Effects of mixed nut consumption on LDL cholesterol, lipoprotein(a), and other cardiometabolic risk factors in overweight and obese adults.

BACKGROUND AND AIMS: Elevated LDL-C, lipoprotein(a) [Lp(a)], and inflammation are associated with greater risk for atherosclerotic cardiovascular events. Consumption of individual nut types decreases these risk factors but knowledge about the effect of mixed nuts on Lp(a) is limited. The objective of this study was to determine the effects of consuming 42.5 g/day of mixed nuts on LDL-C, Lp(a), and inflammatory markers in individuals with overweight or obesity. METHODS AND RESULTS: In a 16-week randomized control trial, 29 participants with overweight or obesity (BMI 25-40 kg/m2) consumed either 42.5 g/day of mixed nuts (cashews, almonds, macadamia nuts, Brazil nuts, pecans, pistachios, walnuts, and peanuts) or 69 g/day isocaloric pretzels. Blood samples were collected at baseline, week 8, and week 16 for analysis on total cholesterol (TC), LDL-C, Lp(a), inflammation markers, glucose, insulin, adiponectin and liver function enzymes. No significant differences were seen in TC, LDL-C, HDL-C, Lp(a), or liver function enzymes between the two groups. Participants consuming mixed nuts had significantly lower body fat percentage and diastolic blood pressure, and higher adiponectin (all P ≤ 0.05). C-reactive protein (CRP) and 8-oxo-deoxyguanosis (8-oxodG) showed non-significant decreasing trends and total antioxidant capacity (TAC) had a non-significant increasing trend in the mixed nut group. CONCLUSION: Consumption of mixed nuts had no evidence of an effect on LDL-C or Lp(a) throughout the intervention. Notably, mixed nut consumption lowered body fat percentage without significant changes in body weight or BMI. Future studies with larger sample sizes investigating the changing trends of CRP, 8-oxodG, and TAC are warranted. CLINICAL TRIAL REGISTER: NCT03375866.

Food-waste anaerobic digestate as a fertilizer: The agronomic properties of untreated digestate and biochar-filtered digestate residue.

Anaerobic digestion produces large quantities of digestate as a by-product, which can potentially be applied as an organic fertilizer, but untreated anaerobic digestate (AD) may contain phytotoxins and the large volume of AD makes transportation and storage difficult. This study explored two relatively inexpensive processing methods to improve the agronomic performance of AD as a fertilizer via vegetable cultivation experiments. We first investigated the effect of dilution on AD's performance using four leafy vegetables (Chinese spinach, water spinach, Chinese cabbage and lettuce). The optimal concentrations of the AD were 20-40% (v/v in 250 mL applications per single-plant pot) for all four vegetables based on shoot fresh weight and comparable to the control treatment using commercial fertilizer. AD application also introduced Synergistetes bacteria into the growing medium, but the overall bacterial diversity and composition were similar to those of the control treatment. Considering the nutrient separation in the liquid and solid fractions of AD and the need to reduce the volume, we then experimented with the recovery of nutrients from both the liquid and solid fractions by filtering AD using two types of wood-based biochar (100 g biochar: 1 L AD) before applying the AD-biochar residues as side dressing at 1% (w/w). Both types of biochar achieved yields comparable to the treatment using a commercial fertilizer for the three vegetables tested (kale, lettuce and rocket salad). Our results show that dilution and biochar filtration can improve the agronomic performance of AD, making it a sustainable substitute for commercial fertilizer.

Biochar utilisation in the anaerobic digestion of food waste for the creation of a circular economy via biogas upgrading and digestate treatment.

A wood waste-derived biochar was applied to food-waste anaerobic digestion to evaluate the feasibility of its utilisation to create a circular economy. This biochar was first purposed for the upgrading of the biogas from the said anaerobic digestion, before treating and recovering the nutrients in the solid fraction of the digestate, which was finally employed as a biofertilizer for the organic cultivation of three green leafy vegetables: kale, lettuce and rocket salad. Whilst the amount of CO2 the biochar could absorb from the biogas was low (11.17 mg g-1), it could potentially be increased by modifying through physical and chemical methods. Virgin as well as CO2-laden biochar were able to remove around 31% of chemical oxygen demand, 8% of the ammonia and almost 90% of the total suspended solids from the digestate wastewater, which was better than a dewatering process via centrifugation but worse than the industry standard of a polytetrafluoroethylene membrane bioreactor. Nutrients were recovered in the solid fraction of the digestate residue filtered by the biochar, and utilised as a biofertilizer that performed similarly to a commercial complete fertilizer in terms of aerial fresh weight growth for all three vegetables cultivated. Contingent on the optimal upgrading of biogas, the concept of a circular economy based on biochar and anaerobic digestion appears to be feasible.

Ontogenetic variation in salinity tolerance and ecophysiology of coastal dune plants.

BACKGROUND AND AIMS: Global climate change includes shifts in temperature and precipitation, increases in the frequency and intensity of extreme weather events and sea level rise, which will drastically impact coastal ecosystems. The aim of this study is to quantify salinity tolerance and to identify physiological mechanisms underlying tolerance across wholeplant ontogeny in two widespread native coastal plant species in Hawai'i, Jacquemontia sandwicensis (Convolvulaceae) and Sida fallax (Malvaceae). METHODS: At the seed, seedling, juvenile and mature ontogenetic stages, plants were exposed to high salinity watering treatments. Tolerance was assayed as the performance of stressed compared with control plants using multiple fitness metrics, including germination, survival, growth and reproduction. Potential physiological mechanisms underlying salinity tolerance were measured at each ontogenetic stage, including: photosynthesis and stomatal conductance rates, leaf thickness, leaf mass per area and biomass allocation. KEY RESULTS: Salinity tolerance varied between species and across ontogeny but, overall, salinity tolerance increased across ontogeny. For both species, salinity exposure delayed flowering. Physiological and morphological leaf traits shifted across plant ontogeny and were highly plastic in response to salinity. Traits enhancing performance under high salinity varied across ontogeny and between species. For J. sandwicensis, water use efficiency enhanced growth for juvenile plants exposed to high salinity, while chlorophyll content positively influenced plant growth under salinity in the mature stage. For S. fallax, transpiration enhanced plant growth only under low salinity early in ontogeny; high transpiration constrained growth under high salinity across all ontogenetic stages. CONCLUSIONS: That salinity effects vary across ontogenetic stages indicates that demographic consequences of sea level rise and coastal flooding will influence population dynamics in complex ways. Furthermore, even coastal dune plants presumably adapted to tolerate salinity demonstrate reduced ecophysiological performance, growth and reproduction under increased salinity, highlighting the conservation importance of experimental work to better project climate change effects on plants.

Effects of Fresh Watermelon Consumption on the Acute Satiety Response and Cardiometabolic Risk Factors in Overweight and Obese Adults.

Although some studies have demonstrated the beneficial effects of watermelon supplementation on metabolic diseases, no study has explored the potential mechanism by which watermelon consumption improves body weight management. The objective of this study was to evaluate the effects of fresh watermelon consumption on satiety, postprandial glucose and insulin response, and adiposity and body weight change after 4 weeks of intervention in overweight and obese adults. In a crossover design, 33 overweight or obese subjects consumed watermelon (2 cups) or isocaloric low-fat cookies daily for 4 weeks. Relative to cookies, watermelon elicited more (p < 0.05) robust satiety responses (lower hunger, prospective food consumption and desire to eat and greater fullness). Watermelon consumption significantly decreased body weight, body mass index (BMI), systolic blood pressure and waist-to-hip ratio (p ≤ 0.05). Cookie consumption significantly increased blood pressure and body fat (p < 0.05). Oxidative stress was lower at four week of watermelon intervention compared to cookie intervention (p = 0.034). Total antioxidant capacity increased with watermelon consumption (p = 0.003) in blood. This study shows that reductions in body weight, body mass index (BMI), and blood pressure can be achieved through daily consumption of watermelon, which also improves some factors associated with overweight and obesity (clinicaltrials.gov, NCT03380221).