Postprandial Alkaline Tide: Does It Exist?

Johnson, C. D.; Molè, Daniela; Pestridge, A.

doi:10.1159/000201228

Cited by 16 publications

(8 citation statements)

References 11 publications

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“…Food intake triggers several physiologic responses that could affect laboratory blood biochemical markers. A meal load increases hydrochloride acid in the stomach and bicarbonate in the blood ("alkaline tide") [14]. In addition, several hormones are stimulated (e.g., insulin, glucagon) and molecules from the gut enter the blood stream [15, 16].…”

Section: Discussionmentioning

confidence: 99%

Influence of a Regular, Standardized Meal on Clinical Chemistry Analytes

et al. 2012

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BackgroundPreanalytical variability, including biological variability and patient preparation, is an important source of variability in laboratory testing. In this study, we assessed whether a regular light meal might bias the results of routine clinical chemistry testing.MethodsWe studied 17 healthy volunteers who consumed light meals containing a standardized amount of carbohydrates, proteins, and lipids. We collected blood for routine clinical chemistry tests before the meal and 1, 2, and 4 hr thereafter.ResultsOne hour after the meal, triglycerides (TG), albumin (ALB), uric acid (UA), phosphatase (ALP), Ca, Fe, and Na levels significantly increased, whereas blood urea nitrogen (BUN) and P levels decreased. TG, ALB, Ca, Na, P, and total protein (TP) levels varied significantly. Two hours after the meal, TG, ALB, Ca, Fe, and Na levels remained significantly high, whereas BUN, P, UA, and total bilirubin (BT) levels decreased. Clinically significant variations were recorded for TG, ALB, ALT, Ca, Fe, Na, P, BT, and direct bilirubin (BD) levels. Four hours after the meal, TG, ALB, Ca, Fe, Na, lactate dehydrogenase (LDH), P, Mg, and K levels significantly increased, whereas UA and BT levels decreased. Clinically significant variations were observed for TG, ALB, ALT, Ca, Na, Mg, K, C-reactive protein (CRP), AST, UA, and BT levels.ConclusionsA significant variation in the clinical chemistry parameters after a regular meal shows that fasting time needs to be carefully considered when performing tests to prevent spurious results and reduce laboratory errors, especially in an emergency setting.

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Section: Discussionmentioning

confidence: 99%

Influence of a Regular, Standardized Meal on Clinical Chemistry Analytes

et al. 2012

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“…Several studies in humans have failed to see alkaline urine and respiratory compensation following feeding (e.g. Brunton, 1933;Johnson et al, 1995). These authors have even suggested that any respiratory or urinary compensation for gastric acid secretion is too small to be of physiological or clinical significance.…”

Section: Discussionmentioning

confidence: 99%

The alkaline tide and ammonia excretion after voluntary feeding in freshwater rainbow trout

Bucking

Wood

2008

Journal of Experimental Biology

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SUMMARYWe investigated the potential acid-base and nitrogenous waste excretion challenges created by voluntary feeding in freshwater rainbow trout, with particular focus on the possible occurrence of an alkaline tide (a metabolic alkalosis created by gastric HCl secretion during digestion). Plasma metabolites (glucose, urea and ammonia) were measured at various time points before and after voluntary feeding to satiation (approximately 5% body mass meal of dry commercial pellets), as was the net flux of ammonia and titratable alkalinity to the water from unfed and fed fish. Arterial blood, sampled by indwelling catheter, was examined for post-prandial effects on pH, plasma bicarbonate and plasma CO 2 tension. There was no significant change in plasma glucose or urea concentrations following feeding, whereas plasma ammonia transiently increased, peaking at threefold above resting values at 12 h after the meal and remaining elevated for 24 h. The increased plasma ammonia was correlated with an increase in net ammonia excretion to the water, with fed fish significantly elevating their net ammonia excretion two-to threefold between 12 and 48 h post feeding. These parameters did not change in unfed control fish. Fed fish likewise increased the net titratable base flux to the water by approximately threefold, which resulted in a transition from a small net acid flux seen in unfed fish to a large net base flux in fed fish. Over 48 h, this resulted in a net excretion of 13·867·μmol·kg -1 more base to the external water than in unfed fish. The arterial blood exhibited a corresponding rise in pH (between 6 and 12 h) and plasma bicarbonate (between 3 and 12 h) following feeding; however, no respiratory compensation was observed, as Pa CO 2 remained constant. Overall, there was evidence of numerous challenges created by feeding in a freshwater teleost fish, including the occurrence of an alkaline tide, and its compensation by excretion of base to the external water. The possible influence of feeding ecology and environmental salinity on these challenges, as well as discrepancies in the literature, are discussed.

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“…This is a baseline score, to which all other supplements and foods can be compared. Previous studies [42] have suggested that diets rich in protein would consume more gastric acids. Consistent with this, Peptone (a tryptic digest of casein) buffers over a large pH range and consumes 4 mEq H + /gram dry weight to reach a pH of 4.…”

Section: Resultsmentioning

confidence: 99%

Buffer Therapy for Cancer

Ribeiro

Silva

Bailey³

et al. 2012

J Nutr Food Sci

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Oral administration of pH buffers can reduce the development of spontaneous and experimental metastases in mice, and has been proposed in clinical trials. Effectiveness of buffer therapy is likely to be affected by diet, which could contribute or interfere with the therapeutic alkalinizing effect. Little data on food pH buffering capacity was available. This study evaluated the pH and buffering capacity of different foods to guide prospective trials and test the effect of the same buffer (lysine) at two different ionization states. Food groups were derived from the Harvard Food Frequency Questionnaire. Foods were blended and pH titrated with acid from initial pH values until 4.0 to determine “buffering score”, in mmol H+/pH unit. A “buffering score” was derived as the mEq H+ consumed per serving size to lower from initial to a pH 4.0, the postprandial pH of the distal duodenum. To differentiate buffering effect from any metabolic byproduct effects, we compared the effects of oral lysine buffers prepared at either pH 10.0 or 8.4, which contain 2 and 1 free base amines, respectively. The effect of these on experimental metastases formation in mice following tail vein injection of PC-3M prostate cancer cells were monitored with in vivo bioluminescence. Carbohydrates and dairy products’ buffering score varied between 0.5 and 19. Fruits and vegetables showed a low to zero buffering score. The score of meats varied between 6 and 22. Wine and juices had negative scores. Among supplements, sodium bicarbonate and Tums® had the highest buffering capacities, with scores of 11 and 20 per serving size, respectively. The “de-buffered” lysine had a less pronounced effect of prevention of metastases compared to lysine at pH 10. This study has demonstrated the anti-cancer effects of buffer therapy and suggests foods that can contribute to or compete with this approach to manage cancer.

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Postprandial Alkaline Tide: Does It Exist?

Cited by 16 publications

References 11 publications

Influence of a Regular, Standardized Meal on Clinical Chemistry Analytes

Influence of a Regular, Standardized Meal on Clinical Chemistry Analytes

The alkaline tide and ammonia excretion after voluntary feeding in freshwater rainbow trout

Buffer Therapy for Cancer

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