High Potassium Diet

One of the places in the Western part of Sicily, characterized by a high presence of oldest old people, is the area of “Monti Sicani”, between the provinces of Agrigento and Palermo. “Monti Sicani” encompasses the area between the cities of Palermo and Agrigento from North to South and between the city of Caltanissetta and Trapani from West to East. The territory is characterized by a hilly area of clayey sandstone or pasture and a mountain area above 900 m, consists of pelagic limestone rocks of the Mesozoic. This area is characterized by olive tree agriculture, which tolerates a large range of soil conditions, preferring a neutral to alkaline soil type.

Looking at the national ratio of centenarian per inhabitants in these area we have found more than a four-fold increase in centenarian, and regarding male female ratio of 1.1:1 times. Since Sicilian population genetics structure is very homogeneous and in Hardy-Weinberg equilibrium [19], the explanation for these data probably resides in the environmental characteristics of the study sample.

In this area, we have found a high number of centenarians in good health, with a notable increase of male centenarians. Unequivocally, their nutritional assessment showed a high adherence to the Mediterranean nutritional profile with low glycemic index food consumed. According to the scores of ADL and IADL, centenarians of both gender demonstrated a good level of independency. They did not have any cardiac risk factors or major age related diseases (e.g. cardiac heart disease, severe cognitive impairment, severe physical impairment, clinically evident cancer or renal insufficiency), although some had decreased auditory and visual acuity. Their life is characterized by social networking, acceptable physical activity and small amount of food divided among three meals, which contain a little amount of carbohydrate and meat and a lot of seasonal fruit and vegetables. In relation to biochemical parameters in centenarians, most biochemical parameters including cholesterol and triglycerides were within normal limits (data not shown) and better than those previously reported in a study of Sicilian elderly. Furthermore, this reported modified Mediterranean-style show a low glycemic load.

The Glycemic index (GI) is defined as a kinetic parameter that reflects the potency of food to raise blood glucose level and glucose clearance. The GI of a specific diet is calculated by averaging the GI values of the food items, statistically weighted by the carbohydrate contribution. Diets based on refined carbohydrate foods that are quickly digested, absorbed, and metabolized (i.e., high glycemic index diets) have been associated with increased risk of lifestyle diseases in particular with an increased risk of type 2 diabetes, because of postprandial hyperglycemia and hyperinsulinemia related to eating high-GI carbohydrates. Low GI is known to protect against heart disease in women, and cross-sectional studies indicate low GI may reduce high-density-lipoprotein cholesterol and triacylglycerol levels in both sexes. More interesting, new observational studies have reported increased risks of coronary heart disease associated with higher intakes of carbohydrates from high glycemic index foods. Epidemiological evidence has emerged linking dietary glycemic index to visceral fat and inflammatory disease mortality. Therefore, the Mediterranean diet is an anti-inflammatory diet: it is puzzling that Italian centenarians are remarkably enriched in “good” genotypes involved in control of inflammation, confirming that a good control of inflammatory responses (genetic and/or environmental) is advantageous for longevity.

Overall, our data confirm our previous suggestion that longevity concerns subjects, living in small town, without pollution, with different working conditions, lifestyles and close adherence to a Mediterranean diet. The reason why longevity has been observed particularly in small municipalities is not surprising. It is a well established, in fact, that individuals with greater access to social support and family network have better health and lower levels of mortality, particularly when adult daughters are present. Nevertheless, our data are collected in a relative small sample of subjects; accordingly, our data needed to be confirmed by larger population-based studies.

To conclude, our work show a segment of our population that is growing faster and represent a typical example of successful ageing. Genetic and environment play a major role in healthy ageing and nutrition has a significant influence. It has been estimated that the number of centenarians will approach 3.2 million world-wide by 2050 and that means an 18-fold increase with respect to the last century. Consequently, understanding the influence of dietary life-style in the process of healthy ageing is of paramount importance to development new strategies leading to healthy life extension. To reach successful ageing it is advisable to follow a diet with low quantity of saturated fat and high amount of fruits and vegetable, rich in phytochemicals.