Effects of L-tryptophan and protein sparing modified fast on plasma tryptophan, carbohydrate craving and appetite control
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Carbohydrate craving has complicated weight reduction for patients using the protein sparing modified fast regimen. Such diets provide adequate amounts of protein but very little carbohydrate. It is believed that such treatment may lead to reduced levels of plasma tryptophan. A reduction in plasma tryptophan could then lead to a decrease in brain tryptophan with subsequent reduction in the formation of its metabolite, serotonin. Brain serotonin depletion is thought to lead to carbohydrate craving. In addition, diminished levels of serotonin in the brain may produce changes in alertness, mood and sleep pattern. The aim of this investigation was to determine the effects of tryptophan supplements on carbohydrate craving, plasma tryptophan levels, appetite control, weight loss, alertness, mood and sleep pattern. Accordingly, adult obese subjects were placed on a protein sparing modified fast supplemented by either L-tryptophan or a placebo in a double blind, randomized cross over design. In a five week study period, subjects received either placebo or tryptophan, 1.0 g after lunch and 1.5 g at bedtime; one for 2-3 weeks followed by the other for 2-3 weeks. A "wash out" period during which time subjects received placebo was included for the week following the second tryptophan supplementation week. Weekly blood samples were collected to determine changes in fasting as well as post-prandial levels of plasma tryptophan. Weight reduction along with dietary adherence were monitored, and behavioral changes including carbohydrate craving, appetite control, alertness, mood and sleep pattern were assessed with the use of four questionnaires. The results showed that tryptophan supplements increased levels of post prandial plasma tryptophan. Weight loss tended to be greater when subjects were on tryptophan than when they were on placebo. Tryptophan administration reduced carbohydrate craving and also tended to decrease appetite. No significant differences were found in measures of alertness mood or sleep patterns. These findings indicate that in subjects undergoing a protein sparing modified fast, tryptophan administration leads to a significant reduction in carbohydrate craving and therefore may be an important adjunct to weight reduction regimen.
PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact firstname.lastname@example.org.Thesis (M.S.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1984 (Nutritional Sciences)Bibliography: leaves 105-117.
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