Quinoa seeds (Chenopodium quinoa Willd.) were mechanically fractionated to pericarps and dehulled seeds using a rice pearling mill. The dehulled seeds were further fractionated to perisperms and embryos, based on the histology of the seeds, using a barley pearling mill. The recoveries of pericarps and dehulled seeds, were 7.9 and 92.1%, and those of embryos and perisperms 23.2, and 68.9%, respectively. These fractions were examined by electron microscopy, and their nutritional compositions were measured. Compared with other tissues, the embryos have higher protein, fat, crude fiber, and dietary fiber contents. The pericarps contained 67.6% of the total saponin content in the whole grain. Phytic acid content in the perisperm was also higher than those in the embryos and perisperms, and represented 60.1% of the total phytic acid content. Among the tissues examined, the perisperms had the highest carbohydrate content (79.7g/100g), while the embryo had the lowest at 32.0%. Thus, pericarp, embryo, and perisperm fractions can be used as new food ingredients based on their chemical compositions.

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The twenty-four-hour energy expenditure (24h-EE) of 41 adults (21 males and 20 females) in sedentary life with light exercises was measured using a whole-body indirect human calorimeter at the National Institute of Health and Nutrition. In a chamber, the subjects were asked not to perform strenuous exercise except for the following prescribed activities, four times of 15-min cycling, four times of 15-min standing, and 15min of stepping. Basal metabolic rate (BMR) was measured in the postabsorptive state. The means and SDs of the measured BMR and 24h-EE were 1, 376±297 kcal and 2, 064±373kcal, respectively. The physical activity level (PAL) calculated as 24h-EE divided by BMR was 1.51±0.12, and the estimated PAL without the prescribed exercises was 1.38±0.12. The mean sleeping metabolic rate (mean energy expenditure for an overnight period)/BMR ratio was 1.03±0.08. These results indicate that the PAL values are higher than those assumed previously.

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The purpose of this study was to investigate the effects of calcium (Ca) supplementation and prolonged exercise on bone strength and the mitochondrial volume density (MVD) of skeletal muscle fibers in young-adult rats. Thirty-six female rats were divided into three calcium-altered groups (low, 0.02%-LCa; medium, 0.74%-MCa; high, 2.24% wt/wt-HCa), which were further subdivided into the no-exercise (NEx) and exercise (Ex) groups. The Ex groups performed running exercise at a speed of 10m/min for 90-180min/ day, for six weeks. Bone strength in the LCa groups significantly decreased by 16.3-23.4% compared with the MCa groups. However, the rate of reduction in bone strength increased by 43.3% in response to running exercise without any decrease in serum Ca²⁺ concentration compared with the reduction rate between the NEx groups (LCa-NEx vs MCa-NEx) and the Ex groups (LCa-Ex vs MCa-Ex). Exercise training induced a significant increase in MVD in the soleus muscle cells of all Ex groups. The MVDs of both the slow-twitch oxidative and fast-twitch oxidative glycolytic fibers in the soleus muscle of the NEx groups were not influenced by dietary calcium content, but MVD for the Ex groups further increased significantly with increasing dietary calcium content (HCa>MCa>LCa). These results suggest that a low-calcium diet impairs metabolism in both skeletal muscle and bone tissues. The HCa diet along with exercise training further upregulated skeletal muscle and bone metabolism, whereas the LCa diet inhibited it to induce a training effect.

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Currently Japan is in the midst of satiation, under which condition, together with genetic predisposition, problems of obesity and related adult diseases will arise unless proper care is taken to positively expedite energy expenditure. In this article, the author reviews the present understanding of the mechanism of energy expenditure and its practical application in humans as well as in animals, focusing on the following four lines of evidence including his own results: (1) the importance of the sympathetic nervous system in controlling energy expenditure of the body, particulaly of the slow-twitch oxidative fibers of skeletal muscles, (2) the function and physiological roles of the mitochondrial uncoupling-protein family (UCP-1-3) in heat-producing organs, particularly in brown adipose tissues, (3) the central effects of leptin and its novel signaling pathway on the glucose and fatty acid metabolism in skeletal muscles, the major working organ involved in the resting-energy metabolism, and (4) an exploratory investigation on the effective components of flavor or spices such as zingerone that stimulate oxygen consumption and decrease respiratory quotient.

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Recently, great advances have been made in both the basic pathophysiology and clinical management of osteoporosis. Osteoporosis is caused by an imbalance between osteoclastic bone resorption and osteoblastic bone formation. Osteoblasts, arising from mesenchymal stem cell, form bones and regulate osteoclast formation. Osteoclasts are derived from hematopoietic stem cells. Bone-resorbing molecules act on osteoblasts to induce RANKL (receptor activator of NF-κB ligand) on the osteoblast surface. RANKL, in turn, binds to its receptor RANK on an osteoclast precursor to enhance osteoclast differentiation. Osteoporosis most often affects postmenopausal women. Estrogen deficiency induces enhanced bone resorption, which is mainly due to the action of bone-resorbing cytokines, such as IL-1, IL-6 and TNF-α. Nutritional factors also contribute to the development of osteoporosis. The deficiency in calcium and vitamin D leads to secondary hyperparathyroidism and enhanced bone resorption. Recently, vitamin K deficiency and vitamin A excess are known to be the risk factors for osteoporotic fracture. For the past several years, many large-scale clinical trials have revealed that potent antiresorptive drugs such as bisphosphonates significantly increase bone mineral density and markedly decrease the incidence of fragility fracture. Based on these advances, the osteoporosis from the viewpont of nutrition should be explored in more detail.

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