Does eating walnuts lower BP? If so, how many walnuts have to be consumed each day? How long does it take before the BP starts to fall?
—Gerard K. Nash, DO, Amarillo, Tex.

There has been one excellent controlled trial of walnuts and BP (N Engl J Med. 1993;328:603-607). Results showed that when 20% of caloric intake was provided by walnuts, there was no effect on BP. A single study cannot answer the question, but a clinically significant effect on BP would seem unlikely.
—Samuel J. Mann, MD (100-4)