Carbohydrates, tryptophan, and behavior: A methodological review.

Abstract

In this methodological review, we examine the behavioral effects of carbohydrates and tryptophan and conclude that high-carbohydrate foods do not provoke hyperactivity, contrary to popular beliefs. Unbalanced carbohydrate meals, however, often induce fatigue and can impair performance among both children and adults. Although tryptophan hastens sleep onset, dulls pain sensitivity, and may reduce aggressiveness, it is unclear whether similar effects can be obtained through carbohydrate ingestion. We provide support for the hypothesis that carbohydrates and tryptophan function similarly and like drugs that modify brain biochemistry and accompanying mood and behavior. We also examine implications for clinical populations who selectively crave carbohydrates.Despite professional skepticism, both anecdotal and empirical evidence continue to suggest that foods affect behavior. The empirical literature has now grown sufficiently to evaluate the validity of beliefs about one nutrient category, carbohydrates.Claims about the psychological effects of carbohydrates, especially sugar, are multiple. They range from the assumption that sugar enhances activity and aggression, to the premise that sugar has an energizing effect on behavior, to the assertion that sugar induces an anxious or depressed mood. Scientific evaluation and dissemination of accurate information about diet-behavior relations may lead to beneficial applications. They may also help to dispel folk wisdoms that can justify ineffective or even harmful health practices.Recent clinical research suggests that certain population subgroups selectively crave carbohydrates, usually as snack foods.Examples include some proportion of individuals with obesity

Altered reward value of carbohydrate snacks for female smokers withdrawn from nicotine

“…Acute nicotine administration increases prefrontal cortical serotonin release and extracellular concentration (Toth et al, 1992;Ribeiro et al, 1993;Summers and Giacobini, 1995), and chronic administration increases release from dorsal raphe (Mihailescu et al, 2002). Discontinuing nicotine diminishes serotonin turnover (Koob and Le Moal, 2001;Watkins et al, 2000) and triggers a withdrawal state that is characterized by dysphoric mood and carbohydrate craving (Spring et al, 1987). Increased carbohydrate snacking, which elevates brain tryptophan influx and serotonin synthesis (Fernstrom and Wurtman, 1971) may represent a form of substance selfadministration that is reinforced by positive mood changes (Spring et al, 1987).…”

“…The distinction is important to the extent that nicotine deprivation increases eating that serves a function different than redressing generalized energy deficits. Elsewhere, it has been suggested that snack self-administration serves a mood regulatory function, possibly via effects on brain serotonin, for clinical syndromes like nicotine withdrawal that are characterized by dysphoric mood, carbohydrate snacking, and weight gain (Bowen et al, 1991;Fernstrom and Wurtman, 1971;Gmnberg, 1986;Spring et al, 1987).…”

Preliminary study: voluntary food intake in dogs during tryptophan supplementation

“…The availability of dietary tryptophan to the brain is largely dependent on the composition of the ingested diet, in particular the ratio of tryptophan to other large neutral amino acids (16) . The concentration of tryptophan in the central nervous system can be increased either by increasing plasma tryptophan or by lowering plasma concentrations of large neutral amino acids (17) .…”

Abuse potential of carbohydrates for overweight carbohydrate cravers

“…We chose to study carbohydrate craving because, arguably, it has the largest empirical evidence base of the putative food addictions (Arbisi et al 1996;van der Ster Wallin et al 1994;Spring et al 1987). Carbohydrate craving has been characterized as an overwhelming drive to compulsively and selectively overconsume carbohydrate-rich, protein-poor foods in response to dysphoric mood, resulting in overweight (Heller and Heller 1993;Wurtman and Wurtman 1995).…”