Robert M. Hackman

Effects of a high dose, aglycone-rich soy extract on prostate-specific antigen and serum isoflavone concentrations in men with localized prostate cancer

The efficacy and safety of consuming high-dose isoflavone supplements for prostate cancer is not clear. A double-blind, placebo controlled, randomized trial was conducted in 53 men with prostate cancer enrolled in an active surveillance program. The treatment group consumed a supplement containing 450 mg genistein, 300 mg daidzein, and other isoflavones daily for 6 mo. Prostate-specific antigen (PSA) was measured in both groups at baseline, 3 mo, and 6 mo, and serum concentrations of genistein, daidzein, and equol were assessed at baseline and 6 mo in the treatment group. Following the completion of the 6-mo double-blind study, men were enrolled in a 6-mo open label trial with the same isoflavone-rich supplement, and PSA was measured at 3 and 6 mo. PSA concentrations did not change in either group after 6 mo or after 12 mo when the open-label study was included. The 6 mo serum concentrations of genistein and daidzein (39.85 and 45.59 μmol/l, respectively) were significantly greater than baseline values and substantially higher than levels previously reported in other studies. Equol levels did not change. Although high amounts of aglycone isoflavones may result in significantly elevated serum concentrations of genistein and daidzein, these dietary supplements alone did not lower PSA levels in men with low-volume prostate cancer.

Potential Biomarker of Myofibrillar Protein Oxidation in Raw and Cooked Ham: 3-Nitrotyrosine Formed by Nitrosation.

The stability of cured meat products is increased by the protection of its proteins from oxidation by sodium nitrite (NaNO2) during processing. This study investigated the effects of NaNO2 (0, 50, 100, 200, and 400 mg/kg) on the physiochemical and structural characteristics of myofibrillar protein (MP) in raw and cooked ham. The NaNO2 showed a dose-dependent antioxidant effect, by inhibiting carbonyl formation, dityrosine formation, and denaturation of MP, and a nitrosative effect, through the formation of 3-Nitrotyrosine (3-NT). The 3-NT content within MP of raw ham had distinct negative correlations with sulfhydryl content and surface hydrophobicity. The 3-NT content within MP of cooked ham had significantly negative correlations with carbonyl, sulfhydryl content and turbidity and had significantly positive correlations with disulfide content. These results indicated that 3-NT may be a potential marker for protein oxidation in raw and cooked cured meat products.

Bioactivity of a flavanol-rich lychee fruit extract in adipocytes and its effects on oxidant defense and indices of metabolic syndrome in animal models.

Many polyphenolic compounds are poorly digested, and have low bioavailability due to their long chain lengths and chemical composition. A processed, flavanol‐rich lychee fruit extract (FRLFE) that is higher in flavanol monomers, dimer and trimers than its unprocessed counterpart, was tested in a variety of models. First, mature visceral adipocytes were treated with 0, 3, 10 or 30 μg/mL FRLFE (day 6–8). Compared with the controls, the treated cells had lower triglyceride concentrations, less lipid accumulation and a smaller lipid droplet size. Adiponectin release was significantly greater in cells receiving 3 or 10 μg/mL FRLFE than in the controls. Second, rats given a single dose of 50 or 100 mg/kg FRLFE had significant increases in plasma (‐)‐epicatechin, 3′‐O‐methyl‐(‐)‐epicatechin, and (+)‐catechin levels, peak values were at approximately 2 h and appreciable concentrations were still detected at 6 h. Rats supplemented daily for 1 week with 50 or 100 mg/kg FRLFE had significantly elevated metabolite concentrations. In response to an oxidative stress, erythrocyte membrane integrity was significantly improved in the 100 mg/kg FRLFE group. Third, 7‐month‐old mice fed a 200 mg/kg FRLFE diet for 10 months showed a significant decrease in glucose, triglyceride and lipid peroxide levels compared with mice fed a control diet. Collectively, these results support the concept that the flavanols present in FRLFE are well absorbed and bioactive. Copyright

Susceptibility of whey protein isolate to oxidation and changes in physicochemical, structural, and digestibility characteristics

Oxidation is an important factor for denaturing of whey protein isolate (WPI) during food processing. We studied the effects of chemical oxidation on physicochemical and structural changes along with in vitro digestibility of WPI in this work. Evaluation of physicochemical changes showed that carbonyl level and dityrosine content increased, whereas total and free thiol group levels decreased for oxidized WPI samples. For the structural changes, protein aggregation was measured by surface hydrophobicity, turbidity, and particle diameter, which was increased for oxidized WPI samples. The increase of the secondary structure β-sheets and antiparallel β-sheet also supported the aggregation of oxidized WPI. A direct quantitative relationship between physicochemical and structural changes and protein digestibility indicated that oxidation-related damage restricts the susceptibility of WPI to proteases. In conclusion, WPI had high susceptibility to oxidative stress, and both physicochemical and structural changes caused by severe oxidative stress could decrease the rate of in vitro digestibility of WPI.

Influence of sodium nitrite on protein oxidation and nitrosation of sausages subjected to processing and storage.

The influence of NaNO2 content on protein oxidation and nitrosation was investigated in cooked sausages at different concentrations (0, 50, 100, 200 and 400 mg NaNO2/kg). Dependent on concentration, NaNO2 had both anti- and pro-oxidant effects on protein oxidation. The antioxidant effects of NaNO2 on the protein oxidation were evidenced by significantly lower carbonyl contents, higher free amines and lower surface hydrophobicities. The pro-oxidant effects of NaNO2 on protein oxidation resulted in a decrease of sulfhydryls and an increase of disulfide bonds. NaNO2 also improved the protein nitrosation inducing the formation of 3-nitrotyrosine (3-NT). Moreover, 3-NT had significant correlations with parameters of protein oxidation, indicating that 3-NT may be a possible marker for protein oxidation. Results of this study contribute to an understanding of the impact of NaNO2 on food quality and help to identify optimal formulations of cured meat products.

Evaluation of antioxidant capacity and flavor profile change of pomegranate wine during fermentation and aging process

Antioxidant properties and flavor characteristic profile of pomegranate wine during winemaking were investigated. The total phenol content and radical scavenging activity exhibited a slightly decrease in the end edge. Punicalagins and gallic acid were revealed to be the most abundant phenolic compounds, followed by ellagic acid and vanillic acid. These constituents were mainly responsible for the effective antioxidant capacity of pomegranate wine. The major changes of flavor qualities occurred in the initial stage, particularly 0-4day of fermentation. Fermentation significantly reduced the relative content of aldehydes, ketones, heterocyclic and aromatic compounds, but promoted the generation of esters and alcohols. This is the first time of using E-nose and E-tongue to monitor odour and taste changes in the brewing process of pomegranate wine. The study may provide a promising instruction for improving functional features and quality control of the pomegranate wine.

Different physicochemical, structural and digestibility characteristics of myofibrillar protein from PSE and normal pork before and after oxidation

PSE pork has a weaker texture than normal pork due to the denaturation by endogenous protease. Changes in the nutritional quality and characteristics of myofibrillar protein (MP) from PSE pork have been scarcely documented. MPs were isolated from both PSE (MPP) and normal pork (MPN) and were oxidized for 12h at 4°C by a hydroxyl radical generating system (10μM FeCl3, 100μM ascorbic acid, 0.1, 1, and 10mM H2O2). The MPP had less aggregation and looser structure with higher surface hydrophobicity. The MPP was also less polymeric, as evidenced by intenser bands on SDS-PAGE and fewer carbonyl-NH2 interactions. The MPP particles were of smaller size, caused by the endogenous protease and oxidation, and reached the critical concentration to enhance the solubility. The altered characteristics of MPP enhanced its in vitro digestion rate and overall digestibility. In addition, the in vitro digestion rate of MPN can be enhanced if the oxidative stress is strong enough (10mM H2O2).

Effects of short-term walnut consumption on human microvascular function and its relationship to plasma epoxide content☆

Improved vascular function after the incorporation of walnuts into controlled or high-fat diets has been reported; however, the mechanism(s) underlying this effect of walnuts is(are) poorly defined. The objective of the current study was to evaluate the acute and short-term effects of walnut intake on changes in microvascular function and the relationship of these effects to plasma epoxides, the cytochrome-P450-derived metabolites of fatty acids. Thirty-eight hypercholesterolemic postmenopausal women were randomized to 4 weeks of 5 g or 40 g of daily walnut intake. All outcomes were measured after an overnight fast and 4 h after walnut intake. Microvascular function, assessed as the reactive hyperemia index (RHI), was the primary outcome measure, with serum lipids and plasma epoxides as secondary measures. Compared to 5 g of daily walnut intake, consuming 40 g/d of walnuts for 4 weeks increased the RHI and Framingham RHI. Total cholesterol and low- and high-density cholesterol did not significantly change after walnut intake. The change in RHI after 4 weeks of walnut intake was associated with the change in the sum of plasma epoxides (r=0.65, P=.002) but not with the change in the sum of plasma hydroxyeicosatetraenoic acids. Of the individual plasma epoxides, arachidonic-acid-derived 14(15)-epoxyeicosatrienoic acid was most strongly associated with the change in microvascular function (r=0.72, P<.001). These data support the concept that the intake of walnut-derived fatty acids can favorably affect plasma epoxide production, resulting in improved microvascular function.

Effects of a dietary strawberry powder on parameters of vascular health in adolescent males

Previous studies have shown that the intake of freeze-dried strawberry powder (FDSP) improves select markers of cardiovascular health in adults with cardiovascular risk factors; however, whether these improvements can be observed in at-risk adolescents is unknown. A randomised, double-blind, cross-over study enrolled twenty-five overweight or obese males, aged 14-18 years, to consume 50 g of a FDSP or a control powder, daily for 1 week. Before and after each test period, measures of microvascular function, plasma nitrate/nitrite, platelet reactivity and blood lipids were collected at baseline and acutely 1 h after FDSP intake. Acute plasma nitrate/nitrite levels increased 1 h after consuming the FDSP during Study Visit 1 before daily FDSP intake (P<0·001) and during Study Visit 2 after 1 week of FDSP intake (P<0·001) compared with control powder intake. As a group, fasting nitrate/nitrite levels did not significantly change after 1 week of control or FDSP intake. However, for those individuals where fasting nitrate levels increased after short-term FDSP intake compared with controls, an increase in reactive hyperaemia index (RHI) was observed (P=0·014), whereas RHI was unchanged in those individuals who did not have a significant increase in nitrate (P=0·396). Taken together, these data support the concept that strawberries can provide vascular health benefits to heavier adolescent males.

Forecasting Nutrition Research in 2020

Abstract : Advances in nutrition during the past century have helped untold numbers of people around the world enjoy healthier and longer lives and be more productive members of society. These advances include the identification of numerous essential nutrients, the identification of common disease states that can arise as a consequence of deficiencies of these essential nutrients, the use of food fortification to correct common deficiencies in the diet, and improvements in agricultural practices and food processing that have resulted in marked advances in food safety and quality. However, many challenges still remain. To a significant extent, these challenges reflect expectations of what constitutes a good diet and what the result of following food guidelines will produce. Moving forward in time in an era of limited economic resources and expanding populations, a critical focus is required to direct attention to the most pressing challenges with the greatest need and opportunity for return on investment. Balancing the desire for quick and effective solutions with the slow, steady, and incremental nature of nutrition research is a struggle confronting academia, industry, and government. To address these challenges, a group of distinguished nutrition scientists gathered for a panel symposium in celebration of the 10th anniversary of the Kosuna Distinguished Lecture in Nutrition at the University of California, Davis. Eight of the panelists were previous Kosuna Distinguished Lecturers. The symposium discussion revolved around 2 questions that were posed to the panel members prior to the meeting: (1) What will be the hottest areas of nutrition research in 2020 and (2) If one were just starting a career in nutrition, what would be a reasonable focus for one s work? A distillation of the discussion follows, organized from the most global to the most individual topics, with some concluding thoughts on the nature of nutrition research.