אני.
טוב, למען הדיוק, אני חולק על ההנחה שזה כך, כל עוד זה לא הוכח. להבנתי תוחלת חיים ארוכה נובעת מאורח חיים (אורח חיים = אורך חיים?
) וגם גנטיקה, בכלל לא ברור עד כמה ואם בכלל יש למערכת הבריאות השפעה על כך. אני לא שולל את האפשרות שיש למע' השפעה, אבל הייתי רוצה לראות הוכחות חותכות לכך. במילים אחרות, תקח אמריקאי שחי
בדיוק כפי שהוא חי כיום, ותשים אותו במע' בריאות נגישה לכל, בכלל לא בטוח שהוא יחיה חיים ארוכים יותר. דווקא קובה זו ראיה לדבריי: למרות שכמעט שאין שם מערכת בריאות, עדיין אנשים חיים שם חיים ארוכים (אם הנתונים על כך בכלל אמינים, עם הקאסטרואים לך תדע). כך שגם אם נגישות למע' מהווה גורם תורם, מן הסתם זה לא גורם משמעותי במיוחד. כדי להבין את הגורם לתוחלת חיים של מקום מסויים יש לבחון בעיקר את אורח החיים של בני המקום (וגם גנטיקה אבל זה סיפור אחר). זה כולל: תזונה, רמת הסטרס בחיים, רמת הקהילתיות/משפחתיות/לבדיות/בדידות, ציפיות חברתיות ביחס בין המינים, רמת הפעילות הגופנית היומיומית, החשיפה לטבע/שמש/ים/אוויר, אכות הסביבה (רעלים שונים באוויר, במים, במוצרי פלסטיק, בחומרי בניה וכד'), ועוד גורמים רבים כאלה. כשתבחן את אורח החיים הקובני, תבין למה למרות שאין להם כמעט מע' בריאות, תוחלת החיים שלהם גבוהה. קח את נושא התזונה. זה נושא ארוך ומסובך עם כל מיני אספקטים שונים, אבל בא נתמקד לרגע על פרט אחד: הגבלת קלוריות. הגבלת קלוריות (מעל לרמת רעב) הוכחה כמועילה לכל מיני דברים.
In human subjects, Calorie Restriction has been shown to lower cholesterol, fasting glucose, and blood pressure. In CR, energy intake is minimized, but sufficient quantities of vitamins, minerals and other important nutrients must be eaten. A small study of long-term CR practitioners in the US at the Washington University School of Medicine in St. Louis studied the effects following a calorie-restricted diet of 10-25% less calorie intake than the average Western diet, which is over caloric. Body mass index (BMI) was significantly lower in the calorie-restricted group when compared with the matched group; 19.6 compared with 25.9. The BMI values for the comparison group are similar to the mean BMI values for middle-aged people in the US.[5] All those on calorie-restricted diets experienced reductions in BMI after starting their diet. Their BMIs decreased from an average of 24 (range of 19.4 to 29.6) to an average of 19.5 (range of 16.5 to 22.8) over the course of their dieting (3–15 years). Nearly all the decrease in BMI occurred in the first year of dieting. It was found that the average total cholesterol and LDL (bad) cholesterol levels for calorie-restricted individuals were the equivalent of those found in the lowest 10% of normal people in their age group. It was found that the average HDL (good) cholesterol levels for calorie-restricted individuals were very high—in the 85th to 90th percentile range for normal middle-aged US men. These positive changes in calorie-restricted individuals were found to occur mainly in the first year of dieting.[5] "The calorie-restricted group also fared much better than the control group in terms of average blood pressure (100/60 vs. 130/80 mm Hg), fasting glucose, fasting insulin (65% reduction), body mass index (19.6 ± 1.9 vs. 25.9 ± 3.2 kg/m2), body fat percentage (8.7% ± 7% vs. 24% ± 8%), C-reactive protein, carotid IMT (40% reduction), and platelet-derived growth factor AB."[6] It was found that the calorie-restricted group had remarkably low triglyceride levels. In fact, they were as low as the lowest 5% of Americans in their 20s. This is more remarkable when it is noted that the calorie-restricted individuals were actually aged between 35 and 82 years. Both systolic and diastolic blood pressure levels in calorie-restricted group were remarkably low, about 100/60, values normally found in 10-year-old children. Fasting plasma insulin concentration was 65% lower and fasting plasma glucose concentration was also significantly lower in the calorie-restricted group when compared with the comparison group." Dr. Luigi Fontana, clinical investigator, says CR practitioners seem to be aging more slowly than the rest of us. "Take systolic blood pressure," he says. "Usually, that rises with age reliably, partly because the arteries are hardening. In my group, mean age is 55, and mean systolic blood pressure is 110: that’s at the level of a 20-year-old." The comparison group's statistics aligned approximately with the US national average on the dimensions considered.[7] Fasting plasma insulin levels[8] and fasting plasma glucose levels[9] are used as tests to predict diabetes. The American CALERIE study began in 2007 and investigates the effects of a 25% reduction in calorie intake on healthy adults over a period of two years.[10] The effect of CR on IGF-1 serum levels seen in rodents appears to only manifest in humans when protein intake is not much higher than the Recommended Dietary Allowance[11] A 2009 research paper showed that a calorie restricted diet can improve memory in normal to overweight elderly. The diet also resulted in decreased insulin levels and reduced signs of inflammation.[12] Scientists believe that memory improvement in this experiment was caused by the lower insulin levels, because high insulin levels are usually associated with lower memory and cognitive function.[13] However, that relation seems to be age-specific since another study, when analyzing people older than 65, those who were underweight had a higher dementia risk than normal or overweight people.[14]
מ
ויקיפדיה זה מה שידוע בנתיים לגבי בניאדם. בעולם החי הממצאים עוד יותר מרשימים, ומצביעים על כך שכנראה כן פני הדברים גם אצל בני אדם (רק שבני אדם חיים שנים רבות יותר, אז יקח לחוקרים עוד הרבה זמן להוכיח זאת באופן סופי):
CR, when not associated with malnutrition,[1] has been shown to improve age-related health and to slow the aging process in a wide range of animals and some fungi. CR is one of the few dietary interventions that has been documented to increase both the median and maximum lifespan in a variety of species, among them yeast, fish, rodents and dogs. There are currently ongoing studies to investigate whether CR works in nonhuman primates, and its effects on human health and metabolic parameters associated with CR in other species. The results so far are positive,[2][3] but the studies are not yet complete, due to the long lifespan of the species.