Eating Fruits and Veggies? Check Urine pH

Noelle Holly, MD

In an article to appear in the upcoming British Journal of Nutrition, researchers at the Norfolk, UK branch of EPIC (European Prospective Investigation into Cancer and Nutrition) have shown that a diet high in fruits and vegetables and low in meat -- what they call an "alkaline" diet -- correlates with alkaline urine.[1]

Urinary biomarkers have been shown to reflect dietary intake and nutritional status with some degree of accuracy. For example, 24-hour urinary excretion of nitrogen and potassium and self-reported, seven-day dietary intake have been shown to correlate.[2]

In the current study, a subpopulation of EPIC (n=363) provided casual and 24-hour urine samples and completed a quantified dietary recall over the past week using a validated self-report tool called the seven-day diary. Individuals with an alkaline diet -- high in fruits in vegetables and low in acidic foods like meats -- were identified as having a low potential renal acid load and alkaline urinary pH, according to the seven-day diary.

As more data on the long-term effects of diet are collected, expect to hear more about dietary acid-base load and other objective markers of dietary habits.

EPIC is the largest prospective cohort study of diet, lifestyle, and health outcomes (including cancer) ever conducted, having followed over a half-million subjects in 10 countries from 1993-1999.[3]

References

1. Welch AA, Mulligan A, Bingham SA, Khaw KT. Urine pH is an indicator of dietary acid-base load, fruit and vegetables and meat intake: results from the EPIC-Norfolk population study. Br J Nutr. 2007; e-pub ahead of print.

2. McKeown NM, Day NE, Welch AA, et al. Use of biological markers to validate self-reported dietary intake in a random sample of EPIC United Kingdom Norfolk cohort. Am J Clin Nutr 2001;74:188-196.

3. The EPIC Project.