Hidemi Todoriki

Caloric Restriction, the Traditional Okinawan Diet, and Healthy Aging The Diet of the World's Longest-Lived People and Its Potential Impact on Morbidity and Life Span

Abstract:  Long‐term caloric restriction (CR) is a robust means of reducing age‐related diseases and extending life span in multiple species, but the effects in humans are unknown. The low caloric intake, long life expectancy, and the high prevalence of centenarians in Okinawa have been used as an argument to support the CR hypothesis in humans. However, no long‐term, epidemiologic analysis has been conducted on traditional dietary patterns, energy balance, and potential CR phenotypes for the specific cohort of Okinawans who are purported to have had a calorically restricted diet. Nor has this cohorts subsequent mortality experience been rigorously studied. Therefore, we investigated six decades of archived population data on the elderly cohort of Okinawans (aged 65‐plus) for evidence of CR. Analyses included traditional diet composition, energy intake, energy expenditure, anthropometry, plasma DHEA, mortality from age‐related diseases, and current survival patterns. Findings include low caloric intake and negative energy balance at younger ages, little weight gain with age, life‐long low BMI, relatively high plasma DHEA levels at older ages, low risk for mortality from age‐related diseases, and survival patterns consistent with extended mean and maximum life span. This study lends epidemiologic support for phenotypic benefits of CR in humans and is consistent with the well‐known literature on animals with regard to CR phenotypes and healthy aging.

The Okinawan Diet: Health Implications of a Low-Calorie, Nutrient-Dense, Antioxidant-Rich Dietary Pattern Low in Glycemic Load

Residents of Okinawa, the southernmost prefecture of Japan, are known for their long average life expectancy, high numbers of centenarians, and accompanying low risk of age-associated diseases. Much of the longevity advantage in Okinawa is thought to be related to a healthy lifestyle, particularly the traditional diet, which is low in calories yet nutritionally dense, especially with regard to phytonutrients in the form of antioxidants and flavonoids. Research suggests that diets associated with a reduced risk of chronic diseases are similar to the traditional Okinawan diet, that is, vegetable and fruit heavy (therefore phytonutrient and antioxidant rich) but reduced in meat, refined grains, saturated fat, sugar, salt, and full-fat dairy products. Many of the characteristics of the diet in Okinawa are shared with other healthy dietary patterns, such as the traditional Mediterranean diet or the modern DASH (Dietary Approaches to Stop Hypertension) diet. Features such as the low levels of saturated fat, high antioxidant intake, and low glycemic load in these diets are likely contributing to a decreased risk for cardiovascular disease, some cancers, and other chronic diseases through multiple mechanisms, including reduced oxidative stress. A comparison of the nutrient profiles of the three dietary patterns shows that the traditional Okinawan diet is the lowest in fat intake, particularly in terms of saturated fat, and highest in carbohydrate intake, in keeping with the very high intake of antioxidant-rich yet calorie-poor orange-yellow root vegetables, such as sweet potatoes, and green leafy vegetables. Deeper analyses of the individual components of the Okinawan diet reveal that many of the traditional foods, herbs, or spices consumed on a regular basis could be labeled “functional foods” and, indeed, are currently being explored for their potential health-enhancing properties.

Caloric restriction and human longevity: what can we learn from the Okinawans?

Caloric (or dietary) restriction (CR) extends lifespan and lowers risk for age associated diseases in a phylogenetically diverse group of species. Whether prolonged CR increases average or maximum lifespan or promotes a more youthful physiology in humans at advanced ages is not yet known. However, available epidemiological evidence indicates that CR may already have contributed to an extension of average and maximum life span in one human population and appears to have lowered risk for age associated chronic diseases in other human populations. We review the human studies in the context of a special human population, older Okinawans, who appear to have undergone a mild form of prolonged CR for about half their adult lives.

High-performance liquid chromatographic determination of α-keto acids in human urine and plasma

A high-performance liquid chromatographic method has been developed for the determination of α-keto acids in human urine and plasma. These acids were prepurified using a column of hydrazide gel and derivatized with o-phenylenediamine into 2-quinoxalinol derivatives, which were extracted into ethyl acetate. The 2-quinoxialinol derivatives were separated by reversed-phase paired-ion chromatography using a 250 × 4 mm-i.d. column packed with LiChrosorb RP-8 (5 μm). This method is sensitive, selective, and reproducible. The α-keto acids in urine and plasma from normal individuals were determined.

Effect of Dietary Vitamin E Supplementation on Murine Nasal Allergy

BACKGROUND Although many studies have reported the effects of dietary vitamin E on the immune response, none so far has assessed its role in nasal allergy. METHODS Female BALB/c mice were randomized into two groups and fed a 20% casein diet (control group, 50 mg vitamin E/kg diet) or this diet supplemented with 535 mg vitamin E/kg diet (vitamin E group, 585 mg vitamin E/kg diet) for 4 weeks. During the fifth week, the mice in each group were divided into two subgroups to form a total of four treatment groups: group A (control), group B [control + toluene diisocyanate (TDI) sensitization], group C (vitamin E supplementation), and group D (vitamin E supplementation + TDI sensitization). Groups B and D were treated with two courses of intranasal application of 5% TDI in ethyl acetate, whereas groups A and C were treated with ethyl acetate alone. A week after second sensitization all groups were provoked by applying 2.5% of TDI in the vehicle and nasal allergic responses were observed for 10 minutes. Splenic lymphoproliferation, splenic cell cytokines, and the total serum IgE were measured. RESULTS Members of group D had lower (P < 0.01) scores of nasal response and sneezed less frequently (P < 0.01) than those of group B. Similarly, splenic lymphoproliferation and production of IL-4 and IL-5 as well as the total serum IgE levels were lower (P < 0.01) in group D than in group B. CONCLUSIONS The results indicate that higher doses of vitamin E supplementation may suppress nasal allergic responses.

Dietary intervention with Okinawan vegetables increased circulating endothelial progenitor cells in healthy young women

OBJECTIVE Circulating endothelial progenitor cells (EPCs) play a critical role in maintaining the integrity of vascular vessels. The number of EPCs inversely correlates with the number of atherosclerotic risk factors. Although nonpharmacological treatment represents the first approach to the primary prevention of atherosclerotic diseases, little is known about the effects of diet on EPCs. We investigated the effect of a dietary intervention with vegetables that are commonly eaten in Okinawa on the number of EPCs. METHODS AND RESULTS Forty-five healthy young women were employed and randomized to a dietary intervention group (n=24) or a control group (n=21). Subjects in the intervention group received typical Okinawan vegetables through home-parcel delivery for 2 weeks. After the dietary intervention, urinary potassium and magnesium excretion increased only in the intervention group and changes were greater than in the control group (p=0.007, 0.010, respectively). The consumption of total vegetables correlated with changes in both urinary potassium and magnesium excretion. Serum folic acid increased and plasma homocysteine decreased in both groups but the change was significant only in the intervention group. The EPCs number significantly increased in the intervention group but did not in the control group. An inverse correlation was observed between EPC number and plasma homocysteine level (r=-0.272, p=0.016). Changes in the EPC number inversely correlated with changes in both serum total cholesterol and low-density lipoprotein cholesterol level (r=-0.555, p=0.0002; r=-0.626, p<0.0001, respectively). CONCLUSIONS The consumption of vegetables increased the number of circulating EPCs; this change might be associated with a homocysteine-lowering effect.

Estimation of caffeine intake in Japanese adults using 16 d weighed diet records based on a food composition database newly developed for Japanese populations

OBJECTIVE Previous studies in Western populations have linked caffeine intake with health status. While detailed dietary assessment studies in these populations have shown that the main contributors to caffeine intake are coffee and tea, the wide consumption of Japanese and Chinese teas in Japan suggests that sources of intake in Japan may differ from those in Western populations. Among these teas, moreover, caffeine content varies widely among the different forms consumed (brewed, canned or bottled), suggesting the need for detailed dietary assessment in estimating intake in Japanese populations. Here, because a caffeine composition database or data obtained from detailed dietary assessment have not been available, we developed a database for caffeine content in Japanese foods and beverages, and then used it to estimate intake in a Japanese population. DESIGN The caffeine food composition database was developed using analytic values from the literature, 16 d weighed diet records were collected, and caffeine intake was estimated from the 16 d weighed diet records. SETTING Four areas in Japan, Osaka (Osaka City), Okinawa (Ginowan City), Nagano (Matsumoto City) and Tottori (Kurayoshi City), between November 2002 and September 2003. SUBJECTS Two hundred and thirty Japanese adults aged 30-69 years. RESULTS Mean caffeine intake was 256.2 mg/d for women and 268.3 mg/d for men. The major contributors to intake were Japanese and Chinese teas and coffee (47 % each). Caffeine intake above 400 mg/d, suggested in reviews to possibly have negative health effects, was seen in 11 % of women and 15 % of men. CONCLUSIONS In this Japanese population, caffeine intake was comparable to the estimated values reported in Western populations.

Potassium excretion in healthy Japanese women was increased by a dietary intervention utilizing home-parcel delivery of Okinawan vegetables.

Potassium, which is abundant in vegetables, is inversely related to blood pressure. Although the situation has changed somewhat in recent years, the Okinawan diet has generally included a large amount of vegetables, and until recently Okinawans had the lowest rates of mortality due to stroke and coronary heart disease in Japan. Based on the hypothesis that these low mortality rates are partly attributable to increased potassium intake resulting from the high vegetable consumption, this study examined whether increasing the consumption of typical yellow-green Okinawan vegetables increases potassium intake. The purpose of this investigation was to determine whether increased consumption of these vegetables should be one of the dietary modifications recommended in public health promotion programs for Okinawans. The study employed 56 healthy, normotensive, free-living Japanese women aged 18–38 years living in Okinawa. They were randomized to a dietary intervention group (n=27) or a control group (n=29). Members of the dietary intervention group received an average weight of 371.4 g/day of a combination of the following vegetables twice weekly through an express home parcel deliver service for a period of 14 days: Goya (Momordica charantia), green papaya (Carica papaya), Handama (Gynura bicolor), Karashina (Brassica juncea), Njana (Crepidiastrum lanceolatium), Fuchiba (Artemisia vulgaris) and Fudanso (Beta vulgaris); and they consumed an average of 144.9 g/day, resulting in a 20.5% increase in their urinary potassium excretion over the baseline (p=0.045). The members of the control group were asked to avoid these vegetables, and the change in potassium excretion in this group was not significant (p=0.595). Urinary sodium and magnesium excretions, systolic and diastolic blood pressures, folic acid, triglycerides and serum high density lipoprotein cholesterol, low density lipoprotein cholesterol and total cholesterols changed non-significantly in both groups. Also, post-intervention urinary potassium excretion correlated positively with vegetable consumption in both the dietary intervention (p<0.0001) and control (p=0.008) groups and with Okinawan vegetable intake in the dietary intervention group (p=0.0004).

Estimation of Trans Fatty Acid Intake in Japanese Adults Using 16-Day Diet Records Based on a Food Composition Database Developed for the Japanese Population

Background The Standard Tables of Food Composition in Japan do not include information on trans fatty acids. Previous studies estimating trans fatty acid intake among Japanese have limitations regarding the databases utilized and diet assessment methodologies. We developed a comprehensive database of trans fatty acid food composition, and used this database to estimate intake among a Japanese population. Methods The database was developed using analytic values from the literature and nutrient analysis software encompassing foods in the US, as well as values estimated from recipes or nutrient compositions. We collected 16-day diet records from 225 adults aged 30 to 69 years living in 4 areas of Japan. Trans fatty acid intake was estimated based on the database and the 16-day diet records. Results Mean total fat and trans fatty acid intake was 56.9 g/day (27.7% total energy) and 1.7 g/day (0.8% total energy), respectively, for women and 66.8 g/day (25.5% total energy) and 1.7 g/day (0.7% total energy) for men. Trans fatty acid intake accounted for greater than 1% of total energy intake, which is the maximum recommended according to the World Health Organization, in 24.4% of women and 5.7% of men, and was particularly high among women living in urban areas and those aged 30–49 years. The largest contributors to trans fatty acid intake were confectionaries in women and fats and oils in men. Conclusions Although mean trans fatty acid intake was below the maximum recommended intake of the World Health Organization, intake among subgroups was of concern. Further public health efforts to reduce trans fatty acid intake should be encouraged.

Within- and Between-Individual Variation in Energy and Nutrient Intake in Japanese Adults: Effect of Age and Sex Differences on Group Size and Number of Records Required for Adequate Dietary Assessment

Background Information on within- and between-individual variation in energy and nutrient intake is critical for precisely estimating usual dietary intake; however, data from Japanese populations are limited. Methods We used dietary records to examine within- and between-individual variation by age and sex in the intake of energy and 31 selected nutrients among Japanese adults. We also calculated the group size required to estimate mean intake for a group and number of days required both to rank individuals within a group and to assess an individual’s usual intake, all with appropriate arbitrary precision. A group of Japanese women (younger: 30–49 years, n = 58; older: 50–69 years, n = 63) and men (younger: 30–49 years, n = 54; older: 50–76 years, n = 67) completed dietary records for 4 nonconsecutive days in each season (16 days in total). Results Coefficients of within-individual variation and between-individual variation were generally larger in the younger group than in the older group and in men as compared with women. The group size required to estimate a group’s mean intake, and number of days required to assess an individual’s usual intake, were generally larger for the younger group and for men. In general, a longer period was required to rank women and older adults. Conclusions In a group of Japanese adults, coefficients of within-individual variation and between-individual variation, which were used to estimate the group size and number of records required for adequate dietary assessment, differed by age, sex, and nutrient.