Estimates of daily net endogenous acid production in the elderly UK population: analysis of the National Diet and Nutrition Survey (NDNS) of British adults aged 65 years and over

Abstract

Dietary intake has been shown to influence acid–base balance in human subjects under tightly controlled conditions. However, the net effect of food groups on alkali/acid loading in population groups is unclear. The aims of the present study were to: (1) quantify estimates of daily net endogenous acid production (NEAP) (mEq/d) in a representative group of British elderly aged 65 years and older; (2) compare and characterise NEAP by specific nutrients and food groups likely to influence dietary acid loading; (3) determine whether geographical location influenced NEAP. The National Diet and Nutrition Survey dataset, consisting of a 4 d weighed record and anthropometric data, was used to estimate dietary acidity. Dietary under-reporters were excluded by analysing only subjects with energy intakes $1·2 £ BMR. NEAP was estimated as the dietary potential renal acid load þ organic acid excretion, the latter as a multiple of estimated body surface area. NEAP was lower in women compared with men (P,0·001), and lower than values reported in a Swedish elderly cohort. Lower dietary acidity was significantly associated with higher consumption of fruit and potatoes and lower consumption of meat, bread and eggs (P,0·02 to P,0·001). Lower intakes of fish and cheese were associated with lower NEAP in men only (P,0·01 to P,0·001). There were regional differences for NEAP, with higher intakes in Scotland/ Northern regions compared with Central/South-Western and London/South-Eastern regions (P¼0·01). These data provide an insight into the acid-generating potential of the diet in the British elderly population, which may have important consequences in this vulnerable group.

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