Hydration Efficacy of a Milk Permeate-Based Oral Hydration Solution

Abstract

Milk permeate is an electrolyte-rich, protein- and fat-free liquid with a similar carbohydrate and mineral content to that of milk. Its hydration efficacy has not been examined. The beverage hydration index (BHI) has been used to compare various beverages to water in terms of post-ingestion fluid balance and retention. Our purpose was to compare the BHI (and related physiological responses) of a novel milk permeate solution (MPS) to that of water and a traditional carbohydrate–electrolyte solution (CES). Over three visits, 12 young subjects consumed 1 L of water, CES, or MPS. Urine samples were collected immediately post-ingestion and at 60, 120, 180, and 240 min. BHI was calculated by dividing cumulative urine output after water consumption by cumulative urine output for each test beverage at each time point. The BHI for MPS was significantly higher at all time points compared to water (all p < 0.001) and CES (all p ≤ 0.01) but did not differ between CES and water at any time point. Drinking 1 L of MPS resulted in decreased cumulative urine output across the subsequent 4 h compared to water and CES, suggesting that a beverage containing milk permeate is superior to water and a traditional CES at sustaining positive fluid balance post-ingestion.

The Beverage Hydration Index: Influence of Electrolytes, Carbohydrate and Protein

“…The BHI for a sports drink (with 3.9% carbohydrate, 21 mmol Na + ) was originally reported as not different from water [ 15 ]. The sports drink in that investigation had 33% lower carbohydrate than in the current study (but similar electrolytes); however, a 6% sports drink was later confirmed [ 16 , 19 ] to be no different from water (BHI < 1.10) in contrast to other observations [ 17 ] and those reported here indicating a higher BHI for sports drinks in young adults. Moreover, adding carbohydrate (at 3, 6, and 12%) retained more fluid compared to placebo water without electrolytes over a 4-h post-exercise rehydration period, but the carbohydrate content per se did not impact fluid retention [ 7 ].…”

“…The type of carbohydrate found in a beverage may also be a factor influencing the BHI. Berry et al [ 16 ] reported a milk permeate solution (devoid of fat and protein) with 4% glucose/galactose had a higher BHI (>1.2) compared to water, unlike a 6% sucrose/glucose sports drink. However, the fact that the milk permeate beverage had much higher mineral content (e.g., 28 mmol/L K + ) and nearly 300 mosmol/kg higher osmolality (with contributions from magnesium, phosphorous, calcium, and chloride) despite a similar sodium and lower carbohydrate makes it difficult to clearly differentiate the impact of the carbohydrate type on BHI.…”

“…BHI assesses the hydration potential of a consumable fluid relative to plain water when individuals are in a resting state and assumes that a beverage with greater diuresis relative to water has less available fluid retained in the total body water pool (and a BHI index below 1.0). Although a relatively new metric for beverages analogous to a scale comparing the glycemic index for foods [ 15 ], the BHI has since been replicated by several other groups [ 14 , 16 , 17 , 18 , 19 ]. Notably, the impact of population-specific variables, such as body mass and sex, appear minimal, and the reproducibility of BHI is reportedly robust [ 19 ].…”

“…The impact of adding electrolytes to water appears to result in a greater fluid retention when using the BHI method [ 13 , 18 ]. However, the minimum level of sodium to accomplish this is not consistent across studies since several report the BHI of sports drinks (~20 mmol sodium) does not necessarily yield a significantly greater BHI compared to the water control [ 15 , 16 , 19 ]. This point bears additional investigation since sports drinks are frequently touted for general public use as a viable beverage for oral rehydration following dehydration.…”

Influence of Nutrient Intake on 24 Hour Urinary Hydration Biomarkers Using a Clustering-Based Approach

“…Nutrients may mediate and/or moderate total body water and fluid homeostasis by influencing the osmotic pathways responsible for intra- and extra-cellular fluid shifts within the body. Determining the types of nutrients that mediate and/or moderate total body water and fluid homeostasis is of continued interest within the scientific literature [ 20 , 21 , 22 , 23 ]. Within sport and exercise settings specifically, investigating how beverage composition optimizes total body water and restores body water deficits has been thoroughly investigated [ 24 ] and evidence shows that the addition of sodium [ 23 , 25 , 26 ], carbohydrates [ 27 ], and protein [ 28 , 29 ] improves water retention and restores body water lost in sweat.…”