By Dr. Mercola

If you enjoy Middle Eastern and Mediterranean cuisine, you’ve likely eaten sumac, perhaps without knowing it. I’m not talking about the wild plant that causes contact dermatitis in the majority of people who touch it. No, the sumac I have in mind is a tart, edible powder used in dry rubs, marinades, salad dressings and spice blends. It gives a pop of deep red color and a lemony tang to chicken, fish, lamb and vegetable dishes.

Most notably, sumac is featured prominently in the spice mix za’atar and also is commonly found on fattoush salad and hummus.¹When ground, sumac powder can be mistaken for paprika, but its tangy punch is distinctive. If you are wondering why you should care about sumac, you may be interested to know this intriguing spice has been called out for its positive effects on your blood sugar levels, in addition to a number of other health benefits.

What Is Sumac?

Not to be confused with poison sumac, which can give you an itchy rash upon contact, the sumac varieties I’m discussing hail from the red berries produced by the sumac bush. While it is native to the Middle East, sumac has spread far and wide to other regions. When ground into a coarse powder, sumac adds a colorful, slightly sour, lemony tang to a variety of dishes.

About sumac, The Kitchn says, “Sumac is a widely used, essential spice in Middle Eastern and Mediterranean cooking. It's used in everything from dry rubs to marinades and dressing. But its best use is sprinkled over food before serving.” Given its increasing popularity, you may be able to find it among other herbs and spices in your local grocery store.

You can easily distinguish edible and poisonous sumac by looking at the berries. The berries of poison sumac varieties are white or gray in color and droop from the branch. In contrast, the edible berries of staghorn sumacs and other nonpoisonous varieties are a deep red color and attached to upright stalks.² Some varieties of sumac are considered to be an invasive species in parts of the U.S. and have proven difficult to eradicate.³

Sumac Is Rooted in History

American Forest shares these interesting facts about sumac:⁴

• With about 250 species worldwide, sumac has been used throughout history as a medicinal herb, a dye, ingredient in wax and a tobacco additive
• As a member of the Anacardiaceae (cashew) family of plants, varieties of sumac can be found in eastern Asia, North America, northeastern Australia and southern Africa, as well as the Middle East
• Native Americans used sumac as an astringent, a gargle for coughs, a treatment for gonorrhea and hemorrhoids and an ingredient in smoking tobacco
• In the fall, if you live in North America, brilliant orange and red sumac leaves will undoubtedly catch your attention in forests, parks and roadside ditches

Sumac Shown to Reduce Blood Sugar Levels for Type 2 Diabetics

A 2014 study⁵ published in the Iranian Journal of Pharmaceutical Research sought to determine the effects of sumac on diabetes. In particular, scientists from Iran and the U.S. sought to determine if sumac would have effects on blood sugar levels, apolipoprotein (apo) B, apoA-I and total antioxidant capacity (TAC) in Type 2 diabetics.

For the three-month double-blind clinical study, 41 diabetic volunteers were randomly assigned either a 3 gram-per-day serving of sumac powder or a placebo. Blood samples were collected before and after the research. As compared to those receiving a placebo, the sumac group experienced significant decreases in blood sugar levels and haemoglobin A1c, as well as apoB, a protein constituent of low-density lipoprotein (LDL cholesterol).

With respect to the sumac group, researchers also noted a significant increase in apoA-I, a component of high-density lipoprotein (HDL cholesterol), and TAC, which, at higher levels, can reduce the incidence of diabetic complications. About the outcomes, the study authors said, “[T]hese results showed the [favorable] effect of sumac consumption on serum glycemic (blood sugar) status, apoB, apoA-I and TAC levels in in Type 2 diabetic patients.”

In a 2013 study, presented in the Journal of Medicinal Plants Research,⁶ a team of Iranian scientists administered an herbal, sumac-containing capsule to 31 Type 2 diabetics three times a day for four weeks to evaluate its effect on blood sugar control. This herbal remedy, which traditionally has been used in the Middle East for diabetes (also known as ziabetes in the region), contains common purslane, pomegranate and Sicilian sumac.

About the research outcomes, the study authors stated, “This study indicated the ziabetes capsule is effective in decreasing fasting and postprandial plasma glucose levels among Type 2 diabetic patients without any side effects.”

Antioxidants: Another Way Sumac Is a Health Booster

Studies performed on the berries of two edible sumac varieties suggest this plant has exceptionally high antioxidant properties.⁷ As you know, your body needs antioxidants because they neutralize free radicals — unstable molecules known to promote aging and chronic disease.

A 2013 study published in the journal Food Chemistry⁸ validated earlier studies by finding staghorn sumac (Rhus hirta L.) to exert significant antioxidant activity. Staghorn sumac is a native tree in Eastern North America whose fruit reportedly has been used by native peoples to treat various illnesses. About staghorn’s antioxidant properties, the study authors noted:

• It has higher antioxidant activity than many common fruits and vegetables
• Its strong antioxidant properties are largely attributed to polyphenols, such as anthocyanins and other flavonoids
• It was found to possess a unique group of anthocyanins with aglycones (anthocyanidins)

Research published in the Journal of Food Biochemistry⁹ in 2014 analyzed the antioxidant capacity of several spice extracts, including the water extracts of Sicilian sumac (Rhus coriaria L.). The other spices evaluated were barberry, cardamom, black pepper, fennel, laurel, nutmeg, red pepper, turmeric and white mustard. The focus of the study centered around identifying potential plant extracts that could be used by the food industry as natural preservatives. The results reflected:

• Sicilian sumac showed the highest antioxidant capacity, followed by laurel and barberry
• Laurel and sumac had the highest concentration of total phenolic content
• Sumac and barberry had the strongest antibacterial activity against four foodborne pathogenic bacteria

Sumac Offers Antifungal and Potential Anti-Atherosclerosis Benefits

A 2011 study published in the German Journal of Biosciences¹⁰ suggests Sicilian sumac seeds may have antifungal action that is effective against Aspergillus flavus. This human pathogen causes a lung infection called aspergillosis that most often affects people with weakened immune systems, such as those suffering from AIDS or undergoing chemotherapy.

Scientists from McGill University’s experimental medicine department in Montreal, Canada, suggest sumac berries might be good for your heart because they offer potential protections against atherosclerosis, also known as hardening of the arteries. Their research investigated sumac’s ability to inhibit vascular smooth muscle cell (VSMC) migration, a key process connected with atherosclerosis.

After extracting and purifying tannins from ground sumac, scientists treated cultured rat carotid VSMCs with different tannin concentrations for 10 days. After observing a 62-percent reduction in VSMC migration in tannin-treated cells, the team concluded tannins extracted from sumac “possess potent antimigratory activity,” and therefore, may be useful in the treatment of atherosclerosis.¹¹

Sumac Nutrition Facts

According to the Jordan Journal of Biological Sciences,¹² sumac is:

• Rich in vitamins A and C (from its fruit and seeds)
• High in minerals like calcium, magnesium and potassium
• Sour mainly due to the presence of organic acids, such as citric, malic and tartaric acids
• Somewhat astringent-tasting due to its tannin content

Making Sumac-ade: A Refreshing Use for This Prolific Shrub

According to the “Handbook of Herbs and Spices — Volume 2,”¹³ Native Americans used the fruits from smooth sumac and staghorn sumac to create a drink called “sumac-ade.” Given the ready supply of edible sumac worldwide, you may want to try this refreshing beverage, which is also referred to as rhus juice. You can make this drink by following the instructions presented in the video above:

• Rinse and place four edible sumac berry cones in a 2-quart pitcher of filtered water
• Gently mash the cones to extract their essence
• Allow the berry cones to soak for a few hours or overnight
• Strain the berry mixture through a piece of cheesecloth or a coffee filter
• Add ice and/or a natural sweetener to taste (optional)

Cautions About Sumac

Before considering adding sumac to your diet, be sure to take note of the following cautions:¹⁴

• Avoid sumac if you are allergic to cashews or any member of the cashew plant family
• Stay away from poison sumac, which you can easily recognize by its white or gray berries; the only safe sumac to eat presents with red berries
• Even sumacs generally considered safe for consumption have the potential to cause skin irritation and other adverse reactions in some people; discontinue using sumac if you experience any unusual reactions
• Be careful when harvesting sumac cones in public areas, especially along roadways, because some areas may have been sprayed with insecticides or pesticides