Low-fat, monounsaturate-rich diets reduce susceptibility of low density lipoproteins to peroxidation ex vivo

Oxidative modification of low density lipoprotein (LDL) plays an important role in the process of atherosclerosis. The susceptibility of LDL to oxidation and the amount of peroxidation products formed are influenced by the lipoprotein content of 18:1n-9, 18:2n-6, and the 18:2n-6/18:1n-9 ratio, which is dependent in part on dietary fatty acids. The purpose of this study was to determine if changing from a typical American diet to a low-fat, monounsaturate-rich diet (LFMR) would result in favorable alterations in the fatty acid composition and oxidative profile of LDL in hypercholesterolemic individuals. Free-living postmenopausal hypercholesterolemic women who routinely consumed a diet moderately high in total fat and total saturates (34 and 11%, respectively) followed an LFMR diet (26% fat, 6% saturated fat, and 14% monounsaturated fat) for 6 mon. Sixteen postmenopausal hypercholesterolemic women already following standard low-fat (LF) diets acted as a control for seasonal variations in serum lipids. LDL from randomly selected subjects (LF n = 6, LFMR n = 5) was evaluated. LFMR diets resulted in LDL with increased concentrations and percentages of 18:1n-9, reduced 18:2n-6/18:1n-9 ratio, and lower percentages of 18:2n-6. No significant changes in LDL fatty acids occurred in the LF group. Conjugated diene lag time increased in both groups during copper-induced in vitro oxidation. Only the LFMR group experienced an increase in lipid peroxide lag time and a decrease in lipid peroxide formation. The LFMR diet was well tolerated and may be of therapeutic value in the treatment of hypercholesterolemia.

Interaction between a semisynthetic diet and indole-3-carbinol on mammary tumor incidence in Balb/cfC3H mice

This paper extends prior studies on the chemoprotective effect of indole-3-carbinol (I3C) on mammary and endometrial tumors in rodent models and focuses on the interplay between standard laboratory chow (Purina Lab Chow 5001), a high omega 6 fatty acid diet (AIN76A), and I3C on the incidence of mouse mammary tumor virus-induced (MMTV) mammary tumors in mice. While the protective effect of I3C was observed in mice maintained on the AIN76A diet from conception, a marked decrease in tumor incidence was observed, which was found to be directly related to the extent of time the mice were maintained on the Purina 5001 diet prior to the switch to the AIN76A control diet. This protective effect of the chow diet against MMTV-induced tumors has not been previously reported. The effects of the chow diet and I3C do not appear to be additive or synergistic.

DHA feeding provides host protection and prevents fibrosarcoma-induced hyperlipidemia while maintaining the tumor response to araC in Fischer 344 rats

Fischer 344 rats were inoculated with fibrosarcoma tumor cells and fed diets containing 5% or 10% (wt/wt) safflower oil or 10% oil containing docosahexaenoic acid (DHA). Animals were then treated with arabinosylcytosine (araC) or saline for six days. Tumor weights were highest in animals fed 10% safflower oil and treated with saline, intermediate in animals fed oil containing DHA and 5% safflower oil and treated with saline, and lowest in araC-treated animals from all diets. Plasma cholesterol and triglyceride levels correlated highly with final tumor size, regardless of diet or treatment group. Animals fed safflower oil had lower intestinal weights than those fed DHA, which histology demonstrated to be a result of differences in villus height and crypt depth. Substantial loss of bone marrow cells occurred in all dietary groups treated with araC; however, the proportion of granulocyte-macrophage precursors remaining in the DHA animals was higher than in saline-treated animals and twofold higher than in the animals fed 10% safflower oil and treated with araC. These data suggest that, even in the face of rapid tumor growth and chemotherapeutic challenge, consumption of a diet rich in DHA can slow tumor growth, prevent hyperlipidemia, enhance bone marrow cellularity, and promote intestinal growth compared with a moderate-fat n--6-rich diet.

Dietary n-3 fatty acids and therapy for rheumatoid arthritis

OBJECTIVE

To examine the potential for dietary n-3 fats to be component of therapy for rheumatoid arthritis (RA).

METHODS

Studies of encapsulated fish oil use in RA were reviewed and critiqued, and possible biochemical mechanisms for fish oil effects were examined. The potential for use of n-3 fats was evaluated within a dietary framework rather than a quasi-pharmaceutical framework.

RESULTS

There is consistent evidence from double-blind, placebo-controlled clinical trials that dietary n-3 fats, supplied as fish oil, can have beneficial effects in RA. The beneficial effects appear modest, but their size and extent may have been moderated by common trial design factors such as high n-6 polyunsaturated fat diets and concurrent antiinflammatory drug use. Mechanisms for the clinical effects of n-3 fats in RA may involve their ability to suppress production of inflammatory mediators, including n-6 eicosanoids and proinflammatory cytokines. Suppression of n-6 eicosanoid and cytokine production will be possible using foodstuffs that are rich in n-3 fats and poor in n-6 fats.

CONCLUSIONS

There are many overlapping biochemical effects of n-3 fatty acids and antiinflammatory pharmaceuticals that could explain the clinical actions of n-3 fats in RA. They suggest that there is the potential for complementarity between drug therapy and dietary choices that increase intake of n-3 fats and decrease intake of n-6 fats. In particular, there is the potential for drug-sparing effects. Future studies with n-3 fats in RA need to address the fat composition of the background diet and the issue of concurrent drug use.

Effect of dietary linoleic/alpha-linolenic acid ratio on growth and visual function of term infants

OBJECTIVES

To determine the effect of alpha-linolenic acid (ALA) intake (or the dietary linoleic acid [LA]/ALA ratio) on the growth and visual function of term infants.

STUDY DESIGN

Normal term infants were assigned randomly and in masked fashion at birth to receive formulas with approximately 16% of total fatty acids as LA and 0.4%, 1.0%, 1.7%, or 3.2% of fatty acids as ALA (LA/ALA ratios of 44, 18.2, 9.7, and 4.8) for the first 4 months of life. The fatty acid pattern of plasma phospholipids was determined shortly after birth and at approximately 21, 60, and 120 days of age. Anthropometric data were obtained at the same times and also at approximately 240 days of age. Transient visual evoked responses (VERs) were measured at approximately 120 and 240 days of age. For comparisons, anthropometric and VER data also were obtained in infants who were exclusively breast-fed for the first 4 months of life.

RESULTS

Infants who received the formula with 3.2% ALA (LA/ALA ratio, 4.8) had higher plasma concentrations of phospholipid docosahexaenoic acid (DHA) but lower concentrations of arachidonic acid at 21, 60, and 120 days of age. Mean weight of this group at 120 days of age was 760 gm less (p < 0.05) than the mean weight of the group that received the formula with 0.4% ALA (LA/ALA ratio, 44). Despite differences in plasma phospholipid DHA contents among groups, neither VER latency nor amplitude differed significantly among formula groups or between any formula group and age-matched, breast-fed infants.

CONCLUSIONS

The highest versus the lowest ALA intake (or the lowest vs the highest LA/ALA ratio) resulted in higher plasma phospholipid DHA content from 21 to 120 days of age but was not associated with improved visual function as assessed by transient VER. Moreover, mean body weight of infants who received the highest versus lowest ALA intake was less at 120 days (p < 0.05). These data suggest that the lower LA/ALA ratios currently recommended for infant formulas should not be adopted until the effect of such ratios on growth are evaluated more completely.

Dietary flax seed in prevention of hypercholesterolemic atherosclerosis

Oxygen free radicals (OFRs) have been implicated in the development of hypercholesterolemic atherosclerosis. Flax seed is the richest source of omega-3 fatty acid and lignans. omega-3 Fatty acid suppresses the production of interleukin-1 (IL-1), tumor necrosis factor (TNF) and leukotriene B4 (LTB4), and of OFRs by polymorphonuclear leukocytes (PMNLs) and monocytes. Lignans possess anti-platelet activating factor (PAF) activity and are antioxidant. PAF, IL-1, TNF and LTB4 are known to stimulate PMNLs to produce OFRs. Flaxseed would, therefore, reduce the levels of OFRs and hence would prevent the development of hypercholesterolemic atherosclerosis. The effects of dietary flax seed on a high cholesterol diet induced atherosclerosis, lipid profile and OFR-producing activity of PMNLs (PMNL-CL) were investigated in rabbits. The rabbits were divided into 4 groups: group I, control; group II, flax seed diet (7.5 g/kg daily, orally); group III, 1% cholesterol diet; and group IV, same as group III but received flax seed (7.5 g/kg daily, orally). Blood samples were collected before and after 4 and 8 weeks on their respective diets for biochemical measurements and aortae were removed at the end of 8 weeks for estimation of atherosclerotic changes. The high cholesterol diet increased the serum level of total cholesterol (TC) and PMNL-CL without altering the levels of serum triglycerides (TG). These changes were associated with a marked development of atherosclerosis in the aorta. Flax seed reduced the development of aortic atherosclerosis by 46% and reduced the PMNL-CL without significantly lowering the serum cholesterol. Flax seed in normocholesterolemic rabbits increased serum total cholesterol and decreased PMNL-CL without significantly affecting the serum TG. Modest dietary flax seed supplementation is effective in reducing hypercholesterolemic atherosclerosis markedly without lowering serum cholesterol. Its effectiveness against hypercholesterolemic atherosclerosis could be due to suppression of enhanced production of OFRs by PMNLs in hypercholesterolemia. Dietary flax seed supplementation could, therefore, prevent hypercholesterolemia-related heart attack and strokes.

Modulation of arterial thrombosis tendency in rats by vitamin K and its side chains

Vitamin K is involved in the biosynthesis of a number of blood coagulation factors and bone proteins. It has been suggested that the vitamin K requirement of bone tissue is higher than that of the liver. Here we report that in rats very high doses of vitamin K affected neither the blood coagulation characteristics nor the blood platelet aggregation rate. This was observed for both phylloquinone and menaquinone-4. Both vitamers were also tested for their effects on the arterial thrombosis tendency in the rat aorta loop model. The mean obstruction times were prolonged at a high intake of menaquinone-4 (250 mg/kg body weight/day), and shortened after a similarly high phylloquinone regimen. Since (a) both vitamers only differ in their aliphatic side chains; and (b) a similar trend was observed after administration of phytol and geranylgeraniol, we conclude that the modulation of the arterial thrombosis tendency is accomplished by the side chain of vitamin K.

X linked adrenoleukodystrophy: clinical presentation, diagnosis, and therapy

X linked adrenoleukodystrophy (X-ALD) is an inherited disorder of peroxisomal metabolism, biochemically characterised by accumulation of saturated very long chain fatty acids. Accumulation of these fatty acids is associated with cerebral demyelination, peripheral nerve abnormalities, and adrenocortical and testicular insufficiency. The lowest estimated birth incidence is one per 100,000. At least six phenotypes can be distinguished, of which the two most frequent are childhood cerebral ALD and adrenomyeloneuropathy. The X-ALD gene has been identified, but thus far no relation between genotype and phenotype has been found. Diagnosis is relatively easy and can be confirmed reliably, and prenatal testing is possible in affected families. Several therapeutic options, some with promising perspectives, are available. Neurologists and other physicians seem not to be familiar with the many facets of X-ALD. In this review, the clinical presentation, the relative frequencies of the different phenotypes, and the diagnostic and therapeutic options are presented.

[Clinical efficacy of eiconol in patients with diabetic retinopathy]

Eiconol, a nutrient additive from sea fish oil, was used in the treatment of 48 patients with diabetic retinopathy. Eiconol normalized lipid metabolism parameters, which were increased, in 79.2% patients: total cholesterol decreased by 19.1%, triglycerides by 27.8%, beta-lipoproteins by 12% vs. the initial level; 74.6% patients developed favorable shifts in the status of the hemoretinal barrier and ocular microcirculation mainly at the expense of improving blood rheology. This resulted in a decrease of the recovery coefficient in photostress test by 23 +/- 1.3%. The therapeutic effect of eiconol was particularly evident during the preclinical and initial stages of manifest diabetic retinopathy and decreased as the diseases augmented in severity. Eiconol monotherapy may be recommended for correction of lipid metabolism and of functional disorders of permeability at the level of vascular and tissue membranes, and for improving the blood rheology during the preclinical stage of diabetic retinopathy. In proliferative diabetic retinopathy it is advisable to add eiconol to a complex of pathogenetic therapy.

gamma-Linolenic acid-containing diet attenuates bleomycin-induced lung fibrosis in hamsters

Although bleomycin (BLM), an antineoplastic drug, is used in the treatment of a variety of tumors, the mechanism(s) that contribute to its induced lung injury and fibrosis are not fully elucidated. Since alterations in the levels of certain fatty acid metabolites have been associated with BLM-induced lung injury, we tested the effects of dietary gamma-linolenic acid (GLA)-containing evening primrose oil on BLM-induced morphological alterations in the hamster lung, the marked elevation of tissue hydroxyproline (a marker for collagen synthesis), and elevated generation of arachidonic acid metabolites (marker of inflammatory mediators). Our data revealed that after 14 d of dietary GLA-containing oil (i) BLM-induced elevation of lung hydroxyproline was suppressed (P < 0.05), (ii) the marked BLM-induced elevation of lung leukotriene B4 (LTB4) (a marker of polymorphanuclear generation of proinflammatory LTB4) was significantly suppressed (P < 0.05). The decrease in LTB4 was accompanied by marked elevations (P < 0.05) of lung prostaglandin E1 (PGE1) and 15-hydroxyeicosatrienoic acid (15-HETrE), both with known antiinflammatory properties. Taken together, data from these studies suggest that dietary GLA-containing oil contributes to tissue elevation of PGE1 and 15-HETrE, which in vivo may attenuate lung inflammation and fibrosis.

Localized proton magnetic resonance spectroscopy in patients with adult adrenoleukodystrophy. Increase of choline compounds in normal appearing white matter

OBJECTIVES

To describe the changes in the results of magnetic resonance imaging and spectroscopy occurring in the normal-appearing white matter of patients with adult adrenoleukodystrophy and to present evidence of a particular change that may serve as a marker for the follow-up of the disease.

DESIGN

Neurologic, magnetic resonance imaging, and localized proton spectroscopic examinations were performed in 11 patients with adult adrenoleukodystrophy and compared with 11 sex- and age-matched controls.

PATIENTS

Eleven patients with adult adrenoleukodystrophy participated in a trial of dietary therapy with glyceryl trioleate and glyceryl trierucate (Lorenzo's oil) in the Fédération de Neurologie and the Institut National de la Santé et de la Recherche Médicale, Unité 134, at the Hôpital de la Salpêtrière in Paris, France.

RESULTS

The results of magnetic resonance imaging of the white matter were normal in 2 patients and showed areas of mild symmetrical hypersignals on T2-weighted images and fluid attenuated inversion recovery sequences, localized in the posterior white matter in 9 patients. The results of spectroscopy indicated that the peak of the area of choline-containing compounds was increased at long echo times in patients with adult adrenoleukodystrophy, which may reflect very long-chain fatty acid accumulation in this disease. The peak of the area of myo-inositol-containing compounds was increased at short echo times in patients with adult adrenoleukodystrophy, which may indicate a rise in this metabolite concentration. The N-acetylaspartate-creatine amplitude ratio was significantly decreased in patients with motor deficit. The significance of this finding remains to be established.

CONCLUSIONS

The results of localized proton magnetic resonance spectroscopy show abnormalities in the cerebral white matter of patients with adult adrenoleukodystrophy, which may contribute to the understanding of the pathophysiologic characteristics of the disease. Although changes in the results of spectroscopy found in this disease are not specific, the increase of choline-containing compounds may reflect the accumulation of very long-chain fatty acids in the central nervous system. Localized proton magnetic resonance spectroscopy may prove a valuable technique, in addition to magnetic resonance imaging, for noninvasive investigation of patients with adult adrenoleukodystrophy undergoing future clinical trials.

Dietary fish oil. Influence on lesion regression in the porcine model of atherosclerosis

We examined the influence of dietary fish oil on lesion regression in a porcine model of atherogenesis. Thirty-two female Yucatan miniature pigs were fed an atherogenic diet for 8 months. A no-regression group (n = 8) was killed to determine the extent of atherosclerosis at 8 months. Three regression groups were switched to normal minipig chow supplemented with either MaxEPA fish oil (FO group, n = 8), a control oil with the ratio of polyunsaturated to monounsaturated to saturated fatty acid matched to that of the fish oil (CO group, n = 8), or no oil supplement (NO group, n = 8) for a further 4 months. Plasma cholesterol levels reached between 15 and 20 mmol/L during the atherogenic phase and returned to normal (2 mmol/L) within 2 months of the beginning of the regression diet. Compared with the NO group, fish oil supplementation during the regression phase caused a decrease in VLDL and HDL cholesterol and an increase in LDL cholesterol. Similarly, the control oil also caused a decrease in VLDL cholesterol; however, in contrast to the FO group, HDL cholesterol increased and LDL cholesterol was unchanged. FO LDL, which had decreased levels of 20:4 (n-6 fatty acid) and increased levels of 18:3, 20:5, and 22:6 (n-3 fatty acids), was shown to be twice as susceptible to copper-mediated oxidation as CO LDL particles. Morphological examination of the major blood vessels revealed a significant reduction in lesion area in the ascending and thoracic aorta as well as the carotid artery after the regression diet; however, there was no significant difference between the fish oil and control oil groups in any of the vessels measured. Therefore, despite increased LDL, decreased HDL, and an increased susceptibility to in vitro oxidation of LDL, fish oil supplementation of a regression diet did not influence lesion regression.

Steatosis and collagen content in experimental liver cirrhosis are affected by dietary monounsaturated and polyunsaturated fatty acids

BACKGROUND AND METHODS

We used thioacetamide administered orally to induce cirrhosis in rats, and after these had recovered for 1 and 2 weeks we examined the effects of dietary supplementation with monounsaturated and n-3 polyunsaturated fatty acids, or with a combination of n-3 and n-6 polyunsaturated fatty acids, on the extent of steatosis and collagen content in the liver.

RESULTS

Nodular cirrhosis, increased collagen content, and lipid accumulation were established after 4 months of treatment with thioacetamide. When the animals were fed a diet rich in oleic acid for 2 weeks, the steatosis and fibrosis decreased. Supplementation with n-3 polyunsaturated fatty acids favored reductions in collagen content but did not reduce the fat accumulation. With a diet supplemented with a mixture of n-3 and n-6 fatty acids we found no reduction in either lipid accumulation or collagen content.

CONCLUSIONS

Fibrosis and steatosis may be influenced by dietary fat, and monounsaturated fat appears to influence favorably the histologic recovery of the damaged liver.

Intervention of transplantable human mammary carcinoma MX-1 chemotherapy with dietary menhaden oil in athymic mice: increased therapeutic effects and decreased toxicity of cyclophosphamide

We investigated the effects of dietary menhaden oil on cyclophosphamide (CP) antineoplastic activity and its protective effect against CP toxicity. We found that dietary menhaden oil (HMO, 20% menhaden oil + 5% corn oil) enhanced the CP antitumor effect at the lowest dose tested (50 mg/kg) compared with the control group (LCO, 5% corn oil). Dietary HMO and CP treatment had a significant effect on the activities of tumor and liver microsomal cytochrome P-450 (CYP) over the controls. Activity of one of the key CP activating enzymes, CYP2B1 (which is similar to human CYP2B6), was significantly enhanced in the liver and tumor by the HMO diet, which could result in the formation of more pharmacologically active CP metabolites and, therefore, increased CP antitumor response. Moreover, the HMO diet exhibited a very significant protective effect against CP acute toxicity. The activity of the CP detoxifying enzyme aldehyde dehydrogenase (ADH) was significantly increased in the liver after HMO feeding; thus the observed protective effect of HMO feeding against CP toxicity may be partially the result of induction of ADH activity in the liver. In summary, our findings suggested that dietary menhaden oil can modulate ADH and CYP activities in a manner that may alter the metabolism of CP and, therefore, improve its therapeutic index by increasing its therapeutic effect and decreasing its toxicity.

[The effect of polyunsaturated fatty acids on the biochemical indices of bronchial asthma patients]

A placebo-controlled study was made of the efficacy of diet additive of omega-3 polyunsaturated fatty acids (diet oil eiconol) in 27 patients with bronchial asthma (BA). It was found that eiconol causes qualitative changes in the disease course: severe attacks of asphyxia occurred less frequently, drug doses were reduced. Provocative tests with allergen after two-week intake of eiconol versus placebo intake showed a significant decline of late allergic response due to compitative replacement of arachidonic acid in cell membranes of inflammation cell effectors by omega-3 polyunsaturated fatty acids inhibiting production of lipid mediators of inflammation.

[The effect of polyunsaturated fatty acids of the omega-3 class on the late phase of the allergic reaction in bronchial asthma patients]

Placebo-controlled study of changes in the course of atopic bronchial asthma (ABA) induced by supplement of the diet with polyunsaturated fatty acids of omega-3 class in 13 patients compared to placebo-treated subjects allowed the conclusion on significant attenuation of late allergic response in patients who had taken eiconol for two weeks. The effects of the acids are explained by a comparative replacement of arachidonic acid in the membranes of cell effectors of the inflammation with omega-3 fatty acids leading to inhibition of production of inflammation lipid mediators.

The fatty acid composition of human gliomas differs from that found in nonmalignant brain tissue

To compare the fatty acid composition of tumor tissue from glioma patients with that of normal brain tissue, tissue samples were obtained from 13 glioma patients and from 3 nonmalignant patients. Following lipid extraction, total fatty acid composition was measured using gas-liquid chromatography. samples were further separated into phospholipids and neutral lipids. Representative samples were then separated into phospholipid classes by thin-layer chromatography and the fatty acid composition assayed. Levels of the polyunsaturated fatty acid (PUFA) docosahexaenoic acid (DHA), were significantly reduced (P = 0.029) in the glioma samples compared with normal brain samples; mean values were 4.8 +/- 2.9% and 9.2 +/- 1.0%, respectively. This reduction in glioma DHA content was also observed in terms of phospholipids (4.6 +/- 2.1% vs. 9.6 +/- 0.8%, P = 0.002). The phosphatidylserine and phosphatidylethanolamine phospholipid classes were reduced in the glioma samples. Differences were also noted in the n-6 PUFA content between glioma and normal brain samples. The glioma content of the n-6 PUFA linoleic acid was significantly greater (P < 0.05) than that observed in the control samples in terms of total lipids. Thus, the fatty acid composition of human gliomas differs from that found in nonmalignant brain tissue.

Essential fatty acid supplementation in chronic hepatitis B

BACKGROUND

Dietary supplementation with essential fatty acids and polyunsaturated lecithin may improve biochemical and histological parameters in liver disease.

METHODS

Ten patients with serological and histological evidence of chronic hepatitis B received capsules of the polyunsaturated fatty acid-rich evening primrose oil in a dose of 4 g daily for 12 months, while a matched group received liquid paraffin capsules as a placebo.

RESULTS

Compared to the placebo group, the patients receiving evening primrose oil showed no improvement in either biochemical or histological indices of liver damage, or in the rate of loss of circulating e antigen.

CONCLUSIONS

Dietary, supplementation with this dose of essential fatty acids is unlikely to be of benefit in chronic hepatitis B.

Membrane fatty acids, niacin flushing and clinical parameters

Clinical definitions of schizophrenia are unreliable and difficult to use. The niacin flush test, which involves prostaglandin-induced vasodilatation, offers a method of exploring essential fatty acid metabolism in schizophrenic patients and may serve to define a subgroup of patients. In a multicentre study of schizophrenic patients with negative symptoms, we have examined the clinical accompaniments of the niacin response. Patients failing to flush with niacin showed significantly reduced levels of arachidonic and docosahexaenoic acids. Conversion from non-flushing to flushing during the 6 month supplementation period was predicted by an increase in arachidonic acid levels in red blood cell membranes irrespective of nature of supplementation. In this study, patients were selected for their negative symptoms and, therefore, it was not surprising that further measures of negative or positive symptoms did not predict flushing. However, an increased score for affective symptoms was significantly associated with a positive flush response. The stability of the niacin test needs to be examined in relation to the periodicity of symptoms in schizophrenia and manic depressive illness. New information on the anandamide system suggests that it may be associated with periodic phenomena and should be investigated in relation to the niacin test.

Effect of three sources of long-chain fatty acids on the plasma fatty acid profile, plasma prostaglandin E2 concentrations, and pruritus symptoms in hemodialysis patients

Patients with chronic renal failure exhibit plasma fatty acid patterns indicative of essential fatty acid deficiency. The plasma fatty acid profile of 25 hemodialysis patients with a history of pruritus symptoms indicated lower 20:3n-9 (eicosatrienoic acid), 20:4n-6 (arachidonic acid), and 20:5n-3 (eicosapentaenoic acid) concentrations; a higher 18:1n-9 (oleic acid) concentration; and above-normal ranges of prostaglandin E2 (PGE2) compared with 22 subjects chosen from a normal population. No significant difference in 22:6n-3 (docosahexaenoic acid) was shown between the hemodialysis patients and the normal subjects. The dietary intake of 20:5n-3 was higher and that of 18:1n-9 lower in the patients compared with the normal population group. In this 8-wk double-blind study the hemodialysis patients were randomly assigned to receive daily supplements of 6 g ethyl ester of either fish oil, olive oil, or safflower oil. At the end of 8 wk of treatment the fish oil group (FO group) had a greater decrease in 18:1n-9 (P < 0.05), greater increases in 20:5n-3 and 22:6n-3 (P < 0.01), and trends toward a greater decrease in 20:4n-6, a greater increase in PGE2 concentrations, and greater improvement in pruritus scores (0.10 > P > 0.05) compared with the other two groups. The increases in 20:5n-3 and 22:6n-3 in the FO group indicate compliance with fish oil supplementation. Results indicate that hemodialysis patients have abnormal fatty acid profiles and increased PGE2 values. Fish oil intervention changes the fatty acid profile and may improve the symptoms of pruritus.

Prevention of cholesterol cholelithiasis by dietary unsaturated fats in hormone-treated female hamsters

We examined the effect of diet on gallstone incidence and the composition of biliary phosphatidylcholines in methyltestosterone-treated female hamsters. These hamsters were fed a nutritionally adequate purified lithogenic diet containing 2% corn oil, 4% butterfat, 0.3% cholesterol, and 0.05% methyltestosterone, resulting in a cholesterol gallstone incidence of 86%. This incidence was lowered when mono- and polyunsaturated fats or fatty acids were added to the diet: 2.5% oleic acid resulted in total prevention of cholesterol cholelithiasis, 2.5% linoleic acid, and 4% safflower oil (78% linoleic acid content) reduced gallstone incidence to 26 and 8%, respectively. An additional 4% butterfat (29% oleic acid content) produced gallstones in 50% of the animals. At the end of the 6-wk feeding period, the bile of all hamsters was supersaturated with cholesterol. The major biliary phosphatidylcholine species in all groups were (sn-1-sn-2): 16:0-18:2, 16:0-18:1, 18:0-18:2, 16:0-20:4, and 18:2-18:2. The safflower oil- and linoleic acid-fed hamsters exhibited an enrichment of 16:0-18:2 (16-18%); added butterfat or oleic acid increased the proportion of 16:0-18:1 (9 and 25%, respectively). We conclude that the phosphatidylcholine molecular species in female hamster bile can be altered by dietary fats/fatty acids and that mono- and polyunsaturated fatty acids play a role in suppressing the induced cholelithiasis.

Dietary fish oil prevents the development of renal damage in salt-loaded stroke-prone spontaneously hypertensive rats

1. Stroke-prone spontaneously hypertensive rats (SHRSP) fed a high salt diet rapidly develop proteinuria, a marker of renal damage. We have recently shown that supplementing the diet of these rats with pure omega-3 fatty acids can inhibit the development of proteinuria. The aim of the present study was to examine the underlying renal pathology and to see whether a similar benefit could be obtained with fish oil or canola oil. 2. Diets containing sodium (2% by weight) and 5% fish oil, canola oil, olive oil or safflower oil (the latter two serving as controls) were fed to groups of eight young SHRSP and the development of hypertension and proteinuria was monitored. After 9 weeks, rats were killed and their kidneys were taken for histological examination and fatty acid analysis. Urinary protein was characterized electrophoretically. 3. Patterns of protein excretion were consistent with the appearance of pathological changes in both glomeruli and tubules. Fish oil inhibited the elevation of blood pressure, prevented the development of proteinuria and minimized histological lesions. However, in rats fed canola oil, hypertension and renal damage were equally severe as in rats fed olive or safflower oil. 4. The prevention of hypertensive renal damage by dietary fish oil may be attributable to the increased incorporation of long-chain omega-3 fatty acids in the kidney.

Dietary Juniperis virginiensis seed oil decreased pentobarbital-associated mortalities among DBA/1 mice treated with collagen-adjuvant emulsions

The propensity of the fatty acid 5,11,14-eicosatrienoic acid (5,11,14-ETA) to replace arachidonic acid in cell membranes, and its inability to be converted to bioactive eicosanoids, suggest that it may be useful in the treatment of autoimmune disorders. Previously, dietary application of oils extracted from 5,11,14-ETA-rich Platycladus orientalis delayed the onset of autoimmune disease in New Zealand Black mice. To gain more knowledge of the efficacy of this fatty acid toward alleviating immunological disorders, a similar oil was used to examine its effects on collagen-induced arthritis in DBA/1 mice, a model characterized by synovial proliferation and joint infiltration by inflammatory cells. Mice were fed AIN76A diet supplemented with 4% (w/w) of either an oil extracted from the seeds of Juniperis virginiensis (0.4% 5,11,14-ETA); a control oil consisting of equal parts olive, linseed and safflower oils; fish oil (90% fish oil and 10% safflower oil); or safflower oil. Mice were immunized with three injections of collagen-adjuvant emulsions, the first injection was intradermal, and the two subsequent injections were intraperitoneal. Mortalities were recorded following a secondary pentobarbital administration intraperitoneally. Mice from the J. virginiensis group had the lowest mortalities (25%) while safflower oil-fed mice had the highest (59%; p < 0.05). While the J. virginiensis group had the lowest mean CD4/CD8 T lymphocyte ratio, the fish oil group had the highest. These observations suggest that manipulation of eicosanoid production by different dietary lipids had different effects on immune responses, possibly through alterations in T lymphocyte subsets. Hypothetically, a downregulation of prostaglandin E2 release could increase the ratio of T helper 1 to T helper 2 lymphocytes and thereby modulate anaphylactic responses. Also, lowered pro-oxidant status may decrease CD4/CD8 T cell ratios and modify immune function.

Supplementation with omega-3 polyunsaturated fatty acids in the management of dysmenorrhea in adolescents

OBJECTIVES

The purpose of the study was to examine whether dietary supplementation with omega-3 fatty acids can relieve symptoms of dysmenorrhea in adolescents.

STUDY DESIGN

Forty-two adolescents with dysmenorrhea were randomly allocated to two groups. In the first group 21 girls received fish oil (1080 mg icosapentaenoic acid, 720 mg docosahexaenoic acid, and 1.5 mg vitamin E) daily for 2 months followed by a placebo for an additional 2 months. In the second group 21 girls received placebo for the first 2 months, followed by fish oil for 2 more months. The Cox Menstrual Symptom Scale was used to assess response to treatment.

RESULTS

There were no significant differences in the Cox Menstrual Symptom Scale between the two groups at baseline after 2 months of placebo administration. After 2 months of treatment with fish oil there was a marked reduction in the Cox Menstrual Symptom Scale from a baseline mean value of 69.9 to 44.0 (p < 0.0004).

CONCLUSIONS

This study suggests that dietary supplementation with omega-3 fatty acids has a beneficial effect on symptoms of dysmenorrhea in adolescents.

Temporary improvement of neurological symptoms with gammaglobulin therapy in a boy with adrenoleukodystrophy

A 10-year-old boy with adrenoleukodystrophy was treated with gammaglobulin in conjunction with a mixture of glyceryl trioleate and glyceryl trierucate. With a high dose of gammaglobulin, clinical improvement, including the reduction of visual field defects, was noted. On magnetic resonance imaging, attenuation of the enhancement of the rim with gadolinium was observed, suggesting repair of the blood-brain barrier. When auditory agnosia developed later, a temporary improvement was again obtained with gammaglobulin. Although the progress of the disease could not be arrested permanently, gammaglobulin therapy seemed to have been associated with temporary improvement of the clinical symptoms in this patient with adrenoleukodystrophy.

Is evening primrose oil of value in the treatment of premenstrual syndrome?

A systematic literature search of clinical trials of evening primrose oil (EPO) for the treatment of the premenstrual syndrome (PMS) was carried out with a view to performing a meta-analysis. Only seven placebo-controlled trials were found but only in five trials was randomization clearly indicated. Inconsistent scoring and response criteria made statistical pooling and hence a rigorous meta-analysis inappropriate. The two most well-controlled studies failed to show any beneficial effects for EPO, although because the trials were relatively small modest effects cannot be excluded. Nonetheless, on current evidence EPO is of little value in the management of premenstrual syndrome.

Bleeding in a patient taking Lorenzo's oil: evidence for a vascular defect

We describe a man with adrenoleukodystrophy receiving Lorenzo's oil (glycerol trioleate and glycerol trierucate) who developed purpura, petechiae, and bleeding. Bleeding time was markedly increased (>20 min), although he had only borderline thrombocytopenia (120 x 10(9)/1) and conventional platelet aggregation studies were normal (except for a borderline response to low concentration collagen), as were results using a new technique employing immobilised von Willebrand factor. Together these results suggest that bleeding in this man resulted from a defect in vascular wall function or in the interaction of platelets with the endothelium.

Dietary fish oil normalize dyslipidemia and glucose intolerance with unchanged insulin levels in rats fed a high sucrose diet

The aim of this study was to investigate the relationship between the lipid-lowering effects of fish oils and concomitant consequences on glucose tolerance and insulin sensitivity in an experimental animal model of hypertriglyceridemia induced by high sucrose intake. To achieve this goal, male Wistar rats were fed a semi-synthetic sucrose rich diet (SRD) (w/w: 62.3% sucrose, 8% corn oil, 17% protein) for 90 days. At the time, a well established and permanent hypertriglyceridemia accompanied by glucose intolerance was present. After that, one half of the animals continued on the SRD up to 120 days. The other half received an SRD in which the source of fat was substituted by cod liver oil (w/w 7% CLO plus 1% corn oil) from day 90 to 120 (SRD+CLO). Control rats were fed a semi-synthetic diet (CD) (w/w: 62.5% corn starch, 8% corn oil, 17% protein) throughout the 120 days experimental period. Results obtained after the experimental period show that the hypertriglyceridemia and glucose intolerance ensuing long term feeding normal rats with a sucrose-rich diet could be completely reversed mediating no change in circulating insulin levels by shifting the source of fat in the diet from corn oil to cod liver oil. These findings suggest that manipulation of dietary fats may play a role in the management of the lipid disorders associated with glucose intolerance and insulin resistance.

[The importance of including polyunsaturated fatty acids in the therapy of obese pregnant women to prevent late toxicosis and to decrease its incidence]

Lipid fatty acid composition and cholesterol levels in platelets, platelet aggregation were investigated in pregnant women with essential or alimentary-constitutional obesity on combined therapy comprising polyunsaturated fatty acids versus those who were treated conventionally. The use of combined therapy allowed to increase the content of polyunsaturated fatty acids in total lipids, to achieve a 32% decrease in platelet cholesterol and a 19% decrease in platelet aggregation. The frequency of late gestosis reduced twice and of severe gestosis 3 times in patients given polyunsaturated fatty acids.

Dietary conjugated linoleic acid modulation of phorbol ester skin tumor promotion

The fatty acid derivative conjugated dienoic linoleate (CLA) has been shown to inhibit initiation and postinitiation stages of carcinogenesis in several experimental animal models. The goal of the present study was to determine the role of increasing levels of dietary CLA in mouse skin tumor promotion elicited by 12-O-tetradecanoylphorbol-13-acetate (TPA). Mice were fed control (no CLA) diet during initiation, then switched to diets containing 0.0%, 0.5%, 1.0%, or 1.5% (wt/wt) CLA during skin tumor promotion by TPA. Body weights of mice fed 0.5%, 1.0%, or 1.5% CLA were similar to each other but were significantly lower (p < 0.05) than weights of mice fed no CLA (0.0%) throughout promotion. A reduction in papilloma incidence was observed in mice fed 1.5% CLA from Weeks 8 to 24 compared with mice fed diets containing 0.0-1.0% CLA (p < 0.05). Twenty-four weeks after tumor promotion was begun, diets containing 1.0% and 1.5% CLA inhibited tumor yield (4.94 and 4.35 tumors/mouse, respectively) compared with diets without CLA (0.0% CLA, 6.65 tumors/mouse, p < 0.05) or 0.5% CLA (5.92 tumors/mouse, p < 0.05). These data indicate that CLA inhibits tumor promotion in a manner that is independent of its anti-initiator activity. Further studies are warranted in identifying cellular mechanisms that are likely to be involved with the antipromoter effects of CLA.

The effect of polyunsaturated fatty acids on the progress of cachexia in patients with pancreatic cancer

Cachexia is common in patients with pancreatic cancer and has been associated with persistent activation of the hepatic acute phase response and increased energy expenditure. Fatty acids have been shown to have anticachectic effects in animal models and to reduce inflammatory mediators in healthy subjects and patients with chronic inflammatory disease. Eighteen patients with unresectable pancreatic cancer received dietary supplementation orally with fish oil capsules (1 g each) containing eicosapentaenoic acid 18% and docosahexaenoic acid 12%. Anthropometric measurement, body composition analysis, and measurement of resting energy expenditure and serum C-reactive protein were performed before and after supplementation with a median of 12 g/day of fish oil. Patients had a median weight loss of 2.9 kg/month (IQR 2-4.6) prior to supplementation. At a median of 3 months after commencement of fish oil supplementation, patients had a median weight gain of 0.3 kg/month (IQR 0-0.5) (p < 0.002). Changes in weight were accompanied by a temporary but significant reduction in acute phase protein production (p < 0.002) and by stabilisation of resting energy expenditure. This study suggests a component fish oil, perhaps EPA, merits further investigation in the treatment of cancer cachexia.

Antitumorigenic effects of limonene and perillyl alcohol against pancreatic and breast cancer

Perillyl alcohol is a natural product from cherries and other edible plants. Perillyl alcohol and d-limonene, a closely related dietary monoterpene, have chemotherapeutic activity against pancreatic, mammary, and prostatic tumors. In addition, perillyl alcohol, limonene, and other dietary monoterpenes have chemopreventive activity. Several mechanisms may account for the antitumorigenic effects of monoterpenes. For example, many monoterpenes inhibit the post-translational isoprenylation of cell growth-regulatory proteins such as Ras. Perillyl alcohol induces apoptosis without affecting the rate of DNA synthesis in both liver and pancreatic tumor cells. In addition, monoterpene-treated, regressing rat mammary tumors exhibit increased expression of transforming growth factor beta concomitant with tumor remodeling/redifferentiation to a more benign phenotype. Monoterpenes are effective, nontoxic dietary antitumor agents which act through a variety of mechanisms of action and hold promise as a novel class of antitumor drugs for human cancer.

[Clinico-biochemical validation of the use of PUFA omega-3 in patients with ischemic heart disease, familial hyperlipoproteinemias and hypertension]

The effectivity of diet AI, containing 20 g of fish oil eiconol, for patients suffering with ischemic heart disease, family hyperlipidemia and hypertension were checked. It was concluded that treatment with eiconol is recommended during 4 weeks 2-3 times per year in dose of 3-6 capsules 3 times a day depending on degree of lipids metabolism and hemocoagulation disturbances.

Dietary omega-3 polyunsaturated fats and breast cancer

Although early experimental investigations concluded that quantitative increases in dietary fat promote mammary tumor growth, recent studies have indicated that not all fatty acid families equally express this tumor-promoting capability. This article provides an overview of some of the experimental evidence demonstrating that the omega-6 polyunsaturated fats have significantly different mammary tumor-promoting capabilities from those of the omega-3 polyunsaturated fats. Collectively, these data indicate that whereas increasing dietary levels of omega-6 polyunsaturated fatty acids enhances tumor development, equivalent increases in dietary levels of omega-3 polyunsaturated fatty acids delay or reduce tumor development. Some of the theoretical mechanisms proposed for these contrasting results and their supporting experimental data are discussed.

Renal effects of dietary supplementation with fish oil in cyclosporine-treated liver transplant recipients

Nephrotoxicity is the main untoward effect of cyclosporine (CsA) treatment. Experimental and clinical data suggest that dietary supplementation with fish oil may lessen cyclosporine nephrotoxicity, possibly by lowering renal thromboxane (Tx) production. We have studied the renal effects of a daily supplementation for 2 months of 12 g fish oil (18% C20:5 n-3 eicosapentaenoic acid [EPA] and 12% C22:6 n-3 docosahexanoic acid [DHA]) in a placebo-controlled (12 g corn oil), prospective, randomized, double-blind study of stable CsA-treated liver transplant recipients. Thirteen patients ingested corn oil capsules and 13 fish oil. Compliance with dietary regimen was confirmed by fatty acid chromatography that showed increased plasma concentrations of EPA (from 0.4 +/- 0.02% to 4.6 +/- 0.5%, P < .0001) and DHA (from 1.8 +/- 0.2% to 3.9 +/- 0.1%, P < .0001) in the fish oil group and increased plasma concentration of linoleic acid (C18:2 n-6) in the corn oil group (from 25 +/- 2% to 28.4 +/- 2%, P < .001). At the end of the 2 months of the study, in the fish oil group the effective renal plasma flow increased by 22% (P = .012), the glomerular filtration rate increased by 33% (P = .057), the renal blood flow increased by 17% (P = .024), and the calculated total renal vascular resistances decreased by 20% (P = .034). In contrast, none of these parameters changed in the corn oil group. The renal functional reserve determined during L-arginine infusion, plasma renin activity (PRA), and plasma aldosterone (PA) remained unchanged during the study in either group.(ABSTRACT TRUNCATED AT 250 WORDS)

Similar effects of rapeseed oil (canola oil) and olive oil in a lipid-lowering diet for patients with hyperlipoproteinemia

OBJECTIVE

To compare the metabolic effects of a lipid-lowering diet containing either low erucic rapeseed (canola) oil or olive oil.

METHODS

Twenty-two hyperlipidemic patients participated in a cross-over study comprising two consecutive 3.5-week treatment periods. The participants were free-living throughout the study period, visiting the metabolic clinic initially and at the end of each treatment period for weighing and blood sampling. All food was prepared daily and weighed out for each individual appropriate to his/her energy requirement.

RESULTS

Total serum cholesterol, low-density lipoprotein and the ratio between low-density and high-density lipoprotein cholesterol decreased to the same extent on the two diets tested, as did the apolipoproteins B, A-I and Lp(a). After adjustment for body weight changes, most of the reported effects remained virtually unaltered. However, there was a slightly greater decrease in low-density lipoprotein cholesterol with the diet containing rapeseed oil (-17%, p < 0.001) than with the olive oil diet (-13%, p < 0.01) with p < 0.04 for the difference between diets. Also, the intravenous glucose tolerance improved to a similar extent on both diets.

CONCLUSIONS

The results indicate that lipid-lowering diets containing either rapeseed oil or olive oil have similar effects on serum lipoprotein concentration and glucose tolerance in hyperlipidemic subjects.

Dietary long-chain polyunsaturated fatty acids influence the recovery of thioacetamide-induced liver cirrhosis in rats

BACKGROUND

The aim of this study was to evaluate the dietary supplementation with omega-3 and omega-6 long-chain polyunsaturated fatty acids on the fatty acid composition of plasma and red blood cell membranes in rats with thioacetamide-induced liver cirrhosis.

METHODS

Thirty-eight female Wistar rats were given 300 mg thioacetamide/L in drinking water for 4 months to induce the experimental liver cirrhosis. Sixteen rats were used as controls. After treatment with thioacetamide, nine rats of each group were killed. Then, thioacetamide-treated rats were divided into three new groups, each receiving a different diet for 2 weeks: a semipurified diet (n = 9), the same diet supplemented with omega-3 long-chain polyunsaturated fatty acids (n = 10), or the same semipurified diet supplemented with omega-3 and omega-6 long-chain polyunsaturated fatty acids simultaneously (n = 10). The remaining control rats were fed the semipurified diet. Liver histology and plasma and erythrocyte fatty acid composition were assessed.

RESULTS

An apparent improvement of the histological damage took place in the rats fed the omega-3+ omega-6-supplemented diet. The diet supplemented with polyunsaturated fatty acids of the omega-3 series induced increases in the omega-3 long-chain polyunsaturated fatty acid levels in total plasma lipids, plasma lipid fractions and in erythrocyte phospholipids, and decreases in omega-6 long-chain polyunsaturated fatty acids in erythrocyte phospholipids during the recovery of rats with thioacetamide-induced liver cirrhosis. The administration of the diet supplemented with both omega-3 and omega-6 long-chain polyunsaturated fatty acids contributed to increase the levels of total plasma saturated, monounsaturated, and omega-6 long-chain polyunsaturated fatty acids from cirrhotic rats.

CONCLUSION

We conclude that the simultaneous supply of long-chain fatty acids of the omega-3 and the omega-6 series can be beneficial to improve the fatty acid status of this experimental model of liver cirrhosis.

Dietary fish oil reduces basal and ultraviolet B-generated PGE2 levels in skin and increases the threshold to provocation of polymorphic light eruption

The sunburn response is markedly reduced by dietary fish oil rich in omega-3 polyunsaturated fatty acids. Because prostaglandins mediate the vasodilatation, we examined the effect of fish oil on ultraviolet (UV) B-induced prostaglandin metabolism. In addition we assessed the potential photoprotective effect of fish oil in light-sensitive patients. Thirteen patients with polymorphic light eruption received dietary supplements of fish oil rich in omega-3 polyunsaturated fatty acids for 3 months. At baseline and 3 months, the minimal erythema dose of UVB irradiation was determined, and a graded UVA challenge given to a forearm to assess the threshold dose for papule provocation. Suction blisters were raised on the other forearm, on control skin, and on skin irradiated with four times the minimal erythema dose of UVB 24 h previously, and blister fluid prostaglandin E2 was measured by radioimmunoassay. Following 3 months of fish oil, the mean minimal erythema dose of UVB irradiation increased from 19.8 +/- 2.6 to 33.8 +/- 3.7 mJ/cm2 (mean +/- SEM), p < 0.01. The UVA provocation test was positive in 10 patients at baseline, and after 3 months nine of these showed reduced sensitivity to papule provocation, p < 0.001. Before fish oil, PGE2 increased from 8.6 (SEM 2.1) ng/ml in control skin to 27.2 (11) ng/ml after UVB, p < 0.01. Following 3 months of fish oil, PGE2 decreased to 4.1 (1) and 9.6 (2.4) ng/ml in control and irradiated skin, respectively, p < 0.05. Reduction of UV-induced inflammation by fish oil may be due, at least partially, to lowered prostaglandin E2 levels. The photoprotection against UVA-provocation of a papular response suggests a clinical application for fish oil in polymorphic light eruption.

Adrenoleukodystrophy: magnetic resonance follow-up after Lorenzo's oil therapy

PURPOSE

To determine the therapeutic value of Lorenzo's oil (a mixture of glyceryl trioleate and glyceryl trierucate oils) in treating the childhood form of adrenoleukodystrophy (ALD), as indicated by magnetic resonance imaging (MRI) follow-up.

PATIENTS AND METHODS

Between January 1992 and March 1994 eight males with biochemically proven ALD, ranging in age from 1 to 28 years, were referred for cerebral MRI and initiation of Lorenzo's oil dietary therapy; treatment continued for a period of 6 to 24 months. Five of the patients underwent follow-up cerebral MRI, and the images were reviewed without knowledge of medical status or chronology of imaging relative to therapy; the other three patients were excluded from the study because follow-up examinations were lacking. Signal abnormalities were evaluated according to a modified Loes scale, which yielded a minimum rating of 0 (for normal findings) and a maximum rating of 35 (for the most severe abnormalities). Because an untreated control group was not available for comparison, the Wilcoxon signed-rank test was used to analyse the results.

RESULTS

There was no statistically significant improvement in the ratings of abnormalities after treatment (p = 0.31, alpha = 0.10). However, the correlation between MRI findings and clinical symptoms was good.

CONCLUSIONS

The Wilcoxon signed-rank test is a useful statistical tool for evaluating the results of studies in which the sample population is small and there is no control group. The authors suggest that although Lorenzo's oil may not be curative, it may have a role in preventing the progress of ALD in asymptomatic patients. A multicentre control trial of Lorenzo's oil treatment, with emphasis on asymptomatic patients, is now underway.

Adrenoleukodystrophy: a link between adrenal insufficiency and school performance

The combination of neurodevelopmental regression and adrenal insufficiency should alert practitioners or emergency room physicians about ALD. Although still unproven, early medical intervention with either gene therapy or bone marrow transplantation may offer more promise to these patients.