Sharon Rabinovitz

ESSENTIAL FATTY ACIDS ARE MEDIATORS OF BRAIN BIOCHEMISTRY AND COGNITIVE FUNCTIONS

Major advances have been made in understanding the biochemistry of essential fatty acids (FA) and their interactions with metabolic pathways leading to the production of longer and more complex fatty acids and lipids. Less understood are the roles played by FA which are known to affect neurotransmitters, peptides, releasing factors, hormones, and a variety of physiological and cognitive processes. Based on empirical findings we propose that (a) FA exert a controlling function in the modulation of neuronal membrane fluidity, and (b) the critical factor in FA action and efficacy is not absolute level but rather the ratio between various groups of FA. This approach unifies the biochemical and cognitive results obtained from many different and unrelated fields of research. J. Neurosci. Res. 56:565–570, 1999. 

Essential fatty acids and the brain: From infancy to aging

The major effects of essential fatty acids (EFA) on brain structure and functions are reviewed. EFA determine the fluidity of neuronal membrane and control the physiological functions of the brain. EFA is also involved in synthesis and functions of brain neurotransmitters, and in the molecules of the immune system. Since they must be supplied from the diet, a decreased bioavailability is bound to induce major disturbances. While the brain needs a continuous supply during the life span, there are two particularly sensitive periods-infancy and aging. EFA deficiency during infancy delays brain development, and in aging will accelerate deterioration of brain functions. In discussing the role of EFA two issues must be considered-the blood-brain barrier, which determines the bioavailability, and the myelination process, which determines the efficiency of brain and retinal functions.

Mixture of essential fatty acids lowers test anxiety

Abstract Test anxiety is an incapacitating academic syndrome. This study shows that administration of a polyunsaturated fatty acid mixture of omega-3 and -6 can improve the behavioral variables associated with this type of anxiety, i.e. appetite, mood, mental concentration, fatigue, academic organization and poor sleep, as well as lowering elevated cortisol level, with a corresponding reduction of anxiety.

Fatty Acids and Brain Peptides

The role of fatty acids (FA) as a mediator and modulator of central nervous system activity in general, and peptides in particular, is only recently becoming understood. This paper reviews numerous findings concerned with the activity of fatty acids, particularly with their interaction with diverse neurochemical systems and their consequences for better understanding neurotransmitters, hormones and peptides. The effects include FA as precursors in the manufacture of neurochemical elements, including enzymes, neurotransmitters, and hormones. Of particular interest is the important changes in neuronal membrane composition that have been attributed to FA. Such changes may account for the changes in thermoregulation, learning, and other functions that accompany dietary manipulation of FA intake. While the total level of FA has been the object of many investigations, this report addresses the need to focus on the ratio of FA, especially alpha-linolenic/linoleic acid, which has been shown to be a critical factor in a number of research studies.

Modulation of Learning and Neuronal Membrane Composition in the Rat by Essential Fatty Acid Preparation: Time-Course Analysis

Previous studies have shown that chronic administration of SR-3 (a 1:4 mixture of α-linolenic and linoleic acid) affects spatial learning, thermoregulation, pain threshold and protection from seizures. The mode of action is unknown. One possible explanation is that the preparation induces changes in the fatty acids profile and in the cholesterol level in the neuronal membrane. This study used 15 independent groups of rats (n = 12) which were given either saline, mineral oil (vehicle) or SR-3 (25 mg/kg) for 0, 1,2, 3, or 4 weeks. The learning performance was measured in the Morris Water tank and the fatty acids profile and the cholesterol level were examined by the GC method in synaptosomes obtained from the frontal cortex of the rats. SR-3 improved the learning performance and induced major changes in the neuronal membrane composition, such as an increase in the total level of fatty acids, an increase in the level of essential fatty acids and a decrease in the cholesterol level. Those changes occurred after 3 weeks of treatment. The biochemical variables can predict the behavioral variables but not vice versa. The changes in the neuronal membrane may result in a modification of the membrane fluidity, which may, in turn, enhance cognitive and neuropharmacological effects.

Anticonvulsant efficiency, behavioral performance and cortisol levels: a comparison of carbamazepine (CBZ) and a fatty acid compound (SR-3)

The role of fatty acids (FA) and their impact on nervous system activity and immune function has attracted much attention. The interest extends beyond a basic understanding of the potential role exerted by FA on the neuronal membrane and its properties, to the implications and clinical significance for many neurological disorders. This is especially true for epilepsy, where many conventional anticonvulsant preparations carry undesired side effects, and a significant number of patients remain refractory to the drug treatment. We report on a comparative examination in rats of carbamazepine (CBZ) and SR-3 (a fatty acid compound) with respect to seizure control efficiency, as well as protective features against cognitive impairment and cortisol level elevation. With pentylenetetrazol (PTZ) induced seizures pre-treated by CBZ, or SR-3, both CBZ and SR-3 were equally effective in providing seizure control and both were superior to the saline control. However SR-3 provided greater protection in Morris Water Maze performance and control of cortisol level elevation.

Fatty Acid Mixture Counters Stress Changes in Cortisol, Cholesterol, and Impair Learning

A mixture of linoleic and α-linolenic acids (free non-esterified unsaturated fatty acids) administered for 3 weeks prior to injection of cortisol (10 mg/kg), or prior to immersion of rats in a 10d`C saline bath, prevented elevation of blood levels of cortisol and cholesterol and deficits in Morris water maze spatial learning that usually accompany such stressful conditions. Differences from controls on all behavioural and biochemical measures were statistically significant (P <. 05). It is proposed that induction of intense stress, and the associated increase in cortisol, cholesterol and other corticosteroids may damage hip-pocampal structures and help account for the cognitive decline witnessed in Alzheimers disease and other age-related conditions. The modulation of these consequences by the fatty acid mixture may provide an alternative strategy for the study of stress markers and for the development of other intervention options in humans.

Essential fatty acid preparation improves biochemical and cognitive functions in experimental allergic encephalomyelitis rats

This study examined the possible effects of a novel mixture of fatty acids, SR-3 (a specific ratio of alpha-linolenic acids), on brain biochemistry and on learning deficits induced by injection of an agent that induces experimental allergic encephalomyelitis. Treatment with SR-3 caused a decrease in myelin and changes in the fatty acid profile of brain synaptosomes, and a learning deficit. Eighteen days of treatment with SR-3 reversed the biochemical and learning deficit significantly, but did not restore them to normal levels. We propose that, most probably, the main action of SR-3 is the modulation of the cholesterol level, which in turn causes the modulation of the fatty acid profile and enhances learning by allowing improved neuronal communication.

Mediation of cognitive function by high fat diet following stress and inflammation.

Abstract In addition to commonly advertised hazards of obesity contributed by excess dietary fat, evidence of alterations in brain chemistry and structure are well documented. This brief review examines the role of nutrients, minerals and certain lipids, primarily the essential fatty acids (FA), that are beneficial to the maintenance of good health and that may offer therapeutic options by dietary supplementation. The review also considers the damaging effects of stress, especially in pre-existing conditions of obesity and diabetes, as studied in both animals and humans. The main focus of this brief review is to examine the effects of a high fat diet on stress and the immune system with particular emphasis on brain and cognitive function.

Effects of Essential Fatty Acid Preparation (SR-3) on Brain Lipids, Biochemistry, and Behavioral and Cognitive Functions

From the time of written history people have tended to divide the world of nutrition into two sections. One section includes all foods that are “fit” for eating, the other section, no less important, includes all the foods that are “unfit” to consume. People have also cherished the belief that certain foods are “good for thought” and other foods are “bad for thought” (Harris, 1985). Furthermore, there are yet those who believe that certain foods contain magical powers. If you want to be brave—it is claimed—the heart of the lion is good food for you. Finally, there is widespread acceptance that certain foods can heal various diseases. The effect of food on thought and behavior has been demonstrated in Alice’s Adventure in Wonderland. Alice not only could change her height when she was drinking the liquid, but also refered to a “treacle well” which could “cure” snakebites and various diseases.