Efficacy of front-of-pack warning label system versus guideline for daily amount on healthfulness perception, purchase intention and objective understanding of nutrient content of food products in Guatemala: a cross-over cluster randomized controlled experiment.

BACKGROUND: Front-of-package warning labels (FOPWL) have been adopted in many countries aiming at reducing the consumption of unhealthy food and drink products and have also been considered in Guatemala. The aim of the study is to evaluate the efficacy of FOPWL versus Guidelines for Daily Amount (GDA) on products' healthfulness perception (HP), purchase intention (PI) and the objective understanding of the nutrient content (UNC) in Guatemala. METHODS: Participants (children and adults) (n = 356) were randomly assigned to evaluate either FOPWL or GDA during a crossover cluster randomized experiment in rural and urban areas across 3 phases of exposure. During phase 1, participants evaluated mock-up images of single products (single task) and compared pairs of products within the same food category (comparison task) without any label. In phase 2, participants evaluated labels only (without any product), and during phase 3, they evaluated the same products and questions from phase 1, now depicting the assigned front-of-package label. We generated indicators for single-task questions and scores for comparison tasks, one for each HP, PI and UNC questions. We used intention-to-treat, difference-in-difference regression analysis to test whether exposure to FOPWL was associated with HP, PI and UNC, compared to GDA. We also tested models for children and adults and by area (rural/urban) separately adjusting for sociodemographic variables. RESULTS: In single tasks, FOPWL significantly decreased the PI (ß -18.1, 95%CI -23.3, -12.8; p < 0.001) and the HP (ß -13.2, 95%CI -18.4, -7.9; p < 0.001) of unhealthy food products compared to GDA. In the comparison task, FOPWL significantly increased the UNC (ß 20.4, 95%CI 17.0, 23.9; p < 0.001), improved PI towards healthier choices (OR 4.5, 95%CI 2.9, 7.0 p < 0.001) and HP (OR 5.6, 95%CI 2.8, 11.1; p < 0.001) compared to GDA. Similar results were found in children and adults and in urban and rural settings. CONCLUSIONS: FOPWL reduces products' healthfulness perception and purchase intention, and increases understanding of products' nutrient content compared to GDA.

Proposition of a feasible protocol to evaluate salt sensitivity in a population-based setting.

Although a variety of techniques have been devised to assess salt sensitivity, most have proven cumbersome from a methodological perspective. We therefore attempted to develop a 2-week method by which participants could be tested in an outpatient setting without requirement of a strict dietary regimen. In this method, subjects take 140 mEq of an NaCl supplement per day for 1 week and 25 mg of hydrochlorothiazide daily for another week while maintaining their customary diet. In our first trial, 8 healthy volunteers submitted to this method, as well as to a widely-used rapid volume expansion and contraction protocol. Blood pressure measurements, blood sampling and 24-h urine collection were performed before, in the middle of, and after each intervention. There was a fair correlation (r = 0.69) between the two protocols with respect to the changes in mean blood pressure (deltaMBP), a measure of salt sensitivity. In our second trial, we tested the method on 82 Japanese subjects who had never been treated with antihypertensive drugs. DeltaMBP was significantly correlated with plasma renin activity (PRA) during salt loading (r = 0.52, p < 0.0001) and with the changes in atrial natriuretic peptide (deltaANP) (r = -0.34, p = 0.0018). When total subjects were divided into two subgroups by age, a similar tendency of correlation was observed. Age, PRA during salt loading, deltaANP, and delta norepinephrine were proven to be significant predictors of salt sensitivity and accounted for 46% of the deltaMBP variances. Based on these results, the dietary method presented here seems to be applicable for a population-based survey. Our preliminary data also suggest that PRA and ANP would be of predictive value in the salt sensitivity test.

Prevalence of overweight and hypertension in Tanzania: Special emphasis on resting energy expenditure and leptin.

1. In the present study we investigated the difference in the distribution of selected cardiovascular disease risk factors among three middle-aged Tanzanian populations with different lifestyles. 2. The prevalence of hypertension and overweight was higher in urban areas than in rural areas. Plasma leptin concentration was also highest in urban areas. Based on these results, we speculated that overweight in the urban population may be partly due to adiposity. 3. Resting energy expenditure was lower in urban areas than in other areas for both genders. These findings suggest that the high prevalence of overweight in the urban population may be partly due to low physical activity levels.

Effects of dietary intake of soy protein and isoflavones on cardiovascular disease risk factors in high risk, middle-aged men in Scotland.

OBJECTIVE: To investigate the effects of soy protein and isoflavones on blood pressure (BP) and cholesterol levels among high risk middle-aged Scottish men. DESIGN: A randomized, double-blind, placebo-controlled, parallel-group dietary intervention study SETTING: Inhabitants on Isles of Lewis and Harris in Scotland SUBJECTS: Sixty-one men with relatively higher BP and/or total cholesterol (TC) levels aged 45 to 59 went through the dietary intervention. INTERVENTION: Diets containing at least 20 g of soy protein and 80 mg of isoflavones were compared to the placebo diets. Intervention period was 5 weeks duration. RESULTS: Significant difference was found in 24-hour urinary isoflavone excretion between the two groups after intervention. Significant reductions from the baselines were observed in systolic BP (SBP) and diastolic BP (DBP), TC and non-high density lipoprotein cholesterol (non-HDL-C) in the soy-containing diet group, but not in the olive oil containing active placebo group. Significant increases in high density lipoprotein cholesterol (HDL-C) were observed in both groups. CONCLUSION: Dietary intakes of soy protein (at least 20 g) and isoflavones (at least 80 mg) for 5 weeks would be effective in reducing CHD risk among high-risk, middle-aged men.

Prevalence of overweight and hypertension in Tanzania: special emphasis on resting energy expenditure and leptin.

1. In the present study we investigated the difference in the distribution of selected cardiovascular disease risk factors among three middle-aged Tanzanian populations with different lifestyles. 2. The prevalence of hypertension and overweight was higher in urban areas than in rural areas. Plasma leptin concentration was also highest in urban areas. Based on these results, we speculated that overweight in the urban population may be partly due to adiposity. 3. Resting energy expenditure was lower in urban areas than in other areas for both genders. These findings suggest that the high prevalence of overweight in the urban population may be partly due to low physical activity levels.

Nutritional variation and cardiovascular risk factors in Tanzania--rural-urban difference.

OBJECTIVE: To assess the relationship between dietary factors and cardiovascular (CVD) risk factors in middle-aged men and women, in urban, rural and pastoral settings in Tanzania. DESIGN: Cross-sectional epidemiological study designed according to the protocol of the World Health Organisation (WHO) Cardiovascular Diseases and Alimentary Comparison (CARDIAC) study. SETTING: Three centres in Tanzania, namely Dar es Salaam (urban), Handeni (rural) and Monduli (pastoral population). SUBJECTS: The subjects, aged 47-57 years, were recruited randomly from administrative lists available from each centre. OUTCOME MEASURES: Blood pressure (BP) was measured using a centrally calibrated automatic BP machine (Khi machine). Dietary history of the participants was obtained using a standard questionnaire designed on the basis of a seven-day recall system. Height, weight, serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDLC), haemoglobin A1c, sodium, potassium and magnesium were measured. RESULTS: The prevalence of hypertension (BP > or = 140/90 mmHg or antihypertensive drug use), obesity (body mass index (BMI) > or = 30 kg/m2) and hypercholesterolaemia (TC > 5.2 mmol/l) were lowest in the rural area. Consumption of green vegetables, milk, coconut milk, meat, and fish varied significantly between the three areas. Important determinants for BP among men were BMI (p < 0.001), and salt intake (p < 0.05). Among women, TC (p < 0.05), age (p < 0.05), BMI (p < 0.001) and coconut milk consumption (p < 0.001) were important BP determinants. Salt intake was positively associated with systolic BP (SBP) and diastolic BP (DBP) in men but not among women (both SBP and DBP p < 0.05 respectively). Dietary determinants of serum TC were meat, fish and green vegetable consumption. CONCLUSION: Differences in dietary habits contributed significantly to the urban-rural-pastoral variations in CVD risk pattern in Tanzania.