Does a Longevity Diet Really Exist? What does it Constitute of?
Certain groups have been found to lead exceptionally longer lives than others, and are, to this end, usually referred to as the 'lucky lot'. The islanders of Okinawa in the Pacific Ocean, for instance, enjoy a significantly high life expectancy of eighty-one years - three years more than the average life expectancy in the U.S. (Jaret, 2014). Of even more significance is the four to seven-year difference in life expectancy between Seventh Day Adventist members, who are largely vegetarians, and the rest of the society (Jaret, 2014). So what then causes these differences and makes these groups so lucky?
Studies have, in the past, suggested that there indeed is such a thing as a longevity diet, and that diet is, in fact, one of the most fundamental components of anti-aging and longevity. So, what then makes a diet more favorable to longevity than another? A number of studies have shown that calorie restriction is the key variable in the relationship between longevity and diets. This text, however, asserts that the protein to non-protein intake ratio, and not calories, is the key determinant of the longevity-diet relationship.
Sanz, et al. (2006) assert that the reduced production of mitochondrial energy is the mechanism behind the effectiveness of calorie restriction. While not disputing the fact that the effectiveness of the same in humans is yet to be proven, the authors argue that by restricting their dietary energy content, organisms avoid damaging their mitochondrial DNA and protein patterns, and in so doing, reduce their risks of contracting disease.
Szalavitz (2012) posits that calorie restricting boosts immunity, minimizes the chances of contracting disease, and, hence extends human life. Trepanowski, Canale, Marshall, Kabir and Bloomer, in the 2011 issue of the Nutrition Journal, partly agree with this; maintaining that whereas it holds true for animals, its effectiveness in regard to humans is quite questionable. Naik (2012) further thwarts the expectations of people engaging in dietary restrictions by asserting that the calorie restriction yields massive health benefits, but has only very negligible effect on the length of an individual's life.
Delaney and Watford (2005), while making reference to a publication by Rafael de Cabo, the lead author of Journal Nature and gerontologist at the Baltimore National Institute on Aging, argue that calorie restriction should not be viewed as the Holy Grail for increasing the life span of every creature on earth - just because it works on rodents and primates does not imply that it automatically works on humans as well.
Simpson and Raubenheimer (2006) compare calorie restriction to the idea of someone not driving their car because they often see people get accidents and crash; so definitely, not driving the car would make it live longer, but then, in as much as this may so, what fun does it bring? They recognize that one may argue that the fun is perhaps that someday, science would discover the solution to aging, making everyone young again, and it would do no harm to keep the car safe until that day, and hence, drive it forever. It can rightly be argued that these arguments would never give rise to a common stand because their advancers have different time preference rates.
Graves (n.d.) puts forward a number of controversies that put the effectiveness of calorie restriction as a technique for increasing the life span of humans to question. These include; is there such a thing as the single standard threshold for calorie consumption for everyone? What are the roles of fasting, vegetarianism, exercise, alcohol, and supplements? What types of foods should face more restrictions; raw or cooked, traditional or organic?
Vegetarianism, for instance, has been found to have serious long-run health consequences. Davies (2011) argues that in addition to the fact that it is extremely difficult to maintain an all-vegetable diet, calorie restriction vegetarians are, more often than not, prone to disease; first, because their diets lack sufficient quantities of Vitamin B12, and secondly because the body, at any one time, contains a substantial pool of amino acids to digest, such that a very negligible amount of protein ingested on a particular day is used in the formation of new proteins, on that very day.
The cooked vs. raw debate is another significant area of concern. Smil (2013) assesses this controversy from two opposing perspectives; that the cooking process generates health-damaging carcinogens on one hand, and that some vegetable nutrients are best absorbed by the human body when cooked, on the other. Of significance too is the argument that raw food raises serious sanitation concerns. To this end, the author opines that most calorie restrictors must be eating their food raw, and disregarding the risk posed on their health by poor sanitation. This somewhat depicts double standards because it entails compromising one aspect of health (hygiene) for the sake of another (nutrition) and disregarding the fact that poor hygiene is, in itself, a contributor to reduced longevity (Fight Aging, 2012).
Whereas it remains undisputable that diet does play a role in aging and longevity, calorie restriction, in light of the controversies and uncertainty surrounding its effectiveness, ought not be used as the key determinant of the longevity-diet relationship. Maxmen (2012) makes reference to a 25-year study conducted on rhesus monkeys, which showed negligible differences in ageing between the control group and the rest of the sample, despite the former being fed 30% less than the latter the entire period. He makes reference to an address by Don Ingram, the study's designer and gerontologist at Louisiana State University, that longevity is more than just a simple calorie count, and that it, rather, it has a lot to do with genetics and healthy diets.
The goal of this text is to prove the effectiveness of the protein-non protein balance in longevity and anti-aging, and in so doing, continue the above line of collaborative comparative healthy living work. A number of studies have employed designs that result in the unequivocal disentanglement of calorie restriction from specific nutrient effects. In Lee et al. (Fanson, Fanson & Taylor, 2012), mated female flies were allowed access to one of twenty-eight diets with varying quantities of yeast and sugar, and the bi-coordinate carbohydrate and protein intakes for each plotted and compared against determined mortality response, and egg production surfaces. The highest longevity, and peak egg production, was recorded when a diet with a protein to carbohydrate concentration of 1:16 was advanced, and continually decreased as the ratio increased.
A similar experiment by Fanson, et al. (Fanson, Fanson & Taylor, 2012) subjected Queensland fruit flies to one of twenty-five choice or twenty-eight no-choice diet treatments and yielded results similar to those of Lee et al., as well as to those obtained, by the same group, from a similar experiment conducted on the Mexican fruit fly.
A recent study by Ja, et al. (Sanz, et al., 2006) confirmed that any attempts to decrease the yeast to sugar ratio caused a substantial reduction in the life span of the Drosophila, "to an extent that maps precisely onto the data of Lee, et al."(Simpson & Raubenheimer, 2006).
The three studies above indicate that there exists a strong relationship between the proteins to sugar intake balance, and that calorie (energy) restriction does not account for lifespan variation because if that were the case, then higher longevity would have been recorded when diets with low protein contents were advanced (Simpson & Raubenheimer, 2006).
Having already noted that a decrease in the protein to carbohydrate ratio decreases longevity, it would be prudent to mention that if the ratio falls too far, that is, if protein intake exceeds optimal levels, longevity could reduce because of the effect of obesity (Dibell, 2007). Herbivores and omnivores have been observed to regulate their protein intakes more than they do carbohydrates and fats. The effect is that a high appetite for protein develops and induces overconsumption of low-protein diets, resulting in obesity and reduced longevity (Dibell, 2007). A number of explanations have been put forward to explain this phenomenon. They include; increased mitochondrial oxygen production, modifications of protein and DNA oxidation, changes in mitochondrial metabolism and the composition of fatty acids in the membrane (Sanz et al., 2006). These have the effect of over-burdening mitochondrial capabilities, and hence reducing the levels of effective oxidation (Sanz, et al., 2006).
Healthy eating, therefore, contributes to longevity more than calorie count does (McTiernan, 2010). A balanced protein to carbohydrate intake ratio is one of the numerous components of a healthy diet. Moreover, if individuals were to effectively maintain an optimum protein to carbohydrate ratio, then their calorie intake would automatically fall into place, and they would not, after all, have to keep calorie count (McTiernan, 2010).
Davies, W, (2011). Wheat Belly: Lose the Wheat, Lose the Weight and Find Your Way Back to Health. New York: Rodale.
Delaney, B. & Walford, L. (2005). The Longevity Diet: Discover Calorie Restriction -- the Only Proven Way to Slow…