The purpose of this work was to determine the effects of varying levels of dietary protein on body composition and muscle protein synthesis during energy deficit (ED). A randomized controlled trial of 39 adults assigned the subjects diets providing protein at 0.8 (recommended dietary allowance; RDA), 1.6 (2×-RDA), and 2.4 (3×-RDA) g kg(-1) d(-1) for 31 d. A 10-d weight-maintenance (WM) period was followed by a 21 d, 40% ED. Body composition and postabsorptive and postprandial muscle protein synthesis were assessed during WM (d 9-10) and ED (d 30-31). Volunteers lost (P<0.05) 3.2 ± 0.2 kg body weight during ED regardless of dietary protein. The proportion of weight loss due to reductions in fat-free mass was lower (P<0.05) and the loss of fat mass was higher (P<0.05) in those receiving 2×-RDA and 3×-RDA compared to RDA. The anabolic muscle response to a protein-rich meal during ED was not different (P>0.05) from WM for 2×-RDA and 3×-RDA, but was lower during ED than WM for those consuming RDA levels of protein (energy × protein interaction, P<0.05). To assess muscle protein metabolic responses to varied protein intakes during ED, RDA served as the study control. In summary, we determined that consuming dietary protein at levels exceeding the RDA may protect fat-free mass during short-term weight loss.

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Resonance Raman spectroscopy (RRS) and reflection spectroscopy (RS) are optical methods applicable to the non-invasive detection of carotenoids in human skin. RRS is the older, more thoroughly validated method, whereas RS is newer and has several advantages. Since collective skin carotenoid levels serve as a biomarker for vegetable and fruit intake, both methods hold promise as convenient screening tools for assessment of dietary interventions and correlations between skin carotenoids and health and disease outcomes. In this manuscript, we describe the most recent optimized device configurations and compare their use in various clinical and field settings. Both RRS and RS devices yield a wide range of skin carotenoid levels between subjects, which is a critical feature for a biomarker. Repeatability of the methods is 3-15% depending on the subject's skin carotenoid level and the uniformity of its local distribution. For 54 subjects recruited from an ophthalmology clinic, we first checked the validity of the relatively novel RS methodology via biochemical serum carotenoid measurements, the latter carried out with high performance liquid chromatography (HPLC). A high correlation between RS skin and serum HPLC carotenoid levels was established (R = 0.81; p < 0.001). Also, a high correlation was found between RS and RRS skin levels (R = 0.94 p < 0.001). Subsequent comparisons of skin carotenoid measurements in diverse age groups and ethnicities included 569 Japanese adults, 947 children with ages 2-5 screened in 24 day care centers in San Francisco, and 49 predominantly Hispanic adults screened at an outdoor health fair event. Depending on the particular subject group, correlation coefficients between the RRS and RS methods ranged between R ∼0.80 and R ∼0.96. Analysis of the Japanese screening showed that, on average, skin carotenoid levels are higher in women compared to men, skin levels do not depend on age, and tobacco smokers have reduced levels versus non-smokers. For the two most ethnically diverse groups with widely varying melanin levels, we investigated the effect of dermal melanin on RS and RRS skin carotenoid levels. The analysis revealed that large variations in skin carotenoid levels remain detectable independent of the particular melanin index. This behavior is consistent with the absence of melanin effects on the skin carotenoid levels generated with the instrument configurations. The RS method has an advantage over RRS in its relative simplicity. Due to its detection of skin reflection over a wide spectral range from the near UV to the near IR, it has the unique ability to quantify each of the major tissue chromophores and take them into account in the derivation of skin carotenoid levels.

Human adenovirus-36 (Ad-36) increases adiposity in chickens, mice, and nonhuman primates and is associated with human obesity. Ad-36 paradoxically reduces serum cholesterol and triglycerides in animal models. Ad-36 increases adipocyte differentiation and triglyceride accumulation in 3T3-L1 cells in vitro. This study evaluated whether three other human adenoviruses increase adiposity in chickens and in 3T3-L1 cells in vitro. We inoculated chickens with human Ad-2, Ad-31, Ad-37, or media at age 3 wk. Food intake and weights were recorded for 3.5 wk, and then chickens were killed and visceral fat, body composition, serum lipids, and viral antibody status were determined. Visceral fat and total body fat were significantly elevated (P < 0.001) in the Ad-37 group compared with all other groups. Final body weights were higher in chickens inoculated with Ad-37 compared with Ad-2, but not significantly higher than in control or Ad-31 groups. Food intake did not differ among groups. Serum cholesterol was elevated in Ad-37 chickens compared with control (P < 0.01) but was not affected by other viruses. Triglycerides were reduced in Ad-37 chickens (P < 0.0001) but were not affected by other viruses. In 3T3-L1 cells in vitro, Ad-31, Ad-36, and Ad-37, but not Ad-2, increased adipocyte differentiation and triglycerides accumulation. In summary, Ad-37 is another human adenovirus that increases adiposity and reduces serum triglycerides in an animal model. However, the response of serum cholesterol is opposite that of Ad-36. Evaluation of other human adenoviruses to determine their effects on adiposity and serum lipids is warranted, but in vitro assays may not be definitive for this purpose.