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Black seed

Also known as: Nigella cretica, Black caraway, Black Cumin, Kalonji, Charnushka, Habbatul baraka, Roman Coriander, Fennel Flower, Thymoquinone, Nutmeg flower, Nigella sativa

Overview

Black seed is the seed oil or whole ground seeds of Nigella sativa — a flowering plant in the buttercup family that grows in certain parts of Asia, Africa, Europe, and the Middle East. Black seed has a long history of use in many cultures, both as a spice in foods and as an herbal medicine. It contains a variety of nutritional compounds like polyunsaturated fatty acids, vitamins, and minerals, as well as an abundance of phytochemicals — thymoquinone (a terpenoid) being considered the most important.

Benefits

Black seed contains many bioactive phytochemicals that likely contribute to its effects, but thymoquinone is considered its main active compound. Further, its content of polyunsaturated fatty acids, vitamins, minerals, and soluble fiber may have positive biological effects. Regardless, our current understanding of how black seed works is largely theoretical and based on animal and in vitro research. Black seed may modulate lipid levels by several possible mechanisms, including reduced cholesterol synthesis (via downregulation of the rate-limiting enzyme HMG-CoA reductase), increased clearance of low-density lipoprotein (LDL) cholesterol from the blood, and increased synthesis of bile acids. Improved glycemic control may be due to reduced intestinal absorption of glucose (via inhibition of the sodium-glucose cotransporter), reduced synthesis of glucose by the liver, and improved integrity of pancreatic beta cells (insulin-secreting cells). Black seed also appears to activate AMPK in skeletal muscle and liver cells, which likely explains some of its antidiabetic and lipid-lowering properties. The anti-inflammatory and antioxidant effects of black seed may occur for several reasons, most likely through increasing the levels of antioxidant enzymes, reducing lipid peroxidation, inhibiting NF-KB activity, and reducing the formation of various inflammatory mediators.

How it works

Black seed has anti-inflammatory and antioxidant effects and immune-modulating properties. Currently, the most well-studied benefits of black seed are for cardiovascular health and metabolic health. Black seed may improve glycemic control by lowering fasting glucose and hemoglobin A1c (HbA1c) by a clinically significant degree. This effect is the greatest in people with type 2 diabetes, but benefits are still observed in other relevant conditions like metabolic syndrome and nonalcoholic fatty liver disease (NAFLD). Black seed may also improve lipid profiles, including reduced triglycerides, low-density lipoprotein (LDL) cholesterol, and total cholesterol, and increased high-density lipoprotein (HDL) cholesterol. This lipid-modulating effect has not been found in people with NAFLD despite other observed benefits in this population (reduced levels of liver enzymes, C-reactive protein, and liver fat). Lastly, black seed may reduce blood pressure, and in people with overweight or obesity, it may cause slight reductions in weight and body mass index (BMI). Most of these effects have been observed in short-term studies (≤12 weeks), meaning the long-term effectiveness of black seed supplementation still needs to be determined. An exception to this is the effect of black seed on glycemic control, with benefits being maintained in some studies spanning 6 to 12 months.

Side effects

Black seed is typically taken in the form of an oil or a ground powder, taken orally at a dosage of 1 to 3 grams daily. For people with type 2 diabetes, preliminary research suggests that 2 grams daily may be the sweet spot for achieving beneficial effects on lipids and blood glucose. For topical use, most research has used preparations containing 10% to 20% black seed applied twice daily. While black seed is available in various forms (seed oil, water extract, or whole ground seed), water extracts seem to be less effective, likely because thymoquinone (the main active compound in black seed) is fat-soluble. The whole ground seed and oil appear similarly effective, although more research comparing the two is needed. It’s important to keep in mind that the chemical composition of black seed can vary greatly depending on how it is grown, harvested, and processed. This could lead to inconsistent effects of black seed with seemingly equivalent doses. Because of the high content of polyunsaturated fatty acids in black seed, storing the supplement in the fridge in a dark, sealed container may help prevent oxidation.

Dosage

Black seed is generally considered to be safe and well-tolerated. The most commonly reported side effects are gastrointestinal in nature, including diarrhea, nausea, vomiting, and heartburn. There have been several case reports of allergic skin reactions following the topical or oral use of black seed, ranging from mild dermatitis and hives to cases of Stevens-Johnson syndrome or drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, both of which are severe hypersensitivity reactions that can result in extensive blistering/rashes, fever, and potential damage to internal organs.

FAQs

What is black seed?

What are some of the traditional and historical uses of black seed?

Black seed has been used as an herbal medicine for thousands of years by many cultures and traditional systems of medicine across Asia, Africa, Europe, and the Middle East. Additionally, black seed has been used as a culinary spice to add flavor to various foods and for food preservation. By many, black seed was considered to be a panacea — a remedy for nearly all diseases — and it has historically been referred to as 'the herb from heaven'. Black seed was supposedly used by several ancient Greek physicians, including Hippocrates, Dioscorides, and Galen. The mention of black seed and its therapeutic properties can be found in several historical texts ranging from the Bible to The Canon of Medicine by the classical Muslim physician Avicenna.

What are black seed’s main benefits?

Does black seed improve skin conditions like acne, psoriasis, or eczema?

Historically, black seed has been used topically to treat a variety of skin ailments thanks to its anti-inflammatory and antimicrobial properties. Clinical research supporting the use of black seed in this context is minimal, but the existing evidence is promising. Black seed lotion or gel may be effective for the management of mild to moderate acne. Preliminary research suggests that black seed applied topically for 8 weeks may reduce the number of comedones, papules, and pustules compared to both a placebo and benzoyl peroxide 5% lotion (a commonly used product for acne). This is supported by in vitro research finding that black seed and thymoquinone possess antibacterial effects against certain bacteria known to contribute to acne.

Could black seed be beneficial during a COVID-19 infection?

Black seed has antiviral, immune-modulating, and anti-inflammatory properties, which makes it a potential candidate for the treatment of COVID-19. Additionally, compounds in black seed might theoretically prevent SARS-CoV-2 from entering human cells by blocking the receptor the virus uses to gain entry, angiotensin-converting enzyme 2 (ACE2).

Does black seed improve symptoms of asthma or allergic rhinitis?

Black seed has anti-inflammatory and immune-modulating properties, and preclinical research suggests it may also reduce histamine release and leukotriene B4 synthesis, making it an interesting candidate for both asthma and allergic rhinitis. Clinical research is limited to a handful of small trials, but so far results have tended to be positive. In allergic rhinitis, several trials have found reductions in symptoms (e.g., itching, sneezing, congestion, runny nose) with black seed supplementation compared to a placebo. Benefits have been demonstrated for mild, moderate, or severe allergic rhinitis with both oral and intranasal black seed.

Does black seed improve symptoms of rheumatoid arthritis?

Black seed has historically been used for the management of rheumatism and conditions associated with pain and inflammation. Current clinical research is limited but has generally been positive. In preliminary research, black seed has been found to reduce symptoms of rheumatoid arthritis in women as measured with the Disease Activity Score-28 (DAS-28) — a validated, objective way of measuring disease activity based on the number of tender or swollen joints — and to reduce the duration of morning stiffness. However, no clear effect on markers of inflammation or antioxidant status has been found in this population.

What are black seed’s main drawbacks?