Higher estimates of daily dietary net endogenous acid production (NEAP) in the elderly as compared to the young in a healthy, free-living elderly population of Pakistan

Abstract

Dietary intake has been shown to influence the acid–base balance in human subjects; however, this phenomenon is poorly understood and rarely reported for the least well-studied segment of older people in a developing country. The aims of the present study were to: (1) quantify estimates of daily net endogenous acid production (NEAP) (mEq/d) in a sample of otherwise healthy elderly aged 50 years and above; and (2) compare NEAP between the elderly and young to determine the effects of aging, which could contribute to changes in the acid–base balance. Analyses were carried out among 526 elderly and 131 young participants (aged 50–80 and 23–28 years, respectively), all of whom were free of discernible disease, nonsmokers, and not on any chronic medication. Selected anthropometric factors were measured and 24-hour dietary recall was recorded. We used two measures to characterize dietary acid load: (1) NEAP estimated as the dietary potential renal acid load plus organic acid excretion, the latter as a multiple of estimated body surface area; and (2) estimated NEAP based on protein and K. For the young and elderly, the ranges of NEAP were 12.1–67.8 mEq/d and 2.0–78.3 mEq/d, respectively. Regardless of the method used, the mean dietary acid–base balance (NEAP) was significantly higher for the elderly than the young (P = 0.0035 for NEAP [elderly, 44.1 mEq/d versus young 40.1 mEq/d]; and P = 0.0035 for the protein:potassium ratio [elderly, 1.4 mEq/d versus young 1.1 mEq/d]). A positive and significant correlation was found between NEAP and energy, protein, and phosphorus (P < 0.05 for all trends). The findings from this study provide evidence of the relatively higher production of NEAP in older people, possibly as an effect of higher consumption of certain acid-producing foods by the elderly.

Ageing Is Associated with Decreases in Appetite and Energy Intake—A Meta-Analysis in Healthy Adults

“…No studies were excluded based on quality of study, although many studies did not report sufficient information for a clear bias assessment. All studies, except four [ 26 , 45 , 46 , 50 ], reported inclusion and/or exclusion criteria, and stated that the participants met these criteria. Of the studies measuring energy intake (49 studies), 18 studies matched the younger and older participants for body weight [ 23 , 26 , 27 , 29 , 30 , 35 , 40 , 45 , 51 , 52 , 54 , 58 , 63 , 69 , 70 , 72 , 76 , 80 ] and 13 studies for BMI [ 26 , 27 , 33 , 40 , 41 , 42 , 45 , 47 , 48 , 49 , 58 , 68 , 76 ] and 11 studies considered gender as a confounder [ 31 , 39 , 43 , 46 , 47 , 52 , 56 , 71 , 75 , 78 , 79 ].…”

“…Twenty-six studies were conducted in the United States [ 20 , 21 , 27 , 28 , 29 , 31 , 35 , 39 , 40 , 42 , 46 , 50 , 53 , 55 , 58 , 59 , 60 , 62 , 63 , 70 , 72 , 73 , 74 , 75 , 78 , 79 , 80 ], 10 in Europe [ 41 , 44 , 45 , 54 , 56 , 67 , 71 , 76 , 77 , 81 ], eight in Australia [ 23 , 34 , 47 , 48 , 49 , 68 , 69 ], two in Asia [ 26 , 43 ], two in Canada [ 51 , 52 ], and one in Chile [ 30 ]. The oldest study was published in 1966 [ 50 ] and the most recent in 2014 [ 17 ].…”

“…Within an individual study, energy intake was significantly less in older than younger adults in five of ten studies that determined energy intake of a single ad libitum buffet-style meal after overnight fasting at the research facility [ 47 , 48 , 60 , 74 , 75 ], six of seven studies which determined energy intake by provided food items during a prolonged period [ 21 , 58 , 59 , 76 , 79 , 80 ], and 24 of 37 studies which determined energy intake by weighed-food records, 24-h food intake recalls, or food frequency questionnaires [ 20 , 26 , 33 , 39 , 42 , 46 , 47 , 48 , 50 , 51 , 52 , 54 , 55 , 56 , 63 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 77 , 78 ] ( Figure 2 ). There were no studies in which energy intake after overnight fasting was significantly higher in older than younger adults.…”

“…In the subgroup of 7035 subjects in which energy intake was measured using weighed food records [ 20 , 28 , 29 , 30 , 31 , 34 , 35 , 39 , 40 , 41 , 43 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 55 , 56 , 63 , 68 , 69 , 70 , 72 , 73 , 74 , 75 , 78 ], 24-h food intake recall [ 26 , 27 , 42 , 54 , 71 , 77 ], or food frequency questionnaires [ 67 ], energy intake was less in the older than the younger adults with a SMD of −0.69 (95% CI: −0.84 to −0.55) ( Figure 2 ) and significant heterogeneity ( I 2 = 77%, p < 0.001). As a group the older adults ( n = 3266, energy intake of 1969 kcal/24 h) had on average 17% ± 8% (~407 kcal/24 h) lower energy intake than the younger adults ( n = 3769, energy intake of 2376 kcal/24 h).…”

Energy Metabolism and Allocation in Selfish Immune System and Brain: A Beneficial Role of Insulin Resistance in Aging

“…How these selfish behaviors of the immune system and brain can be exploited in old age. As we have previously reported that the aged are already having a malfunctioning in their energy metabolism and energy allocation mechanism [89], more prone to pro-inflammatory diets [90], disturbed by changes in their body composition [91] and have compromised immunity [92]…”