Walnuts alter IGF‐1 signaling and lipogenesis genes and reduce TRAMP prostate tumor size and growth

To assess walnut effects on prostate cancer, male TRAMP mice (age 8 wks,n=84; JAX) were fed ad lib either lowfat(LF), highfat(HF) or highfat walnut(WD) diets with equal αandγ tocopherol for 9,18, 24 wks. Prostate wts at 18 weeks were lower in LF(1.1±0.1g) and WD(1.3±.1g) vs HF(2.4±0.6g). WD plasma IGF1 was (59±11vs84±32ng/ml HF, p ≤ 0.03). Prostates(GUI) were probed using GeneChip Mouse Gene 1.0 ST Array and dChip. 11 and 78 genes were differentially expressed (≥ 1.2 fold Δ and p ≤ 0.05) in WD versus HF at 9 and 18 weeks respectively ‐FOXO3A (−1.4 fold at 18 weeks) controls IGF‐1/insulin sensitivity and StearoylCoA Desaturase‐1(−1.93 fold at 9 weeks) controls lipogenesis and tumor formation/growth. Walnuts reduce tumor size and growth via decreased plasma levels and genes associated with growth/IGF‐1 signaling.