The Relationship Between Low Calorie Diet Intake and Longevity
The Relationship between Low Calorie Diet Intake and Longevity
Calories restriction (CR) is a new medical revolution concept developed with the major aim of treating and ultimately preventing various known and unknown causes of degenerative aging processes.
So far, several funded projects have been conducted globally for the past 20 years and there is evidence that 40% life span of the organisms experimented on were recorded to have been prolonged (fightaging.org). The strategy of calorie restriction basically aims at reducing the quantities of calories consumed by the organism to a level that is typically low, while still maintaining other essential nutrients intake (fightaging.org).
The evidence that proves CR purely retards aging and prolongs lifespan was first done on rodents (rats), fruit flies and worms as early as 1930. The reason for the choice of these study animals was because of their shorter life spans contrary to humans who have longer lifespan.
This explains why no experimental conclusion has been made on humans concerning the efficacy of the CR strategy, and that which exist are currently still underway. But researchers have been able to hypothesize that if the CR extends life spans of other mammals and primates, the same can also be said to be the case among humans (Heilbronn & Erick 722).
Mechanisms of Calories Restrictions
Metabolic rate hypothesis
This hypothesis supports the fact that, dietary restrictions (DR) which is achieved through use of special diet free calories given to an organism, precisely retards or slows down the aging process by simply lowering down the rate of body metabolic activities (Masoro 658).
This DR anti-aging factor is believed to emanate from strict regulation of some caloric foodstuffs being consumed; there are two strong factors believed to advocate for this success. First, the rate of energy consumption by an individual organism is the key factor which leads to aging, and secondly there is a positive correlation between metabolic rates and the reactive oxygen species population (Masoro 658).
One study conducted on short lifespan mammals such as rats indicated there is evidence that of all categories of various life spans of organisms, the amount of energy intake per unit body mass is the same in both groups of experimental and control rats (rats not subjected to DR were the control group of the experiment) (Masoro 659).
The study found that the reason behind this was that use of DR always causes the body mass to fall proportionally to match the decreased energy consumption rate. Moreover, in the same rats it was again discovered that oxygen consumption was also the same but only differed across study subjects upon subjection to the various dietary plans; where the DR rats registered low oxygen consumption.
This indicates that less aerobic metabolism activities occurred among this group of rats. All these findings indicate there is evidence that the anti-aging factor developed by the rats subjected to DR is caused by the quantity of energy intake per animal and is not based on the body mass of the organism (Masoro 659).
Eat less live longer
Based on the study done on mice, it was found that when the mice were deprived and subjected to CR diet but under sufficient supply of vitamins and other essential minerals; the mice lived longer than those which were subjected to normal conditions (Nutrition Action Health Letter 13).
This clearly indicated that low caloric foods have a unique characteristic of slowing down the organism (mice) aging, and therefore extending the longevity of the organism. This is the first study ever to be completed on large rodent which was recorded to be successful (Nutrition Action Health Letter 13).
It has been reported by researches that, in spite of the fact that low caloric diet prolongs life span of an organism, there are many more beneficial impacts. First, it’s been clarified that CR suppress or inhibit developments of tumor in every study done on the mice; where the mice was already developing cancerous tumors, the cancer cells were found to be fewer for mice subjected to CR diet (Nutrition Action Health Letter, 13).
This was found to be the most effective way of preventing cancer disease by just following CR, it was also found out that body temperatures for organisms subjected to CR were low. Scientists suggest that it is this low temperature which is more efficient when it comes to repairing of damaged DNA that enables the organism to live longer (Nutrition Action Health Letter 13).
Moreover, it was proved that CR organisms exhibited lower levels of insulin hormone in their system and low blood sugar levels as well.
Despite the fact that there are low insulin levels, there is higher insulin sensitivity which shows that although the organism exhibits high insulin sensitivity, the body is capable of regulating blood sugar with aid of low insulin thus exposing the organism to lower risks of diabetes and cardiovascular diseases (Nutrition Action Health Letter 13).
Finally, low insulin levels in the body of organisms were found to be typical for all living organisms with long life spans.
Calorie restriction evidences
The first human CR study was developed after the World War 1, it was clear that as a result of war the Scandinavians were subjected to semi-starvation which incidentally was found to be the reason for their reduced cardiovascular diseases prevalence (Everits & Couteur 430).
As evidenced, the CR on the people of Norway was also associated with lower reported cases of cancer as well as obesity prevalence both of which were attributed to their type of food intake (Everits & Couteur 430). In the year 1990, a study on healthy adult humans was carried which showed that 20% of physical parameters were reduced on people subjected to CR between 2-6 years.
This is simply because a significant reduction of body weight by the individual, lowered blood sugar, pressure and cholesterol all of which plays key role when it comes to development of age-associated diseases (Everits & Couteur 430).
Decreased food intake
There is evidence by various studies that reduced food intake by an organism generally results to increased lifespan of the organism, in other words, eat less live longer. The same study by Frisard et al also showed that dietary restriction strategy prolonged the lifespan of the organism by retarding many of the aging changes occurring within the organisms.
These findings are consistent with the evidence that diet is the key to prolonged lifespan in organisms while poor diet is the cause of many diseases which may come about over a period of time such as obesity, kidney failure and diabetes all of which are lifestyle diseases.
There is evidence that longevity can also be achieved through proper dietary pattern as this helps in prevention of risky chronic diseases that are lifestyle related. Recently, researchers all over the world have focused on both the positive and negative effects of foodstuffs consumed by organisms based on their pattern of dietary intake.
The hypothesis developed supports the notion that proper diet will always reduce exposure of an organism to many chronic diseases such as hypertension, diabetes and cancer among many others (Willcox, Todoriki & Suzuki 500).
The proposed diet must strictly follow elimination of caloric foodstuffs since it has been proven that low-energy diet with low fats content is beneficial and prolongs life span. Indeed, a recent study carried out on Okinawan populations in Japan clearly proves that proper diet (Okinawan diet) is the single most responsible factor that has significantly extended the longevity of people living there (Willcox et al 511).
Notable to mention is that globally, the long lived individuals on earth have always been reported to be from Japan. According to the study, the Okinawan diet is composed of low calories traditional diet which is highly nutritious with vitamins, minerals and phytonutrients all in complex form of antioxidants and flavonoids (Willcox et al 502).
Generally, the Okinawan diet is mostly composed of high vegetables, legumes like soybeans, low fat and high carbohydrates (Willcox et al 502).
This type of diet is known to promote improved cardiovascular health, reduces risks to diseases such as obesity, cancer, diabetes and many age-associated diseases. The study also found that Okinawan diet has both anti-hypersensitivity effects and anti-inflammatory benefits which reduces majority of inflammatory diseases that destroys the DNA, body cells and tissues which can cause ill health (Willcox et al 503).
Decreased body weight
Weight loss, though is not a primary goal for CR has a greater role when it comes to longevity; however, it has been observed that following correctly the CR diet translates to less food intake which then optimizes an organism’s body weight.
The principle behind this in relation to extending lifespan is that, overweight and increased levels of fat in the body in most cases is harmful to an organism. And over time, the organism is exposed to a variety of chronic diseases such as cancer, diabetes and obesity which eventually causes premature death.
Besides, excessive weight is harmful to overall health of an individual and has implications on lifespan as evidence shows that overweight people have shorter life spans compared to slim individuals (Willcox et al 511, 512).
Decreased fat mass/ adipose tissue retardation hypothesis
This hypothesis is based on the observation that longevity is believed to be extended by retardation of deposited body fats; the assumption is that dietary restrictions reduces the content of fats in the body and therefore retards the aging process (Masoro 657).
In general, when a lot of fats are deposited on the body, the chances of premature deaths caused by various diseases significantly increases.
One experiment conducted on rats in a laboratory setting found that when rats were fed on dietary restriction the absolute fat in their body tissues reduced; not surprisingly then, there was positive correlation between longevity and dietary restriction (Masoro 657). Moreover, it was noted that dietary restricted rats grew fatter, bigger and lived longer than other rats not on DR (Masoro 657).
Decreased oxidative stress/free radicals
This hypothesis is based on a study which shows evidence supporting the fact that prolonged CR in rats will eventually affect biomarkers of oxidative stress. Bearing in mind that no complete experiments have ever been done on humans because of the long duration of human life span, many experiments have only been conducted on rodents, primate and other short lived organisms (Frisard et al 539).
The experiment procedures involved subjecting the experimental rats for 6 months on CR with no exercise done, after 6 months the results obtained revealed that there was much reduction of insulin levels within the body of the rat.
Furthermore, the levels of glucose never changed even though the body temperatures of the higher mammals (humans) were greatly reduced (Frisard et al 1539); it was concluded that based on calories restriction with no exercise, the DNA damage of the rat was reduced.
This is because, the fasting insulin levels and temperatures, which are the only two biomarkers responsible for longevity are decreased by the prolonged CR, thus reducing the rate of metabolism.
Benefits of calorie restriction
Most of the secondary benefits of CR recorded are that, risks of most age-associated diseases among the population have significantly been lowered by a great percentage. In addition, it also offers an opportunity to attain an improved healthy among persons taking excessive consumption of high caloric foods.
The study finds irrefutable evidence that indicates aging can be extended through use of diet restriction. Though, the experiments done were focused on animals evidence of the experiments could be found among humans as is the case among Okinawan people in Japan although this was previously not known to be the cause of their long life spans (Willcox et al 511).
It has been noted throughout this discussion that calories restriction is an effective intervention based on diet which emphasizes low calories consumption but which also still require balanced and proper nutrition.
So far it is the only intervention well developed during the numerous research studies done that have investigated the phenomenon of aging (Redman et al 1862). CR strategies discussed in this paper such as dietary restriction and pattern of dietary intake indicate clear evidence of their impact on longevity.
Everits Arthur & David le Couteur. “Life Extension by Calorie Restriction in Humans.” New York Academy of Sciences. 1114 (2007): 428-433. Print.
. “Calories Restriction Explained.”
Frisard, Martin., Lillian, de Jonge., Leonie, Heilbronn., Jenifer, Rood., Corby, Martin., Marlin, Most., Stephen, Smith., Donald, Williamson & Walter, Deutsch. Effect of 6 “Months calories restriction on biomarkers of longevity, metabolic adaptation and Oxidative stress in overweight individuals.” American medical association, 295.13 (2006): 1539-1548. Print.
Heilbronn, Luise & Erick, Ravussin. “Calories restriction extends lifespan-but which calories?” Plos medicine, 2.8 (2005): 0721-0723. Print.
Masoro, Evans. “Under nutrition and longevity.” Nutrition society 54 (1995): 657-664. Print.
Nutrition Action Health Letter. “Eat less live longer?” Centre for science in the public interest. 30.7 (2003): 13. Print.
Redman, Lonald., Jennifer, Rood., Stephen, Anton., Catherine, Champagne., Steven, Smith & Erick, Ravussin. “Calories restriction and bone health in young, overweight individuals.” Archmed Intern Med, 168.17 (2008): 1859-1866. Print.
Willcox, D., Bradley Willcox., Hidemi Todoriki & Makoto Suzuki. “The Okinawan diet: Health Implications of low-calories, Nutrient-Dense, Antioxidant-Rich dietary pattern low in glycemic load.” Journal of American college of nutrition, 28.4 (2009): 500-516. Print.
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