The aim of this study is to evaluate the effects of A2 milk on gut beneficial bacteria growth, antioxidant activity , digestion, and inflammation improvement
Milk has a high calcium content, and calcium in milk is easily digested and absorbed and has an excellent utilization rate in the body. Milk is rich in lactose, Vitamin D, and peptides that facilitate calcium absorption, and it also contains essential amino acids and bioactive substances that are beneficial to health. Regularly drinking milk has been proven to improve insulin sensitivity, blood pressure, and serum lipid concentrations. Furthermore, milk is reported to be an effective food for nutritional supplementation and improvement in the diet of Koreans, as it contains a well balanced source of essential amino acids that can be lacking in a rice centric diet, along with quality animal protein, calcium, vitamin B2, and other nutrients. However, this increase in dairy consumption can be associated with an increased risk for certain disorders, including digestive disorders. The actual prevalence of lactose intolerance is unclear in Korea, and reports have ranged from 39.1% to 84.1%. In 2010, it was reported that in most individuals who believed they had lactose intolerance, no evidence of problems with lactose absorption could be found, and thus, gastrointestinal symptoms were unlikely to be associated with lactose. Alternatively, A1 β-Casein and β-Casomorphin-7 (BCM-7) has emerged as a major area for research in relation to digestive discomfort following milk consumption. Milk is composed of 80% Casein protein and 20% whey. Among Casein proteins, β-Casein can be divided into the A1 type comprised of A1, B, C, F, and G, and the A2 type with A2, A3, D, E, H, I, and J variants. A1 and A2 type β-Casein proteins differ in their 67th amino acid, with A1 containing Histidine and B2 with Proline. The other remaining variants are only found in low levels or not found in European cattle. Furthermore, BCM-7, which is produced when enzymatic cleavage at the histidine position occurs in A1 β-Casein, has been associated with digestive discomfort. Additionally, milk containing A1 β-Casein has been linked to type 1 diabetes and heart disease. Nevertheless, the majority of dairy cattle in dairy industries continue to produce milk containing A1 β-Casein. Animal tests have shown that milk with A1 β-Casein takes longer to transit through the digestive tract compared to A2 β-Casein containing milk. In addition, a clinical trial reported that the Bristol stool scores in participants who consumed A1 β-Casein milk were higher than those in A2 β-Casein milk. Another clinical trial announced that A2 β-Casein milk alleviated gastrointestinal symptoms of milk hypersensitivity. In addition, there are reports that blood GSH levels, intestinal short chain fatty acids (Acetic acid, butanoic acid), and intestinal beneficial bacteria (Bifidobacterium genus) content are increased. Therefore, this study aims to evaluate the effects of A2 milk on gut beneficial bacteria growth, antioxidant activity , digestion, and inflammation improvement compared to a control (A1/A2 milk) in individuals who experience discomfort after consuming milk.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
DOUBLE
Enrollment
100
Cow's milk that contains only A2 β-Casein
Cow's milk that contains both A1 β-Casein and A2 β-Casein
Seoul National University Bundang Hospital
Seongnam-si, South Korea, South Korea
Gastrointestinal Symptom Rating Scale (GSRS) Total Score
Evaluated through the Gastrointestinal Symptom Rating Scale (GSRS) which uses a 7 point Likert type scale from 1 (no symptoms or normal) to 7(severe symptoms) to rate 15 symptom items including both upper and lower abdominal symptoms. Participants will be given the GSRS to complete.
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Digestive Discomfort Symptom Survey
Participants rate 7 items (abdominal bloating, abdominal pain, borborygmus , fecal urgency, flatulence, diarrhea, nausea) on a numeral rating scale of 0 (Never) to 10 (Very Severe).
Time frame: Surveys given on Screening(week -2), Visit 3(week 2) to recorded once a day; Retrieved on Visit 2(week 0), Visit 4(week 4) to recorded twice a day within 30 minutes to 3 hours after consuming the test food;
Visual analogue scale Irritable Bowel Syndrome (VAS-IBS)
The scale of symptoms felt by 7 items {abdominal symptoms (abdominal pain, diarrhea, constipation, abdominal bloating or flatulence , nausea or vomiting) and health and daily items} is displayed on a 100 mm straight line from 0 mm (very good) to 100 mm (very severe).
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood Marker : Glutathione (GSH)
Serum levels of GSH measured in ug/mL
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood Marker : 8-Oxo-2'-deoxyguanosine (8-OxodG)
Serum levels of 8-OxodG measured in ng/mL
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
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Blood Marker : 5-hydroxymethyl-deoxyuridine (5-OHmdU)
Serum levels of 5-OHmdU measured in ng/mL
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood Marker : High Sensitive C-reactive protein (hs-CRP)
Serum levels of hs-CRP measured in mg/dL
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood marker : Interleukin-4 (IL-4)
Serum levels of IL-4 measured in pg/mL.
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood marker : Interleukin-6 (IL-6)
Serum levels of IL-6 measured in pg/mL
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood Marker : Tumor necrosis factor-α (TNF-α)
Serum levels of TNF-α measured in pg/mL.
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood Marker : Dipeptidyl Peptidase-4 (DPP-IV)
Serum levels of DPP-IV measured in ng/mL.
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood Marker : β-casomorphin-7 (BCM-7)
Serum levels of BCM-7 measured in ug/mL.
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Blood Marker : β casomorphin-10 (BCM-10)
Serum levels of BCM-10 measured in ug/mL.
Time frame: Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Stool marker : Short chain Fatty Acid (SCFA)
SCFA in stool measured in mg/g.
Time frame: Stool collection kit provided on Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4); Retrieved on Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Stool marker : Calprotectin
Calprotectin in stool measured in mg/kg.
Time frame: Stool collection kit provided on Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4); Retrieved on Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Stool marker : Microbiome
Gut microbiome composition (abundance, %) will be measured in stool via 16S ribosomal ribonucleic acid (rRNA)
Time frame: Stool collection kit provided on Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4); Retrieved on Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)
Bowel Frequency and Form
Participants record daily bowel frequency and form. The Bristol Stool Scale will be used to measure stool consistency with type 1 (Separate hard lumps, like nuts hard to pass), type 2 (Sausage shaped but lumpy), type 3 (Like a sausage but with cracks on its surface), type 4 (Like a sausage or snake, smooth and soft), type 5 (Soft blobs with clear cut edges passed easily), type 6 (Fluffy pieces with ragged edges, a mushy stool), and type 7 (watery, no solid pieces, entirely liquid).
Time frame: Journal provided on Screening (week -2), Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4) to record daily; Retrieved on Visit 2 (week 0), Visit 3 (week 2), Visit 4 (week 4), Visit 5 (week 6)