Dietary docosahexaenoic acid suppresses inflammation and immunoresponses in contact hypersensitivity reaction in mice

This study was designed to examine the immunomodulatory effects of dietary docosahexaenoic acid (DHA) in the absence of eicosapentaenoic acid (EPA). We investigated the effects of feeding dietary DHA ethyl ester (DHA-Et) (97% pure) at levels of 4.8 wt% of the total diet and of feeding EPA ethyl ester (EPA-Et) (99% pure) at 4.8 wt% on the inflammatory response in the challenge phase of the contact hypersensitivity reaction (CHR) in the ears of mice sensitized with 2,4-dinitro-1-fluorobenzene (DNFB). The effect of DHA-Et on T lymphocytes at the CHR site was examined using anti-CD4 antibodies. Furthermore, we examined the cytokines formed at the CHR site on the mRNA level. It was found that 24 h after the challenge, DHA-Et but not EPA-Et reduced the ear swelling. Infiltration of inflammatory cells, in particular, CD4-positive T lymphocytes, into the ears in the challenge phase of CHR was observed. DHA-Et reduced the infiltration of CD4-positive T lymphocytes into the ears. DHA-Et also decreased the expression of interferon-gamma, interleukin (IL)-6, IL-1beta, and IL-2 mRNA in ears. These observations suggest that DHA, but not EPA, may exert an antiinflammatory and immunosuppressive effect. The immunosuppressive effectiveness of fish oil may be attributed mainly to DHA.

Polyunsaturated fatty acids and inflammatory bowel disease

The rationale for supplementation with n-3 fatty acids to promote the health of the gastrointestinal tract lies in the antiinflammatory effects of these lipid compounds. The first evidence of the importance of dietary intake of n-3 polyunsaturated fatty acids was derived from epidemiologic observations of the low incidence of inflammatory bowel disease in Eskimos. The aim of this paper was to briefly review the literature on the use of n-3 fatty acids in inflammatory bowel disease (ulcerative colitis and Crohn disease), the results of which are controversial. The discrepancies between studies may reside in the different study designs used as well as in the various formulations and dosages used, some of which may lead to a high incidence of side effects. Choosing a formulation that lowers the incidence of side effects, selecting patients carefully, and paying strict attention to experimental design are critical when investigating further the therapeutic potential of these lipids in inflammatory bowel disease.

Evening primrose oil and borage oil in rheumatologic conditions

Diets rich in arachidonic acid (20:4n-6) lead to the formation of 2-series prostaglandins (PGs) and 4-series leukotrienes (LTs), with proinflammatory effects. Nonsteroidal antiinflammatory drugs are used in rheumatoid arthritis to inhibit cyclooxygenase (prostaglandin-endoperoxide synthase), thereby decreasing production of 2-series PGs. Lipoxygenase activity remains intact, however, allowing LT production (eg, synthesis of LTB(4), a potent inflammatory mediator) to continue. Altering the essential fatty acid (EFA) content of the diet can modify some of these effects. Ingestion of a diet rich in evening primrose oil elevates concentrations of dihomo-gamma-linolenic acid (DGLA; 20:3n-6), which results in the production of 1-series PGs, eg, PGE(1). DGLA itself cannot be converted to LTs but can form a 15-hydroxyl derivative that blocks the transformation of arachidonic acid to LTs. Increasing DGLA intake may allow DGLA to act as a competitive inhibitor of 2-series PGs and 4-series LTs and thus suppress inflammation. The results of in vitro and animal work evaluating EFAs in inflammatory situations are encouraging, which has stimulated clinical workers to evaluate these compounds in rheumatoid arthritis. Several well-controlled, randomized clinical studies have now been completed in which various EFAs were evaluated as treatments. The results of most of these studies suggest some clinical benefit to these treatments; these data are reviewed here.

Effect of supplementation with dietary seal oil on selected cardiovascular risk factors and hemostatic variables in healthy male subjects

The average daily consumption of seal oil by the Inuit people is approximately 8-9 g, yet there is very little information on the effect of seal oil consumption on cardiovascular disease risk factors. In this study, 19 healthy, normocholesterolemic subjects consumed 20 g of encapsulated seal oil containing eicosapentaenoic acid (EPA; 20:5n-3), docosahexaenoic acid (DHA; 22:6n-3), and docosapentaenoic acid (DPA; 22:5n-3) or 20 g of vegetable oil (control) per day for 42 days. Levels of selected cardiovascular and thrombotic risk factors as well as fatty acid profiles of serum phospholipid and nonesterified fatty acid (NEFA) were determined. EPA levels in serum phospholipid and NEFA increased by 4.3- and 2.7-fold, respectively, in the seal oil supplemented group. DHA levels rose 1.5- and 2.1-fold, respectively, and DPA levels rose 0.5- and 0.7-fold, respectively. Arachidonic acid (AA) levels dropped by 26% in both serum phospholipid and serum NEFA. There was a significant decrease in the ratio of n-6 to n-3 fatty acids in serum phospholipid from 7.2 to 2.1 and a significant increase in the ratio of EPA/AA in NEFA. Ingestion of seal oil raised the coagulant inhibitor, protein C, values by 7% and decreased plasma fibrinogen by 18%. No alterations in other hemostatic variables, including plasma activity of Factors VII, VIII, IX, and X and antithrombin, or in the concentrations of von Willebrand Factor, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglyceride, glucose, Apo A-1, or lipoprotein(a) were observed in either group. Other risk factors for cardiovascular disease, including hematocrit, white blood cell count, plasma viscosity, systolic and diastolic blood pressures, heart rate, and platelet aggregation after stimulation with ADP or collagen did not change. Our results indicate that seal oil supplementation in healthy, normocholesterolemic subjects decreased the n-6/n-3 ratio and increased EPA, DHA, and DPA and the ratio of EPA/AA and DHA/AA in the serum phospholipid and NEFA, while exhibiting a modest beneficial effect on fibrinogen and protein C levels.

Pinus pinaster oil affects lipoprotein metabolism in apolipoprotein E-deficient mice

The aim of the present study was to assess the antiatherogenic properties of Pinus pinaster (maritime pine) seed oil. To this end, the effects of P. pinaster oil supplementation on lipoprotein levels and atherosclerotic lesions were compared to those of lard or sunflower oil in apolipoprotein E-deficient mice. Plasma total cholesterol (P < 0.0001) and VLDL + intermediary density lipoprotein (IDL)-cholesterol (P < 0.0001) levels were lower in mice fed P. pinaster and sunflower oil than in those fed the lard diet. In contrast, triglycerides (P < 0.0001) and VLDL + IDL-triglycerides (P < 0.0001) levels were higher in mice fed P. pinaster oil than sunflower oil or lard. The VLDL + IDL lipid composition of apolipoprotein E-deficient mice fed P. pinaster oil was intermediate between that of lard-fed transgenic mice and that of wild-type mice fed nonpurified diet. Using the Triton WR1339 method, the fractional catabolic rate of plasma triglycerides was found to be lower in mice fed P. pinaster oil (P < 0.0001) than sunflower oil or lard diet, suggesting a defective clearance of triglycerides in the P. pinaster group. Finally, the susceptibility of triglyceride-rich lipoproteins to in vitro lipoprotein lipase-mediated lipolysis was lower in the P. pinaster oil-fed group than in the lard-fed group. Despite the differences in VLDL + IDL level and lipid composition, the surface areas of aortic atherosclerotic lesions were not significantly different among mice fed P. pinaster, sunflower or lard diets. In conclusion, the results of the present study indicated that feeding P. pinaster oil had no better preventive effect on aortic atherosclerotic lesion extension in apolipoprotein E-deficient mice than other saturated or polyunsaturated fats.

Progression of abnormalities in adrenomyeloneuropathy and neurologically asymptomatic X-linked adrenoleukodystrophy despite treatment with "Lorenzo's oil"

OBJECTIVES

X-linked adrenoleukodystrophy (X-ALD) is an inherited disorder of peroxisomal fatty acid oxidation, biochemically characterised by the accumulation of saturated very long chain fatty acids (VLCFAs), particularly hexacosanoic acid (C26:0). Dietary treatment with a 4:1 mixture of glyceroltrioleate and glyceroltrierucate ("Lorenzo's oil") normalises plasma VLCFA concentrations, but neither ameliorates nor arrests the rapid progression of neurological symptoms in the cerebral variants of X-ALD. The efficacy of "Lorenzo's oil" in the milder phenotypes of X-ALD was assessed, as this has been much less investigated.

METHODS

Twenty two patients who were treated with "Lorenzo's oil" for at least 12 months for a median period of 2.5 (range 1.0-6.0) years were studied. Two had asymptomatic ALD, four the "Addison only" variant, 13 adrenomyeloneuropathy (AMN), and three were symptomatic female carriers.

RESULTS

The plasma C26:0 concentration normalised or near normalised in 19 patients (86%), in the three others it decreased significantly. Nevertheless, disability as measured with the extended disability status scale score increased mildly (0.5 (95% confidence interval (95% CI) 0.25-1.0)) in the 16 patients with neurological symptoms. Furthermore, one "Addison only" patient and one patient with AMN developed cerebral demyelination, and another "Addison only" patient developed AMN. Adrenocortical insufficiency evolved in one patient with AMN, and hypogonadism in one patient with asymptomatic ALD and two patients with AMN. Nerve conduction, evoked potential studies (SEP, BAEP, VEP), and abnormalities on cerebral MRI did not improve. On the other hand, side effects were often noted-namely, mild increases in liver enzymes (55%), thrombocytopenia (55%), gastrointestinal complaints (14%), and gingivitis (14%). We also found a mild decrease in haemoglobin concentration and leucocyte count.

CONCLUSIONS

The data suggest that treatment with "Lorenzo's oil" neither improved neurological or endocrine function nor arrested progression of the disease. Furthermore, the oil often induced adverse effects. Therefore, it is advocated that "Lorenzo's oil" should not be prescribed routinely to patients with X-ALD who already have neurological deficits.

[Dynamics of malonic aldehyde, transferrin levels and blood antioxidant activity in women with normal pregnancy and pregnancy complicated by toxicosis: effect of eiconol]

Malonic dyaldehyde (MDA) and transferrin (TF) content and total antioxidant activity (AOA) were measured in blood of pregnant women with normal pregnancy (27 women) and preeclamptic pregnancy (46 women) at different pregnancy stages (17-28, 29-34 and 35-40 weeks of pregnancy). It was shown that in normal pregnancy AOA increased from 24 weeks of pregnancy with a maximum at 30 weeks, while MDA level did not change significantly through all time of pregnancy. On the contrary, in preeclamptic pregnancy blood AOA did not change significantly, while MDA content increased at the 26-34 weeks of pregnancy with a maximum at 30-34 weeks of pregnancy. Blood TF content in normal pregnancy increased during pregnancy development with a maximum at 30-34 weeks, while in preeclamptic pregnancy TF changed only a little. These data show the important role of TF in the AOA blood status formation in normal pregnancy, and great pathogenetic role of the absence of such an increase of TF at preeclamptic pregnancy in AOA impairment at this condition. Eiconol (omega-3 polyunsaturated fatty acid concentrate from north fish oil) intake by preeclamptic pregnant women drastically decreased blood MDA level (1,5-2 times compared to the women that did not receive eiconol), especially at 29-34 week of gestation. Blood AOA, that was decreased at preeclampsia increased under influence of eiconol intake at all pregnancy stages studied. Eiconol intake greatly increased also the TF blood content that was decreased at preeclampsia. It is supposed that eiconol ability to increase AOA may be explained by its capacity to increase the level of TF--one of the most important compounds of serum blood antioxidant system.

Effects of Mediterranean diet on lipid levels and cardiovascular risk in renal transplant recipients

BACKGROUND

Renal transplant recipients have an increased incidence of cardiovascular disease. These patients present abnormalities of lipoprotein profile which are persistent and involve an increasing number of individuals, suggesting the opportunity of an early therapeutic intervention.

METHODS

We evaluated the effects of a 10- to 12-week diet based on the American Heart Association step-one diet criteria, modified with an increased intake of monounsaturated fats and alimentary fibers, on lipid profile and lipid-related cardiovascular risk in 78 normolipidemic and hyperlipidemic renal transplant recipients.

RESULTS

Diet led to a significant reduction in total cholesterol levels by 10%, triglycerides by 6.5%, low-density lipoprotein (LDL)-cholesterol by 10.4% and LDL-cholesterol/high-density lipoprotein (HDL)-cholesterol ratio by 10%, whereas HDL-cholesterol levels remained unchanged. Dividing renal transplant recipients into risk classes according to the National Cholesterol Expert Program guidelines and LDL-cholesterol levels, we observed a progressively increasing reduction in total cholesterol and LDL-cholesterol levels among 'desirable LDL-cholesterol', 'borderline high-risk LDL-cholesterol' and 'high-risk LDL-cholesterol' patients, while HDL-cholesterol levels did not change in any group and the LDL-cholesterol/HDL-cholesterol ratio significantly decreased in 'borderline high-risk LDL-cholesterol' and in 'high-risk LDL-cholesterol' patients (respectively by 6.8%, p < 0.05, and by 21.1%, p < 0.0001). Reduction in triglyceride levels was statistically significant only in subjects with 'desirable LDL-cholesterol' (by 12.3%, p < 0.01). Patients in the 'desirable LDL-cholesterol' class increased from 28 (35.9% of total patients) before diet to 45 (57.7% of total patients, p < 0.01), while subjects in the 'high-risk LDL-cholesterol' class reduced from 24 (30.8% of total patients) to 8 (10.2% of total patients, p < 0.005).

CONCLUSION

These data suggest the possibility of a nutritional hypolipidemic approach in renal transplant recipients, even if normolipidemic. Dietetic treatment determined an inversion in the typical trend of renal transplant recipients, reducing instead of increasing the number of subjects with hypercholesterolemia, permitting the selection of individual candidates for further pharmacological treatment by carefully evaluating risk/benefit costs.

Dietary n-3 PUFA increases the apoptotic response to 1,2-dimethylhydrazine, reduces mitosis and suppresses the induction of carcinogenesis in the rat colon

The effect of dietary fish oil on colonic crypt cell apoptosis and proliferation was examined in male Wistar rats, 24 and 48 h after administration of 1,2-dimethylhydrazine (DMH), and its influence on the induction of aberrant crypt foci (ACF) in the distal colon was assessed. Rats (125-150 g) fed a high-fat semi-synthetic diet containing corn oil (CO) were given DMH (30 mg/kg body wt) or a sham injection of EDTA/NaCl. Animals were then fed either the CO diet or a diet in which fish oil (EPA 18.7%; DHA 8%) was substituted for corn oil. Subgroups of rats (n = 5) were killed after 24 and 48 h, and crypt cell apoptosis and proliferation were quantified by morphological criteria in isolated intact crypts from the mid and distal colon. Consumption of the fish oil diet (FO) was associated with increased apoptotic cell death (P < 0.001) and suppression of proliferation (P < 0.05) in colonic crypts both 24 and 48 h after DMH. In a second experiment, animals were given three injections of DMH or sham injections of carrier at weekly intervals. For 48 h after each injection animals were fed either the CO or FO diet, but otherwise maintained on the CO throughout. The number and crypt multiplicity of ACF in the distal colon were determined after 18 weeks, and animals given the FO diet for the 48 h period following carcinogen administration were found to have significantly fewer ACF than rats fed the CO diet (P < 0.05). The data demonstrate that the fatty acid composition of the diet is an important determinant in the induction of carcinogenesis by DMH. The proliferative and apoptotic response of the colonic crypt to carcinogen and fish oil, coupled with the reduced incidence of ACF, suggest n-3 PUFA can protect against the carcinogenic effects of DMH by mediating changes in the balance proliferation and cell death.

Clinical use of lipid emulsions

Substantial progress has been made in the understanding of the metabolism of intravenous lipid emulsions and the delivery of their various components to specific tissues or cells. Lipid emulsions should be considered not only as a means of providing energy substrates but also specific compounds that participate in the regulation of key metabolic functions. Such improved knowledge should find applications in the metabolic care of different types of patients.

Plasma and red blood cell fatty acids in peroxisomal disorders

The demonstration of abnormal levels of fatty acids or plasmalogens in plasma or red blood cells is key to the diagnosis of peroxisomal disorders. We report the levels of 62 fatty acids and plasmalogens in patients with X-linked adrenoleukodystrophy (X-ALD), Zellweger syndrome (ZS), neonatal adrenoleukodystrophy (NALD), and infantile Refsum disease (IRD), both at baseline and after dietary interventions. "Lorenzo's Oil" therapy in X-ALD normalizes the levels of saturated very long chain fatty acids in plasma, but leads to reduced levels of omega 6 and other omega 3 fatty acids, and requires monitoring and appropriate dietary supplements. Patients with ZS, NALD and IRD have reduced levels of docosahexaenoic acid (DHA) and arachidonic acid (AA) which can be normalized by the oral administration of microencapsulated DHA and AA.

[Modification to the erythrocyte membrane lipids in patients with cardiovascular pathology during balneotherapy]

Erythrocyte phospholipids (FL) composition and their elements polyunsaturated fatty acids of omega-6 and omega-3 type were studied in the course of combined balneotherapy of neurocirculatory dystonia and ischemic heart disease (IHD) patients. The balneological factors promoted FL concentration normalization under positive dynamics in clinical symptoms in 62% of patients with neurocirculatory dystonia. The modulating effect occurred in IHD only in those patients who, in addition to balneotherapy, took alimentary omega-3 fatty acids made of sea products as food additives. The intensity of the FL and fatty acid modification to the end of the treatment was related to the severity of the baseline metabolic abnormalities.

Fatty acids in substitute formulas for cow's milk allergy

BACKGROUND

The role of dietary fats in food-related allergic symptoms is increasingly being investigated, since the pivotal role of fat-derived inflammatory substances, e.g., leukotrienes, has been realized. The objective of this study was to describe the fatty acid composition of several commercially available infant formulas that are used as substitutes for adapted cow's milk formulas.

METHODS

Samples of nine formulas (two soy, two extensively hydrolyzed casein, three extensively hydrolyzed whey, and two amino-acid-based formulas) and human milk as control were analyzed by gas chromatography.

RESULTS

The quantity of fatty acids in the formulas was within the breast-milk range. The percentage of energy derived from fat was below the European Society for Pediatric Gastroenterology and Nutrition recommendations in two cases, but, in the others, it roughly met the recommendations. The percentage of energy derived from linoleic acid was as recommended in all but two cases, where it was higher than recommended. As indicated by a quality indicator, the linoleic to alpha-linolenic acid ratio, altogether four formulas were within either the recommendations or the analyzed breast-milk range. In three cases, it was 1.5-2.5 and in two cases 4-5 times higher than recommended.

CONCLUSIONS

There are recommendations for infant formulas to meet nutritional requirements of fat intake, and the analyzed formulas are in most cases within the suggested ranges. However, little is known of requirements in allergic or inflammatory conditions, and whether these described fatty acid compositions are pro- or anti-inflammatory.

Is there a role for dietary polyunsaturated fatty acid supplementation in canine renal disease?

Dogs with spontaneous renal diseases frequently develop progressive uremia. After partial nephrectomy, a similar pattern of progressively declining renal function develops. This pattern may be attributed in part to the development of glomerular hypertension in remnant canine nephrons. Changes in the composition of dietary polyunsaturated fatty acids (PUFA) modify glomerular hemodynamics in normal rats and affect the chronic course of renal disease in partially nephrectomized rats. Thus, dietary PUFA supplementation might alter progressive canine nephropathies. However, the response of dogs with renal insufficiency to dietary manipulations frequently differs substantially from that of laboratory rodents, and the effects of dietary PUFA composition have been poorly characterized in dogs with chronic renal disease. Here we address the hypothesis that dietary PUFA supplementation may delay the progression of chronic renal insufficiency in dogs. In particular, dogs ingesting diets supplemented with (n-6) PUFA exhibited severe glomerular hypertension associated with rapidly progressive renal failure. In contrast, dietary supplementation with (n-3) PUFA prevented deterioration of the glomerular filtration rate and preserved renal structure. The results of these model studies demonstrate that dietary PUFA supplementation may alter renal hemodynamics and the long-term course of renal injury in dogs. Clinical trials to address the potential benefits of dietary (n-3) PUFA supplementation in a variety of spontaneous renal diseases seem warranted.

Importance of dietary gamma-linolenic acid in human health and nutrition

Considerable debate remains regarding the distinct biological activities of individual polyunsaturated fatty acids (PUFA). One of the most interesting yet controversial dietary approaches has been the possible prophylactic role of dietary gamma-linolenic acid (GLA) in treating various chronic disease states. This strategy is based on the ability of diet to modify cellular lipid composition and eicosanoid (cyclooxygenase and lipoxygenase) biosynthesis. Recent studies demonstrate that dietary GLA increases the content of its elongase product, dihomo-gamma-linolenic acid (DGLA), within cell membranes without concomitant changes in arachidonic acid (AA). Subsequently, upon stimulation, DGLA can be converted by inflammatory cells to 15-(S)-hydroxy-8,11,13-eicosatrienoic acid and prostaglandin E1. This is noteworthy because these compounds possess both anti-inflammatory and antiproliferative properties. Although an optimal feeding regimen to maximize the potential benefits of dietary GLA has not yet been determined, it is the purpose of this review to summarize the most recent research that has focused on objectively and reproducibly determining the mechanism(s) by which GLA may ameliorate health problems.

[Study of metabolic and clinical effects of polyunsaturated fatty acids omega-3 from "Eicovit" in patients with ischemic heart disease and familial hyperlipoproteinemia]

The influence of antiatherosclerotic diet with including 15 g preparation "Eikovit" containing fat of freshwater fish on fat acid composition of erythrocytes membrane was studied in 399 patients with ishemic heart disease and hyperlipidemia. Against a background of positive influence on clinical symptoms of diseases, lipids of blood serum, homeostasis expressed influence of PUFA omega-3 in "Eikovit" on biomembrane fat acid composition was noted. It was shown sharp increasing a quota an eicosapentaenic acid by simultaneous reducing PUFA omega-6 level.

Long-term supplementation with eicosapentaenoic acid salvages cardiomyocytes from hypoxia/reoxygenation-induced injury in rats fed with fish-oil-deprived diet

Dietary supplementation of fish oil containing eicosapentaenoic acid (C20:5 n-3, EPA) and docosahexaenoic acid (C22:6 n-3, DHA) has been shown to exert protective effects on ischemic/reperfused hearts. We determined whether deprivation of fish oil from the diet paradoxically enhances susceptibility of cardiomyocytes to hypoxia/reoxygenation-induced injury and whether supplementation with either EPA or DHA overcomes such alterations. Rats were fed with fish-oil-rich (FOR) diet, fish-oil-deprived (FOD) diet alone, FOD diet with EPA (1 g/kg/day), or FOD diet with DHA (1 g/kg/day) for 4 weeks. The FOD diet reduced n-3 polyunsaturated fatty acids (PUFAs) and increased n-6 PUFAs such as linoleic (C18:2) and arachidonic acids (C20:4) in myocardial phospholipids. EPA or DHA supplementation increased its incorporation into phospholipid pools. Cardiomyocytes isolated by treatment with collagenase were subjected to 150 min of hypoxia and subsequent reoxygenation for 15 min. In the FOD diet group, the number of surviving rod-shaped cells after hypoxia and reoxygenation was smaller than that of the FOR group. Supplementation with EPA did not affect the number of rod-shaped cells, but attenuated reoxygenation-induced reduction in the number of square-shaped cells. In contrast, DHA supplementation did not afford any protection. The results suggest that deprivation of fish oil from dietary intake enhances the susceptibility of cardiomyocytes to hypoxic injury, and EPA, but not DHA, is capable of salvaging cardiomyocytes from hypoxia/reoxygenation-induced damage.

Nuts and plasma lipids: an almond-based diet lowers LDL-C while preserving HDL-C

OBJECTIVE

To compare lipid-altering effects of an almond-based diet with an olive oil-based diet, against a cheese and butter-based control diet.

METHODS

Forty-five free-living hyperlipidemic men (n = 12) and women (n = 33) with a mean plasma total cholesterol (TC) of 251 +/- 30 mg/dL followed one of three diets; almond-based, olive oil-based, or dairy-based for 4 weeks. Total fat in each diet was matched, and the study-provided sources of fat comprised the major portion of fat intake.

RESULTS

Reductions in TC and low-density lipoprotein-cholesterol (LDL-C) between the three groups were significantly different from the almond group (both p < 0.001). Within group analysis revealed that the almond-based diet induced significant reductions in TC (p < 0.05), LDL-C (p < 0.001), and the TC:HDL ratio (p < 0.001), while HDL-C levels were preserved. TC and HDL-C in the control diet were significantly increased from baseline (both p < 0.05), while the olive oil-based diet resulted in no significant changes over the study period. Weight did not change significantly.

CONCLUSION

Results suggest that the more favorable lipid-altering effects induced by the almond group may be due to interactive or additive effects of the numerous bioactive constituents found in almonds.

Plant sterol-enriched margarines and reduction of plasma total- and LDL-cholesterol concentrations in normocholesterolaemic and mildly hypercholesterolaemic subjects

OBJECTIVES

To compare effects on plasma total-, LDL-, and HDL-cholesterol concentrations of margarines enriched with different vegetable oil sterols or sitostanol-ester.

DESIGN

A randomized double-blind placebo-controlled balanced incomplete Latin square design with five treatments and four periods of 3.5 weeks. Margarines enriched with sterols from soybean, sheanut or ricebran oil or with sitostanol-ester were compared to a non-enriched control margarine. Sterol intake was between 1.5-3.3 g/d. Two thirds of the soybean oil sterols were esterified to fatty acids.

SETTING

Unilever Research Laboratory, Vlaardingen, The Netherlands.

SUBJECTS

One hundred healthy non-obese normocholesterolaemic and mildly hypercholesterolaemic volunteers aged 45+/-12.8 y, with plasma total cholesterol levels below 8 mmol/L at entry.

MAIN OUTCOME MEASURES

Plasma lipid, carotenoid and sterol concentrations, blood clinical chemistry and haematology, fatty acid composition of plasma cholesterylesters and food intake.

RESULTS

Ninety-five volunteers completed the study. None of the margarines induced adverse changes in blood clinical chemistry, serum total bile acids or haematology. Plasma total- and LDL-cholesterol concentrations were significantly reduced by 8-13% (0.37-0.44 mmol/L) compared to control for margarines enriched in soybean oil sterol-esters or sitostanol-ester. No effect on HDL-cholesterol concentrations occurred. The LDL- to HDL-cholesterol ratio was reduced by 0.37 and 0.33 units for these margarines, respectively. Effects on blood lipids did not differ between normocholesterolaemic and mildly hypercholesterolaemic subjects. Plasma sitosterol and campesterol levels were significantly higher for the soybean oil sterol margarine and significantly lower for the sitostanol-ester margarine compared to control. Dietary intake was very similar across treatments. The fatty acid composition of plasma cholesterylesters confirmed the good compliance to the treatment. All sterol enriched margarines reduced lipid-standardized plasma alpha- plus beta-carotene levels. Plasma lycopene levels were also reduced but this effect was not significant for all products.

CONCLUSIONS

A margarine with sterol-esters from soybean oil, mainly esters from sitosterol, campesterol and stigmasterol, is as effective as a margarine with sitostanol-ester in lowering blood total- and LDL-cholesterol levels without affecting HDL-cholesterol concentrations. Incorporation in edible fat containing products of such substances may substantially reduce the risk of cardiovascular disease in the population.

Moderate intake of n-3 fatty acids for 2 months has no detrimental effect on glucose metabolism and could ameliorate the lipid profile in type 2 diabetic men. Results of a controlled study

OBJECTIVE

To evaluate the effect of a moderate dose of fish oil on glycemic control and in vivo insulin action in type 2 diabetic men with elevated plasma triacylglycerols and to determine the effect of the same treatment on gene expression of GLUT4, lipoprotein lipase (LPL), and hormone-sensitive lipase (HSL) in the abdominal adipose tissue.

RESEARCH DESIGN AND METHODS

A total of 12 type 2 diabetic men were randomly allocated to 2 months of 6 g daily of either fish oil or sunflower oil, separated by a 2-month washout interval, in a double-blind crossover design.

RESULTS

For glucose metabolism, 2 months of fish oil supplementation compared with sunflower oil led to similar fasting plasma insulin, glucose, and HbA1c. Basal hepatic glucose production did not increase after fish oil. There was no difference in insulin suppression of hepatic glucose production nor in insulin stimulation of whole-body glucose disposal measured by the euglycemic-hyperinsulinemic clamp. Fish oil did not ameliorate the low mRNA level of GLUT4 in adipose tissue of these patients. For lipid profile, fish oil lowered plasma triacylglycerol more than sunflower oil (P < 0.05) and tended to increase the amount of mRNA of both LPL and HSL in adipose tissue.

CONCLUSIONS

A moderate dose of fish oil did not lead to deleterious effects on glycemic control or whole-body insulin sensitivity in type 2 diabetic men, with preserved triacylglycerol-lowering capacities.