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Concept: Coffee


It is often suggested that coffee causes dehydration and its consumption should be avoided or significantly reduced to maintain fluid balance. The aim of this study was to directly compare the effects of coffee consumption against water ingestion across a range of validated hydration assessment techniques. In a counterbalanced cross-over design, 50 male coffee drinkers (habitually consuming 3-6 cups per day) participated in two trials, each lasting three consecutive days. In addition to controlled physical activity, food and fluid intake, participants consumed either 4×200 mL of coffee containing 4 mg/kg caffeine © or water (W). Total body water (TBW) was calculated pre- and post-trial via ingestion of Deuterium Oxide. Urinary and haematological hydration markers were recorded daily in addition to nude body mass measurement (BM). Plasma was analysed for caffeine to confirm compliance. There were no significant changes in TBW from beginning to end of either trial and no differences between trials (51.5±1.4 vs. 51.4±1.3 kg, for C and W, respectively). No differences were observed between trials across any haematological markers or in 24 h urine volume (2409±660 vs. 2428±669 mL, for C and W, respectively), USG, osmolality or creatinine. Mean urinary Na(+) excretion was higher in C than W (p = 0.02). No significant differences in BM were found between conditions, although a small progressive daily fall was observed within both trials (0.4±0.5 kg; p<0.05). Our data show that there were no significant differences across a wide range of haematological and urinary markers of hydration status between trials. These data suggest that coffee, when consumed in moderation by caffeine habituated males provides similar hydrating qualities to water.

Concepts: Urine, Water, Hydrogen, Coffee, Dehydration, Caffeine, Deuterium, Drink


Coffee is prepared by the extraction of a complex array of organic molecules from the roasted bean, which has been ground into fine particulates. The extraction depends on temperature, water chemistry and also the accessible surface area of the coffee. Here we investigate whether variations in the production processes of single origin coffee beans affects the particle size distribution upon grinding. We find that the particle size distribution is independent of the bean origin and processing method. Furthermore, we elucidate the influence of bean temperature on particle size distribution, concluding that grinding cold results in a narrower particle size distribution, and reduced mean particle size. We anticipate these results will influence the production of coffee industrially, as well as contribute to how we store and use coffee daily.

Concepts: Coffee, Particle size distribution, Caffeine


There is consistent evidence supporting the ergogenic effects of caffeine for endurance based exercise. However, whether caffeine ingested through coffee has the same effects is still subject to debate. The primary aim of the study was to investigate the performance enhancing effects of caffeine and coffee using a time trial performance test, while also investigating the metabolic effects of caffeine and coffee. In a single-blind, crossover, randomised counter-balanced study design, eight trained male cyclists/triathletes (Mean±SD: Age 41±7y, Height 1.80±0.04 m, Weight 78.9±4.1 kg, VO2 max 58±3 ml•kg(-1)•min(-1)) completed 30 min of steady-state (SS) cycling at approximately 55% VO2max followed by a 45 min energy based target time trial (TT). One hour prior to exercise each athlete consumed drinks consisting of caffeine (5 mg CAF/kg BW), instant coffee (5 mg CAF/kg BW), instant decaffeinated coffee or placebo. The set workloads produced similar relative exercise intensities during the SS for all drinks, with no observed difference in carbohydrate or fat oxidation. Performance times during the TT were significantly faster (∼5.0%) for both caffeine and coffee when compared to placebo and decaf (38.35±1.53, 38.27±1.80, 40.23±1.98, 40.31±1.22 min respectively, p<0.05). The significantly faster performance times were similar for both caffeine and coffee. Average power for caffeine and coffee during the TT was significantly greater when compared to placebo and decaf (294±21 W, 291±22 W, 277±14 W, 276±23 W respectively, p<0.05). No significant differences were observed between placebo and decaf during the TT. The present study illustrates that both caffeine (5 mg/kg/BW) and coffee (5 mg/kg/BW) consumed 1 h prior to exercise can improve endurance exercise performance.

Concepts: Time, Coffee, Caffeine, Exercise physiology, VO2 max, Physical fitness, Decaffeination


Microbial communities are ubiquitous in both natural and artificial environments. However, microbial diversity is usually reduced under strong selection pressures, such as those present in habitats rich in recalcitrant or toxic compounds displaying antimicrobial properties. Caffeine is a natural alkaloid present in coffee, tea and soft drinks with well-known antibacterial properties. Here we present the first systematic analysis of coffee machine-associated bacteria. We sampled the coffee waste reservoir of ten different Nespresso machines and conducted a dynamic monitoring of the colonization process in a new machine. Our results reveal the existence of a varied bacterial community in all the machines sampled, and a rapid colonisation process of the coffee leach. The community developed from a pioneering pool of enterobacteria and other opportunistic taxa to a mature but still highly variable microbiome rich in coffee-adapted bacteria. The bacterial communities described here, for the first time, are potential drivers of biotechnologically relevant processes including decaffeination and bioremediation.

Concepts: Natural selection, Bacteria, Microbiology, Biotechnology, Coffee, Caffeine, Tea, Microorganism


Precise modelling of the influence of climate change on Arabica coffee is limited; there are no data available for indigenous populations of this species. In this study we model the present and future predicted distribution of indigenous Arabica, and identify priorities in order to facilitate appropriate decision making for conservation, monitoring and future research. Using distribution data we perform bioclimatic modelling and examine future distribution with the HadCM3 climate model for three emission scenarios (A1B, A2A, B2A) over three time intervals (2020, 2050, 2080). The models show a profoundly negative influence on indigenous Arabica. In a locality analysis the most favourable outcome is a c. 65% reduction in the number of pre-existing bioclimatically suitable localities, and at worst an almost 100% reduction, by 2080. In an area analysis the most favourable outcome is a 38% reduction in suitable bioclimatic space, and the least favourable a c. 90% reduction, by 2080. Based on known occurrences and ecological tolerances of Arabica, bioclimatic unsuitability would place populations in peril, leading to severe stress and a high risk of extinction. This study establishes a fundamental baseline for assessing the consequences of climate change on wild populations of Arabica coffee. Specifically, it: (1) identifies and categorizes localities and areas that are predicted to be under threat from climate change now and in the short- to medium-term (2020-2050), representing assessment priorities for ex situ conservation; (2) identifies ‘core localities’ that could have the potential to withstand climate change until at least 2080, and therefore serve as long-term in situ storehouses for coffee genetic resources; (3) provides the location and characterization of target locations (populations) for on-the-ground monitoring of climate change influence. Arabica coffee is confimed as a climate sensitivite species, supporting data and inference that existing plantations will be neagtively impacted by climate change.

Concepts: Time, Conservation biology, Coffee, Endangered species, Caffeine, In-situ conservation, Coffea arabica, Coffea


A novel way of cooking rice to maximize the removal of the carcinogen inorganic arsenic (Asi) is presented here. In conventional rice cooking water and grain are in continuous contact, and it is known that the larger the water:rice cooking ratio, the more Asi removed by cooking, suggesting that the Asi in the grain is mobile in water. Experiments were designed where rice is cooked in a continual stream of percolating near boiling water, either low in Asi, or Asi free. This has the advantage of not only exposing grain to large volumes of cooking water, but also physically removes any Asi leached from the grain into the water receiving vessel. The relationship between cooking water volume and Asi removal in conventional rice cooking was demonstrated for the rice types under study. At a water-to-rice cooking ratio of 12:1, 57±5% of Asi could be removed, average of 6 wholegrain and 6 polished rice samples. Two types of percolating technology were tested, one where the cooking water was recycled through condensing boiling water steam and passing the freshly distilled hot water through the grain in a laboratory setting, and one where tap water was used to cook the rice held in an off-the-shelf coffee percolator in a domestic setting. Both approaches proved highly effective in removing Asi from the cooking rice, with up to 85% of Asi removed from individual rice types. For the recycled water experiment 59±8% and 69±10% of Asi was removed, on average, compared to uncooked rice for polished (n=27) and wholegrain (n=13) rice, respectively. For coffee percolation there was no difference between wholegrain and polished rice, and the effectiveness of Asi removal was 49±7% across 6 wholegrain and 6 polished rice samples. The manuscript explores the potential applications and further optimization of this percolating cooking water, high Asi removal, discovery.

Concepts: Water, Coffee, Rice, Cooking, Coffeemaker, Boiling, Coffee percolator, French press


BACKGROUND: Cola is an extremely popular caffeinated soft drink. The media have recently cited a poll in which 16% of the respondents considered themselves to be addicted to cola soft drinks. We find the contrast between the apparent prevalence of cola addiction and the lack of scientific literature on the subject remarkable. To our knowledge, this is the first case of cola dependency described in the scientific literature. CASE PRESENTATION: The patient is a 40-year-old woman, who when feeling down used cola to give her an energy boost and feel better about herself. During the past seven years her symptoms increased, and she was prescribed antidepressant medication by her family doctor. Due to worsening of symptoms she was hospitalised and later referred to a specialised outpatient clinic for affective disorders. At entry to the clinic she suffered from constant tiredness, lack of energy, failing concentration, problems falling asleep as well as interrupted sleep. She drank about three litres of cola daily, and she had developed a metabolic syndrome.The patient fulfilled the ICD-10 criteria for dependency, and on the Yale Food Addiction Scale (YFAS) she scored 40 points. Her clinical mental status was at baseline assessed by the Major Depression Inventory (MDI) = 41, Hamilton Depression - 17 item Scale (HAMD-17) = 14, Young Mania Rating Scale (YMRS) = 2 and the Global Assessment of Functioning (GAF) Scale = 45.During cognitive therapy sessions she was guided to stop drinking cola and was able to moderate her use to an average daily consumption of 200 ml of cola Her concentration improved and she felt mentally and physically better. At discharge one year after entry her YFAS was zero. She was mentally stable (MDI =1, HAMD-17 = 0, YMRS = 0 and GAF = 85) and without antidepressant medication. She had lost 7.2 kg, her waistline was reduced by 13 cm and the metabolic syndrome disappeared. CONCLUSION: This case serves as an example of how the overconsumption of a caffeinated soft drink likely was causing or accentuating the patient’s symptoms of mental disorder. When diagnosing and treating depression, health professionals should pay attention to potential overuse of cola or other caffeinated beverages.

Concepts: Coffee, Addiction, Caffeine, Bipolar disorder, Major depressive disorder, Soft drink, Energy drink, Coca-Cola


BACKGROUND: Various recommendations exist for total water intake (TWI), yet this is seldom reported in dietary surveys. Few studies have examined how real-life consumption patterns, including beverage type, variety and timing relate to TWI and energy intake (EI). METHODS: We analysed weighed dietary records from the National Diet and Nutrition Survey of 1724 British adults aged 19–64 years (2000/2001) to investigate beverage consumption patterns over 24 hrs and 7 days and associations with TWI and EI. TWI was calculated from the nutrient composition of each item of food and drink and compared with reference values. RESULTS: Mean TWI was 2.53 L (SD 0.86) for men and 2.03 L (SD 0.71) for women, close to the European Food Safety Authority “adequate Intake” (AI) of 2.5 L and 2 L, respectively. However, for 33% of men and 23% of women TWI was below AI and TWI:EI ratio was <1 g/kcal. Beverages accounted for 75% of TWI. Beverage variety was correlated with TWI (r 0.34) and more weakly with EI (r 0.16). Beverage consumption peaked at 0800 hrs (mainly hot beverages/ milk) and 2100 hrs (mainly alcohol). Total beverage consumption was higher at weekends, especially among men. Overall, beverages supplied 16% of EI (men 17%, women 14%), alcoholic drinks contributed 9% (men) and 5% (women), milk 5-6%, caloric soft drinks 2%, and fruit juice 1%.In multi-variable regression (adjusted for sex, age, body weight, smoking, dieting, activity level and mis-reporting), replacing 100 g of caloric beverages (milk, fruit juice, caloric soft drinks and alcohol) with 100 g non-caloric drinks (diet soft drinks, hot beverages and water) was associated with a reduction in EI of 15 kcal, or 34 kcal if food energy were unchanged. Using within-person data (deviations from 7-day mean) each 100 g change in caloric beverages was associated with 29 kcal change in EI or 35 kcal if food energy were constant. By comparison the calculated energy content of caloric drinks consumed was 47 kcal/100 g. CONCLUSIONS: TWI and beverage consumption are closely related, and some individuals appeared to have low TWI. Compensation for energy from beverages may occur but is partial. A better understanding of interactions between drinking and eating habits and their impact on water and energy balance would give a firmer basis to dietary recommendations.

Concepts: Nutrition, Coffee, Alcoholic beverage, Calorie, Drink, Food and drink, Drinking, Kefir


The relationship between coffee consumption and coronary heart disease (CHD) has been investigated in several studies with discrepant results. We examined the association between Italian-style (espresso and mocha) coffee consumption and CHD risk.

Concepts: Heart, Heart disease, Coffee, Espresso, Cappuccino, Cafe mocha


It is unclear whether consumption of low-calorie beverages (LCB) leads to compensatory consumption of sweet foods, thus reducing benefits for weight control or diet quality. This analysis investigated associations between beverage consumption and energy intake and diet quality of adults in the UK National Diet and Nutrition Survey (NDNS) (2008-2011; n = 1590), classified into: (a) non-consumers of soft drinks (NC); (b) LCB consumers; © sugar-sweetened beverage (SSB) consumers; or (d) consumers of both beverages (BB), based on 4-day dietary records. Within-person data on beverage consumption on different days assessed the impact on energy intake. LCB consumers and NC consumed less energy and non-milk extrinsic sugars than other groups. Micronutrient intakes and food choices suggested higher dietary quality in NC/LCB consumers compared with SSB/BB consumers. Within individuals on different days, consumption of SSB, milk, juice, and alcohol were all associated with increased energy intake, while LCB and tea, coffee or water were associated with no change; or reduced energy intake when substituted for caloric beverages. Results indicate that NC and LCB consumers tend to have higher quality diets compared with SSB or BB consumers and do not compensate for sugar or energy deficits by consuming more sugary foods.

Concepts: Nutrition, Coffee, Carbohydrate, Sugar, Alcoholic beverage, Diets, Drink, Kefir