Taking Root

As science transforms the pantry into an apothecary, a rich array of whole foods and their components are under investigation as potent agents against disease and degeneration. Most are derived from plants, notably the pigments that give them their bright colors—the skins of blueberries, cherries, grapes, and plums, for example. And then there’s turmeric.

A vividly yellow-orange root clad in a dull dun skin like its cousin ginger, turmeric has long been a staple of the Indian kitchen (in flavoring curries) and a mainstay of Ayurvedic medicine. Typically dried and pulverized, it boasts a star constituent, curcumin, which, like many other plant pigments, is chemically classed as a polyphenol. Turmeric is approximately 2 to 8 percent curcumin.

In their natural habitats, plants turn up polyphenol production in response to ecological stress, and the pigments in turn protect the plants from such environmental insults as drought, fungi, and solar radiation. When consumed by animals—including us—the polyphenols are biologically active.

Sometimes called Asian aspirin, turmeric is thought to be the reason why Alzheimer’s disease is relatively rare in India. Curcumin protects the brain in multiple ways, most strikingly by preventing—and even dissolving—the distinctive build-up of amyloid-beta protein that clogs nerve pathways in Alzheimer’s disease. It also works chemically to fight oxidation and inflammation and activates so many physiologic processes that it may help our bodies repel ills from a cough to cancer.

Its diversity of actions also makes curcumin of interest as a natural antidepressant. Increasingly, depression is seen as a disorder accompanied by, and possibly caused by, inflammation and oxidative insults. Stress, trauma, lack of sleep, unhealthy eating, lack of exercise—all can trigger the immune system to set off inflammatory responses in the body.

Intrigued by reports of curcumin’s effects against neurodegenerative disease, psychologist Adrian Lopresti conducted a pilot study—randomized, double-blind, placebo-controlled—of curcumin as a treatment for depression. He and colleagues at Murdoch University in Perth, Australia, monitored the effect of curcumin in 56 men and women, all diagnosed with moderate to severe major depression. Patients received identical-looking capsules of either the polyphenol or a placebo for eight weeks.

During the first four weeks, both groups improved. But over the next four weeks, the team reports in the Journal of Affective Disorders, the curcumin-treated patients continued to improve—signs of anxiety abated as well as those of depression—while the placebo group experienced no further improvement or worsening of symptoms. That they responded at all Lopresti attributes to the well-established placebo effect in depression.

“Our findings support consistent research that depression is associated with increased inflammation,” says Lopresti, and it may take time for the mechanistic changes to result in a stable effect on mood. “Despite what has been previously believed, depression is not all about brain chemicals such as serotonin.”

Turmeric vs. Depression

• Counters inflammatory activation.
• Combats hyperactivity of the stress hormone system.
• Protects against dysfunction of the cell powerhouses, the mitochondria.
• Deters neural degeneration.
• Restores synaptic plasticity.
• Modulates levels of neurotransmitters.
• Decreases oxidative stress and related damage.

An Atypical Advance

The greatest effects of curcumin occur in a subgroup of patients with atypical depression, a form of the disorder that comprises 25 to 35 percent of all cases and is resistant to other treatment.

• Such patients are mood-reactive; they can be cheered somewhat by positive events, but only temporarily.
• Significantly, they overeat regularly and binge often, gaining sometimes substantial amounts of weight.
• They also sleep excessively and endure leaden paralysis and overwhelming fatigue.
• In addition to its physical manifestations, atypical depression is marked by extreme sensitivity to perceived interpersonal rejection.
• Physiologically, atypical depression is linked to severe neuroinflammation, elevated levels of the stress hormone cortisol, and high levels of inflammatory markers, such as C-reactive protein, in blood.
• Those who have atypical depression may respond to curcumin because of its wide-ranging anti-inflammatory properties.
• Psychologist Adrian Lopresti plans to test the possibility of predicting—from measures of inflammation markers in the blood—which patients might respond best to curcumin.

Fighting on Many Fronts

Because of its multiple modes of action, curcumin is under study in many medical centers as a treatment for a wide array of disorders. Some notable applications:

• Alzheimer's disease

• Mild cognitive impairment

• Multiple sclerosis

• Diabetes

• Ulcerative colitis

• Colon cancer

• Chemotherapy resistance

• Bacterial and viral infections