Volume 90, Issue 3, September (2003), pp. 565-572 © The Author 2003
doi:10.1079/BJN2003946

Medline/PubMed Citation | Related Articles in PubMed | Download to Citation Matcher  

Enteral administration of soyabean lecithin enhanced lymphatic absorption of triacylglycerol in rats

Megumi Nishimukai¹, Hiroshi Hara¹, Yoritaka Aoyama^1
1Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9, Nishi-9, Kita-ku, Sapporo, 060-8589, , Japan

 (Received 16 June 2002–Revised 19 May 2003–Accepted 23 May 2003)

As the physiological roles of dietary lecithin have not yet been clearly defined, we examined the effects of lecithin on lipid absorption in male Wistar rats with a mesenteric lymph cannula. Lymphatic absorption was observed after the infusion of 1 ml emulsion containing 100 mg test oil emulsified with sodium taurocholate (10 g/l) in three separate experiments. Test oils (100 mg) were: soyabean oil (triacylglycerol (TG) source, SO) and soyabean oil+lecithin (75 mg soyabean oil+25 mg lecithin, LE) in Expt 1; SO, LE or soyabean oil+lysolecithin (75 mg soyabean oil plus 25 mg lysolecithin, LY) in Expt 2; hydrolysed soyabean oil (HSO) or HSO+lysolecithin (75 mg HSO+25 mg lysolecithin, HLY) in Expt 3. After LE and LY infusions, lymph flow and the lymphatic output of TG was higher than after SO infusion at 0–30 min and 0–90 min respectively (Expts 1 and 2). Lecithin-induced increases in lymph TG output remained constant when HSO was infused (Expt 3). There were no differences in the TG:phospholipid ratio in the lymph after infusion among the groups; nevertheless, the lymphatic output of TG was much higher after infusion with LE than with SO. Fatty acid was released more efficiently from SO than from LE and LY by in vitro digestion with rat bile–pancreatic juice. These present results demonstrate that a TG emulsion containing soyabean lecithin or its hydrolysates promote lymphatic TG output and suggest that the increases in TG absorption do not depend on TG digestion.

Keywords:
Soyabean lecithin, Lipid absorption, Rats

Abbreviations:
HLY, hydrolysed soyabean oil+lysolecithin, HSO, hydrolysed soyabean oil, LE, soyabean oil+lecithin, LY, soyabean oil+lysolecithin, PC, phosphatidylcholine, PL, phospholipid, SO, soyabean oil, TG, triacylglycerol