14 years ago
Thursday, June 25, 2009
discus the diet and exercise on longevity
Discus the impact of diet and exercise on longevity
Longevity, Latin longaevitas refers to living longer than average. Those people who have achieved a great duration of life are considered to have longevity. Maximum life span of any individual is determined by genes and environmental factors. Greater life span can be achieved throught good diet and exercise and avoidance of hazardous chemicals such as in tobacco. Healthy diet and exercise can prolong life and prevent many age – related diseases. This essay reviews data supporting the benefits of diet and exercise to longevity and potential risks. It also presents researchers’ findings about possible clues to how diet and exercise contribute to longevity.
Human life span has changed in recent years. Human life expectancy rates have increased to 75 years for men and 80 years for women in most developed countries, mainly due to improved sanitation, hygiene, improvement in medicine and better health care system (Fontana & Klein 2007, pp.1-2).
Aging is accompanied by an accumulation of oxidative stress, lower insulin sensitivity, DNA damage, decline in immune function and deterioration of structure and function of cell in all tissues and organs (Fontana & Klein 2007, p. 2). With increase in human life span, there is need to find effective ways to reduce age related diseases and improve quality of life in later years (Roberts & Schoeller 2007p.1).
Calorie Restriction (CR) has been the only proven method that increases maximum lifespan in most animals and it slows progression of many age related diseases (Roberts & Schoeller 2007).Calorie Restriction consists of limiting calorie intake while still maintaining nutritional value of food.
Many studies on rodents and primates yield the benefits of CR.A Calorie Restriction diet has benefits to the body’s immune function, improves insulin sensitivity and reduces oxidative stress (Roberts & Schoeller 2007, p. 2). CR extends life span in rats and mice (Holloszy 1997; Weindruch , Walford & Guthrie 1985).CR may slow some age related diseases such as cardiovascular diseases and diabetes(Lane et al.2001, p.1). Monkeys on caloric restriction diet exhibited better glucose tolerance and insulin sensitivity, lower body temperature, reduced cholesterol and blood pressure (Lane et al. 1999, p. 1; Roth et al. 2000, p.1; Wanagat et al. 1999, p.1). It is believed that oxidative damage to DNA accumulates with aging. CR diet lowered oxidative damage in skeletal muscles of rhesus monkeys (Zainal et al. 2000, p.1).
Though the studies on animals confirm the benefits of CR towards longevity, whether CR can slow down aging processes in humans is unknown, because it would be impossible to apply calorie restriction diet experimentally over the human life (Lee et al. 2001, p.2).However, epidemiological data studies show that CR can have benefits against many age related diseases. For instance, Okinawa Island residents that followed 30 per cent calorie restriction diet had 35 per cent reduced rate of cardiovascular diseases and cancer mortality then other Japanese residents (Fontana & Klein 2007, p. 4). Also, data from the Calorie Restriction Society, a group of people who practice 30 per cent calorie restriction diet in belief that would prolong their longevity, showed improvements in blood pressure, increased insulin sensitivity, improved lipid profile and other improvements in organs function similar to those reported in animals studies (Fontana & Klein 2007, p.4). Similarly, short term studies on humans show great benefits of CR in reduction of body fat in obese people and improvements in blood pressure, lipids and glucose tolerance as well as reduction in risks of developing chronic diseases (Lee et al. 2001, p. 2). Six months Calorie Restriction diet has reduced fasting insulin level and body temperature (biomarkers of longevity) in overweight people (Heilbronn et al.2006, p.1). In addition, participants in Biosphere 2 study had significant changes in body weight, improvements in blood pressure, total serum cholesterol, and fasting glucose after six months of consuming low-fat, low–calorie nutritious diet (Walford,Harris & Gunion 1992, p.1).
One phenotype of CR studied on animals, not gaining weight after early adulthood, excluding pregnancy, is associated with greater longevity in humans, too. There are also reports that occasional dieting has benefits to longevity. The Aerobics Centre Longitudinal Study show that those who reported dieting sometimes in their life had greater life span then those who never dieted , according to follow up data(Lee et al. 2001, p.4). However this study does not apply to those with long term weight stability due to balanced diet.
Long term CR may be feasible especially for lean people due to a low body fat content and to those whose dietary intake is already balanced (Fontana & Klein 2007, p.1). According to a CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy) clinical trial, long term CR could cause mental stress for being hungry all the time and exercise may became impossible due to the lack of energy. Participants of this trial experienced hunger and constipation as well as muscle soreness and joint pain induced by exercising (Racette et al. 2006, p.5). Severe caloric restriction could cause anaemia and anorexia and if prolonged result in high death risk. Caloric Restriction diet may add up to longevity but is certainly not suitable for everyone and is not the one without sacrifice.
Exercise has received less attention in extending maximum life span, in studies on rats. Exercise increased longevity in young rats, but decreased survival time in older rat. This study suggests that there may be a threshold age when exercise does not have benefits in terms of survival (Charles et al. 1983, p.1).However, in humans; the benefits of exercises are overwhelming. Exercise training can improve cardiovascular health as a result of increased oxygen capacity. According to DR. Ken Cooper ( Hempel 1994,p. 1) exercise training had significant effects in reduction of heart attacks among males and females who participated in Cooper Institute of Aerobic Research (Hempel 1994, p.1). Furthermore resistance training has effects in maintenance of strength, muscle mass, bone mineral density and it can prevent and treat musculoskeletal problems such as low back pain (Fletcher et al. 1996,p.3).Moreover exercise can improve balance which is of the particular benefit to elderly people ,since incidence of hip fracture is associated with high death rate (Hempel 1994, p.2).
Exercise can be beneficial for brain function and therefore have importance on the rate of aging (Samorajski et al. 2009, p.1). Reduced mitochondrial function and insulin sensitivity have been associated with aging. Endurance exercises are beneficial in combating age-related mitochondrial dysfunction (Lanza & Nair 2009,p.1). Exercises also normalise blood pressure, stabilise blood insulin level and minimise the risks for coronary artery diseases (Gerald et al. 1996, p. 2, parra.3).
Chronic diseases and cancer are the leading killers of Western society. Diets high in fat and inactivity have been linked with many chronic diseases (Barnard 2004, p.1). On the other hand, healthy diet reach in whole grains, fruits, vegetables, omega 3 and low in fat, with moderate physical activity can prevent many diseases (Roberts & Barnard 2005, p.4). A high fat diet and inactivity have been linked with higher production of oxidative stress closely related to hypertension (Roberts et al. 2002, p. 2).Pitikin Longevity Centre 21-day study demonstrates that high-fibre whole grain diet reach in anti-oxidants and exercise reduce oxidative stress and normalise blood pressure in obese men in as little as 3 weeks (Roberts et al. 2002, pp. 3-4). Diets low in fat can lower cholesterol level and improve insulin sensitivity (Roberts & Barnard 2005, p.5). Weight loss achieved through diet and exercise in obese people improved blood pressure, lipid profile and glucose tolerance (Lee et al. 2001, p.6).Elevated levels of insulin stimulates tumour cell growth and this may cause cancer. Diets high in whole grain, fruits and vegetables and rich in antioxidants combined with regular exercises can prevent many forms of cancer (Barnard 2004, p. 3), and contribute to longevity.
According to Howard Hughes Medicine Institute research (2007 p. 1), ‘diet, exercise and weight control – extends life by signalling through a specific pathway in the brain’. They discovered links with insulin –like pathways and longevity. This pathway is activated in connection with proteins inside the cell called insulin receptor substrates (Irs). When one of the insulin receptor substrates Irs2 gene is stoped in mice it can prolong their life by 18 per cent. Beside, mice with inhibited Irs2 became more active as they aged and had better brain ability to fight free radicals. In a similar way, diet and exercise regulate the insulin levels that reach the brain. Insulin activates Irs2 .Less insulin in the brain means lower Irs2 activity, spontaneously contributing to longer lifespan.
In conclusion, calorie restriction diet has been the only proven dietary method that can slow down aging and prolong life in animal studies. Whether CR can have same effects on humans is unknown, however many studies suggest similar benefits. CR may not be of any benefit to individuals who already eat a balanced diet. Severe caloric restriction can be dangerous. Exercise has many benefits especially on cardiovascular health and in preventing many age related diseases. Healthy diet and physical activity play an important role in promoting vitality and preventing many diseases, thereby contributing to longevity.
Longevity, Latin longaevitas refers to living longer than average. Those people who have achieved a great duration of life are considered to have longevity. Maximum life span of any individual is determined by genes and environmental factors. Greater life span can be achieved throught good diet and exercise and avoidance of hazardous chemicals such as in tobacco. Healthy diet and exercise can prolong life and prevent many age – related diseases. This essay reviews data supporting the benefits of diet and exercise to longevity and potential risks. It also presents researchers’ findings about possible clues to how diet and exercise contribute to longevity.
Human life span has changed in recent years. Human life expectancy rates have increased to 75 years for men and 80 years for women in most developed countries, mainly due to improved sanitation, hygiene, improvement in medicine and better health care system (Fontana & Klein 2007, pp.1-2).
Aging is accompanied by an accumulation of oxidative stress, lower insulin sensitivity, DNA damage, decline in immune function and deterioration of structure and function of cell in all tissues and organs (Fontana & Klein 2007, p. 2). With increase in human life span, there is need to find effective ways to reduce age related diseases and improve quality of life in later years (Roberts & Schoeller 2007p.1).
Calorie Restriction (CR) has been the only proven method that increases maximum lifespan in most animals and it slows progression of many age related diseases (Roberts & Schoeller 2007).Calorie Restriction consists of limiting calorie intake while still maintaining nutritional value of food.
Many studies on rodents and primates yield the benefits of CR.A Calorie Restriction diet has benefits to the body’s immune function, improves insulin sensitivity and reduces oxidative stress (Roberts & Schoeller 2007, p. 2). CR extends life span in rats and mice (Holloszy 1997; Weindruch , Walford & Guthrie 1985).CR may slow some age related diseases such as cardiovascular diseases and diabetes(Lane et al.2001, p.1). Monkeys on caloric restriction diet exhibited better glucose tolerance and insulin sensitivity, lower body temperature, reduced cholesterol and blood pressure (Lane et al. 1999, p. 1; Roth et al. 2000, p.1; Wanagat et al. 1999, p.1). It is believed that oxidative damage to DNA accumulates with aging. CR diet lowered oxidative damage in skeletal muscles of rhesus monkeys (Zainal et al. 2000, p.1).
Though the studies on animals confirm the benefits of CR towards longevity, whether CR can slow down aging processes in humans is unknown, because it would be impossible to apply calorie restriction diet experimentally over the human life (Lee et al. 2001, p.2).However, epidemiological data studies show that CR can have benefits against many age related diseases. For instance, Okinawa Island residents that followed 30 per cent calorie restriction diet had 35 per cent reduced rate of cardiovascular diseases and cancer mortality then other Japanese residents (Fontana & Klein 2007, p. 4). Also, data from the Calorie Restriction Society, a group of people who practice 30 per cent calorie restriction diet in belief that would prolong their longevity, showed improvements in blood pressure, increased insulin sensitivity, improved lipid profile and other improvements in organs function similar to those reported in animals studies (Fontana & Klein 2007, p.4). Similarly, short term studies on humans show great benefits of CR in reduction of body fat in obese people and improvements in blood pressure, lipids and glucose tolerance as well as reduction in risks of developing chronic diseases (Lee et al. 2001, p. 2). Six months Calorie Restriction diet has reduced fasting insulin level and body temperature (biomarkers of longevity) in overweight people (Heilbronn et al.2006, p.1). In addition, participants in Biosphere 2 study had significant changes in body weight, improvements in blood pressure, total serum cholesterol, and fasting glucose after six months of consuming low-fat, low–calorie nutritious diet (Walford,Harris & Gunion 1992, p.1).
One phenotype of CR studied on animals, not gaining weight after early adulthood, excluding pregnancy, is associated with greater longevity in humans, too. There are also reports that occasional dieting has benefits to longevity. The Aerobics Centre Longitudinal Study show that those who reported dieting sometimes in their life had greater life span then those who never dieted , according to follow up data(Lee et al. 2001, p.4). However this study does not apply to those with long term weight stability due to balanced diet.
Long term CR may be feasible especially for lean people due to a low body fat content and to those whose dietary intake is already balanced (Fontana & Klein 2007, p.1). According to a CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy) clinical trial, long term CR could cause mental stress for being hungry all the time and exercise may became impossible due to the lack of energy. Participants of this trial experienced hunger and constipation as well as muscle soreness and joint pain induced by exercising (Racette et al. 2006, p.5). Severe caloric restriction could cause anaemia and anorexia and if prolonged result in high death risk. Caloric Restriction diet may add up to longevity but is certainly not suitable for everyone and is not the one without sacrifice.
Exercise has received less attention in extending maximum life span, in studies on rats. Exercise increased longevity in young rats, but decreased survival time in older rat. This study suggests that there may be a threshold age when exercise does not have benefits in terms of survival (Charles et al. 1983, p.1).However, in humans; the benefits of exercises are overwhelming. Exercise training can improve cardiovascular health as a result of increased oxygen capacity. According to DR. Ken Cooper ( Hempel 1994,p. 1) exercise training had significant effects in reduction of heart attacks among males and females who participated in Cooper Institute of Aerobic Research (Hempel 1994, p.1). Furthermore resistance training has effects in maintenance of strength, muscle mass, bone mineral density and it can prevent and treat musculoskeletal problems such as low back pain (Fletcher et al. 1996,p.3).Moreover exercise can improve balance which is of the particular benefit to elderly people ,since incidence of hip fracture is associated with high death rate (Hempel 1994, p.2).
Exercise can be beneficial for brain function and therefore have importance on the rate of aging (Samorajski et al. 2009, p.1). Reduced mitochondrial function and insulin sensitivity have been associated with aging. Endurance exercises are beneficial in combating age-related mitochondrial dysfunction (Lanza & Nair 2009,p.1). Exercises also normalise blood pressure, stabilise blood insulin level and minimise the risks for coronary artery diseases (Gerald et al. 1996, p. 2, parra.3).
Chronic diseases and cancer are the leading killers of Western society. Diets high in fat and inactivity have been linked with many chronic diseases (Barnard 2004, p.1). On the other hand, healthy diet reach in whole grains, fruits, vegetables, omega 3 and low in fat, with moderate physical activity can prevent many diseases (Roberts & Barnard 2005, p.4). A high fat diet and inactivity have been linked with higher production of oxidative stress closely related to hypertension (Roberts et al. 2002, p. 2).Pitikin Longevity Centre 21-day study demonstrates that high-fibre whole grain diet reach in anti-oxidants and exercise reduce oxidative stress and normalise blood pressure in obese men in as little as 3 weeks (Roberts et al. 2002, pp. 3-4). Diets low in fat can lower cholesterol level and improve insulin sensitivity (Roberts & Barnard 2005, p.5). Weight loss achieved through diet and exercise in obese people improved blood pressure, lipid profile and glucose tolerance (Lee et al. 2001, p.6).Elevated levels of insulin stimulates tumour cell growth and this may cause cancer. Diets high in whole grain, fruits and vegetables and rich in antioxidants combined with regular exercises can prevent many forms of cancer (Barnard 2004, p. 3), and contribute to longevity.
According to Howard Hughes Medicine Institute research (2007 p. 1), ‘diet, exercise and weight control – extends life by signalling through a specific pathway in the brain’. They discovered links with insulin –like pathways and longevity. This pathway is activated in connection with proteins inside the cell called insulin receptor substrates (Irs). When one of the insulin receptor substrates Irs2 gene is stoped in mice it can prolong their life by 18 per cent. Beside, mice with inhibited Irs2 became more active as they aged and had better brain ability to fight free radicals. In a similar way, diet and exercise regulate the insulin levels that reach the brain. Insulin activates Irs2 .Less insulin in the brain means lower Irs2 activity, spontaneously contributing to longer lifespan.
In conclusion, calorie restriction diet has been the only proven dietary method that can slow down aging and prolong life in animal studies. Whether CR can have same effects on humans is unknown, however many studies suggest similar benefits. CR may not be of any benefit to individuals who already eat a balanced diet. Severe caloric restriction can be dangerous. Exercise has many benefits especially on cardiovascular health and in preventing many age related diseases. Healthy diet and physical activity play an important role in promoting vitality and preventing many diseases, thereby contributing to longevity.
Wednesday, June 24, 2009
Reflection on problem solving task
The problem solving task was the good opportunity for us to show some team work. There were four of as in the group, Fadi, Kadijatsu, Latife and myself. Our task was to organise the questioner and survey the fish oil usage among forty people from different ethnic backgrounds. We worked together as a group to collect the information and prepare effective survey questions. After we had enough people interviewed , we collected the data, and Fadi took the responsibility of organising tables and graphs. As the Graphs were not quite what our teacher wonted as to do, we had to do some corrections . In follow-up ,we work collectively in organising our power point presentation. I was happy to write a small report and present our work to other class members.
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