Does daily buttermilk intake improve blood lipid levels in perimenopausal women?

ISRCTN	ISRCTN11974930
DOI	https://doi.org/10.1186/ISRCTN11974930
Sponsor	Latvia University of Life Sciences and Technologies
Funders	ERAF project No. 1.1.1.8/1/24/I/002 "LBTU Doctoral Students Support and Development Initiative", Strengthening Research Capacity in the Latvia University of Life Sciences and Technologies programme project "The study of buttermilk polar lipids"

Submission date: 13/06/2026
Registration date: 25/06/2026
Last edited: 15/07/2026

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Nutritional, Metabolic, Endocrine

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Background and study aims
Changes in hormone levels during perimenopause may affect blood lipid levels and may increase cardiovascular risk. Buttermilk is a dairy product that contains polar lipids, which may influence cholesterol metabolism. The aim of this study is to assess whether daily intake of fermented buttermilk for 28 days affects blood lipid levels in perimenopausal women with moderately elevated low-density lipoprotein cholesterol (LDL-C).

Who can participate?
Women aged 45 to 55 years who are in perimenopause, have moderately elevated LDL-C levels, and have had a stable body weight during the previous 6 months can participate.

What does the study involve?
Participants are randomly allocated to either an intervention group or a control group. Participants in the intervention group consume 250 mL of 0.5% fermented buttermilk every day for 28 days. Participants in the control group do not receive an additional dietary intervention and are asked not to make additional changes to their usual diet during the study period.

All participants complete questionnaires and dietary records about their usual diet and lifestyle. Blood samples are collected at the start of the study and after 28 days. These blood samples are used to measure total cholesterol, LDL-C, high-density lipoprotein cholesterol (HDL-C), triglycerides and alanine aminotransferase (ALAT/ALT).

What are the possible benefits and risks of participating?
Participants receive information about their dietary intake and blood lipid profile. The main risk is related to venous blood sampling. Possible risks include pain or bruising at the puncture site. Less common risks include bleeding, infection, dizziness or fainting.

Where is the study run from?
The study is run from the Latvia University of Life Sciences and Technologies in collaboration with Riga Stradiņš University. Blood samples are collected and analysed in an accredited laboratory in Latvia.

When does the study start, and how long is it expected to run
The study was planned to run from November 2022 to June 2024. Each participant takes part in the intervention period for 28 days.

Who is funding the study?
The study is investigator-initiated and conducted as part of doctoral research at the Latvia University of Life Sciences and Technologies. This research was funded by the “Strengthening Research Capacity in the Latvia University of Life Sciences and Technologies” program project, “The study of buttermilk polar lipids”; by the ERAF project No. 1.1.1.8/1/24/1/002 "LBTU Doctoral Students Support and Development Initiative.”

Who is the main contact?
Svetlana Aleksejeva, Latvia University of Life Sciences and Technologies.
s.aleksejeva@gmail.com, part@lbtu.lv

Contact information

Mrs Svetlana Aleksejeva
Scientific, Principal investigator, Public

Kr. Barona 19
Jūrmala
LV-2010
Latvia

ORCID ID	0000-0001-5920-9333
Phone	+371 29422183
Email	s.aleksejeva@gmail.com

Study information

Primary study design	Interventional
Allocation	Randomized controlled trial
Masking	Open (masking not used)
Control	Placebo
Assignment	Parallel
Purpose	Prevention
Participant information sheet	49710_Informed Consent of the Participant.pdf
Scientific title	Effect of 28-day daily fermented buttermilk consumption on plasma lipid profile in perimenopausal women with moderately elevated LDL cholesterol: a randomised controlled parallel-group dietary intervention study in Latvia
Study acronym	BUTTERMILK
Study objectives	1. To evaluate whether daily consumption of 250 mL fermented buttermilk for 28 days affects plasma LDL-C concentration in perimenopausal women with moderately elevated LDL-C 2. To assess the effect of the intervention on total cholesterol, HDL-C and triglycerides 3. To describe dietary intake and its relationship with plasma lipid profile parameters during the study
Ethics approval(s)	Approved 23/11/2022, Riga Stradiņš University Research Ethics Committee (Dzirciema 16, Riga, LV1007, Latvia; +371 26691306; pek@rsu.lv), ref: 2-PĒK-4/513/2022
Health condition(s) or problem(s) studied	Moderately elevated LDL cholesterol/dyslipidaemia/cardiovascular risk markers in perimenopausal women
Intervention	Participants are randomly allocated to an intervention group or a control group after baseline assessment. Participants in the intervention group consume 250 mL of 0.5% fermented buttermilk daily for 28 days. Participants in the control group receive no additional dietary intervention and are asked not to make additional dietary changes during the 28-day study period. Blood samples are collected at baseline and after 28 days to measure total cholesterol, LDL-C, HDL-C, triglycerides and ALAT. Dietary intake is assessed using a general questionnaire, a 24-hour dietary record, a 72-hour dietary record and a food frequency questionnaire. Participants were randomised using block randomisation to maintain balanced group sizes between the intervention and control groups. A predefined randomisation list was generated in Microsoft Excel before participant enrolment. Following baseline assessment and confirmation of eligibility, participants were assigned sequentially to the next allocation on the randomisation list.
Intervention type	Other
Primary outcome measure(s)	Change in low-density lipoprotein cholesterol concentration (LDL-C) measured using venous blood samples using standard clinical laboratory blood analysis in an accredited laboratory. The result is reported in mmol/L at baseline and after 28 days of intervention.
Key secondary outcome measure(s)	Change in total cholesterol concentration measured using Total cholesterol concentration measured in venous blood samples using standard clinical laboratory blood analysis in an accredited laboratory. The result is reported in mmol/L at baseline and after 28 days of intervention. Change in high-density lipoprotein cholesterol concentration (HDL-C) measured using venous blood samples using standard clinical laboratory blood analysis in an accredited laboratory. The result is reported in mmol/L at baseline and after 28 days of intervention Change in triglyceride concentration measured using venous blood samples using standard clinical laboratory blood analysis in an accredited laboratory. The result is reported in mmol/L at baseline and after 28 days of intervention
Completion date	26/06/2024

Eligibility

Participant type(s)
Age group	Adult
Lower age limit	45 Years
Upper age limit	55 Years
Sex	Female
Target sample size at registration	60
Total final enrolment	61
Key inclusion criteria	1. Women aged 45-55 years 2 .Perimenopausal status 3. Moderately elevated low-density lipoprotein cholesterol within the previous 6 months, defined as LDL-C 3.01-4.12 mmol/L 4. Stable body weight during the previous 6 months, defined as change within +/- 2 kg
Key exclusion criteria	1. Consumption of buttermilk 5-7 times per week 2. History of primary hyperlipidaemia 3. History of cardiovascular disease, including ischaemic heart disease, myocardial infarction, stroke, chronic heart failure, angina or arrhythmia 4. Endocrine diseases, including type 1 or type 2 diabetes, thyroid disorders, adrenal disease or secondary renal failure; 5. Liver disease, including non-alcoholic fatty liver disease, alcoholic fatty liver disease, hepatitis, cirrhosis or chronic liver failure 6. Chronic kidney disease or nephrotic syndrome 7. History of gastrointestinal surgery 8. Hormonal therapy 9) Immunosuppressive therapy; 10) Pharmacological treatment for hyperlipidaemia or hypertension, including medicines or dietary supplements; 11) Lactose intolerance.
Date of first enrolment	10/11/2023
Date of final enrolment	22/04/2024

Locations

Countries of recruitment

Latvia

Study participating centres

Results and Publications

Individual participant data (IPD) Intention to share	No

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article		06/07/2026	15/07/2026	Yes	No
Participant information sheet	Consent form		15/06/2026	No	Yes

Additional files

49710_Informed Consent of the Participant.pdf: Consent form

Editorial Notes

15/07/2026: Publication reference added.
15/06/2026: Trial's existence confirmed by Riga Stradiņš University Research Ethics Committee.