Effects of long-term ingestion of soya phospholipids on serum lipids in humans

Nutritional and physiological responses of broiler chickens to dietary supplementation with de-oiled soyabean lecithin at different metabolisable energy levels and various fat sources

A 42-d study was conducted to investigate the effects of an emulsifier supplementation (de-oiled soyabean lecithin (DSL)) of diets with different levels of metabolisable energy (ME) and various sources of fat on growth performance, nutrient digestibility, blood profile and jejunal morphology of broiler chickens. Diets were arranged factorially (2 × 2 × 2) and consisted of two concentrations of ME (normal and low), two fat sources (soyabean oil (SO) and poultry fat (PF)) and two levels of DSL supplementation (0 and 1 g/kg). A total of 800 1-d-old male broiler chickens were assigned to eight treatments with five replicates/treatment. The results showed the supplemental DSL caused improvements in the overall feed conversion ratio, fat digestibility and jejunal villus height:crypt depth ratio, but the magnitude of the responses was greater in the PF-containing diets, resulting in significant fat × DSL interactions (P<0·05). Abdominal fat percentage was also reduced by the PF-containing diet, but the response was greater in the normal ME diet, resulting in a significant ME × fat interaction (P = 0·048). Dietary DSL supplementation also increased nitrogen-corrected apparent ME values but decreased blood TAG (P = 0·041) and LDL (P = 0·049) concentrations, regardless of the source of fat used or the ME values in the diet. In conclusion, the present study suggests that the improvements in growth performance, fat digestibility and intestinal morphology that can be achieved with DSL supplementation are highly dependent on the degree of saturation of lipid incorporated into broiler chicken diets.

Effects of 12-week supplementation of marine Omega-3 PUFA-based formulation Omega3Q10 in older adults with prehypertension and/or elevated blood cholesterol

Backgrounds

To study the effects of supplementation of a marine omega-3 poly-unsaturated fatty acids (n3-PUFA) formulation (Omega3Q10) in older adults with hypertension and/or hypercholesterolemia.

Methods

A total of 97 people were enrolled to receive 12-week supplementation of either Omega3Q10 (n = 48) or soybean oil (n = 49). Total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and hypertension-related symptoms were determined before and after the supplementation.

Results

There were no baseline differences between the two groups. Omega3Q10 supplementation significantly reduced diastolic blood pressure (DBP) (from 81.6 ± 5.3 mmHg to 79.3 ± 5.2 mmHg, P < 0.05). Blood concentrations of TC and LDL-C decreased significantly and blood HDL-C level increased significantly after 12 weeks of Omega3Q10 (5.5 ± 0.7 vs. 5.3 ± 0.5, P < 0.05; 3.7 ± 0.8 vs. 3.3 ± 0.6, P < 0.05; 1.2 ± 0.6 vs. 1.3 ± 0.5, P < 0.05, respectively) and soybean oil supplementation (5.7 ± 0.8 vs. 5.6 ± 0.7, P < 0.05; 3.6 ± 0.7 vs. 3.4 ± 0.8, P < 0.05; 1.0 ± 0.8 vs. 1.2 ± 0.7, P < 0.05, respectively) but no group differences were found. A significantly greater proportion of the people in the Omega3Q10 group became free from headache and palpitations & chest tightness symptoms after the 12-week supplementation compared to that of the soybean oil group (95.5% vs. 71.4%, P < 0.01; 95.8 vs. 75.5%, P < 0.01, respectively).

Conclusion

12-week supplementation of Fish oil-based PUFA appear to be more effective in improving DBP and hypertension-related symptoms than soybean oil in old adults with hypertension and hypercholesterolemia although both supplementation improved TC, LDL-C and HDL-C concentrations.

Fat lowers fat: purified phospholipids as emerging therapies for dyslipidemia

Dyslipidemia is a major coronary heart disease (CHD) risk factor. In spite of the proven efficacy of statin drugs in reducing CHD burden, there is still much room for the discovery of novel therapeutic agents to address the considerable residual cardiovascular risk that remains after treatment with currently available medications. In particular, there is an urgent demand for drugs capable of boosting the concentration and/or function of high-density lipoprotein (HDL) and apolipoprotein A-I (apo A-I), thereby promoting reverse cholesterol transport. Phospholipids are naturally occurring fats that play indispensible role in human health via their structural, energy storage, signal transduction and metabolic functions. Supplementation with either purified or mixed preparations of bioactive phospholipids has been reported to ameliorate a range of nutritional and cardiovascular disorders. Moreover, several lines of evidence have supported the efficacy of dietary phospholipids in reducing serum and hepatic contents of cholesterol and triglycerides, while increasing HDL-C and apo A-I levels. These beneficial effects of phospholipids could be attributed to their ability in reducing intestinal cholesterol absorption, enhancing biliary cholesterol excretion and modulating the expression and activity of transcriptional factors and enzymes that are involved in lipoprotein metabolism. Given their extreme safety and biocompatibility, dietary supplementation with phospholipid preparations, in particular phosphatidylinositol, appears as a novel and effective strategy that could be used as an alternative or adjunctive therapy to the current medications. The present review outlines the in-vitro, in-vivo and clinical findings on the anti-dyslipidemic effects of three most abundant phospholipids in the human body and diet namely phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol.

Dietary phospholipids ameliorate fructose-induced hepatic lipid and metabolic abnormalities in rats

Overconsumption of fructose results in hepatic dyslipidemia, which has a documented correlation with metabolic syndrome. We examined whether the ingestion of phospholipids (PL) from soybeans prevents fructose-induced metabolic abnormalities. Rats were fed either a fructose-free diet (C), a 60% fructose diet (F), or a 60% fructose plus 3% PL diet (F-PL) for 10 wk. At wk 8, plasma glucose concentrations after glucose loading were significantly higher in rats fed the F diet than in rats fed the C and F-PL diets, which did not differ from one another. The concentrations of hepatic TG, diglycerides, ceramides, and oleates in rats fed the F diet for 10 wk was significantly higher than those in rats fed the C diet. The increases were prevented by concurrent PL ingestion; concentrations did not differ between the F-PL and C groups. Dietary fructose increased the mRNA expression of SREBP1, ChREBP, and genes related to lipogenesis. PL completely inhibited these increases. Furthermore, reflecting the difference at the mRNA level, lipogenic enzyme activities were greater in rats fed the F diet than in rats fed the C diet, and PL ingestion suppressed the increased activities by fructose feeding. Treatment of cultured Hep-G2 cells with fructose for 24 h increased the levels of SREBP1 and ChREBP nuclear proteins, which were suppressed by culture with purified PL components, especially phosphatidylethanolamine and phosphatidylinositol. These findings indicate that PL prevents fructose-induced metabolic abnormalities in association with alterations of the hepatic lipid profile by inhibiting de novo lipogenesis.

Toxicity studies of Asahi Kasei PI, purified phosphatidylinositol from soy lecithin

Although phosphatidylinositol (PI) is an important component in all plants and animals, there is no toxicity report when purified PI is orally administrated to animals. As a safety evaluation of PI, acute, subchronic and genotoxicity studies were conducted with purified PI from soy lecithin (Asahi Kasei PI). Up to 2,000 mg/kg of Asahi Kasei PI was administrated once orally to male and female rats. There were no deaths or any clinical sign in any group throughout the observation period. Then, Asahi Kasei PI was repeatedly administered orally to male and female rats at daily doses of 100, 300 and 1,000 mg/kg for 13 weeks. Neither death nor any toxicological signs during the administration period and no changes related to the test substance administered were observed in any group with regard to body weight, food consumption, ophthalmoscopy, hematology, blood biochemistry, necropsy, organ weights or histopathology. Based on these results, the no-observed-adverse effect level (NOAEL) of Asahi Kasei PI was considered to be 1,000 mg/kg/day for male and female rats. Genotoxicity evaluation of Asahi Kasei PI was also carried out by the bacterial reverse mutation test (Ames test) and in vitro chromosome aberration test in compliance with the Japanese guidelines on genotoxicity testing of pharmaceuticals, the OECD guidelines for testing chemicals and guidelines for designation of food additives and for revision of standards for use of food additives. The results indicate neither increases of revertant colonies nor chromosome aberration, suggesting that Asahi Kasei PI has high safety in genotoxicity.

Effect of soybean phospholipids on canthaxanthin lipoproteins transport, digestibility, and deposition in rainbow trout (Oncorhynchus mykiss) muscle

This study was designed to assess the effect of dietary soybean phospholipids on canthaxanthin transport by serum lipoproteins and canthaxanthin muscle deposition in trout. Three groups of 12 immature trout in triplicate with a mean body weight of 130 g were fed with three experimental diets containing (1) canthaxanthin plus lecithin plus fish oil, (2) canthaxanthin plus lecithin, and (3) canthaxanthin alone, for 12 days. The two major lipoprotein classes in rainbow trout are high-density lipoproteins, which transport principally carotenoids present in the serum, and low-density lipoproteins, which are responsible for the transport of cholesterol, both independently of the administered diet. In addition, very low density lipoproteins are responsible for triglyceride transport in serum. Nevertheless, the amount of canthaxanthin in the serum increased when carotenoid was associated with phospholipids plus fish oil. When canthaxanthin is transported by lecithin plus fish oil, the amount of phospholipids, cantaxanthin, and cholesterol deposited in muscle increased but not significantly. The highest apparent canthaxanthin digestibility coefficient was obtained when canthaxanthin was carried by lecithin plus fish oil. The administration of canthaxanthin carried by phospholipids improved its accumulation in the muscle of rainbow trout. This accumulation could be enhanced if the time of administration of canthaxanthin is increased.

Effects of soybean D-LeciVita product on serum lipids and fatty acid composition in type 2 diabetic patients with hyperlipidemia

BACKGROUND AND AIM

Hyperlipidemia is one of the major risk factors of cardiovascular complication in diabetes. High intake of soy product has been suggested to prevent cardiovascular disease. The purpose of this study was to evaluate if dietary supplement of soybean D-LeciVita product, rich in polyunsaturated phospholipids (with 12% lecithin, 35% soy protein) affects serum lipids and serum and erythrocyte phospholipid fatty acid composition in type 2 diabetic patients.

METHODS AND RESULTS

Forty-seven patients (men and post-menopausal women) with isolated hypertriglyceridemia (IHTG) and combined hyperlipidemia (CHL), aged 43-70 years, were given 15g of D-LeciVita powder as a water suspension in a single evening dose during the follow-up period of 12 weeks. Patients kept their diabetic diet relatively constant. Treatment was associated with a significant (p < or = 0.001) decrease in serum total cholesterol and triglyceride levels by 12% and 22%, respectively. LDL-cholesterol decreased by 16% and HDL-cholesterol increased by 11% (p < or = 0.001). Our study shows a 27% decrease in LDL-cholesterol (p < or = 0.001) and a 12% increase in HDL-cholesterol (p < or = 0.01) in CHL type 2 diabetic patients. Triglyceride levels decreased in type 2 diabetic patients with IHTG and CHL by 29% and 13%, respectively (p < or = 0.01 and p < or = 0.05). Our results show decrease in SFA and increase in n-6 and n-3 PUFA in serum and erythrocyte phospholipids. SFA decreased and n-3 PUFA increased in serum and erythrocyte phospholipids in IHTG and CHL groups.

CONCLUSION

The present study indicated that added to a regular diet, soybean D-LeciVita product (combination of soy protein and lecithin) is associated not only with lipid-lowering effects but also with more favorable serum phospholipids fatty acid profile in type 2 diabetic patients with hyperlipidemia.

Phosphatidylinositol increases HDL-C levels in humans

Studies have shown that phosphatidylinositol (PI) can stimulate reverse cholesterol transport by enhancing the flux of cholesterol into HDL and by promoting the transport of high density lipoprotein-cholesterol (HDL-C) to the liver and bile. The goal of this study was to determine the safety and therapeutic value of PI after oral administration to normolipidemic human subjects. We performed a randomized 2 week study in 16 normolipidemic subjects. Subjects received either 2.8 or 5.6 g of PI, with or without food. PI was well tolerated by all subjects. PI significantly affected the levels of HDL-C and triglyceride in the plasma of subjects receiving PI with food. The lower dose showed a 13% increase in HDL-C, whereas the high dose showed an increase of 18% over the 2 week period. Both low- and high-dose groups showed significant increases in plasma apolipoprotein A-I. The high dose of PI also decreased plasma triglycerides by 36% in the fed subjects. These data suggest that after only 2 weeks, PI may have a comparable therapeutic value to niacin, with negligible side effects.

Dietary soybean phosphatidylcholines lower lipidemia: mechanisms at the levels of intestine, endothelial cell, and hepato-biliary axis

The beneficial metabolic effects of dietary soybean lecithin on lipid metabolism are now more clearly established. The intestinal absorption of cholesterol is decreased by soybean phosphatidylcholine-enriched diet and results in a cholesterol-lowering effect. There is an enhancement of the cholesterol efflux by endothelial cells incubated with soybean phosphatidylcholines, and a stimulation of the reverse cholesterol transport by high density lipoprotein-phosphatidylcholines. As a result of all these processes, phosphatidylcholines provided by the soybean lecithin metabolism appear to be key molecules controlling the biodynamic exchanges of lipids. They regulate homeostasis of cholesterol and fatty acids by decreasing their synthesis and promoting cholesterol oxidation into bile salts. Finally, the outcome is the increase in bile secretion of these lipids and/or their metabolite forms. Such findings constitute promising goals in the field of nutritional effects of soybean lecithin in the treatment or prevention of hyperlipidemia and related atherosclerosis.

Cholesterol-lowering effect of soyabean lecithin in normolipidaemic rats by stimulation of biliary lipid secretion

The purpose of the present study was to assess the role of the liver in the plasma-cholesterol-lowering effect of soyabean lecithin. Normolipidaemic rats were fed on lecithin-enriched or control diets with the same amount of protein. The lecithin diets contained 200 g/kg high-fat commercial semi-purified soyabean lecithin (230 g/kg total lipids as soyabean phosphatidylcholine) or 200 g/kg high-fat purified soyabean lecithin (930 g/kg total lipids as soyabean phosphatidylcholine). The control diets were a lowfat diet (40 g fat/kg) and a high-fat triacylglycerol-rich diet (200 g fat/kg). The high-fat diets were isoenergetic. The cholesterol-lowering effect of the lecithin-enriched diets was associated with significantly lower levels of plasma total- and HDL-cholesterol and significantly higher levels of bile phosphatidylcholine (PC), bile salts and cholesterol. These findings suggest that the liver plays a major role in the reduction of plasma cholesterol, the increased biliary lipid being provided by both HDL and the hepatic microsomal pools of PC and cholesterol.

Soybean phospholipid dependent reductions in triacylglycerol concentration and synthesis in the liver of fasted-refed rats

The effect of dietary soybean phospholipid on the activities of hepatic triacylglycerol-synthesizing enzymes was compared with soybean oil in fasted-refed rats. Soybean oil at the dietary level corresponding to 20% but not at 5% fatty acid level (21.2 and 5.3% on weight bases, respectively) significantly decreased liver microsomal diacylglycerol acyltransferase activities measured with the endogenous diacylglycerol substrate. Dietary soybean phospholipid even at the dietary level corresponding to 2% fatty acids (3.4% on weight base) significantly decreased the acyltransferase activities measured with endogenous substrate. The dietary phospholipid further decreased the parameter as the dietary level increased, and at the 5% fatty acid level, it was lower than that obtained with soybean oil at 20% fatty acid level. Soybean oil and phospholipid decreased the diacylglycerol acyltransferase activities measured with the saturating concentration of exogenous dioleoylglycerol substrate only when the activities were expressed in terms of total activity (mumol/min per liver) but to much lesser extents. Dietary phospholipid compared to the oil profoundly decreased not only hepatic triacylglycerol but also microsomal diacylglycerol levels. It was indicated that the availability of microsomal diacylglycerol as the substrate for diacylglycerol transferase is the critical determinant in regulating hepatic triacylglycerol synthesis and concentration in this experimental situation. Alterations in the activities of microsomal glycerol 3-phosphate acyltransferase and of the enzymes in fatty acid synthesis could account for the phospholipid-dependent decrease in the microsomal concentration of this intermediate in triacylglycerol synthesis.