All of us want to live until ripe old age in a healthy condition with minimal disabilities. While accidents and several diseases cut short the possibilities of living long, aging is another aspect which also curtails the chances of living to the fullest potential. There is lot of research going on to increase the life span of humans and most of this research is aimed at treatment and prevention of some diseases and also slowing of the process of aging. While advances in medical research have introduced many medicines to treat these diseases and decrease cellular aging, nutritional or diet modification-oriented approaches to increase lifespan are gaining momentum. This article discusses dietary approaches to living long.
What is aging and what happens during aging?
Aging is a process of wear and tear of cells in the body which brings about many physiological changes in various organ systems of the body. These physiological changes can lay background for the development of several diseases which further contrtibute to the disabilities of the aging. Some of the examples of physiological changes of aging are decreased cardiac output, decreased responses to various hormonal changes, progressive increase in blood pressure contributing to hypertension, heart failure, stroke and coronary artery disease, decreased vital capacity of the lungs and decreased weight, volume and function of various organs of the body (Boss and Seegmiller, 1981). The main cause for these changes is long term exposure of the cells of the body to free radicals which are natural by-products of metabolism.
Diet which helps in increasing longevity
The food we eat everyday constitutes of specific nutrients which help in the functioning of the body. These are carbohydrates, lipids, proteins, vitamins, fiber and minerals. Any diet is interplay of these basic constituents. While carbohydrate and fats are good sources of energy, proteins provide amino acids essential for growth and repair of the cells and cell structures of the body. Minerals and vitamins are essential for various activities in the body. Fiber is essential for proper functioning of the intestines. Other than provision of energy, fats also contain fat soluble vitamins (Sarafino, 1998). While each of these constituents of diet has a purpose, excess of any of these, especially fat and carbohydrates can cause devastating consequences on the health of an individual.
Diets vary from family to family and person to person based on the gender, culture and personal taste variations (Sarafino, 1998). Research has shown that many individual diets are not healthy and can lead to various diseases (Sarafino, 1998). For example, diets which are rich in saturated fats can contribute to atherosclerosis due to deposition of fatty plaques in the blood vessels. Diets high in salt can contribute to hypertension and diets high in saturated fat and low in fiber can lead to cancer. Excess intake of food can lead to overweight and obesity which can in turn cause many other health-related problems like diabetes, arthritis, hypertension and cardiac disease (Sarafino, 1998).
Hence the question arises as to what is the correct composition of these constituents in a diet for healthy living. A balanced diet would contain 40% carbohydrate, 30% fat and 30% protein. It is preferable to get the carbohydrates from low-glycemic index foods like unrefined foods rich in fiber, fruits, vegetables, seeds, nuts and fish. Sources of carbohydrates like honey, mollases, white sugar and high fructose corn syrup and, processed grains are best avoided. The fat that is consumed must be free of cholesterol and must have decreased quantity of saturated fatty acids.
Many interventions have been recommended by experts to improve on diets so that health of the individual can be enhanced and minimal side effects are produced as a result of the diet. While some diets focus on minimizing single nutritional components like cholesterol, many diets look into the all the constituents of a diet.
During metabolism, cells produce certain unstable oxygen molecules known as free radicals which damage cells. As age advances, more and more free radicals are produced which lead to aging and some diseases like stroke, atherosclerosis, Alzheimer’s disease, diabetes mellitus type-2 and Parkinson’s diseases (Mattson, cited in Nakazawa, 2006). Free radicals are also formed in response to sir pollution, ultraviolet rays, smoking and passive smoking (Ward, 2008). Research has shown that vegetables and fruits like spirulina, broccoli, spinach, cranberries, cherries, gapes, blueberries and red apples have ample amounts of anti-oxidants which prevent cellular aging. According to Bickford and colleagues (cited in Nakazawa, 2006), these vegetables not only decrease oxidative damage, but also improve neuronal function of the brain and suppress inflammatory substances in the brain. Through their studies on various normal and diseased animals, Bickford and colleagues (cited in Nakazawa, 2006) reported that antioxidants are useful in delaying the progression of various diseases which tend to develop with advancement in age.
While this is one method to increase longevity, there is overwhelming research which states that eating less number of calories can increase longevity by decreasing several diseases like cardiovascular and type-2 diabetes and also by decreasing the risk of neurodegenerative diseases. Some studies have reported that low-calorie and lo-fat diets significantly decrease the risk for Parkinson’s disease and Alzheimer’s disease. Low calorie intake helps hippocampal neurons resist degeneration by amnestic toxin kainic acid. Dietary restriction also causes decrease in apoptosis and excitotoxicity (Mattson, 2003).
According to Mattson (2006; cited Nakazawa, 2006), overeating leads to increased metabolism, increased insulin surge and increased roaming free radicals, thus casing more cellular damage. Decrease in calorie consumption decreases the free radicals and thus decreasing the process of aging and disease formation. Hence Mattson proposed that eating 25% less than normal can increase the chances of extending life. Matson and Miller (Nakazawa, 2006) recommend while men should aim at only 500 calories each for breakfast and lunch, women should eat only 300 calories at each meal. Then, both the sexes can eat 1000 calories dinner.
Along with increased serving of fruits and vegetables, Bickford recommends nuts and flax seed also because these are loaded with omega-3 and omega-6 fatty acids and vitamin E (Nakazawa, 2006). Mattson suggests that skipping a meal here and there can eliminate free radicals which accumulate during a heavy meal (Nakazawa, 2006).
According to the National Heart Lung and Blood Institute (NHLBI) and the American Heart Association (2006), DASH diet or Dietary Approaches to Stop Hypertension is an ideal dietary plan to prevent and control hypertension. This plan was designed after evaluating the results of four large studies sponsored by the NHLBI. The DASH diet constitutes of a certain number of servings every day from various groups of food. The number of servings depends on the calorie requirements of the individual. DASH diet emphasizes on vegetables, low-fat dairy foods, fruits, whole grains, poultry, nuts and fish. Foods like fats, sweets, sugar-containing beverages and fats are to be avoided. Even salt-added processed foods also are to be avoided. The DASH diet not only reduces hypertension, but also decreases obesity and cholesterol levels, thus reducing chances of stroke and heart attack. The fruits and vegetables cause antioxidation and thus prevent wear and tear.
According to Willcox (Cited in Ward, 2008), “the most beneficial diets rely heavily on fresh vegetables, fruits, and legumes — foods that are naturally lower in calories and packed with nutrients.” The main antioxidants available in these foods are vitamins E and C, polyphenols and anthocyanins (Ward, 2008). Nuts are cholesterol-free sources of protein and they must be substituted for fatty meats. While almonds have high Vitamin E levels, pecans are rich in antioxidants and walnuts are rich in omega-3s. Fish has omega-3 fats which reduces building up plaque in the arteries and also decreases triglyceride levels in the blood. Fish is a good source of protein with low saturated fat and low cholesterol content (Ward, 2008). Olive oil is rich in beneficial compounds of plant and monosaturated fats. It has no trans- fats (Ward, 2008). Legumes have complex carbohydrates and are rich in fiber, thus causing steady glucose and insulin levels. They also have good amounts of antioxidants. Whole grains are much better than processed or ground grains. They have natural nutrients like fiber, vitamin B-complex and Vitamin E. Some of the nutritious whole grains are barley, millet, oatmeal, cracked wheat, whole-wheat and wild rice. Dairy products are excellent sources of calcium which is essential for the strengthening of bones. Adequate Vitamin D levels may reduce cancers of colon, breast and prostrate (Ward, 2008).
Aging and age-related diseases are the main causes of decreased life-span of any individual. Though advances in pharmacology claim to have developed drugs which prevent aging, many dietary interventions have come-up which are supposed to increase longevity. A well-balanced diet which is rich in fruits and vegetables and which has less number of calories is likely to help a person stay healthy and live longer.
Boss, G.R. and Seegmiller, J.E. (1981). Age-Related Physiological Changes and Their Clinical Significance. West J Med, 135(6), 434- 440
Mattson, M.P. (2003). Gene–Diet Interactions in Brain Aging and Neurodegenerative Disorders. Annals of Medicine, 139(5, part-2), 441-444. Retrieved on 25th July 2009 http://www.annals.org/cgi/content/full/139/5_Part_2/441
Nakazawa, D.J. (2006). Living Longer: Diet. AARP. Retrieved on 25th July 2009 http://www.aarpmagazine.org/health/living_longer_diet.html
NHLBI. (2008). Blood Pressure. U.S. Department of Health and Human Sciences. Retrieved on 25th July 2009 http://www.nlm.nih.gov/medlineplus/ency/article/003398.htm
Sarafino, E.P. (1998). Health Psychology: Biopsychological Interactions: Lifestyles to Enhance Health and Prevent Illness. London: John Wiley and Sons
Ward, E.M. (2008). Aging Well: Eating Right for Longevity. WebMD. Retrieved on 25th July 2009 http://www.webmd.com/diet/foods-for-longevity-8/live-longer-diet.