Racial differences in potassium (K) intake and urinary K excretion may contribute to the higher BP observed in black compared with white individuals. Although black individuals typically consume less dietary K than white individuals, the lower urinary K excretion observed in black individuals may reflect more than differences in intake. In this study, data from the Dietary Approaches to Stop Hypertension (DASH) trial (413 white and black participants) were used to evaluate urinary K excretion in black and white individuals with similar K intake. At screening, mean urinary K excretion was higher in white than black individuals (mean ⌬ ϭ 645 mg/d for white minus black individuals, adjusted for age, gender, and weight; P Ͻ 0.001). After a 3-wk run-in period during which all participants received a low-K control diet, a significant racial difference remained (mean ⌬ ϭ 201 mg/d, adjusted for age, gender, and caloric intake; P Ͻ 0.001). Participants were then randomly assigned to continue the control diet or switch to a high-K diet (either a high fruit/vegetable diet or the DASH diet) for 8 wk. At the end of intervention, the mean difference in urinary K in white compared with black individuals after adjustment for age, gender, and caloric intake was Ϫ6 mg/d (P ϭ 0.95) in the control group, 163 mg/d in the fruits/vegetables group (P ϭ 0.39), and 903 mg/d in the DASH group (P Ͻ 0.001). Racial differences in urinary K excretion seem to reflect more than intake differences; further studies are needed to understand their potential impact on clinical outcomes.

The authors compared effects of macronutrients on self-reported appetite and selected fasting hormone levels. The Optimal Macronutrient Intake Trial to Prevent Heart Disease (OMNI-Heart) (2003)(2004)(2005) was a randomized, 3-period, crossover feeding trial (n ¼ 164) comparing the effects of 3 diets, each rich in a different macronutrient. Percentages of kilocalories of carbohydrate, fat, and protein were 48, 27, and 25, respectively, for the protein-rich diet; 58, 27, and 15, for the carbohydrate-rich diet; and 48, 37, and 15 for the diet rich in unsaturated fat. Food and drink were provided for each isocaloric 6-week period. Appetite was measured by visual analog scales. Pairwise differences between diets were estimated using generalized estimating equations. Compared with the protein diet, premeal appetite was 14% higher on the carbohydrate (P ¼ 0.01) and unsaturated-fat (P ¼ 0.003) diets. Geometric mean leptin was 8% lower on the protein diet than on the carbohydrate diet (P ¼ 0.003). Obestatin levels were 7% and 6% lower on the protein diet than on the carbohydrate (P ¼ 0.02) and unsaturated-fat (P ¼ 0.004) diets, respectively. There were no between-diet differences for ghrelin. A diet rich in protein from lean meat and vegetables reduces self-reported appetite compared with diets rich in carbohydrate and unsaturated fat and can be recommended in a weight-stable setting. The observed pattern of hormone changes does not explain the inverse association between protein intake and appetite. appetite; cross-over studies; diet; dietary carbohydrates; dietary fats; dietary proteins; ghrelin; leptin Abbreviations: OMNI-Heart, Optimal Macronutrient Intake Trial to Prevent Heart Disease; SD, standard deviation.The effects of macronutrients on appetite are controversial. Some research suggests a satiety hierarchy in which protein is more satiating than carbohydrate and carbohydrate is more satiating than fat (1). Short-term (<1 week) crossover trials, often single-meal studies, suggest that diets higher in protein decrease appetite and energy intake (2, 3). Trials examining the effect of protein on appetite over a longer period (>2 weeks) corroborate findings from shorterterm studies in settings of weight loss and maintenance of weight loss (4, 5). Other research suggests that there is no difference among macronutrients (6). Public perception is that fat is more satiating than protein and carbohydrate (7).Although clinical trials provide some evidence that shortterm exposure to diets rich in protein may reduce appetite (2-5), mechanisms are unclear. One possible explanation is that dietary protein affects concentrations of appetite hormones. Under this scenario, appetite hormones are mediating variables. Leptin purportedly decreases food intake by signaling the availability of energy reserves (8). Obestatin and ghrelin are products of the same gene but may have opposing effects on weight regulation, according to data from animal models (9); while obestatin may reduce energy intake, ghrelin probably promotes meal initi...

Data from this longitudinal study suggest that a higher protein intake does not have an adverse effect on bone in premenopausal women. Cross-sectional analyses suggest that low vegetable protein intake is associated with lower BMD.