Sesame Oil: Is It Good for You?

Sesame (Sesamum indicum L.) is one of the earliest human production and consumption oil crops in the family of Pedaliaceae, rape, soybean, and peanuts, known as China’s four major oil crops. Due to its highly aromatic odor and mellow flavor, sesame is extensively produced and well-liked. Sesame can be divided into three categories based on the color of the germplasm: white sesame, black sesame, and yellow sesame. Black and white sesame are the most prevalent and widely grown dominant species. Black sesame has strong growth ability, lodging resistance, and drought resistance, whereas white sesame has high oil content and good quality and has the largest planting area and distribution ^[1].

Fat, protein, vitamins, minerals, and dietary fiber are all abundant in sesame seeds. Unsaturated fatty acids, fat-soluble vitamins, amino acids, and other nutrients are abundant in sesame oil, which is obtained through traditional oil production methods. Studies have found that sesame seeds contain 21.9% protein and 61.7% fat, and are rich in minerals. In addition to being rich in nutrients, sesame also contains many important functional components such as sesamin, sesamolin, sesamol, sesaminol, sesamolin phenol, and other lignan-like active ingredients. Each component of sesame has a different content depending on the extraction method and external growing conditions, e.g., hot-pressed sesame oil has a higher content of sesamol, sesamin, and total lignans than cold-pressed and refined sesame oil ^[1].

Sesame oil is an aromatic oil extracted from sesame seeds and is a traditional product from the primary processing of sesame seeds, which can be used as edible oil. Linoleic and linolenic acids, as well as large quantities of biologically active compounds such as lignans, natural vitamin E, and phytosterols, are abundant in sesame oil. Sesame seed oil obtained by cold pressing has a high quality and nutritional content. The main unsaturated fatty acid in sesame oil is linoleic acid (46.9%), followed by oleic acid (37.4%). These fatty acids are essential fatty acids because they cannot be synthesized in the organism and must be obtained through the diet ^[1].

Health Benefits of Sesame Oil

Osteoarthritis (OA)

Sesame oil showed an attenuation of quadriceps muscle dysfunction in osteoarthritis (OA) rats. Lower muscle strength and muscle weakness are related to both increased interleukin (IL)-6 production and decreased citrate synthase (CS) activity in a number of animal illness models. Myosin heavy chain (MHC) typing change is one of the major causes of muscle weakness in various pathogenic situations. Lower muscular strength/muscle weakness in the quadriceps is related to decreased MHC IIa fiber in OA patients. In the present study, sesame oil effectively improved muscle dysfunction and elevated MHC IIa gene expression. It is likely that enhancing MHC IIa gene expression may be involved in sesame oil exerted attenuation of muscular dysfunction, at least partially ^[2].

Sesame oil may improve quadriceps muscle dysfunction by inhibiting muscular oxidative stress during the initiation of OA. Increased oxidative stress in skeletal muscle is sufficient to cause muscular atrophy, according to genetic evidence. Elevated reactive oxygen species (ROS) generation can contribute to muscle dysfunction by oxidative damage, degradating contractile proteins, or activating calpain and ubiquitin proteolytic systems. Overproduction of ROS alters the fiber type and muscle function by regulating MHC gene expression. In addition, inhibiting endogenous antioxidant expression in mice results in significant loss of skeletal muscle mass and muscle weakness. In the present study, sesame oil may decrease joint pain by improving oxidative stress associated muscle dysfunction ^[2].

Sesamin has been shown in studies to have anti-inflammatory properties. It is well recognized that TNF-α is crucial in the development of rheumatoid arthritis. Khansai et al., found that sesamin significantly reduced the mRNA expression of IL-6 and IL-1 in human primary synovial fibroblast cell lines, indicating that sesamin inhibited TNF-α-induced pro-inflammatory cytokine mRNA expression. The major sesamin metabolites found in human plasma after oral administration of sesamin are sesamin catechol conjugates. Catechol glucuronides exert anti-inflammatory effects through demyelination in macrophage-like J774.1 cells, thereby inhibiting the expression of interferon beta and inducible nitric oxide synthase. In murine macrophage-like J774.1 cells, it was found that SC1, one of CYP450’s sesamin metabolites, has more potent anti-inflammatory properties than sesamin itself ^[1].

Cardiovascular Disease and Lipid and Lipoprotein Levels

It is generally known that lipids and lipoproteins play a causative role in cardiovascular disease (CVD). LDL-C and HDL-C are raised by dietary saturated fatty acids (SFA), which are present in milk, butter, cheese, cattle, lamb, hog, poultry, palm oil, and coconut oil. The increase in LDL-C is due to a decrease in hepatic LDL clearance and an increase in LDL production secondary to a decrease in hepatic LDL receptors. Sesame oil contains monounsaturated fatty acids (MUFA) which can decrease LDL-C by increasing hepatic LDL receptor activity ^[3].

Not all meta-analyses, but the majority, have been unable to show that MUFA intake reduces cardiovascular events. However, one meta-analysis and the Nurses’ Health Study and Health Professionals Follow-Up Study, two very large observational studies, found that MUFA from plant sources was beneficial while MUFA from other sources was not protective from developing cardiovascular events ^[3].

Metabolic syndrome

Insulin resistance, dyslipidemia, hypertension, and abdominal obesity are all part of the metabolic syndrome, which raises the risk of type 2 diabetes and CVD. Inflammation and oxidative stress play a substantial role in the development of metabolic syndrome. Moreover, the metabolic syndrome is diagnosed by metabolic biomarkers such as increased triglycerides (TG) and decreased HDL, hypertension, obesity, insulin resistance, and elevated oxidative stress. These factors are the main causes of increase in mortality of patients with cardiovascular disease, type 2 diabetes, and strokes all over the world. Insulin sensitivity is increased by polyunsaturated fatty acids (PUFA), which have been shown to have various positive impacts on human health. Monounsaturated fatty acids (MUFA) reduce insulin resistance and TG through promoting fatty acid oxidation ^[4].

Sesame oil is rich in MUFA, omega 6 Polyunsaturated fatty acids (PUFA) (83%-90%), such as oleic acid and linoleic acid, respectively. Sesame oil contains tocopherol, sesamin, sesamolin, polyphenols, phytosterols, flavonoids, and sesamol lignans that have anti-inflammatory and anti-mutagenic effects. Moreover, consuming this oil improves blood pressure, insulin levels, and fasting blood glucose (FBG). Vitamin B6, magnesium, calcium, copper, iron, and zinc are all found in sesame oil, which reduces blood pressure, hyperlipidemia, and lipid peroxidation by increasing enzymatic and nonenzymatic antioxidants. Sesamin, which is present in sesame oil, has anti-atherosclerotic effects that help to control blood pressure ^[4].

The current systematic review and meta-analysis includes 12 clinical trials. They provided the evidence to show how consuming sesame oil improved metabolic biomarkers. Overall results showed sesame oil consumption significantly reduced FBG (-3.268 mg/ dl), and malondialdehyde (MDA; -4.847 mg/dl) compared to the control group. Also, HbA1C (-2.057%), systolic blood pressure (SBP; -2.679 mmHg), diastolic blood pressure (DBP; -1.981 mmHg), body weight (-0.346 kg), and body mass index (BMI; -0.385 kg/m²) were all significantly lower than baseline. However, no reduction effect was identified for insulin serum ^[4].

References

1. Wei P, Zhao F, Wang Z, Wang Q, Chai X, Hou G, Meng Q. Sesame (Sesamum indicum L.): A Comprehensive Review of Nutritional Value, Phytochemical Composition, Health Benefits, Development of Food, and Industrial Applications. Nutrients. 2022 [cited 2023 March 10]; 14: 1-26. Available form: https://www.mdpi.com/2072-6643/14/19/4079
2. Hsu D, Chu P, Jou I. Enteral sesame oil therapeutically relieves disease severity in rat experimental osteoarthritis. Food Nutrition Research. 2016 [cited 2023 March 14]; 60: 29807. Available form: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4816814/
3. Feingold K. The Effect of Diet on Cardiovascular Disease and Lipid and Lipoprotein Levels. Endotext [Internet]. 2021 [cited 2023 March 14]. Available form: https://www.ncbi.nlm.nih.gov/books/NBK570127/
4. Atefi M, Entezari M, Vahedi H, Hassanzadeh A. The effects of sesame oil on metabolic biomarkers: a systematic review and meta-analysis of clinical trials. Journal of Diabetes & Metabolic Disorders. 2022 [cited 2023 March 14]; 21: 1065-80. Available form: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9167273/