John Rivers (1945-1989): his contribution to research on polyunsaturated fatty acids in cats.

John Rivers was a remarkable person, with enormous courage and a very generous spirit. He made a significant and long-lasting impact on the science of nutrition, disaster relief and the lives of those with whom he worked. His contribution to the understanding of the essential fatty acid requirements and metabolism in the cat while working at the Nuffield Institute of Comparative Medicine is described in this paper, together with background information on the polyunsaturated fatty acid research undertaken in the Biochemistry Department at the Institute

Incorporation of radioactive polyunsaturated fatty acids into liver and brain of developing rat

The incorporation of radioactivity from orally administered linoleic acid-1-14C, linolenic acid-1-14C, arachidonic acid-3Hg, and docosahexaenoic acid-14C into the liver and brain lipids of suckling rats was studied. In both tissues, 22 hr after dosing, 2 distinct levels of incorporation were observed: a low uptake (from 18:2-1-14C and 18:3-1-14C) and a high uptake (from 20:4-3H8 and 22:6-14C). In adult rats, the incorporation of radioactivity into brain lipids from 18:2-1-14C and 20:4-3H was considerably lower than the incorporation into the brains of the young rats. In the livers of the suckling rats, the activity from the 18 carbon acids was associated mostly with the triglyceride fraction, whereas the activity from the 20:4-3H8 and 22:6-14C was concentrated in the phospholipid fraction. In the brain lipids, the activity from the different fatty acids was associated predominantly with the phospholipids. In the liver and brain phospholipid fatty acids, some of the activity in the 18:2-1-14C and 18:3-1-14C experiments was associated with 20 and 22 carbon polyunsaturated fatty acids; however, radioactivity from orally administered 20:4-3H8 and 22:6-14C was incorporated intact into the tissue phospholipid to a much greater extent compared with the incorporation of radioactivity into 20:4 and 22:6 in the experiments where 18:2-1-14C and 18:3-1-14C, respectively, were administered. Possible reasons for these differences are discussed. Rat milk contains a wide spectrum of polyunsaturated fatty acids, including linoleate, linolenate, arachidonate, and docosahexaenoate. During the suckling period in the rat, there is a rapid deposition of 20:4 and 22:6 in the brain. The results of the present experiments suggested that dietary 20:4 and 22:6 were important sources of brain 20:4 and 22:6 in the developing rat. © 1975 American Oil Chemists' Society

Long-chain polyunsaturated fatty acids in the mammalian brain.

Long-chain polyunsaturated fatty acids in the mammalian brain

Introduction: More than 50 years of research on polyunsaturated fatty acid metabolism

Why would anyone be interested in lipids and fatty acids for more than 50 years? It is because this field is fascinating, because there is such a great variety of research and application in biology, medicine, agriculture, and nutrition, and many of the discoveries are of fundamental importance to everyday lives. It only takes a few minutes of searching PubMed (https://www.ncbi.nlm.nih.gov/pubmed) to realize that nutrition is being overrun by large-scale research studies, many of which involves the microbiome, with huge teams, including experts in molecular biology, metabolomics, bioinformatics, medicine, immunology, and the microbiome itself. However, it is encouraging that lipid scientists and multidisciplinary collaborators in fields such as arthritis, chronic headache pain relief, maternal and infant nutrition, psychiatry and basic brain research, are conducting multidisciplinary studies. The future is bright if such multidisciplinary collaborations continue

Commentary on the workshop statement

Commentary on the workshop statemen

High Linoleic Acid in the Food Supply Worldwide-What are the Consequences?

The macronutrient composition of food supply in China has altered dramatically in the past 70 years. Fat (oil) has increased more than 4.2-times while the carbohydrate content has declined by 34%. Vegetable oils are the major component of the fat intake and since these oils are rich in linoleic acid, there has been a significant rise in the consumption of this fatty acid (as much as a 4-fold rise). Linoleic acid has essential functions in the body in skin and as a precursor of prostaglandins and related compounds. The current intakes of linoleic acid are well in excess of the minimum requirements. In this review, the effects of a food supply rich in linoleic acid on pain in arthritis and headache, non-alcoholic fatty liver and neural function are explored, with emphasis on lipid mediators derived from linoleic acid and other long chain polyunsaturated fatty acids. The current world food systems have created an imbalance of dietary linoleic acid in relation to n-3 polyunsaturated fatty acids, and an imbalance in the lipid mediators derived from these polyunsaturated fatty acids which may be contributing to sub-optimal health status

Docosahexaenoic acid and the brain- what is its role?

Docosahexaenoic acid (DHA) is a 22-carbon omega 3 PUFA highly enriched in the neuronal cell membranes and rod outer segment membranes. When DHA is depleted from these cell membranes it is replaced nearly quantitatively by a 22-carbon omega 6 PUFA, docosapentaenoic acid, which has similar, but less potent, biophysical and physiological properties to DHA. It is speculated that omega 6-docosapentaenoic acid is a buffer to prevent the possible catastrophic effects of DHA depletion on brain and visual function. The primary insult from the loss of DHA from cell membrane glycerophospholipids, and replacement by omega 6-docosapentaenoic acid, is on the flexibility/compression of the membrane lipids which affects the optimal function of integral membrane proteins (receptors, voltage-gated ion channels and enzymes). This leads to effects on second messenger systems, and subsequently affects neurotransmitter concentrations due to 'weakened' signals from the initiating receptors. Remembering there are more than 80 billion neurones and many times more synaptic connections between neurons, a very small loss of "efficiency" in signal due to altered properties of membrane proteins would likely result in meaningful changes in brain and visual function. Additionally, impairment of neurotransmission could be due, in part, to sub-optimal brain energy metabolism (glucose entry into the brain), which is significantly reduced in omega 3 deficiency. Many studies report that dietary omega 3 deficiency results in changes in learning, coping with stress, behavioural changes, and responses in visual function. It is thus concluded that DHA is an essential fatty acid for optimal neuronal function

Fatty acid composition of liver lipids during development of rat

The fatty acid composition of triglycerides and phospholipids from rat liver was determined throughout the period of growth in the rat. Major changes in the triglyceride fatty acid composition were observed during the period studied. The triglycerides from fetal and newborn rats contained only a small percentage of polyunsaturated acids compared with suckling and weanling rats. During the suckling phase the liver triglycerides were rich in long chain polyunsaturated acids such as 20:4, 20:5, 22:5, and 22:6; once the pups were weaned, the percentage of these acids in the liver triglycerides fell. In these experiments, 18:2 and 18:3 were the only polyunsaturated acids in the maternal diet. However, the stomach contents of the suckling pups contained 18:2 and 18:3, as well as the long chain polyunsaturated acids. Radioactive 18:3 and 22:6 were fed to suckling pups, and the results suggested that the LCP in the rat liver triglycerides during the suckling period were derived from the long chain polyunsaturated acids in the dam's milk, rather than by synthesis from either 18:2 or 18:3 within the pups. © 1974 American Oil Chemists' Society

Will the relationship between "long-chain PUFA and brain" ever achieve the same status as the "calcium and bone' relationship?

Will the relationship between "long-chain PUFA and brain" ever achieve the same status as the "calcium and bone' relationship

The good oil: Omega 3 polyunsaturated fatty acids

The good oil: Omega 3 polyunsaturated fatty acid