In this Time Machine post, we travel back to 1938 to check out a manuscript on the importance of amino acids in nutrition authored by Dr. William Cumming Rose (1887-1985), professor of biochemistry at the University of Illinois, published in Physiological Reviews. His research on the importance of amino acids in the physiology of an organism culminated in 124 research, review or biographical articles and his receipt of the National Medal of Science in 1966.

In The Nutritive Significance of the Amino Acids, Dr. Rose explains how amino acids are either produced by the body or obtained from proteins during digestion. This detailed review pointed out that amino acids serve many purposes in the body beyond being a source of energy, “One of the most astounding attributes of living things is the unerring accuracy with which specific tissue components are manufactured out of the variable mixture of amino acids circulating in the blood.” Moreover, certain amino acids are essential for growth, development and normal physiology. Lysine and tryptophan, for example, play an important role in normal growth because they are building blocks for tissue proteins. Insufficient dietary intake of these amino acids can, therefore, stunt growth. Other essential (or ‘indispensable’) amino acids that must be obtained from the diet include histidine, valine, leucine, isoleucine, phenylalanine, methionine, and threonine (Rose, 1938).

Deficiency in valine results not only in weight loss and appetite suppression, but studies have shown that animals become unusually sensitive to touch and develop a staggering gait showing impaired coordination. In addition, they appear to move around in circles (Rose, 1938). Given that the loss of valine results in appetite suppression, it is perhaps not surprising that central administration of valine to the hypothalamus in juvenile rainbow trout, Oncorhynchus mykiss) results in overeating. The hypothalamus is where hunger and satiety are perceived in the brain. In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers discovered that valine in the brain affects not only brain metabolism, but also whole body metabolism in rainbow trout (Comesaña et al., 2024).

Although I am clearly not a fish, I am going to blame brain valine overload anyway for my tendency to overeat at Thanksgiving. I mean turkey and dairy products do contain valine after all…bring on the scalloped potatoes!!

Sources:

William C. Rose. The nutritive significance of the amino acids. Physiological Reviews. 18(1): 109-136, 1938.

Comesaña S, Antomagesh F, Soengas JL, Blanco AM, Vijayan MM. Valine administration in the hypothalamus alters the brain and plasma metabolome in rainbow trout. Am J Physiol Regul Integr Comp Physiol. 327(2): R261-R273, 2024.

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Categories: Diet and Exercise, Time Machine

Tags: amino acids, appetite, development, diet, essential amino acids, fitness, health, Hyperphagia, medicine, nutrition, protein, rainbow trout, science, valine