Alkaline mineral water lowers bone resorption even in calcium sufficiency:: Alkaline mineral water and bone metabolism☆
Introduction
The beneficial effects of numerous mineral waters on bone metabolism are mainly attributed to their calcium content [1], [2], [3], [4], [5], [6]. Calcium-rich mineral waters are an alternative to dairy products as their bioavailability is similar or even better [7]. They have decreased bone resorption, but only in short-term trials or in calcium and oestrogen deficiency [3]. Minerals other than calcium, especially bicarbonate, also have a positive effect on bone metabolism [8], [9]. Nutritional acid load contributes to the age related bone loss [10]. To keep pH constant, the organism uses buffer systems such as bone, expiration of CO2 and renal excretion of acids [11]. The endogenous production of acid, consequent to a normal Western diet, is about 1 mEq/kg body weight, per day [12]. To buffer this, 2 mEq of calcium is necessary [12]. The more acid precursors a diet contains, the greater the need for buffering [13] and the enhancement of bone resorption. In addition, with advanced age, the ability to excrete acids by the kidney declines [14].
In vitro, an efflux of calcium from bone tissue is already noted after 3 h incubation in an acidic medium [15]. Indeed, bone has been shown to contribute to the maintenance of the extra-cellular fluid pH [16]. A low acid diet could contribute to the maintenance of bone mineral density [17]. In healthy subjects, supplements of potassium bicarbonate, potassium citrate, and even mineral water rich in bicarbonates decreased the calciuria and bone resorption markers [18], [19], [20], [21].
We investigated whether a high bicarbonate and calcium intake from an alkaline mineral water decreases bone resorption more than a high calcium intake from an acid water, in healthy subjects on a balanced diet adapted to their energetic needs.
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Subjects and methods
For this open, randomized, controlled study, thirty female dieticians or student dieticians were recruited. The inclusion criteria were good health, 18–45 years and BMI 18.5–25 kg/m2. The exclusion criteria were medication interfering with calcium metabolism (diuretics, corticoids), pregnancy, and inclusion in other protocols. They were declared healthy after completion of a medical questionnaire. Out of the 30 participants, 23 were on the contraceptive pill.
The subjects were randomized into 2
Results
The two groups were comparable in age (group A: 26.3 yrs ± 7.6; group B: 26.3 yrs ± 7.3) and BMI (group A: 20.6 ± 1.8 kg/m2; group B: 21.3 ± 2.3 kg/m2). The blood formula and the glycaemia were all in the reference limits. There were no significant differences among the two groups in any of the laboratory values, as well as in age, height, weight and BMI.
Being dieticians, the participants showed excellent compliance and perfect understanding of the diet plan. All 30 volunteers completed the study.
Discussion
A 4-week dietetic intervention with 1.5 daily litres of calcium-rich mineral waters showed that additional bicarbonate enhances inhibition of bone resorption. The effect of calcium-rich mineral water on bone resorption has already been shown, but in postmenopausal, calcium-deficient women [3], [23]. Our study was performed in calcium- and oestrogen-sufficient women.
Since all subjects followed the same diet plan, it can be assumed that all differences observed were not influenced by changes in
Conclusion
In conclusion, the present study showed that a bicarbonate- and calcium-rich alkali mineral water decreased bone resorption more than a calcium-rich acidic mineral water, in healthy pre-menopausal subjects on a calcium sufficient balanced diet. Further investigations need to be undertaken to study whether these positive effects are maintained on the long-term and if they can influence bone mineral density.
Acknowledgments
EW: performed the study and wrote the manuscript.
MAK: provided permanent scientific supervision.
JMA: performed all statistical tests.
PB: wrote the research protocol, directed and coordinated the study and supervised the manuscript.
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2022, Advances in Chronic Kidney DiseaseCitation Excerpt :In contrast, a community-based study showed that incomplete dRTA was not associated with lower BMD.70 In addition to the epidemiological studies linking acidosis to worse skeletal outcomes, interventional studies examined the impact of alkali therapy on parameters of bone health (Table 2) using different preparations including alkaline water,71,72 fruits and vegetables,73-75 sodium bicarbonate,76,77,78 potassium bicarbonate,79–81 or potassium citrate38,42,74,82–87,88 in a range of doses. The studies also varied in design (uncontrolled vs controlled, parallel vs cross-over design), duration (2 weeks to 2 years), the use of placebo vs nonalkaline control salt (eg, KCl for KCitrate or KHCO3), and outcomes (bone turnover or BMD).
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2021, The Lancet Diabetes and EndocrinologyCitation Excerpt :The bioavailability of calcium from calcium-rich mineral waters is excellent, and probably comparable with that from dairy products.22 Alkaline water rich in bicarbonates might decrease parathyroid hormone (PTH) and bone turnover markers.23 The recommended dietary calcium intake is 800–1200 mg per day,5 which is a compromise between various national recommendations.24
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This study was funded by the Foundation for Research on Osteoporosis and Bone Diseases, Lausanne, Switzerland. The manufacturers generously provided the mineral water.