Oxidized low-density lipoprotein (LDL) is considered to be an important risk factor in the atherogenic progression of coronary artery disease (CAD). The aims of our study were to evaluate the preventive effects of food factors on atherosclerotic diseases. In an in vitro study, we demonstrated that the catechin group as well as vitamin C or uric acid regenerated vitamin E from vitamin E radicals, and that the antioxidant activities of vegetables or soybeans depended on their polyphenol contents. Single-dose studies in healthy volunteers indicated inhibitory effects of chocolate or green tea against LDL oxidation ex vivo. We also demonstrated that daily consumption of green tea may have potent antiatherogenic effects such as anti-inflammatory actions, as well as antioxidant effects in vivo, and that green tea intake is inversely associated with the incidence of myocardial infarction in Japanese patients who undergo coronary angiography for suspected CAD. Green tea intake may be protective against MI, especially in patients with gene polymorphism related to the prevalence of CAD. These results suggest that ordinary intake of antioxidant foods may be useful for preventing atherosclerotic diseases.

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Glycolipids are widely distributed in nature. Although glycolipids are ingested daily in various foods, details of their intestinal absorption and nutritional function are unclear. We have developed optimal HPLC conditions for separation and quantification of glycolipids using an evaporative light-scattering detector. In animal studies, we found that completely deacylated galactosylglycerols are not absorbed or degraded in the intestine after oral administration of glyceroglycolipids. Moreover, dietary supplementation with plant glycolipids may help to improve the lower digestive tract environment. We also investigated the digestion and absorption of dietary sphingoglycolipids, and our results indicated that uptake of sphingosine is significantly higher than those of other sphingoid bases prepared from plant and yeast. P-glycoprotein (MDR1) in intestinal cells probably contributes to this selective absorption of sphingosine from dietary sphingolipids in the digestive tract. The apoptosis-inducing activity of various sphingoid bases was also confirmed. We demonstrated that formation of aberrant crypt foci induced by 1,2-dimethylhydrazine could be inhibited in the mouse large intestine by maize and yeast cerebrosides. These findings offer new insight into the nutritional function of dietary glycolipids.

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Basic principles of Japanese dietary reference intakes (DRIs) published in 2005 for saturated fatty acids are described in detail and evidence tables used for their establishment are presented. Increased intake of saturated fatty acids leads to increased incidences of obesity, diabetes, and myocardial infarction, whereas decreased intake leads to an increased incidence of brain (intraparenchymal) hemorrhage. Therefore, the tentative dietary goal (DG) for saturated fatty acids in individuals more than 18 years of age was set between 4.5% and 7% energy. Obesity due to increased intake of saturated fatty acids eventually causes diabetes, and an increase in saturated fatty acids leads to an increase in LDL-cholesterol concentration that eventually causes myocardial infarction. Many intervention studies have indicated that diets in which saturated fatty acids account for less than 10% energy (NCEP step I diet) or 7% energy (NCEP step II diet) effectively reduce LDL-cholesterol concentration and obesity. Large-scale observation studies have indicated that increased intake of saturated fatty acid or habits to eat more saturated fatty acids may lead to increased dose-dependent incidences of diabetes and myocardial infraction. Median intake of saturated fatty acids in Japanese more than 18 years of age in 2001 was 4.9-7.2% energy in males and 5.4-7.9% energy in females. Considering current saturated fatty acid intakes in Japanese and the dose-dependent effects of saturated fatty acids on the incidence of diabetes and myocardial infarction, the upper limit of saturated fatty acid intake was set at 7% energy. Observation studies targeting Japanese populations have indicated that a lower intake of saturated fatty acids increases the incidence of brain hemorrhage. One study has shown that middle-aged Japanese individuals who had a lower intake of saturated fatty acids had a dose-dependently increased incidence of intraparenchymal hemorrhage, after consideration of confounding factors such as blood pressure, BMI, blood cholesterol, smoking and alcohol consumption. In another study, Japanese living in Hawaii who ate less that 10 g/day saturated fatty acid had a 2-fold increased incidence of stroke. Considering these two studies, the lower intake limit for saturated fatty acids was set at 4.5% energy.

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The purpose of this study was to investigate the relationship between bone mass and lifestyle, physical fitness and body composition in 394 Japanese junior high school students of both genders. We measured transmission index (TI) and speed of sound (SOS) at the calcaneus using an AOS-100 instrument (ALOKA Co., Ltd., Tokyo). Osteo sono-assessment index (OSI) was calculated from the TI and the SOS, and used as an index of bone mass. OSI was found to increase with age, and there was no significant difference in OSI between the genders. Height, weight, BMI and lean body mass had a significant association with OSI in both males and females. There was no significant relationship between OSI and intake of calcium-rich foods. OSI was correlated with indicators of muscle strength (grip strength, standing broad jump, repetitive sideways jump) and endurance. Subjects, both male and female, who habitually exercised showed high OSI values. Female subjects after menarche had higher OSI values than those before menarche. In junior high school students, not only OSI but also height and weight increased. Furthermore height and weight have an effect on OSI. The present findings suggest that OSI is significantly related to habitual exercise and physical fitness. However, there is no significant relationship between OSI and dietary habits.

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