Proposal for an Empirical Japanese Diet Score and the Japanese Diet Pyramid.

A traditional Japanese diet (JD) has been widely regarded as healthy, contributing to longevity. The modern Japanese lifestyle has become markedly westernized, and it is speculated that the number of people who eat JD is decreasing. A simple evaluation of people with low adherence to JD will help improve dietary life. We developed a simple assessment tool that can capture JD, and examined factors associated with low adherence to JD. A total of 1458 subjects aged 18 to 84 years completed a brief self-administered diet history questionnaire. We constructed an empirical Japanese diet score (eJDS) consisting of 12 items from the common characteristics of a JD. In our participants, 47.7% of subjects reported low adherence to JD and only 11.1% demonstrated high adherence. In multivariate logistic regression analysis, younger age persons, physically inactive persons, and heavy drinkers were associated with low adherence to JD. Based on the cutoff values of eJDS, we proposed to create a Japanese diet pyramid that is easy to use visually. In conclusion, the eJDS and the Japanese diet pyramid will be useful tools for nutrition education and dietary guidance.

The World Health Organization's Healthy Diet Indicator and its associated factors: A cross-sectional study in central Kinki, Japan.

The Healthy Diet Indicator (HDI), which is based on adherence to World Health Organization's (WHO) nutrition guidelines, is used worldwide. In 2015, the WHO updated the Fact Sheet for their recommended healthy diet. We investigated diet quality assessed by the updated HDI (HDI-2015) and factors related to adherence to this diet in a Japanese population. We conducted a cross-sectional study of 1370 participants from 8 workplaces, 1 college, and 2 communities. All participants completed a brief-type self-administered diet history questionnaire. The HDI-2015 assesses 7 components: fruits and vegetables, total fat, saturated fatty acid, polyunsaturated fatty acid, free sugar, dietary fiber, and potassium. Only 6.6% of subjects demonstrated high adherence to HDI-2015 (met ≥6 components), whereas 52.0% demonstrated moderate adherence (4-5 components), and 41.4% demonstrated low adherence (0-3 components). Male sex, older age, and regular physical activity were associated with higher adherence. The contemporary Japanese population has an overall low diet quality as evaluated by the updated HDI score. Improving adherence to healthier dietary patterns may promote better health in Japan.

Development of a Mediterranean diet score adapted to Japan and its relation to obesity risk.

BACKGROUND: The Mediterranean diet (MD) is well known as a healthy diet that protects against several chronic diseases. However, there is no appropriate and easy index to assess adherence to the MD pattern in Japan. OBJECTIVE: The aim of this study was to develop a novel instrument to measure MD adherence adapted to a Japanese diet and to examine its association with overweight/obesity risk. METHODS: A cross-sectional nutritional survey provided the data for construction of a novel MD score. In total, 1,048 subjects who were employees and university students, aged 18-68 years (645 men and 403 women), completed a 58-item brief-type self-administered dietary history questionnaire. We constructed a Japanese-adapted MD score (jMD score) focusing on 13 components. Adherence to the jMD was categorized as low (score 0-4), moderate (5-7), or high (8-13). RESULTS: Men had higher jMD scores than women, and adherence to the jMD score increased with age. Only 11.6% of subjects showed high adherence to the jMD, whereas 29.6% showed low adherence. A higher jMD adherence was associated with a higher intake of favorable nutrients with the exception of salt. The jMD adherence was significantly associated with a reduced likelihood of having overweight/obesity for the highest category compared with lowest category (odds ratio [OR] 0.50, 95% confidence interval [CI] 0.30-0.85, p-trend=0.017) after adjusting for age, sex, smoking, physical activity, alcohol intake, and hypertension. A two-point increment in jMD score was related to a reduced likelihood of having overweight/obesity with an odds ratio of 0.76 (95% CI 0.65-0.90, p=0.002). CONCLUSIONS: Our novel jMD score confirmed reasonable associations with nutrient intakes, and higher MD adherence was associated with a lower prevalence of overweight/obesity.

Diet quality and adherence to a healthy diet in Japanese male workers with untreated hypertension.

OBJECTIVES: As Japanese societies rapidly undergo westernisation, the prevalence of hypertension is increasing. We investigated the association between dietary quality and the prevalence of untreated hypertension in Japanese male workers. DESIGN AND METHODS: We conducted a cross-sectional study of 433 male workers who completed a brief food frequency questionnaire. Adherence to the WHO-based Healthy Diet Indicator (HDI), the American Heart Association 2006 Diet and Lifestyle Recommendations, the Dietary Approaches to Stop Hypertension (DASH) diet, and Mediterranean-style diet was assessed using four adherence indexes (HDI score, AI-84 score, DASH score and MED score). Hypertension classes were classified into three categories: non-hypertension, untreated hypertension and treated hypertension (ie, taking antihypertensive medication). RESULTS: The prevalence of untreated hypertension and treated hypertension was 22.4% and 8.5%, respectively. Patients with untreated hypertension had significantly lower HDI and AI-84 scores compared with non-hypertension. DASH and MED scores across the three hypertension classes were comparable. After adjusting for age, energy intake, smoking habit, alcohol drinking, physical activity and salt intake, a low adherence to HDI and a lowest quartile of AI-84 score were associated with a significantly higher prevalence of untreated hypertension, with an OR of 3.33 (95% CI 1.39 to 7.94, p=0.007) and 2.23 (1.09 to 4.53, p=0.027), respectively. CONCLUSIONS: A lower dietary quality was associated with increased prevalence of untreated hypertension in Japanese male workers. Our findings support a potential beneficial impact of nutritional assessment using diet qualities.

Adherence index to the American Heart Association Diet and Lifestyle Recommendation is associated with the metabolic syndrome in Japanese male workers.

BACKGROUND: As Japanese societies rapidly undergo Westernization, the prevalence of metabolic syndrome is increasing. We investigated the association between dietary habits and the prevalence of metabolic syndrome using a new adherence index to optimal dietary habits based on the American Heart Association Diet and Lifestyle Recommendation (AHA-DLR). METHODS: We conducted a cross-sectional study of 503 male workers who completed a brief food frequency questionnaire. Adherence to the AHA-DLR was assessed using a 10-component adherence index (AI-84; a total possible score of 84 points). Metabolic syndrome was defined according to the most recently published harmonized criteria by the International Diabetes Federation in conjunction with the National Heart, Lung, and Blood Institute, American Heart Association, World Heart Federation, International Atherosclerosis Society, and International Association for the Study of Obesity. RESULTS: The prevalence of metabolic syndrome was 26.6% and the AI-84 score ranged from 5 to 56 points. Subjects with metabolic syndrome had a significantly lower AI-84 score compared with those without (27.1 ± 9.1 vs. 28.9 ± 9.2, p=0.042). After adjusting for age, energy intake, smoking habit and physical activity, a higher AI-84 score was associated with a significantly lower prevalence of metabolic syndrome, with an odds ratio of 0.778 (95% CI 0.614-0.986, p=0.038) for each 10-point score increment. CONCLUSIONS: A lower AI-84 score was associated with increased prevalence of metabolic syndrome. Our findings support a potential beneficial impact of nutritional assessment using adherence to the AHA-DLR for prevention of metabolic syndrome.

Surrogate markers of insulin resistance in assessing individuals with new categories "prehypertension" and "prediabetes".

BACKGROUND: There are few data on the impact of insulin resistance on the recently defined categories of prehypertension (PHT) and prediabetes (PDM). The aim of this study was to examine associations of surrogate markers of insulin resistance with PHT/PDM. METHODS: Subjects included 554 individuals who underwent a 75-g oral glucose tolerance test (OGTT). They were classified into four groups using a severity score for high blood pressure and glucose tolerance. Insulin resistance was measured using the homeostasis model assessment of insulin resistance (HOMA-R) and three surrogate markers obtained from 75-g OGTT values (ISI-composite, Stumvoll index, and OGIS index). RESULTS: HOMA-R increased significantly, but the other three surrogate indices decreased with increasing severity score. Of these markers, the OGIS index was mostly associated with prevalent PHT/PDM and the odds ratio for insulin resistance was 3.61 (95% CI 1.68-7.76, p=0.001) for subjects with either PHT or PDM and 29.98 (12.81-70.18, p<0.001) for subjects with both PHT and PDM. CONCLUSIONS: PHT and PDM frequently coexist in relatively lean Japanese subjects. Decreased insulin sensitivity may contribute to the underlying status of PHT/PDM. Among the surrogate markers of insulin resistance, the OGIS index is the most sensitive for assessment of PHT/PDM status.

Utility of elevated 2-hour postload plasma glucose as an alternative to elevated fasting glucose as a criterion for the metabolic syndrome.

We hypothesize that many persons with postchallenge hyperglycemia (PCH) but who do not meet the National Cholesterol Education Program (NCEP) criteria characterize a phenotype that is similar to the metabolic syndrome (MS) traits. Subjects included 725 Japanese who underwent a 75-g oral glucose tolerance test. If 2-hour plasma glucose of 7.8 mmol/L or higher was present, subjects with fasting glucose of less than 6.1 mmol/L could have one component of the MS (PCH-MS). Data obtained by the 75-g oral glucose tolerance test were used to calculate 3 insulin sensitivity indexes according to formulas proposed by Matsuda and DeFronzo (insulin sensitivity index composite), Stumvoll et al (Srumvoll index), and Mari et al (oral glucose insulin sensitivity index). Based on the PCH-MS and NCEP-MS criteria, 395 had neither PCH-MS nor NCEP-MS, 85 had PCH-MS, and 245 had NCEP-MS. Subjects with PCH-MS exhibited higher systolic blood pressure and triglyceride levels, lower high-density lipoprotein cholesterol levels, and lower insulin sensitivity than those who had neither PCH-MS nor NCEP-MS. A similar profile was observed when subjects with NCEP-MS were compared with those who had neither PCH-MS nor NCEP-MS. All 3 indexes of insulin sensitivity were significantly lower in subjects with PCH-MS than in those who had neither PCH-MS nor NCEP-MS, and approximately 66% of PCH-MS was in an insulin-resistant state. On the other hand, there was no statistical difference in the values between PCH-MS and NCEP-MS. Our data support the addition of abnormal 2-hour plasma glucose as a criterion for the MS, when fasting glucose is normal.

Metabolic syndrome and new category 'pre-hypertension' in a Japanese population.

OBJECTIVE: To examine whether insulin resistance and metabolic syndrome are associated with pre-hypertension, a new stage developed by the Joint National Committee on Prevention, Detection, Education and Treatment of High Blood Pressure (JNC-7). PATIENTS AND METHODS: Subjects included 506 Japanese taking no anti-hypertensive medication. Subjects were divided into three groups according to blood pressure status using the JNC-7 criteria. Normotension (NTN) was defined as a Systolic Blood Pressure (SBP) < 120 mmHg and a Diastolic Blood Pressure (DBP) < 80 mmHg, pre-hypertension (PHT) as a SBP 120-139 mmHg or a DBP 80-89 mmHg and hypertension (HTN) as a SBP > or = 140 mmHg or a DBP > or = 90 mmHg. The metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III as modified for waist circumference criteria by the Regional Office for the Western Pacific Region of WHO. Insulin sensitivity was assessed by plasma glucose and insulin concentrations obtained at fasting or during a 75 g oral glucose tolerance test. RESULTS: There were no differences with respect to age, gender or glucose intolerance status among the three groups. The mean values of body mass index were similar between NTN and PHT, but were significantly higher in HTN than in other groups. The prevalence of the metabolic syndrome was 9.9% in NTN, 19.2% in PHT and 35.5% in HTN, respectively. The prevalence increased linearly with worsening of blood pressure status (p < 0.0001). An increase in the number of metabolic syndrome components (MS score) was also associated with a progress in blood pressure status. Even in the non-obese persons, the prevalence of the metabolic syndrome and the MS score increased linearly with worsening in blood pressure status. The homeostasis model assessment of insulin resistance (HOMA-R) was significantly higher in PHT and HTN than in NTN and increased significantly with worsening in blood pressure status. Furthermore, the quantitative insulin sensitivity check index (QUICKI) and the insulin sensitivity index proposed by Stumvoll et al. decreased significantly with worsening in blood pressure status. CONCLUSIONS: The metabolic syndrome is prevalent even in the pre-hypertensive stage in a Japanese population and insulin resistance contributes to the underlying mechanisms of these abnormalities.

Homeostasis model assessment of insulin resistance, quantitative insulin sensitivity check index, and oral glucose insulin sensitivity index in nonobese, nondiabetic subjects with high-normal blood pressure.

To investigate the relationships between high-normal blood pressure (BP) and insulin resistance, we examined insulin sensitivity in 306 nonobese and nondiabetic Japanese subjects with various BP categories (optimal BP, normal BP, high-normal BP, and hypertension). Insulin sensitivity was measured from fasting plasma glucose and insulin values and those during a 75-g oral glucose tolerance test by five formulas: the homeostasis model assessment of insulin resistance (HOMA-R), the quantitative insulin sensitivity check index (QUICKI), the oral glucose insulin sensitivity (OGIS) index, and two insulin sensitivity indexes (ISI-composite and ISI-stumvoll). The HOMA-R was significantly higher, and the QUICKI was significantly lower in subjects with hypertension than in subjects with optimal BP. Both HOMA-R and QUICKI values showed that high-normal BP patients had a higher (but not significant) degree of insulin resistance than optimal BP patients. The OGIS index was significantly lower in subjects with high-normal BP or hypertension than in subjects with optimal BP. The ISI-composite was significantly lower in subjects with high-normal BP or hypertension than in subjects with optimal BP, and it was also significantly lower in subjects with hypertension than in subjects with normal BP. The ISI-stumvoll was significantly lower in subjects with high-normal BP or hypertension than in subjects with optimal BP. The OGIS index, ISI-composite, and ISI-stumvoll significantly decreased with increasing severity of BP status among the normotensive groups (optimal BP, normal BP, and high-normal BP). These findings indicate that insulin resistance is present even in the high-normal BP categories of nonobese and nondiabetic Japanese individuals.

Pancreatic beta-cell function and insulin sensitivity in japanese subjects with impaired glucose tolerance and newly diagnosed type 2 diabetes mellitus.

To clarify whether pancreatic beta-cell function and/or insulin resistance contributes to development of glucose intolerance in Japanese subjects, we investigated 551 subjects who underwent a 75-g oral glucose tolerance test (OGTT). Subjects were divided into 3 groups: normal glucose tolerance (NGT, n = 238), impaired glucose tolerance (IGT, n = 211), and newly diagnosed type 2 diabetes mellitus (n = 102). The diabetics were subdivided into 3 subgroups as follows: diabetes with normal fasting glucose (fasting plasma glucose [FPG] < 110 mg/dL), diabetes with impaired fasting glucose (FPG 110 to 125 mg/dL), and diabetes with diabetic fasting glucose (FPG >or= 126 mg/dL). Insulinogenic index as early-phase insulin secretion, homeostasis model assessment (HOMA-beta and HOMA-resistance), and 4 different formulas of insulin sensitivity index were assessed by plasma glucose and insulin concentrations obtained at fasting or during a 75-g OGTT. Both early-phase insulin secretion and insulin sensitivity were low even in the IGT stage compared with NGT. The transition from IGT to diabetes was accompanied by a progressive deterioration of insulin reserve as well as insulin resistance. During the further progression in diabetes, insulinogenic index decreased additionally, whereas declines in insulin sensitivity were relatively small. In conclusion, both impaired insulin secretion and insulin resistance may contribute to the underlying mechanisms of glucose intolerance in Japanese subjects.