Doctors diagnose depression by the presence of symptoms. There is no specific biological test that confirms the diagnosis—such as a throat culture to confirm strep throat or a troponin blood test to confirm heart attack. But that may be about to change. It turns out that depression is associated with low levels of a certain nutrient that is easily detected in blood. If you’re thinking, So what? You already know if you’re depressed, read on to learn how testing for this nutrient might lead to better treatment for this devastating illness.

In a study led by researchers at The Rockefeller University, 71 patients being treated for major depression had their blood levels of acetyl-L-carnitine (ALC) compared with blood levels of ALC in 45 people without depression. ALC, an amino acid and one of the body’s building blocks for protein that is naturally produced in the brain and liver, increases brain energy and helps with the production of brain neurotransmitters (chemical messengers). Participants in both groups were ages 20 to 70 and matched for age and sex.

The results showed that low levels of ALC were strongly associated with depression. Patients with depression had lower levels of ALC, on average, than people without depression. Patients with the lowest ALC levels had the most severe depression…depression that had started at earlier ages…and were most likely to have treatment-resistant depression. (Patients with the lowest ALC levels were also more likely to be female and to report having been abused or neglected in childhood.)

While the researchers say that more clinical trials are needed before recommending treating depression with supplements of ALC (or its precursor L-carnitine), there is research to support such use. Studies have found that ALC improves depressive symptoms in rodents. And a few small studies have found that ALC supplements are effective at treating depression in elderly people. ALC and L-carnitine supplements are widely sold over the counter in stores and online.

Should you take ALC or L-carnitine if you are being treated for depression? Bottom Line expert Andrew Rubman, ND, medical director of Southbury Clinic for Traditional Medicines and author of the Bottom Line blog “Nature Doc’s Patient Diary,” notes that ALC is naturally available in animal-based foods such as beef, chicken, milk and cheese—although you may need more ALC than you can get from food to help with depression. Discuss with your health-care professional whether ALC or L-carnitine supplements may be something for you to try—and if so, what would be an appropriate dose. (Important: ALC supplements potentially can cause psychosis in people with bipolar disorder. L-carnitine supplements have not been found to have that effect.)

Related Articles