Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Bioavailability of soluble oxalate from tea and the effect of consuming milk with the tea


Objectives: To measure the availability of oxalate normally extracted when making tea from two commercially available black teas bought from a supermarket in Christchurch, New Zealand in July 2001.

Design, subjects and intervention: A randomized double crossover study. Six students and four staff consumed six cups of each brand of tea both with and without added milk over a 24 h period. A total urine collection was taken for the initial 6 h followed by a further 18 h. The oxalate content of the urine voided was measured using an enzyme kit method and the availability of the soluble oxalate consumed was measured for the 6 h and the total 24 h sample.

Setting: University campus.

Results: The mean soluble oxalate content of black tea in the two different commercial tea bags was respectively 6.1 and 6.3 mg soluble oxalate/g tea. The mean availability of the oxalate extracted from tea measured over a 6 h period ranged from 1.9 to 4.7% when tea was consumed without milk. The availability of the soluble oxalate from tea ranged from −3.0 to 2.3% for each of the two brands of tea investigated over a 24 h period.

Conclusion: These studies show that consuming black tea on a daily basis will lead to a moderate intake of soluble oxalate each day, however the consumption of tea with milk on a regular basis will result in the absorption of very little oxalate from tea.

Sponsorship: Lincoln University.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type



Prices may be subject to local taxes which are calculated during checkout


  • Albihn, PBE & Savage, GP (2001a). The effect of cooking on the location and concentration of oxalate in three cultivars of New Zealand-grown oca (Oxalis tuberosa Mol). J. Sci. Food Agric., 81, 1–7.

    Article  Google Scholar 

  • Albihn, PBE & Savage, GP (2001b). The bioavailability of oxalate from oca (Oxalis tuberosa). J. Urol., 166, 420–422.

    Article  CAS  Google Scholar 

  • Barilla, DE, Notz, C, Kennedy, BS & Pak, CYC (1978). Renal oxalate excretion following oral loads in patients with ileal disease and with renal and absorptive hypercalciurias, effect of calcium and magnesium. Am. J. Med., 64, 579–585.

    Article  CAS  Google Scholar 

  • Brinkley, L, MgGuire, J, Gregory, J & Pack, CYC (1981). Bioavailability of oxalate in foods. Urology, 17, 534–553.

    Article  CAS  Google Scholar 

  • Brinkley, LJ, Gregory, J & Pak, CYC (1990). A further study of oxalate bioavailability. J. Urol., 144, 94–99.

    Article  CAS  Google Scholar 

  • Charrier, MJS, Savage, GP & Vanhanen, L (2002). Oxalate content and calcium binding capacity of tea and herbal teas. Asia Pacific J. Clin. Nutr., (in press)

  • Curhan, GC, Willett, WC & Rimm, EB et al (1996). Prospective study of beverage use and the risk of kidney stones. Am. J. Epidemiol., 143, 240–247.

    Article  CAS  Google Scholar 

  • Curhan, GC, Willett, WC, Speizer, FE & Stampfer, MJ (1998). Beverage use and risk for kidney stones in women. Ann. Intern. Med., 128, 534–540.

    Article  CAS  Google Scholar 

  • Finch, AM, Kasidas, GP & Rose, GA (1981). Urine composition in normal subjects after oral ingestion of oxalate-rich foods. Clin. Sci., 60, 411–418.

    Article  CAS  Google Scholar 

  • Heaney, RP, Weaver, CM & Recker, RR (1988). Calcium absorbability from spinach. Am. J. Clin. Nutr., 47, 707–709.

    Article  CAS  Google Scholar 

  • Holmes, RP, Goodman, HO & Assimos, DG (1996). Metabolic effects of an oxalate-free-diet. In:Urolithias, ed. CYC Pak, M I Resnick & GM Preminger, pp.167–168, Dallas, TX: Millet

    Google Scholar 

  • Liebman, M & Chai, W (1997). Effect of dietary calcium on urinary oxalate excretion after oxalate loads. Am. J. Clin. Nutr., 65, 1453–1459.

    Article  CAS  Google Scholar 

  • Marangella, M, Futtero, M, Bruno, M & Linari, F (1982). Hyperoxaluria in ideopathic calcium stone disease: further evidence of intestinal hyperabsorbtion of oxalate. Clin. Sci., 63, 381–385.

    Article  CAS  Google Scholar 

  • Marshall, RW, Cochran, M & Hodgkinson, A (1972). Relationships between calcium and oxalic acid intake in the diet and their excretion in the urine of normal and renal-stone-forming subjects. Clin. Sci., 43, 91–99.

    Article  CAS  Google Scholar 

  • Masai, M, Ito, H & Kotake, T (1995). Effect of dietary intake on urinary oxalate excretion in calcium renal stone disease. Br. J. Urol., 76, 692–699.

    Article  CAS  Google Scholar 

  • Massey, LK (2000). Tea oxalate. Nutr. Rev., 58, 88–89.

    Article  CAS  Google Scholar 

  • Massey, LK, Roman-Smith, H & Sutton, RAL (1993). Effect of dietary oxalate and calcium on urinary oxalate and risk of formation of calcium oxalate kidney stones. J. Am. Diet. Assoc., 93, 901–906.

    Article  CAS  Google Scholar 

  • McKay, DW, Sevior, JP, Comerford, A, Vasdev, S & Massey, LK (1995). Herbal tea: An alternative to regular tea for those who form calcium oxalate stones. J. Am. Diet. Assoc., 95, 360–361.

    Article  CAS  Google Scholar 

  • Noonan, SC & Savage, GP (1999). Oxalate content of foods and its effect on humans. Asia Pacific J. Clin. Nutr., 8, 64–67.

    Article  CAS  Google Scholar 

  • Savage, GP, Vanhanen, L, Mason, SL & Ross, AB (2000). Effect of cooking on the soluble and insoluble oxalate content of some New Zealand foods. J. Food Comp. Anal., 13, 201–206.

    Article  CAS  Google Scholar 

  • Weaver, CM, Heaney, RP, Nickel, KP & Packard, PI (1997). Calcium bioavailability from high oxalate vegetables: Chinese vegetables, sweet potatoes, potatoes and rhubarb. J. Food. Sci., 62, 524–552.

    Article  CAS  Google Scholar 

  • Zarembski, M & Hodgkinson, A (1962). The oxalic content of English diets. Br. J. Nutr., 16, 627–663.

    Article  CAS  Google Scholar 

Download references


The authors wish to acknowledge Trevor Walmsley, Canterbury Health Laboratories, Christchurch, NZ, for his assistance with the analysis of urinary oxalate and Professor D McNeil, Plant Sciences, Lincoln University for his assistance with the statistical analysis of the data.

Author information

Authors and Affiliations



Guarantor: GP Savage.

Contributors: MJSC carried out the study, LV provided technical support, GPS supervised the study and wrote the manuscript.

Corresponding author

Correspondence to G P Savage.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Savage, G., Charrier, M. & Vanhanen, L. Bioavailability of soluble oxalate from tea and the effect of consuming milk with the tea. Eur J Clin Nutr 57, 415–419 (2003).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


This article is cited by


Quick links