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RES E AR C H Open Access
Effect of urine pH changed by dietary
intervention on uric acid clearance mechanism of
pH-dependent excretion of urinary uric acid
Aya Kanbara
1
, Yoshisuke Miura
1
, Hideyuki Hyogo
2
, Kazuaki Chayama
2
and Issei Seyama
1*
Abstract
Background: The finding reported in a previous paper - alkalization of urine facilitates uric acid excretion - is
contradictory to what one might expect to occur: because food materials for the alkalization of urine contain fewer
purine bodies than those for acidification, less uric acid in alkaline urine should have been excreted than in acid
urine. To make clear what component of uric acid excretion mechanisms is responsible for this unexpected finding,
we simultaneously collected data for the concentration of both creatinine and uric acid in serum as well as in urine,
in order to calculate both uric acid and creatinine clearances.
Methods: Within the framework of the Japanese government’s health promotion program, we made recipes which
consisted of protein-rich and less vegetable-fruit food materials for H
+
-load (acidic diet) and others composed of
less protein and more vegetable-fruit rich food materials (alkaline diet). This is a crossover study within some
limitations. Healthy female students, who had no medical problems at the regular physical examination provided
by the university, were enrolled in this consecutive 5-day study for each test. From whole-day collected urine, total
volume, pH, organic acid, creatinine, uric acid, titratable acid and all catio ns (Na
+
,K
+
,Ca
2+
,Mg
2+
,NH
4
+
) and anions
(Cl
−
,SO
4
2−
,PO
4
−
) necessary for the estimation of acid–base balance were measured. In the early morning before
breakfast of the 1st, 3rd and 5th experimental day, we sampled 5 mL of blood to estimate the creatinine and uric
acid concentration in serum.
Results and discussion: Urine pH reached a steady state 3 days after switching from ordinary daily diets to specified
regimens. The amount of acid generated ([SO
4
2−
] + organic acid − gut alkali)was linearly related with the excretion of
acid (titratable acid + [NH
4
+
] − [HCO
3
−
]), indicating that H
+
in urine is generated by the metabolic degradation of
food materials. Uric acid and excreted urine pH retained a linear relationship, as reported previously. Among the five
factors which are associated with calculating clearances for both uric acid and creatinine, we identified a conspicuous
difference between acidic and alkaline diets in the uric acid concentration in serum as well as in urine; uric acid in the
serum was higher in the acidic group than in the alkaline group, while uric acid in the urine in the acidic group was
lower than that in the alkaline group. These changes of uric acid in acidic urine and in serum were reflected in the
reduction of its clearance. From these observations, it is considered that uric acid may be reabsorbed more actively in
acidic urine than in alkaline urine.
Conclusion: We conclude that alkalization of urine by eating nutritionally well-designed alkaline -prone food is
effective for removing uric acid from the body.
Keywords: Hyperuricemia, Gout, Dietary intervention, Acid–base
* Correspondence: seyamai@gaines.hju.ac.jp
1
Department of Nutrition and Health Promotion, Faculty for Human
Development, Hiroshima Jogakuin University, 4-13-1 Ushita-higashi
Higashi-ku, Hiroshima 732-0063, Japan
Full list of author information is available at the end of the article
© 2012 Kanbara et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative
Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Kanbara et al. Nutrition Journal 2012, 11:39
http://www.nutritionj.com/content/11/1/39
Introduction
In a previous paper (2010) [1], we reported a potential
utilization of dietary intervention for reducing hyperuri-
cemia :diet-induced alkaline urine excretes more uric
acid than acidic urine. Taking into account the observa-
tions by Griesch and Zöllner (1975) [2] and Clifford,
Riumallo, Young and Scrimshaw (1976) [3] that purine
bodies loading through the diet induce a proportional
increase in serum uric acid concentration, the more pur-
ine bodies were loaded in the acidic diet, the more uric
acid should have been excreted in the urine. However,
what we observed in a previous study was the exact op-
posite. One way to resolve this issue is to measure sim-
ultaneously the concentrations of both uric acid and
creatinine in serum as well as in urine, to calculate uric
acid and creatinine clearances. By so doing, one can ob-
tain information on how uric acid is handled along the
renal tubule after the filtration, in such a way that uric
acid reabsorption proceeds in the proportion of decrease
in urine pH.
In this report, we provide conclusive evidence for the
efficiency of dietary intervention for the prevention of
hyperuricemia by showing that acidic urine causes less
uric acid to be excreted from the body than alkaline
urine does.
Methods
Subjects
Eighteen female university students (five students for
2010 and thirteen students for 2011), 21-22 years old,
participated in this study. The ethics committee at Hiro-
shima Jogakuin University approved the study protocol.
All subje cts signed informed consent documents. Al-
though four out of the eighteen participants during the
acidic diet period and three during the alkaline diet
period were obliged to discontinue the project due to
menstruation, the rest continued to participate in this
project. Thus, this became a crossover study in which
subjects were not completely overlapped. The health
condition of all participants was monitore d by measur-
ing body weight, changes in which were very limited
during the experiment periods (within less than 1% com-
pared to body weight at the beginning).
Diet
Values for protein, energy and purine contents were
extracted from the available data in the standard tables
of food composition in Japan 5th revised and enlarged
edition issued by the Ministry of Education, Culture,
Sports, Science and Technology Japan for all diets
ingested by the eighteen subjects. Resu ltant calculation
of the contents of whole protein and purine bodies in
food materials yielded 56.2 g/d in the alkaline diet and
95.4 g/d in the acidic diet for protein, and 351 mg/d in
the alkaline diet and 494 mg/d in the acidic diet for pur-
ine bodies, respectively. Amino acids in the diet which
can generate an acid in the catabolic process, such as ar-
ginine, lysine, 1/2 histidine, methionine and cystein (in
mmol), were present in 57 mmol/d in the alkaline diet
and 124 mmol/d in the acidic diet. Each diet period
lasted five days. During each five-day period, diets made
by different recipes but using the same compositions of
natural food materials were served. Foods used during
the experimental period in 2011 for both the acidic and
alkaline diets are listed in the Appendix as representative
data. Subjects had free access to mineral water. The first
and second diet periods were separated by one month.
Collection of specimens
Twenty-four-hour urine specimens were collected in
bottles and stored in a refrigerator. Volume, pH, titrat-
able acid, organi c acid and creatinine were measured in
a sample from urine collected the day before the meas-
urement. A four mL urine sample for each experimental
day for every person was stored in a deep freezer for
later ion analysis. Blood samples were collected in the
early morning before breakfast on the 1st, 3rd and 5th
experimental days.
Analytical methods
According to Lennon, Lemann, Jr. and Litzow (1966)
[4], the production of endogenous acid is determined by
the sum of 1) the oxidation of sulfate in the sulfur-
containing amino acids, 2) the endogenous formation of
unmetabolized organic acids, and 3) the net gastrointes-
tinal absorption of alkali produced by the oxidation of
organic cations and anions. Using the simplified method
proposed by Oh (1989) [5], data necessary for the net
gastrointestinal absorption of alkali (Na
+
,K
+
,Ca
2+
,Mg
2+
,
NH
4
+
,Cl
−
,PO
4
−
,SO
4
2–
) (mEq) were obtained using HPLC.
The details of methods employed may be consulted in a
previous paper [1]. The excretion of endogenous acid
consists of titratable acid, ammonium ion and bicarbon-
ate ion [4]. Titratable acid was estimated as the amount
of 0.1 mol NaOH necessary to titrate back to pH 7.4
from urine pH. Organic acid salts were measured by the
Van Slyke and Palmer method (1920) [6]. The organic
acid salt measured was corrected for titration of creatin-
ine which was determined by the Folin method. Bicar-
bonate concentration ([HCO
3
−
]) was calculated using the
Henderson-Hasselbach equation for which the solubility
coefficient of carbon dioxide was taken as 0.0309 mmol/
mmHgL and P
Ka
and P
CO2
were assumed to be 6.10
and 40 mmHg, respectively. Urine pH was measured at
37 °C with a pH meter. Uric acid was measured by the
conventional uricase-peroxidase method, using an
autoanalyzer.
Kanbara et al. Nutrition Journal 2012, 11:39 Page 2 of 7
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Statistical analysis
Data were presented as mean ± SD. The student t test
was used to test the significance of changes in measured
parameters between the acidic and alkaline periods. Dif-
ferences were assumed to be significant when p < 0.05.
Results
Relationship between acid generation in the body and
acid excretion in urine
In order to confirm that the proper loading of acid had
been achieved, we measured several factors related to
the endogenous fixed acid production and urinary acid
excretion. We listed urinary ammonium, phosphate, ti-
tratable acid, bicarbonate and sulfate together with urin-
ary pH as typical representatives in Table 1 and cationic
and anionic ion species in relation to the net gastrointes -
tinal absorption of alkali in Table 2. The significant dif-
ference in urine [SO4 2−] between the acidic and
alkaline diets was associated with the amount of sulfur-
containing amino acid in foods of 28.8 mmol/d in the
acidic and 14.5 mmol/d in the alkaline diets. Urinary
ammonium, phosphate and sulfate were inversely related
to the time course of urinary pH. On the intake of the
alkaline diet, these values were significantly lower than
those in the acidic diet (Table 1). It is interesting that
gut alkali {([Na
+
]+[K
+
] + [Ca
2+
] + [Mg
2+
])-([Cl
−
] + 1.8
[PO
4
−
])} in the acidic diet yielded much smaller value
than in the alkaline diet (Table 2, bottom line). Because
the gener ation of acid is calculated by ([SO
4
2−
] + organic
acid − gut alkali) [4], gut alkali in the acidic diet contri-
butes to the small decrease of acidity compared with
that in the alkaline diet.
The calculated total effective fixed acid production
correlated closely with renal acid excretion (Tables 1 and
2), indicating that the metabolic degradation of food
materials results in H
+
appearing in urine.
Effect of urine pH on uric acid excretion
It took 3 days to reach a steady level of urine pH of 6.7
in the alkaline diet and pH 5.9 in the acidic diet after
switching from an ordinary daily diet to either of the
designed diets (Figure 1 and Table 1). When urine pH
reached a steady state on the third experimental day,
data for the excretion of uric acid in urine on the last
three experimental days, a s expressed a s uric acid excre-
tion in mg per day (mg/d), were plotted against urine
pH (Figure 2A). The amount of excreted uric acid
increased with the increase in luminal pH, and this gen-
eral trend is consistent with the finding in our previous
paper. However, when these data were examined in de-
tail, two different regression lines could be applied to
each group of data for acidic and alkaline diets. Given
that the content of purine bodies in the alkaline diet was
less than in the acidic diet and uric acid in serum is said
to be dependent on the loading of purin e bodies [2,3], it
is reasonable to deduce that the data for alkaline diet
may have been underestimated compared with those for
the acidic diet. When one roughly corrects these data
for the loading difference in purine bodies by multiply-
ing the data for alkaline urine by the ratio of purine bod-
ies in the acidic diet and that in the alkaline of 1.74 for
the year 2010 and of 1.4 for 2011 , data appear to be
aligned along a single straight regression line, as shown
Table 1 Comparison of estimated urinary excretion of
ions associated with the acid–base balance
alkaline diet (n=30) acidic diet (n=27) p
urine volume (L/d) 1.37 ± 0.35 1.37 ± 0.65 NS
pH 6.51 ± 0.34 5.92 ± 0.28 <0.01
ammonium (mmol/d) 24.11 ± 12.78 52.13 ± 13.27 <0.01
phosphate (mmol/d) 24.64 ± 10.37 35.76 ± 14.69 <0.01
sulfate (mmol/d) 9.94 ± 3.25 21.51 ± 6.21 <0.01
titratable acid (mEq/d) 8.7 ± 3.6 25.6 ± 4.1 <0.01
urinary bicarbonate
(mEq/d)
4.7 ± 2.3 0.8 ± 0.4 <0.01
uric acid (mg/d) 413.4 ± 81.7 302.8 ± 134.7 <0.01
Table 2 Comparison of gut alkali ions excretion in acidic diet with those in alkaline diet
alkaline diet acidic diet p (between *and**)
1st day 3 ~ 5 day* 1st day 3 ~ 5 day**
(n = 13) (n = 30) (n = 14) (n = 27)
Na
+
(mEq/d) 124.4 ± 56.2 94.8 ± 37.1 134.4 ± 58.3 108.6 ± 46.5 NS
K
+
(mEq/d) 63.4 ± 38.0 66.7 ± 19.6 55.6 ± 30.0 34.6 ± 11.5 <0.05
Mg
2+
(mEq/d) 4.9 ± 3.4 5.8 ± 4.2 6.8 ± 4.7 5.0 ± 4.1 NS
Ca
2+
(mEq/d) 3.3 ± 3.3 1.7 ± 1.7 5.5 ± 4.3 2.6 ± 1.8 NS
CI
–
(mEq/d) 127.2 ± 35.4 72.9 ± 24.9 86.1 ± 35.8 89.1 ± 29.3 NS
PO
4
2-
(mEq/d) 30.1 ± 12.7 27.6 ± 9.9 42.1 ± 19.3 52.7 ± 15.1 <0.01
gut alkali(mEq/d) 38.5 ± 97.3 66.3 ± 38.1 14.3 ± 88.1 8.7 ± 45.3 <0.01
Kanbara et al. Nutrition Journal 2012, 11:39 Page 3 of 7
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Figure 1 Effect of acidic (square) and alkaline (diamond) diets on urine pH. Data are presented as mean ± SD. Asterisks indicate the
statistical significance between the two groups (p < 0.002).
Figure 2 Relationship between excreted uric acid as expressed in mg uric acid in urine per day and urine pH. In A. Diamonds indicate
data for the alkaline diet and squares those for the acidic diet. The equation for the straight line obtained by the least square method is
y = 118.9x-335.8 (r2 = 0.2098, n = 57, p < 0.01). In B. Corrected relationship between excreted uric acid as expressed in mg uric acid in urine per
day and urine pH. Given the loading difference of purine bodies, data for uric acid excreted in alkaline urine were multiplied by correction factors,
as described in the text. The equation for the straight line obtained by the least square method is y = 332.25x-1525.6 (r2 = 0.5406, n = 57, p < 0.01).
Kanbara et al. Nutrition Journal 2012, 11:39 Page 4 of 7
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in Figure 2B, indicating, at least in part, that their load-
ing difference may well be responsible for the data
scattering.
Differential effects of urine pH on the clearances for
creatinine and for uric acid
We conducted simultaneous measurements of creatinine
and uric acid in both the serum and urine in order to
confirm which factor was responsible for the pH
dependent uric acid excretion. Necessary data were
available to calculate both creatinine and uric acid clear-
ances − creatinine and uric acid concentrations in both
serum and urine, as shown in Table 3. In this paper, be-
cause data for the first experimental day was not under
influence of designed diets but of ordinary diets, it is
reasonable to use them hereafter as baseline data. We
calculated the absolute creatinine clearance and uric acid
clearance with a correction of body surface area [7]: the
mean value of creatinine clearance in alkaline urine was
133.9 ± 19.7 (n = 19) mL/mi n/1.73 m
2
and that in acidic
urine 138.8 ± 21.4 (n = 19) mL/min/1.73 m
2
respectively.
Although the difference in dietary protein loading
should have produced a fluctuation of blood flow in the
kidney [8], which in turn might increase urine volume
and affect creatinine clearance, its fluctuation in our case
was limited, as seen in Table 2. In spite of the difference
in mean values, statistical significance was not recog-
nized (p > 0.1). On the other hand, it is noteworthy that
the uric acid clearance with a correction of body surface
area only in acidic urine significantly decreased from the
baseline value of 10.0 ± 1.8 (n = 14) mL/min/1.73 m
2
to
the mean value on the 3rd and 5th experimental day s of
6.0 ± 2.2 (n = 19) mL/min/1.73 m
2
, while that in the alka-
line urine remained more or less unchanged in the range
between the baseline value of 8.9 ± 2.0 (n = 13) mL/min/
1.73 m
2
and the mean value of the 3rd and 5th experi-
mental days of 8.6 ± 2.3 (n = 19) mL/min/1.73 m
2
. Statis-
tical significance was recognized (p < 0.02) in the
difference of mean values on the 3rd and 5th experimen-
tal days between acidic and alkaline urine. In the case of
uric acid, the mean concentrations of excreted uric acid
changed from 37.4 ± 17.1 (n = 14) mg/dL for the acidic
diet and 45.3 ± 20.4 (n = 13) mg/dL for the alkaline diet as
the ba seline value to 25.9 ± 10.0 (n = 19) mg/dL of aver-
age value for the 3rd and 5th experimental days in the
acidic diet and to 37.0 ± 11.2 (n = 19) mg/dL for the 3rd
and 5th experimental days in the alkaline diet, respect-
ively (Table 3). Meanwhile, the mean concentration of
uric acid in serum for the ba seline value in the acidic diet
of 4.3 ± 0.6 mg/dL increased to 4.9 ± 0.6 (n = 19) mg/dL
for the 3rd and 5th experimental days, but that in the
alkaline diet of 4.2 ± 0.8 remained in the same range of
4.3 ± 0.8 (n = 19) mg/dL for the 3rd and 5th experimental
days, respectively (Table 3). These data indicate that the
disparity of the serum concentration of uric acid be-
tween the two diets at least depends on the difference
in purine bodies loading , because, in our experiment,
the acidic diet contained more purine body at 494 mg/d
than the alkalin e diet at 351 mg/d. The data obtained
are consistent with previous reports [2,3] that serum uric
acid concentration is proportion al to dietary loading of
purine body. When the uric acid clearance was calcu-
lated, the difference in uric acid con centration in both
urine and serum between the acidic and alkaline diets
showed a strikingly lower uric acid clearance in the
acidic diet compared with that in the alkaline diet
(Table 3).
In the circumstance, as in this study, in which healthy
students live sedentary lives, taking nearly ordinary diets,
these stable creatinine clearances may be reasonably
assumed to be close to the glomerular filtration rate.
Thus, to make it easy to resolve what mechanism was at
work here, we took the ratio of uric acid clearance to
creatinine clearance:fractio nal uric acid excretion, calling
it R where R = ([uric acid in a unit urine] × [creatinine in
a unit serum]/[uric acid in a unit serum] × [creatinine
in a unit urine]) × 100 (%). While creatinine clearances
in both acidic and alkaline diets remain in a similar
range, it has been found that uric acid clearance in an
acidic diet is suppressed. Thus , it is reasonable to assume
that R in an alkaline diet should be larger than in an
acidic diet. As shown in Figure 3, that was the case. R in
the alkaline diet on both the 3rd and 5th experimental
days was consistently greater than that in the acidic diet
after the settling down of urine pH to a steady state level.
Discussion
The most conspicuous result in this study is the
provision of additional experimentally prov en evidence
for the previous study, that uric acid excretion is more
favorable in alkaline urine than in acidic urine. The
strategy taken here for reconfirming our previous study
Table 3 Effect of diet-induced H
+
load on factors for both
creatinine and uric acid clearances
alkaline diet acidic diet p
(n = 19) (n = 19)
serum uric acid (mg/dL) 4.3 ± 0.8 4.9 ± 0.6 <0.01
serum creatinine (mg/dL) 0.58 ± 0.08 0.63 ± 0.06 NS
urine uric acid (mg/dL) 37.0 ± 11.2 25.9 ± 10.0 <0.01
urine creatinine (mg/dL) 78.9 ± 24.3 79.3 ± 18.0 NS
urine volume (mL/day) 1270 ± 436 1429 ± 320 NS
Uric acid clearance (mL/min/1.73 m
2
) 8.6 ± 2.3 6.0 ± 2.2 <0.01
Creatinine clearance (mL/min/1.73 m
2
) 133.9 ± 19.7 138.8 ± 21.4 NS
All numerical data were collected from records during the 3rd and 5th
experimental days.
Kanbara et al. Nutrition Journal 2012, 11:39 Page 5 of 7
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was to collect data for calculating the clearances for both
uric acid and creatinine. As seen in Table 3, among the
five parameters, uric acid and creatinine concentrations,
both in urine and in serum and urine volume, a differ-
ence between alkaline and acidic diets is only detected in
the concentration of uric acid in serum and in urine. Both
the decrease in uric acid excretion and the increase in
serum uric acid concentration in the acidic diet during
the 3rd and 5th experimental days made the uric acid
clearance significantly lower than that in the alkaline diet.
Taking into account that in the physiological condition
urate handling involves urate glomerular filtration fol-
lowed by a complex array of reabsorptive and secretory
mechanisms taking place in the proximal tubules, result-
ing in fractional excretion of urate being 10% [9] of glom-
erular filtrate, either secretive or reabsorptive function of
uric acid may be able to participate in excretion of urate
modified by the change in urine pH. Although the relative
importance of the reabsorption and secretion mechan-
isms has not yet been determined in detail due to the
complexity of renal urate handling, a dominant factor for
controlling urate excretion is considered to be reabsorp-
tion, because a hereditary dysfunction of URAT 1(urate/
organic anion exchanger)-lack of reabsorption of luminal
urate through URAT 1- causes severe hypouricemia [10].
Thus, for the sake of simplicity in this paper modification
of renal urate transport by the change in urine pH is ten-
tatively assumed to be confined to the reabsorption
mechanism. The findings so far obtained show that uric
acid excretion was greater in the alkaline diet than in the
acidic diet, indicating that reabsorption ability may be
enhanced in an acidic medium. Further confirmation of
reabsorption enhancement in an acidic medium is given
by the calculation of clearances for both creatinine and
uric acid. Resultant creatinine clearances for acidic and
alkaline diets were in a similar range, indicating that the
glomerular filtration rate in both acidic and alkaline diets
remains stable. As shown in Figure 3, Rs in the alkaline
diet are consistently larger than in the acidic diet after
urine pH has settled down to a steady state level. These
findings strongly indicate that, after complicated absorp-
tion and secretion processes on both apical and basolat-
eral membranes in the proximal tubule have taken part in
uric acid transport after filtration [9-11], uric acid
excretes more favorably in alkaline urine than in acidic
urine. The molecular identity responsible for pH-
dependent uric acid transport is still unclear, but at the
moment not quantitative but qualitative characteristics of
human organic anion transporter 4 (hOAT4) [12] support
our findings, because a main urate transporter in the
proximal tubule is claimed to be URAT1 [9].
Since the study was conducted exclusively on female stu-
dents, experiments of the same kind need to be performed
on male students, on older populations and also on people
with hyperuricemia at baseline for generalization of dietary
intervention. Given the recent dramatic increase in the inci-
dence of gout and hyperuricemia associated with cardiovas-
cular diseases and metabolic syndrome [13], it is highly
desirable to introduce a safe and economic way to reverse
these trend s. The dietary intervention procedure for cardio-
vascular diseases [14] and diabetes mellitus, including
metabolic syndrome [15] and cancer [16], shares with its
similar focus on gout and hyperuricemia the recommenda-
tion of taking a sufficient amount of alkaline-rich fruits and
vegetables. Because people can take a preventive procedure
for these diseases without side effects by following this sug-
gestion, we believe that the dietary intervention we are pro-
posing is one of the best choices.
Figure 3 Change in fractional uric acid excretion, Rs (uric acid clearance/creatinine clearance) were obtained and plotted on each
experimental day. Asterisks indicate the statistical significance between the two groups (p < 0.002).
Kanbara et al. Nutrition Journal 2012, 11:39 Page 6 of 7
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Appendix
(alkaline diet)
White rice 100 g, rye bread 70 g, pasta 80 g , starch 20 g,
hard tofu 50 g, silken tofu 50 g, pressed tofu 30 g, fried
tofu 6 g, okara 40 g, green soybeans 10 g, milk 150 g, car-
rot 20 g, leaf vegetable 65 g, tomato 120 g, pepper (red &
yellow) 30 g, pumpkin 80 g, green onion 15 g, onion 50 g,
cucumber 60 g, cabbage 60 g , lettuce 30 g, garlic 5 g, po-
tato 100 g, aroid 45 g, yam 30 g, mushroom 40 g, kiwi
70 g, pineapple 50 g, walnuts 15 g , dried seaweed 1 g,
sugar 8 g, honey 20 g, olive oil 5 g, salad oil 10 g, dressing
8 g, butter 10 g, soy saurce 5 g, vinegar 3 g, soup prepared
from dried bonito and tangle 180 g, alcohol for cooking
15 g, miso(fermented soybeans paste) 7 g, sauce 20 g,
Japanese basil 1 g, sweet cooking rice wine 4 g, salt 0.5 g,
pepper 0.06 g, mayonnaise 10 g.
(acidic diet)
White rice 185 g, roll 75 g, pasta 20.5 g, starch 6 g, pork
shoulder 90 g, cero 90 g, chicken breast fillet 30 g, squid
30 g, egg 100 g, processed cheese 20 g, carrot 50 g, broccoli
20 g, snap pea 20 g, asparagus 20 g, green onion 10 g, bam-
boo sprout 40 g, corn 25 g, onion 50 g, burdock 15 g,
sprout 20 g, tomato saurce 15 g, soy source 6 g, salt 0.8 g,
sweet cooking rice wine 12 g, alcohol for cooking 20 g,
pepper 0.09 g, miso 9 g, consommé 1 g, soup prepared
from dried bonito and tangle 170 g, mayonnaise 9 g, butter
3 g, salad oil 6 g, sugar 9 g, strawberry jam 20 g.
Competing interests
The authors declare that they have no competing interests.
Acknowledgments
This work was supported in part by a Hiroshima Jogakuin University research
grant.
Author details
1
Department of Nutrition and Health Promotion, Faculty for Human
Development, Hiroshima Jogakuin University, 4-13-1 Ushita-higashi
Higashi-ku, Hiroshima 732-0063, Japan.
2
Department of Medicine and
Molecular Sciences, Graduate School of Biomedical Sciences, Hiroshima
University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
Authors’ contributions
AK carried out the analysis of all urine contents and the integration of data
into the report. YM, HH and KC participated in the design of the study and
helped to draft the manuscript. IS conceived of the study, helped to draft
the manuscript and participated in analysis and integration of data. All
authors read and approved the final manuscript.
Received: 17 December 2011 Accepted: 7 June 2012
Published: 7 June 2012
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doi:10.1186/1475-2891-11-39
Cite this article as: Kanbara et al.: Effect of urine pH changed by dietary
intervention on uric acid clearance mechanism of pH-dependent
excretion of urinary uric acid. Nutrition Journal 2012 11:39.
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