Nutrition Expert: Saba Shaikh, Practicing Clinical Nutritionist, Mumbai.
Kalonji, also known as Nigella sativa, black seed, and black cumin, is a flowering plant native to Southern Europe, North Africa, and Southwest Asia.
Its seeds have long been used in herbal medicine to treat a variety of diseases and conditions ranging from diabetes to arthritis (1).
More recently, the herb has gained popularity for its purported weight loss benefits.
What is Kalonji?
Kalonji is an annual flowering plant that can grow 8–35 inches (20–90 cm) tall (2).
Its fruits contain numerous black seeds that have been used traditionally in Southeast Asian and Middle Eastern countries to treat diseases and conditions like diabetes, pain, and digestive tract problems (2).
The Prophet of Islam, Muhammad, even believed the seeds to be a remedy for all diseases except death (2).
Today, it’s known that kalonji seeds and oil contain active compounds called phytochemicals, including phytosterols. These have demonstrated a wide range of therapeutic benefits, including weight loss (1).
Packed With Antioxidants
Antioxidants are substances that neutralize harmful free radicals and prevent oxidative damage to cells.
Research shows that antioxidants can have a powerful effect on health and disease.
In fact, some studies indicate that antioxidants may protect against several types of chronic conditions, including cancer, diabetes, heart disease and obesity (3).
Several compounds found in kalonji, such as thymoquinone, carvacrol, t-anethole and 4-terpineol, are responsible for its potent antioxidant properties (4).
One test-tube study found that kalonji essential oil also acted as an antioxidant (5).
However, further research is needed to determine how the antioxidants found in kalonji may impact health in humans.
May Lower Cholesterol
Cholesterol is a fat-like substance found throughout your body. While you need some cholesterol, high amounts can build up in your blood and increase your risk of heart disease.
Kalonji has been shown to be especially effective at lowering cholesterol.
One review of 17 studies found that supplementing with kalonji was associated with significant decreases in both total and “bad” LDL cholesterol, as well as blood triglycerides.
Interestingly, it also found that kalonji oil had a greater effect than kalonji seed powder. However, only seed powder increased levels of “good” HDL cholesterol (6).
Another study in 57 people with diabetes showed that supplementing with kalonji for one year decreased total and LDL cholesterol, all while increasing HDL cholesterol (7).
Lastly, a study in 94 people with diabetes had similar findings, reporting that taking 2 grams of kalonji daily for 12 weeks reduced both total and LDL cholesterol (8).
Could Have Cancer-Fighting Properties
Kalonji is high in antioxidants, which help neutralize harmful free radicals that may contribute to the development of diseases like cancer.
Test-tube studies have found some impressive results regarding the potential anti-cancer effects of kalonji and thymoquinone, its active compound.
For instance, one test-tube study found that thymoquinone induced cell death in blood cancer cells (9).
Another test-tube study showed that kalonji extract helped inactivate breast cancer cells (10).
Other test-tube studies suggest that kalonji and its components may also be effective against several other types of cancer, including pancreatic, lung, cervical, prostate, skin and colon cancers (11).
However, there is no evidence on the anti-cancer effects of kalonji in humans. Studies are needed to examine whether kalonji has any cancer-fighting benefits when used as a spice or taken as a supplement.
Can Help Kill off Bacteria
Disease-causing bacteria are responsible for a long list of dangerous infections, ranging from ear infections to pneumonia.
Some test-tube studies have found that kalonji may have antibacterial properties and be effective at fighting off certain strains of bacteria.
One study applied kalonji topically to infants with a staphylococcal skin infection and found that it was as effective as a standard antibiotic used to treat bacterial infections (12).
Another study isolated methicillin-resistant Staphylococcus aureus (MRSA), a strain of bacteria that is difficult to treat and resistant to antibiotics, from the wounds of diabetic patients.
Kalonji killed off the bacteria in a dose-dependent manner in over half of the samples (13).
Several other test-tube studies have shown that kalonji can help inhibit the growth of MRSA, as well as many other strains of bacteria (14).
Yet, human studies are limited, and more research is needed to look at how kalonji may affect different strains of bacteria in the body.
Can Aid in Blood Sugar Regulation
High blood sugar can cause many negative symptoms, including increased thirst, unintentional weight loss, fatigue and difficulty concentrating.
Left unchecked in the long term, high blood sugar can lead to even more serious consequences, such as nerve damage, vision changes and slow wound healing.
Some evidence shows that kalonji could help keep blood sugar steady and thus prevent these dangerous adverse side effects.
One review of seven studies showed that supplementing with kalonji improved levels of fasting and average blood sugar (15).
Similarly, another study in 94 people found that taking kalonji daily for three months significantly reduced fasting blood sugar, average blood sugar and insulin resistance (16).
Kalonji May Not Be for Everyone
While kalonji has been associated with many health benefits and is generally safe when used as a spice or seasoning, taking a kalonji supplement or using kalonji oil may have risks.
For example, there have been reports of contact dermatitis after applying kalonji to the skin. If you plan on using it topically, be sure to do a patch test by applying a small amount first to make sure it does not cause an adverse reaction (17).
Furthermore, some test-tube studies have found that kalonji and its components may influence blood clotting. If you take medication for blood clotting, be sure to talk with your doctor before taking kalonji supplements (18).
Additionally, while some animal studies have found that kalonji can be safely consumed during pregnancy, one animal study found that the oil could slow down uterine contractions when used in large amounts (19).
If you are pregnant, be sure to use it in moderation and consult your doctor if you have any concerns.