Effect of different protocols of caffeine intake on metabolism and endurance performance

Competitive athletes completed two studies of 2-h steady-state (SS) cycling at 70% peak O2 uptake followed by 7 kJ/kg time trial (TT) with carbohydrate (CHO) intake before (2 g/kg) and during (6% CHO drink) exercise. In Study A, 12 subjects received either 6 mg/kg caffeine 1 h preexercise (Precaf), 6 × 1 mg/kg caffeine every 20 min throughout SS (Durcaf), 2 × 5 ml/kg Coca-Cola between 100 and 120 min SS and during TT (Coke), or placebo. Improvements in TT were as follows: Precaf, 3.4% (0.2-6.5%, 95% confidence interval); Durcaf, 3.1% (-0.1-6.5%); and Coke, 3.1% (-0.2-6.2%). In Study B, eight subjects received 3 × 5 ml/kg of different cola drinks during the last 40 min of SS and TT: decaffeinated, 6% CHO (control); caffeinated, 6% CHO; decaffeinated, 11% CHO; and caffeinated, 11% CHO (Coke). Coke enhanced TT by 3.3% (0.8-5.9%), with all trials showing 2.2% TT enhancement (0.5-3.8%; P < 0.05) due to caffeine. Overall, 1) 6 mg/kg caffeine enhanced TT performance independent of timing of intake and 2) replacing sports drink with Coca-Cola during the latter stages of exercise was equally effective in enhancing endurance performance, primarily due to low intake of caffeine (∼1.5 mg/kg).

Dietary intake and dietary patterns related to blood pressure

 A sample of middle-aged Australians were consuming excessive amounts of salt from convenience foods and staple foods and consumed insufficient dietary potassium from fruits and vegetables. There needs increased awareness of the dietary sources of salt and potassium to assist in population blood pressure reduction.

Nutrient and core and non-core food intake of Australian schoolchildren differs on school days compared to non-school days.

Overall the diets of Australian schoolchildren are suboptimal, but differences in nutrient and food intake on school versus non-school days have not been assessed. The aim of this study was to examine differences in nutrient and core and non-core food intake on school days versus non-school days in Australian schoolchildren aged 6-16 years. Cross-sectional analysis of the 2007 Australian Children's Nutrition and Physical Activity Survey. Dietary intake was assessed via one 24-h dietary recall. A school day was defined as Monday-Friday, a non-school day included Saturday, Sunday and public/school holidays. Independent t-tests and χ(2) tests were used to assess differences in continuous and categorical variables, respectively. Multiple linear and logistic regression was used to adjust for confounders. Forty-eight per cent of recalls were completed on a non-school day. On non-school days primary schoolchildren aged 6-11 years (n = 1334) and secondary schoolchildren aged 12-16 years (n = 1362) had significantly higher absolute intakes of sugars, total fat and saturated fat (all P < 0.05). In addition the energy density of foods consumed was greater (P < 0.001), but there was no difference in the energy density of fluids. The sodium density of the diet did not differ across day types. On non-school days, total core food intake was ~30% higher and children were more likely to consume sugar-sweetened beverages, fried potatoes and take-away pizzas and burgers (all P < 0.05). Important differences in the intake of sugar, total fat, and saturated fat and noncore foods exist on non-school days compared to school days in Australian schoolchildren. To improve the diets of schoolchildren there is scope for strategies that target non-school day eating practices.

Macronutrient intake and depressive symptoms among Japanese male workers: the Furukawa Nutrition and Health Study

This study was aimed to examine the cross-sectional association of protein, carbohydrate, and fat intake with depressive symptoms among 1794 Japanese male workers aged 18-69 years who participated in a health survey. Dietary intake was assessed with a validated self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Odds ratio of depressive symptoms (CES-D scale of ≥16) was estimated by using multiple logistic regression with adjustment for covariates including folate, vitamin B6, vitamin B12, polyunsaturated fatty acid, magnesium, and iron intake. Multivariable-adjusted odds ratio of depressive symptoms for the highest quartile of protein intake was 26%, albeit not statistically significant, lower compared with the lowest. The inverse association was more evident when a cutoff value of CES-D score ≥19 was used. The multivariable-adjusted odds ratios (95% confidence intervals) for the highest through lowest quartile of protein intake were 1.00 (reference), 0.69 (0.47-1.01), 0.69 (0.44-1.09), and 0.58 (0.31-1.06) (P for trend=0.096). Neither carbohydrate nor fat intake was associated with depressive symptoms. Our findings suggest that low protein intake may be associated with higher prevalence of depressive symptoms in Japanese male workers.

Salt intake assessed by 24 h urinary sodium excretion in a random and opportunistic sample in Australia

The gold standard method for measuring population sodium intake is based on a 24 h urine collection carried out in a random population sample. However, because participant burden is high, response rates are typically low with less than one in four agreeing to provide specimens. At this low level of response it is possible that simply asking for volunteers would produce the same results.

Protocol for the implementation and evaluation of a community-based intervention seeking to reduce dietary salt intake in Lithgow, Australia

Excess dietary salt is a leading risk for health. Multiple health, government, industry and community organisations have identified the need to reduce consumption of dietary salt. This project seeks to implement and evaluate a community-based salt reduction intervention.