Modeled replacement of traditional soybean and canola oil with high-oleic varieties increases monounsaturated fatty acid and reduces both saturated fatty acid and polyunsaturated fatty acid intake in the US adult population.

BACKGROUND: High-oleic (HO) seed oils are being introduced as replacements for trans fatty acid (TFA)-containing fats and oils. Negative health effects associated with TFAs led to their removal from the US Generally Recognized As Safe list. HO oils formulated for use in food production may result in changes in fatty acid intake at population levels. Objectives: The purposes of this study were to 1) identify major food sources of soybean oil (SO) and canola oil (CO), 2) estimate effects of replacing SO and CO with HO varieties on fatty acid intake overall and by age and sex strata, and 3) compare predicted intakes with the Dietary Reference Intakes and Adequate Intakes (AIs) for the essential fatty acids (EFAs) α-linolenic acid (ALA) and linoleic acid (LA). Design: Food and nutrient intakes from NHANES waves 2007-2008, 2009-2010, 2011-2012, and 2013-2014 in 21,029 individuals aged ≥20 y were used to model dietary changes. We estimated the intake of fatty acid with the replacement of HO-SO and HO-CO for commodity SO and CO at 10%, 25%, and 50% and evaluated the potential for meeting the AI at these levels. RESULTS: Each modeling scenario decreased saturated fatty acids (SFAs), although intakes remained greater than recommended for all age and sex groups. Models of all levels increased the intake of total monounsaturated fatty acids (MUFAs), especially oleic acid, and decreased the intake of total polyunsaturated fatty acids (PUFAs), particularly LA and ALA. Replacement of traditional with HO oils at 25-50% places specific adult age and sex groups at risk of not meeting the AI for LA and ALA. Conclusions: The replacement of traditional oils with HO varieties will increase MUFA intake and reduce both SFA and PUFA intakes, including EFAs, and may place specific age and sex groups at risk of inadequate LA and ALA intake.

Essential Fatty Acid Deficiency in 2015: The Impact of Novel Intravenous Lipid Emulsions.

The fatty acids, linoleic acid (18:2ω-6) and α-linolenic acid (18:3ω-3), are essential to the human diet. When these essential fatty acids are not provided in sufficient quantities, essential fatty acid deficiency (EFAD) develops. This can be suggested clinically by abnormal liver function tests or biochemically by an elevated Mead acid and reduced linoleic acid and arachidonic acid level, which is manifested as an elevated triene/tetraene ratio of Mead acid/arachidonic acid. Clinical features of EFAD may present later. With the introduction of novel intravenous (IV) lipid emulsions in North America, the proportion of fatty acids provided, particularly the essential fatty acids, varies substantially. We describe a case series of 3 complicated obese patients who were administered parenteral nutrition (PN), primarily using ClinOleic 20%, an olive oil-based lipid emulsion with reduced amounts of the essential fatty acids, linoleic and α-linolenic, compared with more conventional soybean oil emulsions throughout their hospital admission. Essential fatty acid profiles were obtained for each of these patients to investigate EFAD as a potential cause of abnormal liver enzymes. Although the profiles revealed reduced linoleic acid and elevated Mead acid levels, this was not indicative of the development of essential fatty acid deficiency, as reflected in the more definitive measure of triene/tetraene ratio. Instead, although the serum fatty acid panel reflected the markedly lower but still adequate dietary linoleic acid content and greatly increased oleic acid content in the parenteral lipid emulsion, the triene/tetraene ratio remained well below the level, indicating EFAD in each of these patients. The availability and use of new IV lipid emulsions in PN should encourage the clinician to review lipid metabolism based on the quantity of fatty acids provided in specific parenteral lipid emulsions and the expected impact of these lipid emulsions (with quite different fatty acid composition) on measured fatty acid profiles.

Omega-3 fatty acid deficient male rats exhibit abnormal behavioral activation in the forced swim test following chronic fluoxetine treatment: association with altered 5-HT1A and alpha2A adrenergic receptor expression.

Omega-3 fatty acid deficiency during development leads to enduing alterations in central monoamine neurotransmission in rat brain. Here we investigated the effects of omega-3 fatty acid deficiency on behavioral and neurochemical responses to chronic fluoxetine (FLX) treatment. Male rats were fed diets with (CON, n = 34) or without (DEF, n = 30) the omega-3 fatty acid precursor alpha-linolenic acid (ALA) during peri-adolescent development (P21-P90). A subset of CON (n = 14) and DEF (n = 12) rats were administered FLX (10 mg/kg/d) through their drinking water for 30 d beginning on P60. The forced swimming test (FST) was initiated on P90, and regional brain mRNA markers of serotonin and noradrenaline neurotransmission were determined. Dietary ALA depletion led to significant reductions in frontal cortex docosahexaenoic acid (DHA, 22:6n-3) composition in DEF (-26%, p = 0.0001) and DEF + FLX (-32%, p = 0.0001) rats. Plasma FLX and norfluoxetine concentrations did not different between FLX-treated DEF and CON rats. During the 15-min FST pretest, DEF + FLX rats exhibited significantly greater climbing behavior compared with CON + FLX rats. During the 5-min test trial, FLX treatment reduced immobility and increased swimming in CON and DEF rats, and only DEF + FLX rats exhibited significant elevations in climbing behavior. DEF + FLX rats exhibited greater midbrain, and lower frontal cortex, 5-HT1A mRNA expression compared with all groups including CON + FLX rats. DEF + FLX rats also exhibited greater midbrain alpha2A adrenergic receptor mRNA expression which was positively correlated with climbing behavior in the FST. These preclinical data demonstrate that low omega-3 fatty acid status leads to abnormal behavioral and neurochemical responses to chronic FLX treatment in male rats.

A dairy fat matrix providing alpha-linolenic acid (ALA) is better than a vegetable fat mixture to increase brain DHA accretion in young rats.

Achieving an appropriate DHA status in the neonatal brain is an important goal of neonatal nutrition. We evaluated how alpha-linolenic acid (ALA), provided for six weeks after weaning by different dietary fat matrix, improved brain DHA content of young male rats born from deficient-dams. The level of ALA achieved was based on the fat composition of usual infant vegetable formula. A palm oil-blend diet thus providing 1.5%ALA was compared to dairy fat-blend-based diets that provided either 1.5%ALA or 2.3%ALA, or a rapeseed oil diet providing 8.3%ALA (n-6/n-3 ratio were, respectively 10,10,5,2.5). The 1.5%ALA-dairy-fat-blend was superior to 1.5%ALA-palm-oil-blend to restore values of brain DHA, while the 2.3%ALA-dairy-fat-blend exhibited a further increase and reached the values obtained with pure rapeseed diet (8.3%ALA). Dairy-fat-blends enriched with ALA appear to be an interesting strategy for achieving optimal DHA levels in the brain of post-weaning rats. Providing dairy fat as well as a reduction of the LA/ALA ratio should be reconsidered to design infant formula.

Regulation of rat brain polyunsaturated fatty acid (PUFA) metabolism during graded dietary n-3 PUFA deprivation.

Knowing threshold changes in brain lipids and lipid enzymes during dietary n-3 polyunsaturated fatty acid deprivation may elucidate dietary regulation of brain lipid metabolism. To determine thresholds, rats were fed for 15 weeks DHA-free diets having graded reductions of α-linolenic acid (α-LNA). Compared with control diet (4.6% α-LNA), plasma DHA fell significantly at 1.7% dietary α-LNA while brain DHA remained unchanged down to 0.8% α-LNA, when plasma and brain docosapentaenoic acid (DPAn-6) were increased and DHA-selective iPLA(2) and COX-1 activities were downregulated. Brain AA was unchanged by deprivation, but AA selective-cPLA(2), sPLA(2) and COX-2 activities were increased at or below 0.8% dietary α-LNA, possibly in response to elevated brain DPAn-6. In summary, homeostatic mechanisms appear to maintain a control brain DHA concentration down to 0.8% dietary DHA despite reduced plasma DHA, when DPAn-6 replaces DHA. At extreme deprivation, decreased brain iPLA(2) and COX-1 activities may reduce brain DHA loss.

Gender affects liver desaturase expression in a rat model of n-3 fatty acid repletion.

Dietary n-3 polyunsaturated fatty acids (PUFA) are major components of cell membranes and have beneficial effects on human health. Docosahexaenoic acid (DHA; 22:6n-3) is the most biologically important n-3 PUFA and can be synthesized from its dietary essential precursor, alpha-linolenic acid (ALA; 18:3n-3). Gender differences in the efficiency of DHA bioconversion have been reported, but underlying molecular mechanisms are unknown. We compared the capacity for DHA synthesis from ALA and the expression of related enzymes in the liver and cerebral cortex between male and female rats. Wistar rats, born with a low-DHA status, were supplied with a suboptimal amount of ALA from weaning to 8 weeks of age. Fatty acid composition was determined by gas chromatography, the mRNA expression of different genes involved in PUFA metabolism was determined by RT-PCR (low-density array) and the expression of proteins was determined by Western blot analysis. At 8 weeks, DHA content was higher (+20 to +40%) in each phospholipid class of female livers compared to male livers. The "Delta4," Delta5 and Delta6 desaturation indexes were 1.2-3 times higher in females than in males. The mRNA expression of Delta5- and Delta6-desaturase genes was 3.8 and 2.5 times greater, respectively, and the Delta5-desaturase protein was higher in female livers (+50%). No gender difference was observed in the cerebral cortex. We conclude that female rats replete their DHA status more readily than males, probably due to a higher expression of liver desaturases. Our results support the hypothesis on hormonal regulation of PUFA metabolism, which should be taken into account for specific nutritional recommendations.

Decreased brain docosahexaenoic acid content produces neurobiological effects associated with depression: Interactions with reproductive status in female rats.

Decreased tissue levels of docosahexaenoic acid (DHA; 22:6n-3) are implicated in the etiologies of non-puerperal and postpartum depression. With the aim of determining neurobiological sequelae of decreased brain DHA content, this study examined the effects of a loss of brain DHA content and concurrent reproductive status in adult female Long-Evans rats. An alpha-linolenic acid-deficient diet and breeding protocols were used to produce virgin and parous female rats with cortical phospholipid DHA levels 23-26% lower than virgin and parous rats fed a control diet containing adequate alpha-linolenic acid. Parous dams were tested/euthanized at weaning (postnatal day 20) of the second litter; virgin females, during diestrus. Decreased brain DHA was associated with decreased hippocampal BDNF gene expression and increased relative corticosterone response to an intense stressor, regardless of reproductive status. In virgin females with decreased brain DHA, serotonin content and turnover in frontal cortex were decreased compared to virgin females with normal brain DHA. In parous dams with decreased brain DHA, the density of 5-HT(1A) receptors in the hippocampus was increased, corticosterone response to an intense stressor was increased, and the latency to immobility in the forced swim test was decreased compared to parous dams with normal DHA. These findings demonstrate neurobiological alterations attributable to decreased brain DHA or an interaction of parous status and brain DHA level. Furthermore, the data are consistent with findings in depressed humans, and thus support a role for DHA as a factor in the etiologies of depressive illnesses, particularly postpartum depression.

Omega 6 to omega 3 fatty acid imbalance early in life leads to persistent reductions in DHA levels in glycerophospholipids in rat hypothalamus even after long-term omega 3 fatty acid repletion.

Failure to provide omega 3 fatty acids in the perinatal period results in alterations in nerve growth factor levels, dopamine production and permanent elevations in blood pressure. The present study investigated whether changes in brain (i.e., hypothalamus) glycerophospholipid fatty acid profiles induced by a diet rich in omega 6 fatty acids and very low in alpha-linolenic acid (ALA) during pregnancy and the perinatal period could be reversed by subsequent feeding of a diet containing ALA. Female rats (6 per group) were mated and fed either a low ALA diet or a control diet containing ALA throughout pregnancy and until weaning of the pups at 3 weeks. At weaning, the pups (20 per group) remained on the diet of their mothers until 9 weeks, when half the pups were switched onto the other diet, thus generating four groups of animals. At 33 weeks, pups were killed, the hypothalamus dissected from the male rats and analysed for glycerophospholipid fatty acids. In the animals fed the diet with very little ALA and then re-fed the control diet containing high levels of ALA for 24 weeks, the DHA levels were still significantly less than the control values in PE, PS and PI fractions, by 9%, 18% and 34%, respectively. In this group, but not in the other dietary groups, ALA was detected in all glycerophospholipid classes at 0.2-1.7% of the total fatty acids. The results suggest that omega 6-3 PUFA imbalance early in life leads to irreversible changes in hypothalamic composition. The increased ALA and reduced DHA proportions in the animals re-fed ALA in later life are consistent with a dysfunction or down-regulation of the conversion of ALA to 18:4n-3 by the delta-6 desaturase.

Effects of an n-3-deficient diet on brain, retina, and liver fatty acyl composition in artificially reared rats.

Rat pups born to dams fed a diet with 3.1% of total fatty acids as alpha-linolenic acid (LNA) were fed, using an artificial rearing system, either an n-3-deficient (n-3-Def) or an n-3-adequate (n-3-Adq) diet. Both diets contained 17.1% linoleic acid, but the n-3-Adq diet also contained 3.1% LNA. The percentage of brain docosahexaenoic acid (DHA) continuously decreased (71%) with time over the 29 days of the experiment, with concomitant increases in docosapentaenoic acid (DPAn-6). In the retina, the percentage of DHA rose in the n-3-Adq group, with an apparent increased rate around the time of eye opening. However, there was a flat curve for the percentage of DHA in the n-3-Def group and a rising DPAn-6 with time. Liver DHA was highest at the time of birth in the n-3-Adq group but fell off somewhat over the course of 29 days. This decrease was more pronounced in the n-3-Def group, and the DPAn-6 rose considerably during the second half of the experiment. This method presents a first-generation model for n-3 deficiency that is more similar to the case of human nutrition than is the commonly employed two-generation model.

Serotoninergic neurotransmission is affected by n-3 polyunsaturated fatty acids in the rat.

We explored the effects of chronic alpha-linolenic acid dietary deficiency on serotoninergic neurotransmission. In vivo synaptic serotonin (5-HT) levels were studied in basal and pharmacologically stimulated conditions using intracerebral microdialysis in the hippocampus of awake 2-month-old rats. We also studied the effects of reversion of the deficient diet on fatty acid composition and serotoninergic neurotransmission. A balanced (control) diet was supplied to deficient rats at different stages of development, i.e. from birth, 7, 14 or 21 days of age. We demonstrated that chronic n-3 polyunsaturated fatty acid dietary deficiency induced changes in the synaptic levels of 5-HT both in basal conditions and after pharmacological stimulation with fenfluramine. Higher levels of basal 5-HT release and lower levels of 5-HT-stimulated release were found in deficient than in control rats. These neurochemical modifications were reversed by supply of the balanced diet provided at birth or during the first 2 weeks of life through the maternal milk, whereas they persisted if the balanced diet was given from weaning (at 3 weeks of age). This suggests that provision of essential fatty acids is durably able to affect brain function and that this is related to the developmental stage during which the deficiency occurs.

The role of dietary n-6 and n-3 fatty acids in the developing brain.

The dietary requirements for essential fatty acids and the possibility of a specific role for the polyunsaturated fatty acid docosahexaenoic acid (DHA) is one of the most controversial areas in infant nutrition. DHA is found in unusually high concentrations in the brain and is selectively accumulated during fetal and infant brain growth. DHA can be synthesised through a complex series of chain elongation-desaturation reactions from alpha-linolenic acid, but the efficiency of this process in young infants is not clear. Clinical studies on the potential benefits to neural development of dietary DHA have yielded conflicting results. Recent studies have provided evidence that plasma DHA is available to developing brain and that DHA is involved in dopamine and serotonin metabolism. These findings should guide clinical studies to more sensitive measures of the functional roles of dietary n-3 fatty acids and to clinical conditions where n-3 fatty acids may have benefit.

Nutritional deprivation of alpha-linolenic acid decreases but does not abolish turnover and availability of unacylated docosahexaenoic acid and docosahexaenoyl-CoA in rat brain.

We applied our in vivo fatty acid method to examine concentrations, incorporation, and turnover rates of docosahexaenoic acid (22:6 n-3) in brains of rats subject to a dietary deficiency of alpha-linolenic acid (18:3 n-3) for three generations. Adult deficient and adequate rats of the F3 generation were infused intravenously with [4, 5-(3)H]docosahexaenoic acid over 5 min, after which brain uptake and distribution of tracer were measured. Before infusion, the plasma 22:6 n-3 level was 0.2 nmol ml(-1) in 18:3 n-3-deficient compared with 10.6 nmol ml(-1) in control rats. Brain unesterified 22:6 n-3 was not detectable, whereas docosahexaenoyl-CoA content was reduced by 95%, and 22:6 n-3 content in different phospholipid classes was reduced by 83-88% in deficient rats. Neither plasma or brain arachidonic acid (20:4 n-6) level was significantly changed with diet. Docosapentaenoic acid (22:5 n-6) reciprocally replaced 22:6 n-3 in brain phospholipids. Calculations using operational equations from our model indicated that 22:6 n-3 incorporation from plasma into brain was reduced 40-fold by 18:3 n-3 deficiency. Recycling of 22:6 n-3 due to deacylation-reacylation within phospholipids was reduced by 30-70% with the deficient diet, but animals nevertheless continued to produce 22:6 n-3 and docosahexaenoyl-CoA for brain function. We propose that functional brain effects of n-3 deficiency reflect altered ratios of n-6 to n-3 fatty acids.

[Pathology of placenta of rats induced by fatty acid deficiency]. / Patología de la placenta de rata inducida por la deficiencia de ácidos grasos.

Lipids are important cell components, both from the structural and the functional point of view. Besides, they intervene in transporting functions, cell recognition and immunity. Essential Fatty Acids (EFA) are important for the functional and structural maintenance of animal organisms. In our laboratory, it was demonstrated that one group of pregnant rats fed on an EFA deficient diet, and other group of rats fed on the same diet but with 5% of corn oil (rich in linoleic acid) showed alterations on the development of the metrial gland. In the present work, 57 female rats of a Wistar strain were fed since weaning with one of the following diets: EFAD: deficient in essential fatty acids, COD: EFAD + 5% corn oil (linoleic acid sufficient but alpha-linoleic acid deficient); SAD: EFAD + 5% soy oil (both EFA sufficient) and CD: commercial diet. After 3 months the animals were sacrificed on the 13 th. day of gestation. Uteru's horns were dissected and the implantation sities were fixed on formol and embebbed in parafin. The observations were carried out with H/E coloured cross-sections and the corialantoidea placenta, the cities of implantations and the sitios of reabsortions were studied. The metrial gland of DAGE and DAM rats presented structural modifications compared to DC rats. The most relevant findings were: indifferentiation of the granulated metrial gland cells and an increase in the amount of connective tissue. In DAS rats, on the contrary, the aspect of the metrial gland was similar to the observed in the DC group. In the DAGE and the DAM groups Labyrinthium was enlarged with vascular septum group. Mean while DAS was similar to group DC (thin and vascular). Differences in the cities of implantations and reabsortions were not detected. The present results suggest that alpha-linolenico acid is essential for the rat placenta to reach normal development.

The fatty acid composition of human milk in northern Nigeria.

The authors previously reported that the milk of Yoruba women in southwestern Nigeria was deficient in alpha-linolenic acid and contained a high percentage (42%) of medium chain-length fatty acids (MCFA, C10-C14). In the present study, the authors used capillary gas-liquid chromatography to analyze the milk of Hausa women in the northern region of Nigeria. The milk of the Hausa women contained 27% MCFA, 10.6% linoleic acid, 0.41% alpha-linolenic acid, 0.52% arachidonic acid, and 0.32% docosahexaenoic acid. The proportion of alpha-linolenic acid in the serum phospholipids of a subset of exclusively breastfed infants (n = 15; mean age, 6.2 +/- 0.3 months) was below the limit of detection (< 0.03%). While the milk of women in northern Nigeria is adequate with regard to n-3 and n-6 fatty acids, to satisfy the requirements for alpha-linolenic acid, it may be necessary to supplement the infants of these women after the first 6 months of life.

Patología de la placenta de rata inducida por la deficiencia de ácidos grasos / Pathology of placenta of rats induced by fatty acid deficiency

Los lípidos son componentes importantes de las células, tanto desde el punto de vista estructural como funcional. Además de intervenir en funciones de transporte, reconocimiento celular e inmunidad, los Acidos Grasos Esenciales (AGE) , son importantes para el mantenimiento funcional y estructural de los organismos animales. En nuestro laboratorio se demostró que ratas preñadas alimentadas con dietas deficientes en ácidos grasos esenciales (DAGE ) y otras con las mismas dietas pero suplementadas con 5 por ciento de aceite de maíz, ( rico en ácido linoleico ) mostraron alteraciones en el desarrollo placentario. En el presente trabajo, 57 ratas hembras de una cepa Wistar fueron alimentadas desde el destete con una de las siguientes dietas: 1: DAGE; 2 :DAM (dieta DAGE más aceite de maíz , alta proporción de ácido linoléico); 3: DAS (dieta DAGE más aceite de soja, alta proporción de ácidos linoleico y a-linolénico) y 4 :DC (dieta comercial). Después de los 3 meses de edad los animales fueron preñados y se sacrificaron al 13 día de la gestación. Los cuernos uterinos fueron disecados y los sitios de implantación se fijaron en formol y se incluyeron en parafina. Las observaciones se realizaron sobre cortes coloreados con H/E , y se estudió la placenta corioalantoidea , el número de implantaciones y el de reabsorciones . La glándula metrial de ratas DAGE y DAM presentaron modificaciones estructurales en relación a las DC. Los hallazgos más notables fueron : Indiferenciación de las células granulares metriales y aumento de la cantidad de tejido conectivo. En las ratas DAS ,en cambio,el aspecto de la glándula metrial era similar a lo observado en el grupo DC. En los grupos DAGE y DAM el laberinto estaba ensanchado, con septos vasculares pero en el grupo DAS eran similares al DC, delgados y vasculares. No se detectaron diferencias en el número de implantaciones y reabsorciones. Los presentes resultados sugieren que el ácido a-linolénico dietético es esencial para que la placenta de rata alcance su desarrollo normal. (Au)

Chronic n-3 polyunsaturated fatty acid diet-deficiency acts on dopamine metabolism in the rat frontal cortex: a microdialysis study.

The effects of alpha-linolenic acid diet deficiency on rat dopaminergic metabolism were investigated in the frontal cortex of male 2-3 month-old rats using the microdialysis method. Increased basal levels of dopamine metabolites were observed in the frontal cortex of awake deficient rats, without modification of dopamine levels. Moreover, using KCl perfusion which releases newly synthesized dopamine, no difference was observed in anaesthetized deficient rats versus control rats. In addition, a decrease in dopamine release was observed in anaesthetized deficient rats versus control rats after tyramine stimulation, which is known to induce release of dopamine from vesicular stores. A working model is proposed which suggests that a chronic n-3 polyunsaturated fatty acids (PUFA) deficiency may lead to modifications in the internalization of dopamine in the storage pool in the frontal cortex.

Retinal light damage in rats with altered levels of rod outer segment docosahexaenoate.

PURPOSE: To compare retinal light damage in rats with either normal or reduced levels of rod outer segment (ROS) docosahexaenoic acid. METHODS: Weanling male albino rats were maintained in a weak cyclic light environment and fed either a nonpurified control diet or a purified diet deficient in the linolenic acid precursor of docosahexaenoic acid (DHA). Half the rats on the deficient diet were given linseed oil, containing more than 50 mol% linolenic acid, once a week to maintain ROS DHA at near normal levels. Diets and linseed oil supplementation were continued for 7 to 12 weeks. To replenish DHA in their ROS, some 10-week-old rats on the deficient diet were given linseed oil three times a week for up to 3 additional weeks. Groups of animals were killed at various times for ROS fatty acid determinations or were exposed to intense green light using intermittent or hyperthermic light treatments. The extent of retinal light damage was determined biochemically by rhodopsin or photoreceptor cell DNA measurements 2 weeks after exposure and morphologically by light and electron microscopy at various times after light treatment. RESULTS: Rats maintained for 7 to 12 weeks on the linolenic acid-deficient diet had significantly lower levels of DHA and significantly higher levels of n-6 docosapentaenoic acid (22:5n-6) in their ROS than deficient-diet animals supplemented once a week with linseed oil or those fed the nonpurified control diet. As determined by rhodopsin levels and photoreceptor cell DNA measurements, deficient diet rats exhibited protection against retinal damage from either intermittent or hyperthermic light exposure. However, the unsaturated fatty acid content of ROS from all three dietary groups was the same and greater than 60 mol%. In 10 week-old deficient-diet rats given linseed oil three times a week, ROS DHA was unchanged for the first 10 days, whereas 22:5n-6 levels declined by 50%. After 3 weeks of treatment with linseed oil, ROS DHA and 22:5n-6 were nearly the same as in rats supplemented with linseed oil from weaning. The time course of susceptibility to retinal light damage, however, was different. Hyperthermic light damage in rats given linseed oil for only 2 days was the same as for rats always fed the deficient diet. Six days after the start of linseed oil treatment, retinal light damage was the same as in rats given the linseed oil supplement from weaning. Morphologic alterations in ROS of linseed oil-supplemented rats immediately after intermittent light exposure were more extensive than in either the deficient-diet animals or those fed the control diet. The deficient-diet rats also exhibited better preservation of photoreceptor cell nuclei and structure 2 weeks after exposure. CONCLUSIONS: Rats fed a diet deficient in the linolenic acid precursor of DHA are protected against experimental retinal light damage. The relationship between retinal light damage and ROS lipids does not depend on the total unsaturated fatty acid content of ROS; the damage appears to be related to the relative levels of DHA and 22:5n-6.

alpha-Linolenic acid dietary deficiency alters age-related changes of dopaminergic and serotoninergic neurotransmission in the rat frontal cortex.

The effects of alpha-linolenic acid diet deficiency on rat dopaminergic and serotoninergic neurotransmission systems were investigated in the frontal cortex, striatum, and cerebellum of male rats 2,6,12, and 24 months of age. The diet deficiency induced severe decrease in the 22:6n-3 fatty acid levels in all regions and a compensatory increase in n-6 fatty acid levels. A recovery in the levels of 22:6n-3 was observed in deficient rats between 2 and 12 months of age; however, this recovery was lower in frontal cortex than in striatum and cerebellum. In the striatum and cerebellum, dopaminergic and serotoninergic receptor densities and endogenous dopamine and serotonin levels were affected by aging regardless of the diet. In contrast, a 40-75% lower level of endogenous dopamine in the frontal cortex occurred in deficient rats according to age. The deficiency also induced an 18-46% increase in serotonin 5-HT2 receptor density in the frontal cortex during aging, without variation in endogenous serotonin level, and a 10% reduction in density of dopaminergic D2 receptors. Monoamine oxidase-A and -B activities showed specific age-related variations but regardless of the diet. Our results suggest that a chronically alpha-linolenic-deficient diet specifically affects the monoaminergic systems in the frontal cortex.

Preferential reduction in adipose tissue alpha-linolenic acid (18:3 omega 3) during very low calorie dieting despite supplementation with 18:3 omega 3.

We have previously reported that the relative content of 18:3 omega 3 in adipose triglyceride (TG) of women was reduced following major weight loss while on a very low calorie diet (VLCD). In an attempt to prevent this loss of 18:3 omega 3 reserves, we have tested two VLCD supplemented with varying amounts of 18:3 omega 3. The formula (FORM) and food VLCD (2.1-3.0 MJ or 500-700 kcal/d) contained 20 g/d of fat and provided the recommended dietary allowance for minerals and vitamins. FORM subjects (Group 1) were 5 women [initial body mass index (BMI) of 36.8, 168% ideal body weight (IBW) who received 20 g/d of canola oil (1.6 g 18:3 omega 3). Their mean weight loss was 23.9 kg in a 4-5 mon period. Food VLCD subjects (Group 2) were 6 women (BMI 33.9, 155% IBW) supplemented with 2 g/d of linseed oil (1.1 g 18:3 omega 3). Their mean weight loss was 17.4 kg in a 2-3 mon period. Needle biopsies of adipose tissue were obtained from Group 1 before, at midpoint and after weight loss; and from Group 2 before and after weight loss. The adipose TG and serum (Group 1) were separated and their fatty acid composition determined by thin-layer and gas chromatography. In Group 1, adipose 18:3 omega 3 fell from 0.65 to 0.59 wt%, then to 0.52 wt% during weight loss. In Group 2, it fell from 0.77 to 0.64 wt%. The fall in adipose 18:3 omega 3 with weight loss was significant at P = 0.01 (Group 1) and P < 0.01 (Group 2).(ABSTRACT TRUNCATED AT 250 WORDS)