April 29, 2013

Fava beans’ impact on urine sodium

Eating fava beans increases dopamine in blood and urine, but does not stimulate urinary sodium excretion.


Fava beans contain high concentrations of dopa – the precursor to dopamine – and have been used as complementary medicine by patients with Parkinson disease to improve motor skills (like the medication L-dopa). Dopamine in the kidney regulates blood pressure and volume by increasing sodium excretion in the urine, and could worsen the orthostatic hypotension (low blood pressure on standing) experienced by many patients with Parkinson disease.

Emily Garland, Ph.D., research associate professor of Medicine, and colleagues sought to determine the relationship between dietary fava beans, plasma and urine dopamine levels, and urinary sodium excretion. In healthy volunteers, they found that fava bean consumption raised plasma and urinary dopa and dopamine levels. The substantial increase in plasma and renal dopamine, however, did not stimulate urinary sodium excretion, they report in the American Journal of Clinical Nutrition.

The findings are consistent with a variable role for renal dopamine in regulating sodium excretion, and they suggest that fava beans are unlikely to worsen orthostatic hypotension in patients with Parkinson disease.

This research was supported in part by grants from the National Institutes of Health (HL071784, RR024975).