Serum and macular responses to antioxidant supplementation verus a carotenoid-rich dietary intervention in the elderly.

Journal ArticleThe aim of this study was to observe responses of serum antioxidants, oxidative stress biomarkers, and macular carotenoid pigments to antioxidant supplements or dietary intervention in a single-masked, randomized, pilot clinical study of elderly subjects receiving antioxidant supplements or a dietary intervention. Methods: From a pool of ninety-eight community volunteers, forty-eight male and female subjects (age 65-85) with the lowest baseline serum lutein + zeaxanthin levels were selected and randomly assigned to receive for 12 weeks one of two different antioxidant supplements or a diet rich in fruits and vegetables containing approximately matched levels of four classes of carotenoids: carotenes, the xanthophylls lutein and zeaxanthin, and lycopene. Forty-six completed the study. Both supplements and diet also were rich in vitamins C and E. Outcome measures were changes from baseline: 1) in serum levels of antioxidant micronutrients (vitamins C and E, lutein, zeaxanthin, and carotene); 2) in levels of indicators of oxidative stress: serum lipid peroxides (LPO) and urinary 8-hydroxydeoxyguanosine (8-OHdG); and 3) macular pigment, measured by heterochromatic flicker photometry. Results: Interventions to promote eye health by either diet or supplementation showed consistent serum responses, with substantial improvements within twelve weeks. Serum lutein and vitamin C increased for all groups (p< 0.05), and lipid peroxides decreased for all subjects (p< 0.05); nonetheless, mean macular pigment did not increase significantly during the designated timeframe. Conclusion: Supplementation of elderly individuals potentially at risk for AMD with two different types of antioxidant formulations exhibited positive serum responses similar to a dietary intervention containing approximately comparable levels of carotenoids. This pilot study indicates that the ocular supplements tested in this study elicited responses in serum parameters similar to daily consumption of four servings of carotenoid-rich fruits and vegetables. The study also provides useful criteria for the design of larger-scale and longer-term studies of antioxidant supplementation in an elderly population potentially at risk for AMID

Effect of leucine supplementation on fat free mass with prolonged hypoxic exposure during a 13-day trek to Everest Base Camp: A double-blind randomized study

pre-printLoss of body weight and fat free mass (FFM) are commonly noted with prolonged exposure to hypobaric hypoxia. Recent evidence suggests protein supplementation, specifically leucine, may potentially attenuate loss of FFM in subcaloric conditions during normoxia. The purpose of this study was to determine if leucine supplementation would prevent the loss of FFM in subcaloric conditions during prolonged hypoxia. Eighteen physically active male (n=10) and female (n=8) trekkers, completed a 13-day trek in Nepal to Everest Base Camp with a mean altitude of 4140 m (range 2810-5364 m). In this double-blind study, participants were randomized to ingest either leucine (LEU) (7 g leucine, 93 kcal, 14.5g whey-based protein) or an isocaloric isonitrogenous control (CON) (0.3 g LEU, 93 kcal, 11.3 g collagen protein) twice daily prior to meals. Body weight, body composition, and circumferences of bicep, thigh, and calf were measured pre and post trek. There was a significant time effect for body weight (-2.2%±1.7%), FFM (-1.7%±1.5%), fat mass (-4.0% ± 6.9%), and circumferences (p< 0.05). However, there was no treatment effect on body weight (CON -2.3 ± 2.0%; LEU -2.2 ± 1.5%), FFM (CON -2.1 ± 1.5%; LEU -1.2 ± 1.6%), fat mass (CON -2.9% ± 5.9%; LEU -5.4% ± 8.1%), or circumferences. Although a significant loss of body weight, FFM, and fat mass was noted in 13 days of high altitude exposure, FFM loss was not attenuated by leucine. Future studies are needed to determine if leucine attenuates loss of FFM with longer duration high altitude exposure

Orthostatic responses to dietary sodium restriction during heat acclimation

Several studies have shown that individuals consuming low-salt diets and working in the heat have an increased risk or incidence of heat injury, suggestive of inadequate cardiovascular adjustment. Furthermore, others have shown that prolonged work in hot climates can precipitate orthostatic hypotension and syncope. This study was designed to evaluate the effects of moderate-salt (MS) and low-salt (LS) diets on the circulatory responses and incidence of presyncopal symptoms to an orthostatic test (OT) during successive days of heat acclimation (HA). Seventeen unacclimatized male soldiers (mean +/- SE: age 20+/-1 yrs) participated in this two-phase study. The first phase consisted of a seven day dietary stabilization period during which all subjects consumed similar diets of about 4000 kcal/day containing 8g NaCl and lived in a dormitory setting (21 C, 30% RH). The second phase commenced on day eight and consisted of dietary NaCl restriction and 10 days HA (days 8-17). Volunteers were randomly assigned to either the MS diet (n=9) providing 8g NaCl/day or the LS diet (n=8) furnishing just 4g NaCl/day. The acquisition of HA was manifested in both groups by reductions in exercising rectal temperature and heart rate (HR); these characteristics were similar in the MS and LS diets. The OT was performed at 21 C on day seven of the stabilization phase and on days 9, 11, 13, 15, and 17 of the HA phase, before and after 8.5 hr of intermittent treadmill walking in a hot environment. Blood pressure (BP) and HR responses at 1,2, and 4 min and any presyncopal symptoms were recorded after assuming an upright position from recumbency. All subjects completed the OT before and after prolonged exercise in the heat without incidence of either hypotension or presyncopal symptoms irrespective of dietary-salt intake and day of HA. The results indicate that the prolonged work in the heat can be performed without orthostatic hypotension or syncope while consuming 4g NaCl/day with adequate fluid replacement. Furthermore, the circulatory responses to OT showed no improvement with successive days of HA irrespective of dietary-salt intake

Associations of Fruit & Vegetable Intake with Serum Carotenoids, & Skin Carotenoids Measured with Raman Spectroscopy (RS)

Peer reviewed: YesNRC publication: N

Associations of antioxidant status, oxidative stress, with skin carotenoids assessed by Raman Spectroscopy (RS)

Peer reviewed: YesNRC publication: N