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Living longer, looking lovely

2010; Wiley; Volume: 9; Issue: 2 Linguagem: Inglês

10.1111/j.1473-2165.2010.00501.x

1473-2165

Zoe Diana Draelos,

Dietary Effects on Health

Ponce de Leon’s search for the fountain of youth continues today. We are no longer looking for a fountain, but we are searching for youth creams, lasers, light devices, injections, vitamins, and nutritional supplements to fulfill our dreams of physical immortality. Despite many efforts to prolong youth, there are only two ways shown to prevent aging. One solution is to die young so no one knows what you look like as you age. This is not a viable option for most. The second solution to aging that has been demonstrated as scientifically valid is caloric restriction. Caloric restriction is an interesting concept that may hold some of the keys to aging prevention. There are social groups that practice caloric restriction, but I want to critically examine the animal data developed to date surrounding this idea. The observation that caloric restriction prevents aging was made in mice fed 60% fewer calories than needed to maintain their body weight from birth. Mice fed a 60% calorie restricted diet lived almost twice as long as their ad lib fed age-matched counterparts. However, it is not possible to feed a human a 60% caloric restricted diet from birth, as sexually maturity does not occur and most would consider this child abuse. A new concept in caloric restriction was developed by Dr Weinrich and colleagues in his animal laboratory at the University of Wisconsin. He fed monkeys a 30% caloric restricted diet from age 10. Age 10 in monkeys corresponds to age 40 in humans. Thus, the effects of caloric restriction after middle-age were investigated. In addition, Dr Weinrich micronutrient supplemented his monkeys so that all trace minerals and vitamins were provided. The monkey that was ad lib fed developed osteoporosis, renal disease, decreased brain mass, muscle loss, and loss of hair. The monkey that was 30% calorically restricted possessed normal brain mass, normal renal function, and excellent muscle tone. This research demonstrated that many of the findings associated with normal aging might not be normal. How many times have we as physicians said, “Do not worry, this is normal with aging?” Maybe we need to ask ourselves, “Is aging normal?” This research on caloric restriction suggests that normal aging, consisting of reduced renal function, diabetes, macular degeneration, cataracts, liver disease, hair loss, muscle wasting, bone loss, and dementia, may not be totally normal. Perhaps these diseases are associated with too much food. Evolutionarily, humans were designed to survive under poor conditions. The most common poor condition encountered was an inadequate food supply. Early man did not have a refrigerator, freezer, or pantry stocked with dried and canned foods. Early man ate what he could to survive when it was available. He most certainly did not have three well-balanced meals daily, which brings up another point to ponder. Where did the idea come from that humans need three meals daily for health? Why not one meal daily? Why not six meals daily? After all, in “Lord of the Rings” by J. R. Tolkien, the hobbits ate first breakfast, second breakfast, brunchfast, and lunch all before noon! The idea that we needed three balanced meals constructed according to the food pyramid was popularized in the 1960s. Three large meals containing an excess of meat proteins probably are healthy for aging kidneys. Furthermore, it is unreasonable to think that all bodies are metabolically identical. Perhaps some need less protein due a kidney filtration defect and more bulk due to slow gastrointestinal transport time. Others may have a lactase deficiency, more common with advancing age, that is milk intolerant. There is no doubt that each individual needs to determine what type of eating habits and diet make them feel and look healthy. It is not possible to conduct a 5-year IRB-approved double-blind, placebo-controlled caloric restriction study in humans for many obvious reasons. However, an inadvertent experiment in caloric restriction was conducted. In Tucson, Arizona, a privately funded project was initiated to determine the viability of a self-contained living environment, known as Biosphere II. This human research project was a forerunner to future experiments to design living quarters for remote outposts beyond the confines of our planet. Volunteers agreed to live in the Biosphere, maintain their own water supply, harvest their own crops, cultivate their own fish and other sources of meat, provide their own activities, and balance their own atmosphere. It is the last activity that caused termination of the experiment. The Biosphere was made out of cement, and with age cement gives off carbon dioxide. The bioactive cement poisoned the atmosphere and decreased the food supply. It is estimated that the Biosphere inhabitants were inadvertently 20–30% calorically deprived before the experiment was terminated. The caloric restriction resulted in depression, loss of ambition, aggression, perceptions of low quality of life, reduced desire for social interaction, etc. I am not sure that caloric restriction is the secret to a long, wonderful life; however, there are some important messages from this concept. Certainly, the widening of America and the increased body mass of children translates into decreased longevity. The higher incidence of diabetes, a state of premature aging, is equally concerning. No matter how good medicine becomes, obesity will reduce both the quality and quantity of life. Perhaps we need to revisit the concept of three sizeable meals daily and re-examine snacking practices. Perhaps the food pyramid needs to be modernized to prevent childhood obesity. Maybe intermittent fasting, which is believed by some to reset human gluconeogenesis, is a beneficial activity. There is no doubt that modern eating practices in the United States require reassessment. So, what really is the secret to living longer and looking lovely? It is interesting to note that people who eat a calorically restricted diet do not look lovely. They may live longer, although this remains to be proven, but they have sallow skin, temporal wasting, hollow cheeks, and an overall cachetic appearance. Pictures of calorically deprived humans bring back the horrors of wartime death camps and the sadness of terminal illness. This is most certainly not looking lovely. The fountain of youth remains as elusive in 2010 as it did for Ponce de Leon.