impact on their future cardiovascular health. The worldwide development of obesity can be explained, in part, by the “Western diet” that contains small amounts of essential n-3 polyunsaturated fatty acids (PUFAs), which are well known to prevent cardiovascular disease [1].
We recently showed that obese children have lower n-3 concentrations in serum phospholipids than age-matched lean controls [2]. We found correlations between n-3 PUFAs and different markers of metabolic syndrome. Whether low n-3 serum phospholipid concentrations in young obese subjects hamper vascular function and increase inflammatory activity remains to be elucidated.
In obese children and adolescents, radial artery intima thickness may constitute an early sign of vascular wall atherogenic and inflammatory processes. Using a new ultrasound system with very high-resolution and a discrimination power of 30 μm3, obese children have been shown to have increased arterial intimal thickness compared to lean controls, a change that is not detected by traditional measurements of the intima-media complex [4]. Endothelial dysfunction occurs in obese children [5], indicating early atherosclerosis. In addition, positive associations have been found between high serum n-3 levels and endothelial function in young adults with risk factors for cardiovascular disease [6], [7].
Given the improved lipid profile and reduced magnitude of inflammation evident in adults with increasing n-3 concentrations, we wanted to examine the effect of n-3 supplementation on vascular structure and function in obese adolescents and its possible relationship to inflammation and oxidative stress.
Section snippets
Study subjects
A total of 108 patients aged 14–17 years and referred to an outpatient clinic for the treatment of obesity were invited to enroll in the study in 2005. Of these patients, 47 agreed to participate in an informational meeting and 31 agreed to participate in the present study. One subject was excluded before the study began due to smoking, one moved abroad, three dropped out during the study, and one was excluded due to poor compliance, which left 25 subjects (14 females and 11 males) who
Results
No differences were found between n-3 and placebo treatment periods regarding anthropometrical measures, including weight, waist, hip, and the waist/hip (W/H) ratio, though a significant difference was found for height (Table 1). LDL cholesterol levels were reduced after n-3 treatment, but even more so after placebo treatment (8% vs. 13%, respectively, p = 0.047). Free fatty acids were lower after n-3 treatment compared to placebo treatment (reduced by 7.5%, p = 0.05). No difference was found
Discussion
The present study establishes that vascular function improves after 3 months of n-3 supplementation in obese adolescents. Obese children demonstrate elevated inflammation, which can affect the endothelium and vascular wall [14]. One may surmise that this elevated inflammation, which may be caused by relatively lower (vs. lean controls) serum n-3 concentrations, can be reduced by n-3 supplementation. Indeed, our present results showed that n-3 treatment decreases the number of lymphocytes,
Conflict of interest
The authors declare that they do not have any conflicts of interest to declare.
Funding
This study was supported by the Swedish Medical Research Council, the Gothenburg Medical Society, the Swedish Heart and Lung Foundation, the Sahlgrenska University Hospital, the Ågrenska Foundation, the Committee for Public Health of the Western Region of Sweden, and the funds of Gustav V and Queen Victoria. Capsules were provided by Equazen, Ltd. (UK), and BS received a grant from IQ Medical, Ltd. (Sweden).
Acknowledgements
The authors would like to thank Charlotte Eklund and Gun Bodehed-Berg at Clinical Physiology, Sahlgrenska University Hospital, and Berit Holmberg at Lipid Research Laboratory, Queen Silvia Children's Hospital for excellent technical assistance.
References (26)
- et al.
Omega-3 fatty acids and coronary heart disease risk: clinical and mechanistic perspectives
Atherosclerosis
(2008) - et al.
Presence of increased stiffness of the common carotid artery and endothelial dysfunction in severely obese children: a prospective study
Lancet
(2001) - et al.
Ascorbyl free radical reflects catalytically active iron after intravenous iron saccharate injection
Free Radic Biol Med
(2008) - et al.
Methodological approaches to optimize reproducibility and power in clinical studies of flow-mediated dilation
J Am Coll Cardiol
(2008) - et al.
Mediterranean-inspired diet lowers the ratio of serum phospholipid n-6 to n-3 fatty acids, the number of leukocytes and platelets, and vascular endothelial growth factor in healthy subjects
Am J Clin Nutr
(2006) - et al.
Consumption of (n-3) fatty acids is related to plasma biomarkers of inflammation and endothelial activation in women
J Nutr
(2004) - et al.
n-3 Fatty acids and urinary excretion of nitric oxide metabolites in humans
Am J Clin Nutr
(1997) - et al.
Association of n-3 polyunsaturated fatty acids with stability of atherosclerotic plaques: a randomised controlled trial
Lancet
(2003) - et al.
n-3 Fatty acids from fish or fish-oil supplements, but not alpha-linolenic acid, benefit cardiovascular disease outcomes in primary- and secondary-prevention studies: a systematic review
Am J Clin Nutr
(2006) - et al.
Serum phospholipid fatty acids, adipose tissue, and metabolic markers in obese adolescents
Obesity (Silver Spring)
(2006)