Effect of nutrition education in reducing sodium intake and increasing potassium intake in hypertensive adults.

BACKGROUND/OBJECTIVES: Hypertension is the major risk factor for cardiovascular disease, a leading cause of deaths in Korea. The objective of this study was to evaluate the effect of a nutrition education in reducing sodium intake and increasing potassium intake in hypertensive adults. SUBJECTS/METHODS: Subjects who participated in this study were 88 adults (28 males and 60 females) who were pre-hypertension or untreated hypertensive patients aged ≥ 30 yrs in Gyeonggi Province, Korea. These subjects were divided into 2 groups: a low-sodium education (LS) group and a low-sodium high-potassium education (LSHP) group. Nutrition education of 3 sessions for 12 weeks was conducted. Blood pressure, blood and urine components, nutrient intake, and dietary behavior were compared between the two education groups. RESULT: Blood pressure was decreased in both groups after the nutrition education (P < 0.05). In the LSHP group, levels of blood glucose (P < 0.05), total cholesterol (P < 0.01), and low-density lipoprotein-cholesterol (P < 0.05) were decreased after the program completion. Sodium intake was decreased in both groups after the nutrition education (P < 0.05). However, Na/K ratio was only decreased in the LS group (P < 0.05). Intake frequency of fish & shellfish was only significantly reduced in the LS group (P < 0.05), while intake frequencies of cooked rice, noodles & dumplings, breads & snacks, stew, kimchi, and fish & shellfish were reduced in the LSHP group (P < 0.05). Total score of dietary behavior appeared to be effectively decreased in both groups after the education program (P < 0.001). CONCLUSIONS: This education for reducing sodium intake was effective in reducing blood pressure and sodium intake. The education for enhancing potassium intake resulted in positive changes in blood glucose and serum cholesterol levels.

Difference in 24-hour urine sodium excretion between controlled and uncontrolled patients on antihypertensive drug treatment.

The objective of this study was to evaluate the association between sodium intake and blood pressure (BP) control in hypertensive patients taking antihypertensive medications by using 24-hour urine collection and 24-hour ambulatory BP. This is a cross-sectional community-based study and conducted in 2011 and 2012. A total of 1128 participants were recruited from five cities in Korea. Among them, 740 participants who had complete 24-hour urine collection and valid 24-hour ambulatory BP data were included in this study. Participants were divided into four groups: normotensives (NT, n = 441), untreated hypertensive patients (UTHT, n = 174), controlled hypertensive patients (CHT, n = 62), and uncontrolled hypertensive patients (UCHT, n = 63). UCHT and CHT groups showed higher mean age than NT and UTHT groups. UCHT and UTHT groups showed higher 24-hour systolic BP (SBP) and diastolic BP (DBP) than NT and CHT groups. UCHT group had the highest level of 24-hour urine sodium. Multivariate analysis adjusted with age, gender, body mass index, estimated glomerular filtration rate, and use of diuretics showed higher level of 24-hour urine sodium in UCHT group than that in CHT group. Multivariate logistic regression analysis revealed independent association of the amount of 24-hour urine sodium with uncontrolled BP in hypertensive patients on antihypertensive drug treatment. Higher level of 24-hour urine sodium excretion in uncontrolled hypertensive patients suggests that excessive sodium intake could be associated with blunted BP lowering efficacy of antihypertensive medications.

Estimating 24-Hour Urine Sodium From Multiple Spot Urine Samples.

The authors developed an equation to estimate 24-hour urine sodium (24HUNa) using the average of three spot urine (SU) samples (morning-first, morning, and evening) from 74 individuals and validated this equation using the average of three SU samples (morning-first, daytime, and evening) from 174 additional individuals. Compared with previously published equations using a single SU sample, the currently developed equation using the average of three SU samples showed much lower bias from measured 24HUNa (-2.9 vs >10 mmol/24 h). The intraclass and concordance correlation coefficients of the proposed equation using the average of three SU samples were 0.909 and 0.832, respectively. The limits of agreement were -64.1-58.3 mmol/24 h and approximately 100 mmol/24 h for the currently developed and previously published equations, respectively. All equations showed a tendency to overestimate or underestimate 24HUNa in a manner dependent on the level of 24HUNa but irrespective of the number of SU samples considered. Nonetheless, among the currently tested equations, our equation using the average of three SU samples provided the best estimation of 24HUNa at a population level.

Relationship between 24-h urine sodium/potassium ratio and central aortic systolic blood pressure in hypertensive patients.

Studies evaluating the relationship between measured 24-h urine sodium (24HUNa), potassium (24HUK) and aortic blood pressure (BP) are rare, and no such study has been performed with an Asian population. We evaluated the relationship between 24HUNa, 24HUK, casual BP, 24-h ambulatory BP and aortic BP by analyzing data from 524 participants with valid 24-h urine collection, 24-h ambulatory BP and central BP measurements (mean age 48.1±9.8 years, 193 men). Hypertension was defined as a 24-h ambulatory BP ⩾130/80 mm Hg or current treatment for hypertension (n=219). The participants with hypertension and high 24HUNa (mean 210.5±52.0 mmol per day, range 151.0-432.0) showed higher 24-h systolic (P=0.037) and diastolic BP (P=0.037) and aortic systolic BP (AoSBP, P=0.038) than the participants with hypertension and low 24HUNa (mean 115.7±25.0 mmol per day, range 45.6-150.0), adjusted for confounders. The participants with hypertension and a high ratio of 24HUNa and 24HUK (24HUNa/24HUK, mean 4.03±1.00, range 2.93-7.96) had higher AoSBP than the participants with hypertension and a low 24HUNa/24HUK ratio (mean 2.13±0.54, range 0.53-2.91), adjusted for confounders (P=0.026). The participants with hypertension demonstrated a significant linear relationship between AoSBP and 24HUNa/24HUK ratio that was independent of 24HUNa, according to the multiple regression analysis (P=0.047). In hypertensive patients, 24HUNa/24HUK was positively and more strongly related to AoSBP compared with 24HUNa alone. The result indicates that high sodium and low potassium intake may increase the subsequent risk of cardiovascular disease by elevating AoSBP.

One portion size of foods frequently consumed by Korean adults.

This study aimed to define a one portion size of food items frequently consumed for convenient use by Koreans in food selection, diet planning, and nutritional evaluation. We analyzed using the original data on 5,436 persons (60.87%) aged 20 ~ 64 years among 8,930 persons to whom NHANES 2005 and selected food items consumed by the intake frequency of 30 or higher among the 500 most frequently consumed food items. A total of 374 varieties of food items of regular use were selected. And the portion size of food items was set on the basis of the median (50th percentile) of the portion size for a single intake by a single person was analyzed. In cereals, the portion size of well polished rice was 80 g. In meats, the portion size of Korean beef cattle was 25 g. Among vegetable items, the portion size of Baechukimchi was 40 g. The portion size of the food items of regular use set in this study will be conveniently and effectively used by general consumers in selecting food items for a nutritionally balanced diet. In addition, these will be used as the basic data in setting the serving size in meal planning.

Salt usage behaviors are related to urinary sodium excretion in normotensive Korean adults.

High sodium intake is considered to be the major risk factor for hypertension but studies about sodium intake on prevention and management of hypertension is limited due to the difficulties in assessment of sodium intake. Dietary sodium comes not only from naturally occurring sodium in foods but also from the added sodium during processing, cooking and at the table. Present study was conducted to identify salt usage behavior questions related to urinary sodium excretion among normotensive adult Koreans. The test version of the salt usage questionnaire included six items of salt usage behaviors and nine items of high salt containing foods. A survey was conducted in 189 adults over 18 years of age in three age groups in both genders. Each participant answered the questionnaire and collected one 24-hour urine and urine samples were analyzed for sodium contents. Correlation analyses between scores of the questions and sodium excretion in 24-hour urine were performed to identify question items related to sodium excretion. Among fifteen questions, scores of three questions on salt usage behaviors were significantly correlated to urinary sodium excretion (r=0.17~0.19; p <0.05) and the sum of scores of the three questions showed higher correlation coefficients. (r=0.26, p <0.001) The salt usage behavior questions developed in this study would be useful in predicting sodium intake and in studying the relationship between sodium intake and health among Korean adults.