The effect of a phenylalanine and tyrosine restricted diet on elemental balance studies and plasma aminograms of patients with disseminated malignant melanoma

Abstract

Previous studies indicate dietary phenylalanine and tyrosine restriction may be of value in managing advanced cancer patients. To further evaluate this approach, we performed a 60-day study in which four patients with advanced malignant melanoma received formula diets via nasogastric tube containing only 8 mg total phenylalanine and tyrosine per kg lean body mass per day. Two of three patients completing elemental balance studies were in negative nitrogen, potassium, and phosphorus balance, suggesting an essential nutrient deficiency. Three patients tolerated the diet well, but one was non-compliant. Although no serious toxicity developed, serum albumin, total iron binding capacity and cholesterol significantly decreased (p less than 0.01) in the three complaint patients. Fasting plasma phenylalanine and tyrosine values did not significantly change during the study, but two-hour postprandial plasma phenylalanine and tyrosine concentrations fell below normal and were significantly lower than preprandial levels (p less than 0.01). There were no tumor responses.

Nanobiotechnological Nanocapsules Containing Polyhemoglobin-Tyrosinase: Effects on Murine B16F10 Melanoma Cell Proliferation and Attachment

“…Melanoma cells show specific amino acid-dependence for Tyrosine (Tyr) and phenylalanine (Phe) [11–14] and also arginine [15, 16]. Tyr/Phe deprivation induces G 0 /G 1 cell cycle arrest in murine melanoma [17] and induces apoptosis by inhibiting integrin/focal adhesion kinase (FAK) pathway and activating caspases [18–20].…”

Acceptability and tolerance of a low tyrosine and phenylalanine diet in patients with advanced cancer – a pilot study

“…In the present study, there was a variable response between patients. Previous studies in cancer patients have reported either no change (Lawson et al ., 1985) or decreases to the lower end of the normal range (Lorincz et al ., 1969), whereas in normal subjects tyr decreased and phe remained unchanged (Norris et al ., 1990).…”

“…Over the last 30 years a series of small, uncontrolled human studies have reported stabilization and regression of metastatic melanoma (Demopoulos, 1966; Lawson et al ., 1985), Hodgkins lymphoma, ovarian cancer and choroidal melanoma with a low tyr/phe (10 mg kg −1 body weight) diet (Lorincz & Kuttner, 1965; Edmund et al. , 1974; Stevens, 1976).…”

Dietary Manipulation of Amino Acids for Cancer Therapy

“…The stabilization of choroidal malignant melanoma has also been reported [89]. In 1985, no tumor responses were observed in three patients with disseminated malignant melanoma who received a low Phe/Tyr diet for two months [90]. In 2002, three patients with metastatic melanoma and three patients with metastatic breast cancer agreed to consume a low-protein diet providing approximately 10 mg/kg Phe/Tyr per day; the diet was based on several fixed products and complemented with different foods [91].…”