One of the major goals that health-conscious people have is to live for as long as possible - assuming a good quality of life. There are several aspects of significance when it comes to maximum longevity.
Avoiding Death
I would think that the most sensible thing to do would be to look at what is most likely to stand in your way of staying alive; namely, death. Therefore, it would be best to look at what kinds of things are statistically more likely to kill you. Life is somewhat a game of statistics - although there are many things that could eventually cause you to die, it would make sense to first look at those statistically most probable. Below is a list of the Top 10 causes of death in Australia:
Cancer |
Coronary Heart Disease |
Stroke |
Influenza and Pneumonia |
Heart Failure |
Respiratory Disease |
Kidney Failure |
Injuries |
Diabetes |
Accidents |
Most significantly, the top 3 leading causes of death among Australians (Cancer, CHD & Stroke) make up for approximately 70% of all cases of death.
Moreover, several of the other causes of death are related to these causes. For example, Heart Failure may occur due to CHD or Chronic Lower Respiratory Disease such as Emphysema. Pneumonia may occur due to impaired immune function caused by cancer. Diabetes may lead to CHD or Kidney Failure, etc.
The important thing to note is that a significant portion of all these diseases may be preventable through lifestyle changes including diet. A significant portion of accidents are obviously avoidable, such as motor vehicle accidents (MVA's). Most road fatalities include either speed, alcohol, fatigue, or a combination of both (this may be a case of 'do as I say, not as I do' folks....) Put simply, most MVA's should not occur.
Whilst most Pneumonia fatalities often occur either in the very old or those with immune disorders, a significant portion of fatalities from the Influenza virus may be preventable through yearly vaccination. Flu shots are especially recommended for elderly persons, those suffering from chronic respiratory disease, or those with immune system disorders.
Chronic Lower Respiratory Diseases include Bronchitis and Emphysema. A large proportion of these diseases are simply due to smoking.
Whilst Type I Diabetes can not be prevented, it only makes up for approximately 10% of all cases of Diabetes in Western civilizations such as Australia, the UK and the U.S. Type II diabetes (a.k.a. late/adult onset diabetes) is usually related to obesity and poor dietary habits. Diabetes usually leads to visual problems such as glaucoma, circulation problems which may result in amputations, kidney problems as well as an increased risk of CHD and Stroke. Unlike Type I Diabetics, Type II Diabetics produce enough insulin, it's just that their bodies cells becomes resistant to the insulin. Insulin resistance often occurs due to excess body fat, and a significant portion of Type II Diabetes cases could be avoided by healthy weight management and sensible dietary practices.
The most common causes of death however include Coronary Heart Disease and Stroke (collectively called 'Cardiovascular Disease') and Cancer. Theoretically, if your goal is to live as long as possible, these are the two things that you should spend the most effort trying to avoid.
Read more about Cardiovascular Disease
Overall Lifespan and the Ageing Process
If we were to assume that all major causes of death could be avoided, it would still be of interest whether there is anything we can do to actually slow the ageing process and know what things affect out potential lifespan (longevity).
Sex and genetics appear to affect a persons lifespan, with women tending to live slightly longer, as well as those with a family history of long living people. Because the actual biological mechanisms of ageing are not well understood, we can not know what modifiable aspects would be necessary to slow the ageing process.
Calorie Restriction
The only significant thing to come out of animal studies in this respect is that of calorie restriction. Reducing total energy (calorie) intake has been shown to increase the life expectancy of various animals such as worms, grasshoppers, flies, spiders, and even mammals such as rodents, dogs and apes. Some evidence also suggests that calorie restriction may help protect against chronic degenerative diseases commonly experienced in old age, though this topic is poorly understood and not without controversy.
This theory has not been adequately tested in humans, and may have unfavorable consequences among those taking a faddish approach to calorie restriction. For example, it is very common for elderly people to lose their appetite and motivation for eating much. As a consequence, their food choices can become mundane and often lead to malnourishment, which we know can result in significant health problems such as muscle wasting and immune function impairment.
Given the lack of evidence from human studies, readers should be careful to eat well, stay active and maintain a healthy body weight, but be careful not to limit calorie intake too much. Very Low Calorie Diets (VLCD's) are classified as those providing between 400-800 Calories per day, and are associated with a plethora of health complications and side effects such as dry mouth, headache, dizziness/orthostatic hypotension, fatigue, cold intolerance, dry skin, menstrual irregularities, hair loss (especially when continued long-term) and constipation. Read more....
Resveratrol
The only evidence of any particular foodstuff improving longevity is a substance which grape skins produce in response to fungal infection, called 'resveratrol'. Although peanuts, berries and grapes provide some resveratrol, the most significant dietary source comes from red wine. Resveratrol has been found to extend the lifespan of worms, fruit flies, fish and mice - initially thought to be through similar biochemical pathways as those occurring in calorie restriction, though more recent evidence suggest other mechanisms.
Although some evidence suggests that regular drinkers or red wine have a decreased risk of heart disease, there is no evidence that resveratrol would have life extending properties in humans, as the amount needed to replicate the same dose used in animals would translate to approximately 50 bottles of wine per day. No evidence exists to verify that long-term exposure to this dose would be safe or not, and given the considerable difference between human and animal metabolism, it would be unwise to try experimenting on yourself.
Long Lived Cultures
Another common school of thought is to examine the diets and lifestyles of long living populations around the world, and try to replicate it. Stories of super healthy, long living people have been the topic of many snake oil salesman's pitch in order to sell magic juices, books or other secrets to good health and longevity.
The cultures most commonly used as the basis of exaggeration include the Caucus mountains in Soviet Georgia, the Hunza valley in Pakistan and the village of Vilcabamba in Ecuador. As it turns out, none of these populations are as long lived as the myths would indicate. (Read More....)
The population with the highest actual average lifespan at the moment and the highest proportion of people over the age of 100 (centenarians) are the people of Okinawa, Japan. Even mystical tales of the wise old Okinawans have been the basis of fad diet books including 'The Great Australian Diet' and even 'The Okinawan Diet Plan'.
Although the Japanese are less likely to suffer health problems common among westerners (such as bowel cancer and heart disease) they still have their own health problems such as gastric cancer - the rates of which are much higher than in westernized countries.
Whilst the typical Okinawan dietary practices may be healthier than the average westerner, the average life expectancy of an Okinawan is approximately 81.2 years. The average life expectancy of an Australian is 80.4 years. I'm not terribly excited.
See Also
Yu BP . Why calorie restriction would work for human longevity. Biogerontology. 2006 May 5;
