Food groups associated with measured net acid excretion in community-dwelling older adults



Acid-producing diets have been associated with adverse health conditions. Dietary acid load can be estimated from dietary intake data, but the available methods require a full dietary assessment. We sought to identify a simpler means to estimate 24-h urinary net acid excretion (NAE), a robust measure of net endogenous acid production, using self-reported intakes of fruits, vegetables (acid-neutralizing foods), grain and/or protein (acid-producing foods) acquired by two different methods in community-dwelling older adults. Identifying food groups associated with NAE by using a method not requiring a full diet assessment could have a broad clinical application.


Fruit, vegetable, protein and grain servings/day were estimated with a widely used food frequency questionnaire (study A, n=162, 63±8 years). Differences in their intakes across NAE categories (<5, 5 to <15, 15 to <50, 50 milliequivalents (mEq)/day) were analyzed using analysis of variance. The findings were verified in a second study, which estimated dietary intakes, using a more detailed record-assisted 24-h recall (study B, n=232, 67±6 years).


Fruit intake was significantly associated with NAE in both studies. In study A, fruit intake was 9% lower with each categorical NAE increase (unstandardized beta=−0.21, P=0.01) and 7% lower with each categorical NAE increase in study B (unstandardized beta=−0.18; P=0.02). Grain intake was positively associated with NAE in study B only (unstandardized beta=+0.14; P=0.01). Vegetable and protein intake were not associated with NAE in either study.


The inverse association between fruit intake and NAE suggests low self-reported fruit intake may be an indicator of acid-producing diets in older adults.

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  1. 1

    Adeva MM, Souto G . Diet-induced metabolic acidosis. Clin Nutr 2011; 30: 416–421.

  2. 2

    Pizzorno J, Frassetto LA, Katzinger J . Diet-induced acidosis: is it real and clinically relevant? Br J Nutr 2010; 103: 1185–1194.

  3. 3

    Dawson-Hughes B, Harris SS, Palermo NJ, Gilhooly CH, Shea MK, Fielding RA et al. Potassium bicarbonate supplementation lowers bone turnover and calcium excretion in older men and women: a randomized dose-finding trial. J Bone Miner Res 2015; 30: 2103–2111.

  4. 4

    Jehle S, Hulter HN, Krapf R . Effect of potassium citrate on bone density, microarchitecture, and fracture risk in healthy older adults without osteoporosis: a randomized controlled trial. J Clin Endocrinol Metab 2013; 98: 207–217.

  5. 5

    Tabatabai LS, Cummings SR, Tylavsky FA, Bauer DC, Cauley JA, Kritchevsky SB et al. Arterialized venous bicarbonate is associated with lower bone mineral density and an increased rate of bone loss in older men and women. J Clin Endocrinol Metab 2015; 100: 1343–1349.

  6. 6

    Chan R, Leung J, Woo J . Association between estimated net endogenous acid production and subsequent decline in muscle mass over four years in ambulatory older Chinese people in Hong Kong: a prospective cohort study. J Gerontol A Biol Sci Med Sci 2015; 70: 905–911.

  7. 7

    Dawson-Hughes B, Castaneda-Sceppa C, Harris SS, Palermo NJ, Cloutier G, Ceglia L et al. Impact of supplementation with bicarbonate on lower-extremity muscle performance in older men and women. Osteoporos Int 2010; 21: 1171–1179.

  8. 8

    Yenchek R, Ix JH, Rifkin DE, Shlipak MG, Sarnak MJ, Garcia M et al. Association of serum bicarbonate with incident functional limitation in older adults. Clin J Am Soc Nephrol 2014; 9: 2111–2116.

  9. 9

    Akter S, Eguchi M, Kurotani K, Kochi T, Pham NM, Ito R et al. High dietary acid load is associated with increased prevalence of hypertension: the Furukawa Nutrition and Health Study. Nutrition 2015; 31: 298–303.

  10. 10

    Goldenstein L, Driver TH, Fried LF, Rifkin DE, Patel KV, Yenchek RH et al. Serum bicarbonate concentrations and kidney disease progression in community-living elders: the Health, Aging, and Body Composition (Health ABC) Study. Am J Kidney Dis 2014; 64: 542–549.

  11. 11

    Driver TH, Shlipak MG, Katz R, Goldenstein L, Sarnak MJ, Hoofnagle AN et al. Low serum bicarbonate and kidney function decline: the Multi-Ethnic Study of Atherosclerosis (MESA). Am J Kidney Dis 2014; 64: 534–541.

  12. 12

    Macdonald HM, Black AJ, Aucott L, Duthie G, Duthie S, Sandison R et al. Effect of potassium citrate supplementation or increased fruit and vegetable intake on bone metabolism in healthy postmenopausal women: a randomized controlled trial. Am J Clin Nutr 2008; 88: 465–474.

  13. 13

    Garcia AH, Franco OH, Voortman T, de Jonge EA, Gordillo NG, Jaddoe VW et al. Dietary acid load in early life and bone health in childhood: the Generation R Study. Am J Clin Nutr 2015; 102: 1595–1603.

  14. 14

    Luis D, Huang X, Riserus U, Sjogren P, Lindholm B, Arnlov J et al. Estimated dietary acid load is not associated with blood pressure or hypertension incidence in men who are approximately 70 years old. J Nutr 2015; 145: 315–321.

  15. 15

    Bell JA, Whiting SJ . Effect of fruit on net acid and urinary calcium excretion in an acute feeding trial of women. Nutrition 2004; 20: 492–493.

  16. 16

    Remer T, Manz F . Potential renal acid load of foods and its influence on urine pH. J Am Diet Assoc 1995; 95: 791–797.

  17. 17

    Remer T, Manz F . Estimation of the renal net acid excretion by adults consuming diets containing variable amounts of protein. Am J Clin Nutr 1994; 59: 1356–1361.

  18. 18

    Johnston R, Poti JM, Popkin BM . Eating and aging: trends in dietary intake among older Americans from 1977-2010. J Nutr Health Aging 2014; 18: 234–242.

  19. 19

    Dietary Guidelines for Americans 2015-2020. United Stated Department of Agriculture and Department of Health and Human Services; 2016.

  20. 20

    Sebastian A, Frassetto LA, Sellmeyer DE, Merriam RL, Morris RC Jr . Estimation of the net acid load of the diet of ancestral preagricultural Homo sapiens and their hominid ancestors. Am J Clin Nutr 2002; 76: 1308–1316.

  21. 21

    Poupin N, Calvez J, Lassale C, Chesneau C, Tome D . Impact of the diet on net endogenous acid production and acid-base balance. Clin Nutr 2012; 31: 313–321.

  22. 22

    Lennon EJ, Lemann Jr J, Litzow JR . The effects of diet and stool composition on the net external acid balance of normal subjects. J Clin Invest 1966; 45: 1601–1607.

  23. 23

    Frassetto LA, Todd KM, Morris Jr RC, Sebastian A . Estimation of net endogenous noncarbonic acid production in humans from diet potassium and protein contents. Am J Clin Nutr 1998; 68: 576–583.

  24. 24

    Dawson-Hughes B, Harris SS, Palermo NJ, Castaneda-Sceppa C, Rasmussen HM, Dallal GE . Treatment with potassium bicarbonate lowers calcium excretion and bone resorption in older men and women. J Clin Endocrinol Metab 2009; 94: 96–102.

  25. 25

    Block G, Woods M, Potosky A, Clifford C . Validation of a self-administered diet history questionnaire using multiple diet records. J Clin Epidemiol 1990; 43: 1327–1335.

  26. 26

    Jorgensen K . Titrimetric determination of the net excretion of acid/base in urine. Scand J Clin Lab Invest 1957; 9: 287–291.

  27. 27

    Chan JC . The rapid determination of urinary titratable acid and ammonium and evaluation of freezing as a method of preservation. Clin Biochem 1972; 5: 94–98.

  28. 28

    Washburn RA, Smith KW, Jette AM, Janney CA . The Physical Activity Scale for the Elderly (PASE): development and evaluation. J Clin Epidemiol 1993; 46: 153–162.

  29. 29

    Huston HK, Abramowitz MK, Zhang Y, Greene T, Raphael KL . Net endogenous acid production and mortality in NHANES III. Nephrology (Carlton) 2015; 20: 209–215.

  30. 30

    Raphael KL, Zhang Y, Wei G, Greene T, Cheung AK, Beddhu S . Serum bicarbonate and mortality in adults in NHANES III. Nephrol Dial Transplant 2013; 28: 1207–1213.

  31. 31

    Yaroch AL, Tooze J, Thompson FE, Blanck HM, Thompson OM, Colon-Ramos U et al. Evaluation of three short dietary instruments to assess fruit and vegetable intake: the National Cancer Institute's food attitudes and behaviors survey. J Acad Nutr Diet 2012; 112: 1570–1577.

  32. 32

    Block G, Gillespie C, Rosenbaum EH, Jenson C . A rapid food screener to assess fat and fruit and vegetable intake. Am J Prev Med 2000; 18: 284–288.

  33. 33

    Pollard CM, Daly AM, Binns CW . Consumer perceptions of fruit and vegetables serving sizes. Public Health Nutr 2009; 12: 637–643.

  34. 34

    Dijkstra SC, Neter JE, Brouwer IA, Huisman M, Visser M . Misperception of self-reported adherence to the fruit, vegetable and fish guidelines in older Dutch adults. Appetite 2014; 82: 166–172.

  35. 35

    Alexy U, Kersting M, Remer T . Potential renal acid load in the diet of children and adolescents: impact of food groups, age and time trends. Public Health Nutr 2008; 11: 300–306.

  36. 36

    Wells HF, Buzby JC . Dietary Assessment of Major Trends in U.S. Food Consumption, 1970-2005. United States Department of Agriculture Economic Research Service 2008.

  37. 37

    Amodu A, Abramowitz MK . Dietary acid, age, and serum bicarbonate levels among adults in the United States. Clin J Am Soc Nephrol 2013; 8: 2034–2042.

  38. 38

    Welch AA, Mulligan A, Bingham SA, Khaw KT . Urine pH is an indicator of dietary acid-base load, fruit and vegetables and meat intakes: results from the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk population study. Br J Nutr 2008; 99: 1335–1343.

  39. 39

    Rebholz CM, Coresh J, Grams ME, Steffen LM, Anderson CA, Appel LJ et al. Dietary acid load and incident chronic kidney disease: results from the ARIC study. Am J Nephrol 2015; 42: 427–435.

  40. 40

    Massey LK . Dietary animal and plant protein and human bone health: a whole foods approach. J Nutr 2003; 133: 862S–865SS.

  41. 41

    Schatzkin A, Kipnis V, Carroll RJ, Midthune D, Subar AF, Bingham S et al. A comparison of a food frequency questionnaire with a 24-hour recall for use in an epidemiological cohort study: results from the biomarker-based Observing Protein and Energy Nutrition (OPEN) study. Int J Epidemiol 2003; 32: 1054–1062.

  42. 42

    Hu FB, Rimm E, Smith-Warner SA, Feskanich D, Stampfer MJ, Ascherio A et al. Reproducibility and validity of dietary patterns assessed with a food-frequency questionnaire. Am J Clin Nutr 1999; 69: 243–249.

  43. 43

    Hebert JR, Clemow L, Pbert L, Ockene IS, Ockene JK . Social desirability bias in dietary self-report may compromise the validity of dietary intake measures. Int J Epidemiol 1995; 24: 389–398.

  44. 44

    Miller TM, Abdel-Maksoud MF, Crane LA, Marcus AC, Byers TE . Effects of social approval bias on self-reported fruit and vegetable consumption: a randomized controlled trial. Nutr J 2008; 7: 18.

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This study was funded by NIH/NIAMS grant numbers R01AR060261 and R01AR052322 and also received support from the US Department of Agriculture, Agricultural (USDA) Research Service, under agreement No. 58-1950-7-707. Any opinions, findings, conclusion or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the USDA.

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Correspondence to M K Shea.

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Shea, M., Gilhooly, C. & Dawson-Hughes, B. Food groups associated with measured net acid excretion in community-dwelling older adults. Eur J Clin Nutr 71, 420–424 (2017). https://doi.org/10.1038/ejcn.2016.195

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