Amino Acid Phenylalanine Helps Us Make Good — And Bad — Decisions

Are you an optimist, or a pessimist? Do you ever make bad decisions? The level of dopamine—created from the amino acid phenylalanine—in your brain could be influencing your ability to make good decisions.

A recent interesting study from University College London investigated whether high levels of dopamine makes us unrealistically optimistic. Have you ever purchased a lottery ticket? Humans are generally optimistically biased when making predictions about our future. We habitually underestimate the likelihood of negative events. But why? Is the amino acid phenylalanine to blame?

Researchers Tali Sharot, Marc Guitart-Masip, et al., from the Department of Cognitive, Perceptual and Brain Sciences at the University College London, developed a double-blind placebo-controlled intervention study to investigate. Dopamine is a brain chemical—a neurotransmitter–produced from the essential amino acid phenylalanine. Phenylalanine can elevate mood, decrease pain, and help memory and learning.  But can we have too much?

The researchers created a test to see if dopamine makes us unrealistically optimistic. Test subjects were given dihydroxy-L-phenylalanine—to produce dopamine—and asked to perform a belief update test. They were asked to estimate the likelihood of experiencing 40 different types of adverse life events, such as having their car stolen.

Dihydroxy-L-phenylalanine raises dopamine, affects decision-making

The dopamine created from the dihydroxy-L-phenylalanine made every answer highly optimistic. Negative events were significantly underestimated with high levels of dopamine. In addition, raised levels of dopamine makes us less likely to learn from unpleasant experiences.

The researchers concluded that manipulation of the neurotransmitter dopamine—by taking dihydroxy-L-phenylalanine—makes us unrealistically optimistic. So controlling dopamine can help us make better decisions.

Sources: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3424419/