Comparing Response of Sheep and Cow Milk on Acute Digestive Comfort and Lactose Malabsorption: A Randomized Controlled Trial in Female Dairy Avoiders

Aahana Shrestha; Linda M Samuelsson; Pankaja Sharma; Li Day; David Cameron-Smith; Amber M Milan

doi:10.3389/fnut.2021.603816

Comparing Response of Sheep and Cow Milk on Acute Digestive Comfort and Lactose Malabsorption: A Randomized Controlled Trial in Female Dairy Avoiders

Front Nutr. 2021 Feb 15:8:603816. doi: 10.3389/fnut.2021.603816. eCollection 2021.

Authors

Aahana Shrestha^{1

2}, Linda M Samuelsson³, Pankaja Sharma^{1

2}, Li Day³, David Cameron-Smith^{1

2

4}, Amber M Milan^{1

3}

Affiliations

¹ The Liggins Institute, The University of Auckland, Auckland, New Zealand.
² Riddet Institute, Palmerston North, New Zealand.
³ AgResearch Ltd., Te Ohu Rangahau Kai, Palmerston North, New Zealand.
⁴ Singapore Institute for Clinical Sciences, Agency for Science, Technology, and Research, Singapore, Singapore.

Abstract

Background: Sheep milk (SM) is a possible alternate dairy source for those who experience digestive symptoms with cow milk (CM). While both the milks contain lactose, one of the causes for self-reported intolerance to CM, the composition of SM and CM also differs across proteins and fats, which have been shown to impact digestive processes. Objective: To compare the acute digestive comfort and lactose malabsorption of SM to CM in female dairy avoiders. Method: In a double-blinded, randomized cross over trial, 30 dairy-avoiding females (aged 20-30 years) drank 650 mL of SM or CM (each reconstituted from spray dried powder) following an overnight fast, on two separate occasions at least 1 week apart. Blood samples were collected for glucose and insulin assessment, and single nucleotide polymorphisms of the lactase (LCT) gene (C/T₁₃₉₁₀ and G/A₂₂₀₁₈). Breath H₂ and visual analog scale (VAS) digestive symptom scores were recorded at fasting and regular intervals over 4 h after ingestion. Results: Eighty percentage of study participants were lactase non-persistent (LNP; CC₁₃₉₁₀ and GG₂₂₀₁₈ genotype). Digestive symptoms, including abdominal cramps, distension, rumbling, bloating, belching, diarrhea, flatulence, vomiting, and nausea, were similar in response to SM and CM ingestion (milk × time, P > 0.05). Breath H₂ was greater after CM than SM (72 ± 10 vs. 43 ± 6 ppm at 240 min, P < 0.001), which may be due to greater lactose content in CM (33 vs. 25 g). Accordingly, when corrected for the lactose content breath H₂ did not differ between the two milks. The response remained similar when analyzed in the LNP subset alone (n = 20). Conclusions: Despite a higher energy and nutrient content, SM did not increase adverse digestive symptoms after ingestion, relative to CM, although there was a reduced breath H₂ response, which could be attributed to the lower lactose content in SM. The tolerability of SM should be explored in populations without lactose intolerance for whom underlying trigger for intolerance is unknown.

Keywords: bovine milk; dairy avoidance; digestive comfort; lactose intolerance; milk intolerance; ovine milk; postprandial.