Influence of Diet on Lipid Content of the Rat's Brain

Abstract

Previous studies on the blood lipids in epilepsy 1 and in acute infectious diseases 2 indicated to us the need for further information regarding the factors which control the lipid content of the tissues. The present report deals with the influence of various diets on the total fatty acid, cholesterol and phospholipid content of the rat's brain. The interest of earlier workers appears to have centered chiefly in cholesterol. Page and Menschick, 3 Chanutin and Ludewig 4 and others have shown that the cholesterol content of the rabbit's liver is greatly increased by prolonged ingestion of this substance, whereas that of the brain is not changed. Best and Ridout 5 found that the livers of cholesterol-fed rats could be prevented from becoming excessively fatty by addition of choline to the diet. A high fat diet is said to inhibit and a high carbohydrate diet to accelerate deposition of cholesterol in the liver. 4 The effect of diet on the phospholipid content of the brain appears not to have been investigated.

A series of experiments covering a wide range of diets and extending over periods of from 1 1/2 to 13 1/2 months proved fairly definitely that the lipid content of the growing rat's brain tends to remain strikingly uniform. Between 3 and 6 normal rats from our own stock colonies were placed at the age of 3 weeks on one of the following special diets: 1. High-carbohydrate (80%), 2. high-fat (85%), 3. high-protein (80%), 4. low-fat (20%), 5. fat-free (Burr and Burr), 6. standard stock diet (Jackson), 7. standard control diet (Chanutin and Ludewig), 8. the latter plus 2.5% added cholesterol, 9. the same plus 5% added cholesterol, and finally, 10. the standard control diet plus 1.25% cholesterol and 1.30% choline.