Does the regular consumption of Sri Lankan black tea have a significant effect on blood lipid levels in adults compared to a control group?

Study Setting National Institute of Fundamental Studies (NIFS), Kandy Sri Lanka, in collaboration with the Tea Research Institute of Sri Lanka who will be involved in the selection of tea samples, preparation of extracts and quality control.

The clinical trial component of the study will be conducted at the Faculty of Medicine, University of Ruhuna: The Faculty of Medicine, University of Peradeniya and affiliated teaching hospitals; Base Hospital Wathupitiwala and physician-led private clinics in Galle, Gampaha and Kandy districts.

A total of 70 patients with marginally high blood lipid levels will be recruited. All eligible participants will receive a clear explanation of the study protocol and will be required to provide written informed consent prior to enrollment.

All participants will undergo baseline screening, including assessment of lipid profile, fasting blood sugar (FBS), thyroid-stimulating hormone (TSH), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and serum creatinine. Anthropometric measurements: weight, height, waist circumference. Blood pressure will also be recorded. These measurements will be recorded as initial baseline values.

Randomization Participants will be randomly assigned into two groups (n=35 each) using a randomization protocol. Random allocation ensures that each participant has an equal chance of being assigned to the intervention or control group. Participants will be randomized 1:1 to the black tea group or placebo group using blocked randomization with randomly varied block sizes (4 and 6) to maintain allocation balance during enrollment. The randomization sequence will be computer-generated and concealed in sequentially numbered, opaque, sealed envelopes. Envelopes will be opened only after obtaining informed consent and completing baseline assessments. The study will be conducted in a single-blind manner, with participants unaware of treatment allocation.

Intervention

• Intervention group: Receives high-quality Sri Lankan black tea (BOPF grade)

• Control group: Receives a placebo tea (BM grade; off-grade)

Both groups will be instructed to infuse pre-sealed tea bags in hot water and consume twice daily for six months. Pre-sealed tea bag (2g) is dipped into one cup of freshly boiled water (140 mL). The Tea should be allowed to brew for 6 minutes Consumption of tea: tea should be drunk about two hours before a meal or 2 hours after a meal, preferably morning and afternoon within 20 minutes of preparation. BM and BOPF are grades of black tea that have a similar taste and typical black tea color, but they differ in particle size and total phenolic content. BOPF is a high-quality tea grade that contains the highest amount of total polyphenols and fetches the highest price at tea auctions. Black tea BOPF and BM tea grades are available in the market.

In addition, all participants will receive standard lifestyle modification advice, including regular physical activity, dietary control, smoking cessation and reduced alcohol consumption

Follow-up will be conducted through regular phone calls to monitor compliance. Participants experiencing side effects or concerns will be advised to contact one of the consultant physicians involved in the study.

Participants who fail to comply regularly with the assigned regimen will be excluded from the final analysis.

Follow-up measurements (repeated at 3 months and 6 months): -Fasting serum levels: Total-C, LDL-C, HDL-C, TG, FBS, AST, ALT, creatinine -Anthropometric measurements -Blood Pressure

2–5 mL of blood will be collected during each follow-up visit.

Blinding This will be a single-blind randomized clinical trial.

Participants will be unaware of whether they are receiving the intervention or the placebo tea. However, the members of the research team will be aware of group assignments.

1. Individuals aged 20 to 75 years both male and female
2. Dyslipidemia diagnosed through a fasting lipid profile (defined as LDL-C 130–189 mg/dL, TG 150-499 mg/dL, total cholesterol >200 (LDL <190 or TG <500) without additional comorbidities or cardiovascular risk factors ( <20%WHO CVS risk score)

(This category do not warrant pharmacological interventions but only lifestyle modification as the management).

1. Present and past history of diabetes mellitus, cardiovascular disease, chronic kidney disease, hypothyroidism, or chronic inflammatory conditions.
2. Primary hypercholesterolemia falling into a category that requires pharmacological treatment to reduce cholesterol levels (LDL-C >190 mg/dL; increased 10-year risk of atherosclerotic cardiovascular disease).
3. Currently on pharmacological treatment for dyslipidemia management.
4. Pregnant and breast feeding mothers