Volume 89, Issue 4, April (2003), pp. 523-532 © The Author 2003
doi:10.1079/BJN2002805

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Influence of very low dietary intake of marine oil on some functional aspects of immune cells in healthy elderly people

Shaliha Bechoua¹, Madeleine Dubois¹, Evelyne Véricel¹, Paul Chapuy², Michel Lagarde¹ and Annie-France Prigent^1,*
1Institut National de la Santé et de la Recherche Médicale U352, Laboratoire de Biochimie et Pharmacologie, INSA-Lyon, France
²Service de Gériatrie, Hôpital des Charpennes, Villeurbanne, France

 (Received 7 May 2002–Revised 21 October 2002–Accepted 5 November 2002)

Ageing is a multifactorial process involving decreased antioxidant defences and immune functions. n-3 Polyunsaturated fatty acids have been associated with human health benefits, especially against inflammatory and autoimmune diseases. However, their immunomodulatory effects were usually observed with high dosages (>2 g/d) known to increase lipid peroxidation. In contrast, very low doses, that may prevent lipid peroxidation, might affect the immune system differently. To study the latter hypothesis further, we investigated whether the supplementation of healthy elderly people with very low doses of marine oil (MO), a docosahexaenoate (DHA)- and eicosapentaenoate (EPA)-rich triacylglycerol, was able to affect lymphocyte proliferation and biochemical markers known to be altered with age. In a randomized, double-blind design, twenty healthy elderly subjects were assigned to a placebo group (600 mg sunflower oil/d) or to a group consuming 600 mg MO/d providing 150 mg DHA + 30 mg (EPA) for 6 weeks. At day 42, the proliferative responses of lymphocytes to several mitogens were significantly (P<0·01) decreased in the MO group compared with control values. This was accompanied by a slight lowering of their cytosolic cyclic nucleotide phosphodiesterase (PDE) activity, a marked and significant (P<0·05) increase of their particulate PDE activity (+56–57 %) and a slight but significant (P<0·05) increase in cyclic nucleotide intracellular levels. At the same time, the glutathione peroxidase activity was markedly and significantly (P<0·01) depressed in the MO group. None of these modifications could be seen in the placebo group. Collectively, these results demonstrate that even very low doses of n-3 fatty acids are sufficient to affect the immune responses of elderly subjects.

Abbreviations: DHA; docosahexaenoic acid; EPA; eicosapentaenoic acid; GSH-Px; glutathione peroxidase; MO; marine oil; PA, phosphatidic acid; PBMN; peripheral blood mononuclear cells; PDE; phosphodiesterase; PE, phosphatidylethanolamine PUFA; polyunsaturated fatty acid; SO; sunflower oil
Corresponding Author: Dr Annie-France Prigent, fax +33 4 72 43 85 24, email prigent@insa-lyon.fr

Keywords:
n-3 Fatty acids: Docosahexaenoic acid: Lymphocyte proliferation: Cyclic nucleotide phosphodiesterase: Glutathione peroxidase: Immune function in human ageing