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The Role of Exercise and Nutrition for Obesity and Metabolic Syndrome
| Toshio Moritani Ph.D., FACSM |
| Graduate School of Human and Environmental Studies, Kyoto University | |
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Our daily energy intake per person reached the peak value of 2,226 Kcal at the year of 1975 and has dramatically dropped down to 1,902 Kcal at 2004 which is nearly identical to the value immediately after the World War II. Obese individuals have sharply increased despite of this dramatic decline in the energy intake. This may be the result of “relative energy surplus” caused by the declined energy expenditure far exceeding the decreased energy intake due to modern industrialization. Recent studies in exercise physiology and medicine have clearly established evidence that the so-called “Deadly Quartet” such as obesity, diabetes, hypertension, and hyperlipidemia depend not only on aging, but also on chronic physical inactivity and eating habit. Bray has proposed the MONA LISA hypothesis, an acronym for Most Obesities kNown Are Low In Sympathetic Activity indicating that obesity is associated with a relative or absolute reduction in the activity of the thermogenic component of the sympathetic nervous system. It is now well recognized that “middle age obesity” is strongly associated with the depressed autonomic nervous system (ANS) activity with aging, particularly the sympathetic thermogenic responses to a high-fat diet and irregular food intake pattern.
Our series of studies have suggested the potential reversibility in ANS activity regulating fat metabolism and appetite control function by regularly performed exercise training in the middle aged individuals and obese children with depressed ANS activity.
In other word a habitual exercise plays a vital role in enhancing not only the fat and glucose metabolism, but also the ANS activities for prevention of obesity and appetite control system. Recent studies have clearly indicated that obese individuals with exercise habits have a much lower mortality rate and incidence of diseases than lean individuals with little exercise due possibly to the effects of exercise on enhanced immune functions and myocytokines for prevention and improvement of lifestyle-related diseases. Finally, our recent studies on functional muscle electrical stimulation on glucose utilization during hyperinsulinemic euglycemic clamp will be discussed together with the most recent topics on brain derived neurotrophic factors.
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Nutritional approaches to optimizing physical performance
| Richard Gannon, Trent Stellingwerf and Elizabeth Offord Cavin |
| Nestlé Research Center, Dept of Nutrition and Health, Lausanne, Switzerland | |
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Performance can be defined as the way in which someone or something functions. Therefore, from growing children, to peak physical function in adults to ageing populations, optimizing physical performance throughout the lifespan is highly relevant. Accordingly, there is both published scientific data, and emerging hypotheses, showing the synergistic effects of nutrition with exercise on many functionally beneficial outcomes.
Optimal bone health is important for physical performance throughout life. This is especially true during early growth and development and again in later adulthood. In children, nutrition (especially optimal intakes of calcium and vitamin D) plays an important role in achievement of peak bone mass which, in turn, is critical for prevention of osteoporosis in later life. Indeed, calcium derived from milk has been shown to be particularly effective in improving bone mineral density of 7-8 year old girls. Physical activity is also an important modulator of bone mass accrual since the mechanical strain induced by weight-bearing exercise stimulates bone formation. Thus the combined effects of nutrition with exercise can lead to optimal bone mineral density from childhood into adulthood.
Active adults and athletes are in need of the right type of acute energy intakes to propel their daily lifestyles, as well as having optimal macronutrients to ensure they are getting the most adaptation out of their exercise. Recently, it has been shown that taking in a blend of carbohydrates (~60-80 g/hr of a 2:1 ratio of glucose: fructose) during exercise can result in a ~40% greater uptake and oxidation rate of the energy as compared to taking in the same amount of glucose alone. In a recent study in university students, this blend of carbohydrates was shown to improve cycling performance by 8%, as compared to the single CHO source of glucose.
Aging is an inevitable process that includes bone loss (risk of osteoporosis) and muscle wasting (sarcopenia). Nutrition and exercise both play a role in bone and muscle maintenance with age. For example, optimal dietary intakes of micronutrients adapted to the life stage (especially calcium and vitamin D but also vitamins C and K, magnesium and zinc) are important for bone maintenance from healthy adults through to the aging population. Current research is
investigating bioactive nutrients which can help to prevent bone loss with age through modulation of the bone formation and resorption processes .
The major cause of muscle wasting in elderly is that aging muscle becomes “anabolically resistant” to nutrients and exercise compared to young and healthy muscle. Therefore, the synergistic effects of exercise 'enhancing' the effectiveness of nutrition may be even more important in older populations than compared to the young. For example, it has been shown that taking as little as 6g of essential amino acids immediately before resistance (weight) training can result in 2.5 times greater muscle protein synthesis than when this nutrition is taken several hours after the exercise. Thus, the timing of nutrition in conjunction with exercise appears to be crucial in maximizing the benefits of nutrition. This is not only important in young and healthy populations looking to gain lean muscle mass, but also in elderly populations where the functional long-term benefits of muscle can impact the quality of life. These benefits can include such simple things as an elderly person being able to raise themselves out of a chair, or still having their independence to be able to go to the grocery store.
Taken together, there is a growing scientific body of evidence showing the positive effects which both nutrition and exercise can have on performance benefits in different populations. However, it remains to be clarified what is the most ideal macronutrient blend, feeding pattern, type of carbohydrate and/or protein (whole intact proteins vs. hydrolyzed) and the intake timing to optimize recovery and adaptation after different types of exercise stimuli and in differing populations throughout the lifespan.
In this presentation, we will review recent advances in the area of nutrition and physical performance, focusing on the effect of nutrients on bone and muscle metabolism and functional physiological outcomes throughout the lifespan. We will present results of research performed at the Nestlé Research Center and/or in collaboration with international experts in the field.
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Changes in energy metabolism during exercise and TGF-β in the brain
| Toru Fushiki |
Division of Food Science and Biotechnology
Graduate School of Agriculture, Kyoto University | |
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Exercise is a physiologic activity that precipitously and intensively consumes energy, and the development of food products for supplying energy and alleviating fatigue is generating great interest. Also, the feeling of fatigue after exercise is important as a fatigue model, and fatigue-relieving effects are drawing attention as a new functional indicator of food products.
Research has been conducted on energy substrates and body fluids given that changes in metabolic energy and fatigue caused by exercise are considered peripheral phenomena. For instance, the notion that energy sources during exercise will switch from carbohydrates to fats is one of the major postulates of exercise physiology, but no study has considered regulation of this phenomenon by the central nervous system. Lactate accumulation and oxygen supply are the major focus of studies on fatigue caused by exercise. While improvements through food products have been sought, the extent of such research has yet to include the central nervous system.
We have considered that the involvement of the central nervous system cannot be insignificant since energy metabolism and fatigue are crucial events related to sustaining life. World pioneering studies that demonstrate the involvement of the central nervous system have been presented by members of this society. Such studies include those by Shimazu and Saito demonstrating that satiety center stimulation in the hypothalamus promotes peripheral energy metabolism. We consider peripheral and central nerves to be involved in everything related to exercise in some capacity, and are integrated into a system that facilitates smooth functioning as a whole. We feel that the “fatigue and nutrition” field is important in this respect.
At this satellite symposium, we would like to demonstrate that the central nervous system is possibly coordinating physiologic activities such as exercise, energy metabolism, and fatigue. In particular, Inoue and colleagues, members of our laboratory, have found that TGF-β, a cytokine, is activated in the brain by analyzing cerebrospinal fluid of fatigued mice. Ishikawa and colleagues in the Inoue group found that administering a TGF-β-specific antibody into cerebrospinal fluid inhibits the promotion of lipid metabolism in rats during endurance exercises. Also, Shibakusa and colleagues reported that administration of TGF-β into the brain augments ketone body release from the rat liver by electrically stimulating the leg muscles of anesthetized rats.
These studies demonstrate that TGF-β, which is induced in the brain by exercise, promotes fat mobilization, and suggest that brain cytokines influence various physiological phenomena related to energy metabolism during exercise.
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