Za'atar, an aromatic blend of spices that typically includes some combination of dried thyme, sumac, oregano, marjoram, sesame seeds, and salt, is ubiquitous throughout the Middle East, sprinkled over bread, yogurt, olive oil, and other foods for a savory kick.

Mentioned throughout the Bible in reference to a specific wild variety of oregano, za'atar developed a reputation for medicinal properties throughout the Mediterranean as early as the 12th century, notes NPR's blog The Salt, when the medieval philosopher and physician Maimonides is thought to have prescribed it to patients for its purported health benefits.

More recent research confirms that za'atar herbs do in fact boast significant health-enhancing properties, since sumac, thyme, and oregano are all chock full of flavonoids, organic compounds that are important dietary sources of antioxidants that can protect cells from damage.

Some scientists even speculate that one of za'atar's components might actually boost mood and cognition in low doses.

Sumac Health Benefits

Sumac is rich in gallic acid, which research suggests has anti-fungal, anti-viral, and cancer-fighting properties, and quercetin, which also seems to an anti-inflammatory agent effective against cancer.

A 2009 study also suggested that sumac can protect DNA from errors during cell reproduction in animals, though research on human cells was inconclusive.

Thyme and Oregano Health Benefits

Thyme and oregano are both rich in thymol and carvacrol, similar organic compounds called phenols that have antiseptic and antimicrobial properties. Like gallic acid, they are also effective in suppressing funguses and other microorganisms.

A 2010 study found that thymol and carvacrol can weaken drug-resistant strains of disease-causing bacteria like Salmonella and Staphylococcus aureus, making the microbes more susceptible to antibiotics.

In lab tests, the antioxidants in thyme were even powerful enough to fight off acne-causing bacteria.

A fluid extract of thyme also helped patients with acute bronchitis and phlegmy coughing fits minimize their respiratory symptoms — which, as The Salt notes, echoes Maimonides' prescription of za'atar to treat colds.

Brain-Boosting Za'atar?

In certain parts of the Middle East, folk tradition suggests that za'atar has brain-boosting properties - The Salt recounts that Syrian children are often encouraged to sprinkle the spice mix on meals before exams.

Scientific literature on the health benefits of za'atar herbs like thyme, oregano, and sumac for human intelligence is minimal, though some researchers are beginning to speculate that the carvacrol, the phenol found in thyme and oregano, may have cognitive and mood-enhancing properties, at least in rodents.

A 2011 study found that in mice, specific doses of an oregano extract elevated levels of serotonin, a vital brain neurotransmitter involved in regulating mood, learning, sleep, and appetite, working like a low-impact version of the selective serotonin reuptake inhibitor (SSRI) drugs that are commonly prescribed as antidepressants in humans.

Another study published last month showed that when fed to rats, steady low doses of carvacrol can boost levels of serotonin and dopamine, which is also involved in mood, learning, and feelings of reward, possibly increasing feelings of well-being and reinforcing other positive brain processes.

Finally, a 2012 study found that in rats, thymol and carvacrol helped alleviate some symptoms of dementia caused by beta-amyloid, a protein linked to Alzheimer's disease. When dosed with the compounds before being placed in a water maze, cognitively impaired rats learned how to navigate the labyrinth more quickly than expected.

Of course, it's not at all clear that the mood and cognition-enhancing health benefits of thyme and oregano compounds for rodents can translate to humans.

More research is necessary before anyone can recommend pouring za'atar over your meals for a brain boost, though recent studies have found strong protective effects against cognitive decline from eating a Mediterranean diet rich in olive oil — which is more than compatible with za'atar, flavor-wise. Just go easy on the salt when creating your own blend.

Check out za'atar recipes and eating ideas at Mama's Lebanese Kitchen, Serious Eats, and The Kitchn.

Sources:

Azizi Z, Ebrahimi S, Saadatfar E, et al. Cognitive-enhancing activity of thymol and carvacrol in two rat models of dementia. Behavioural Pharmacology. 2012.

Chakraborty A, Ferk F, Simić T, et al. DNA-protective effects of sumach (Rhus coriaria L.), a common spice: results of human and animal studies. Mutation Research. 2009.

Chen Q, Chen H. Extraction and deglycosylation of flavonoids from sumac fruits using steam explosion. Food Chemistry. 2011.

Kemmerich B, Eberhardt R, Stammer H. Efficacy and tolerability of a fluid extract combination of thyme herb and ivy leaves and matched placebo in adults suffering from acute bronchitis with productive cough. Arzneimittelforschung. 2006.

Palaniappan K, Holley RA. Use of natural antimicrobials to increase antibiotic susceptibility of drug resistant bacteria. International Journal of Food Microbiology. 2010.

Zotti M, Colaianna M, Morgese MG, et al. Carvacrol: From Ancient Flavoring to Neuromodulatory Agent. Molecules. 2013.