Hyperlipidemia is defined as an elevation of plasma cholesterol, lipid, or lipoprotein levels above normal due to abnormal fat metabolism or function, and individuals with hyperlipidemia are approximately twice as likely to develop cardiovascular disease. The first approach to treating hyperlipidemia is lifestyle changes, including dietary therapy and physical activity. In addition to traditional methods, treatments also include pharmacological interventions, and research on natural products and complementary therapies is increasing to increase the effectiveness of these treatment approaches. In this context, Nigella Sativa (NS) oil has emerged as a promising natural option in the treatment of hyperlipidemia and obesity in recent years.

The aim of this study was to examine the effects of NS oil supplementation given together with dietary intervention in individuals diagnosed with mild obesity.

The main questions it aims to answer are:

• Does Nigella Sativa supplementation improve blood lipid profiles in overweight or obese individuals?
• Does Nigella Sativa supplementation improve body composition in overweight or obese individuals?

Participants were individuals who were diagnosed with hyperlipidemia according to American Heart Association criteria as a result of medical evaluation by a cardiologist and who were deemed appropriate to use black seed oil supplements. Those who volunteered to participate in the study were included in the study.

The researchers are examining whether there is any effect on biochemical and anthropometric parameters by giving Nigella Sativa supplementation to a group in addition to a low-calorie diet for eight weeks.

This research, which is a randomized controlled intervention study, was conducted between June 2023 and February 2024 with adult individuals with a BMI>25 kg/m2 who applied to the Cardiology Polyclinic of Karamürsel State Hospital and were referred to a nutrition and diet specialist after being diagnosed with hyperlipidemia according to AHA criteria by the physician.

Sample Selection and Randomization The sample size of the study was calculated using the G-Power 3.1.9 analysis program with a medium effect size (d=0.60), 90% power, α: 0.05 and 1-β: 0.95, with a minimum of 32 people in each group, 64 people were included. The 64 people who met the inclusion criteria were assigned to the intervention (n=32) and control (n=32) groups using the block randomization method, with similar age and gender.

Inclusion Criteria from the Study Individuals who were diagnosed with hyperlipidemia between the ages of 18-65, who did not have any serious comorbidities (kidney, liver and immune deficiency, oncological and psychiatric diseases), who were not pregnant or breastfeeding, who did not take any nutritional supplements including black seed, who did not have a known history of allergy to black seed and its products, who did not use medications that could interact with black seed oil (anticoagulant, antihypertensive, etc.), who did not use antilipidemic or anticholesterolemic medications, who did not do heavy exercise, who did not consume alcohol regularly and who did not have any special diet requirements were included in the study.

Data Collection Tools Research data were recorded using a questionnaire form, anthropometric measurements, biochemical tests and the IPAQ form.

Survey Form: Sociodemographic information, smoking and nutritional habits of the participants were recorded in the survey form.

Anthropometric Measurements: At the beginning and end of the study, body weights and analyses were performed using a bioelectrical impedance (BIA) device (Tanita Perfecto) with a sensitivity of 50 grams in accordance with the measurement standards. According to the BIA analysis, fat ratio (%), fat mass, fat-free mass, muscle mass and total body water were evaluated. At the beginning and end of the study, waist, hip and neck circumferences were measured with a non-stretchable tape measure, paying attention to anthropometric measurement standards. Waist/height and waist/hip values were calculated. Height (cm) was measured with a stadiometer in the Frankfort plane, standing and with the head upright. The body mass index (BMI) of the participants was calculated according to the body weight (kg) / height (m)2 formula and classified according to the World Health Organization (WHO) criteria.

International Physical Activity Questionnaire Short Form (IPAQ): IPAQ-Short form, developed by Craig et al. and whose Turkish validity and reliability study was conducted by Öztürk, was used to assess the physical activity levels of the participants. Physical activity levels were classified as light, moderate and vigorous active.

Biochemical Tests: Participants' biochemical tests (total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, fasting blood glucose, ALT and AST) were analyzed in the hospital biochemistry laboratory using routine methods at the beginning and end of the study from blood samples taken by a nurse after at least 12 hours of fasting and without consuming alcohol for 24 hours before.

Research Plan In this study, 64 hyperlipidemic individuals with BMI>25 kg/m2 were divided into 2 groups as control (n=32 individuals) and intervention (n=32 individuals). The control group was given a low-fat, low-cholesterol weight loss diet specific to the individual for 8 weeks, while the intervention group (n=32) was given a similar diet along with 2x900 mg black seed oil in softgels. Questions regarding the participants' sociodemographic characteristics, smoking, alcohol consumption and physical activity habits were recorded on a questionnaire form through face-to-face interviews. Participants attended face-to-face dietician control interviews every two weeks to observe compliance with the nutrition programs throughout the study.

Diet Plan: While determining the daily energy needs of the participants, the resting metabolic rate was calculated with the Mifflin-St.Jeor formula. The physical activity levels of the individuals were determined using the IPAQ-Short Form. The thermic effect of the nutrients was taken as 10% and the total daily energy requirement was calculated. In order for the participants to lose weight, 500 calories were subtracted from the total energy requirement. A nutrition program was given in accordance with the diet recommendations created by the American Heart Association (AHA) for hyperlipidemic individuals.

Black seed oil: In this study, black seed oil in the form of 900 mg softgels was administered orally to the intervention group at a dose of 2x900 mg. Black seed oil obtained by the cold-pressing method (TAB İlaç Sanayi A.Ş., Esenyurt, İstanbul) is in softgel form. The product is a licensed supplement with the TR-34-K-210340 certificate by the Turkish Standards Institute (TSE) and the Food Supplement Approval Number 003683-21.12.2017 of the Ministry of Agriculture and Forestry. Some studies investigating the effects of black seed oil on hyperlipidemia and other health problems show that 1-2 g of black seed or 500-1000 mg of black seed oil per day may be effective. These doses are usually taken in two divided doses daily. Moreover, a daily therapeutic dose of 2000 mg N.S has been considered safe in previous studies. Human and animal models showed no serious side effects or toxicological effects caused by the plant. The black seed oil capsules given to the participants were provided by the researcher.

Inclusion Criteria:

• Adults individuals who were diagnosed hyperlipidemia
• Individuals suitable for taking Nigella satvia supplement
• Individuals BMI>25 kg/m2

Exclusion Criteria:

• Chronic liver disease,
• Chronic kidney disease,
• Heart failure, infarction or cerebrovascular disease,
• Pregnant and breastfeeding women,
• Severe psychiatric disorders,
• Oncological diseases,
• Individuals using medications that could interact with black seed oil (anticoagulant, antihypertensive, etc.)
• Individuals using antilipidemic or anticholesterolemic medications
• Individuals did not do heavy exercise
• Individuals using any nutritional supplement
• Individuals have a known history of allergy
• Individuals did not consume alcohol regularly
• Individuals with special dietary needs