Background The minerals, vitamins, soluble dietary fibers, and flavonoids of seaweed are protective for preventing cardiovascular diseases. However, the association between seaweed intake and risk of cardiovascular disease has not been established. Objectives We examined the dietary intake of seaweed and its impact upon stroke and ischemic heart disease risk among a Japanese study population. Methods We surveyed 40,707 men and 45,406 women from 2 large cohorts (age range: 40–69 y). Seaweed intake was determined by FFQ at baseline (1990–1994). Incidences of stroke and ischemic heart disease were ascertained until the end of 2009 (Cohort I) or 2012 (Cohort II). Sex-specific cardiovascular disease HRs (95% CIs) were estimated using Cox proportional hazard models after stratification by area and adjustment for cardiovascular disease risk and dietary factors. Results During 1,493,232 person-years of follow-up, 4777 strokes (2863 ischemic stroke, 1361 intraparenchymal hemorrhages, and 531 subarachnoid hemorrhages) and 1204 ischemic heart disease cases were identified. Among men, significant multivariable HRs (95% CIs) for almost daily consumption compared with almost no consumption of seaweed were seen in ischemic heart disease [0.76 (0.58, 0.99); P-trend = 0.04] and total cardiovascular diseases [0.88 (0.78, 1.00); P-trend = 0.08]. Among women, such inverse associations were 0.56 (0.36, 0.85; P-trend = 0.006) for ischemic heart disease and 0.89 (0.76, 1.05; P-trend = 0.10) for total cardiovascular diseases. No significant associations were observed between seaweed intake and risk of total stroke or stroke types among either men or women. Conclusions Seaweed intake was inversely associated with risk of ischemic heart disease.

Seaweeds contain minerals, vitamins, soluble dietary fibers, and flavonoids, which are regarded as preventive agents against lifestyle-related diseases. Seaweeds are consumed commonly in East Asian countries including Japan. Thus, intake of seaweeds might contribute to Japanese longevity via prevention of lifestyle-related diseases. Recently, 2 large Japanese cohort studies have reported the association of seaweed intake with reduced risk of cardiovascular diseases. On the other hand, seaweeds also contain iodine and heavy metals such as arsenic species, which are considered to have adverse effects on health. We here reviewed studies of the association between seaweed intake and mortality from or incidence of cancer and cardiovascular diseases, and their risk factors such as blood pressure or serum lipids. We also summarized the adverse effects of iodine and arsenic species in seaweeds. Although seaweeds have not been widely consumed in Western countries, dietary diversification and an increased proportion of immigrants from East Asia may increase seaweed consumption in those countries. Further epidemiological studies including observational and interventional studies are necessary to clarify the effects of seaweeds on disease and health.

Purpose We evaluated the association between total soy, soy product (natto, miso and tofu) and isoflavone intake and incident disabling dementia in a Japanese population. Methods We conducted a population-based prospective study in 18,991 men and 22,456 women. Intake of soy products and isoflavone was calculated using a validated food frequency questionnaire when participants were 45–74 years old (1995 and 1998). Incident disabling dementia was defined by the daily living disability status related to dementia in the long-term care insurance program of Japan from 2006 to 2016. Multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) of disabling dementia were calculated by quintiles of total soy, individual soy product and isoflavone intake, using Cox proportional hazard regression models. Results Total soy product intake was not associated with disabling dementia risk in both men and women. By individual soy products, natto intake was marginally inversely associated with disabling dementia in women (trend P = 0.050). When we stratified by age, this inverse association was clearer in women aged under 60 years (multivariate HR for the highest versus lowest quintile was 0.78, 95% CI 0.59–1.04, trend P = 0.020 for those aged under 60 years and 0.90, 95% CI 0.77–1.05, trend P = 0.23 for those aged 60 years and older, respectively). Any soy product or isoflavone intake was not associated with disabling dementia risk in men. Conclusions Although total soy product intake was not associated with disabling dementia risk, natto intake may contribute to reducing the risk of disabling dementia in women, especially in those aged under 60 years.

ongoing, long-term, prospective cohort study involving children born in 1989 within 87 communities of Ibaraki Prefecture, Japan. In 1992, we distributed a health questionnaire to parents who attended community-based health checkups for 3-year-old children. From a total of 10,526 children who had the checkups, questionnaires for 4,592 were returned by mail. We subsequently carried out followup surveys when they were 6 years old (2,141 subjects; follow-up rate, 46.6%) and 12 years old (2,375 subjects; follow-up rate, 51.7%) based on postal surveys sent to their parents. We included 822 boys and 668 girls who had completed 6-and 12-year-old questionnaires and provided valid information on eating habits, height and weight. Independently, some junior high schools carried out health checkups for 12 year olds; 25 municipal education boards permitted usage of the health checkup data for the present study (number of participants, 615). Additionally, in the survey at age 12, we asked parents for permission to obtain S peed eating is considered as a risk factor for the development of obesity, 1 but there is limited evidence in the literature with regards to children. 2 Furthermore, an associative link between habitual speed eating and subsequent effect on blood pressure (BP) is also scarce. In order to gain a greater understanding of this association in children, we conducted a long-term cohort study to examine the association between habitual speed eating at 6 years old and follow-up body mass index (BMI) as well as BP at 12 years old among Japanese children. Our hypothesis was that children who continued speed eating from 6 to 12 years old would have higher BMI and BP levels at 12 years old compared with slower eaters at either age. Methods Study SubjectsThe Ibaraki Children's Cohort (IBACHIL) Study is an Background: Habitual speed eating is a risk factor of obesity but evidence of this in children is limited. We examined the association between speed-eating habit and subsequent body mass index (BMI) and blood pressure (BP) among Japanese children. Methods and Results:The community-based study comprised 1,490 Japanese boys and girls who were born in 1989, involved in the Ibaraki Children's Cohort Study at age 3 years, and had returned questionnaires at both ages 6 and 12 years. In a subsample, we measured BP (n=263). Speed-eating habit was categorized into 4 groups: Never, Quit, Newly, and Continuous. Sex-specific mean values of questionnaire-based BMI and measured BPs at age 12 were examined according to speed-eating habit. Children with continuous speed eating had a higher BMI at age 12 than those who had never had a speed-eating habit (20.0 vs. 17.9 kg/m 2 for boys (P<0.001); 20.0 vs. 18.4 kg/m 2 (P<0.001) for girls). Systolic BP at age 12 was higher in boys with continuous speed eating than in those without (117 vs. 110 mmHg, P=0.01), but such a difference was not observed in girls (112 vs. 111 mmHg, P=0.95). Conclusions:Habitual speed eating was positively associated with subsequent BMI among boys and girls as well ...

We examine the validity and reproducibility of a food frequency questionnaire (FFQ) in a subsample of participants in the Japan Public Health Center-based Prospective Cohort Study using a database of polyphenol-containing foods commonly consumed in the Japanese population. Participants of the validation study were recruited from two different cohorts. In Cohort I, 215 participants completed a 28-d dietary record (DR) and the FFQ, and in Cohort II, 350 participants completed DRs and the FFQ. The total polyphenol intake estimated from the 28-d DR and FFQ were log-transformed and adjusted for energy intake by the residual method. Spearman correlation coefficients (CCs) between estimates from the FFQ and 28-d DR as well as two FFQs administered at a 1-year interval were computed. Median intakes of dietary polyphenols calculated from the DRs were 1172 mg/d for men and 1024 mg/d for women in Cohort I, and 1061 mg/d for men and 942 mg/d for women in Cohort II. The de-attenuated CCs for polyphenol intake between the DR and FFQ were 0⋅47 for men and 0⋅37 for women in Cohort I and 0⋅44 for men and 0⋅50 for women in Cohort II. Non-alcoholic beverages were the main contributor to total polyphenol intake in both men and women, accounting for 50 % of total polyphenol intake regardless of cohort and gender, followed by alcoholic beverages and seasoning and spices in men, and seasoning and spices, fruits and other vegetables in women. The present study showed that this FFQ had moderate validity and reproducibility and is suitable for use in future epidemiological studies.