For most people blood pressure varies significantly, even from moment to moment. So if you eat a particular food and check your pressure a little later, it could be higher or lower without any connection to the food.

It could go lower especially if you're confident the food will work, because you could be more relaxed next time you measure.

What makes "real" hbp a problem is that it's too high most all the time.

Doctors don't usually diagnose hbp unless they've seen it consistently high over some period of time.

My personal experience and belief is that diet and exercise are extremely important, particularly in the long run, but special foods and supplements by themselves won't help much. The studies that support them are usually small and inconclusive, but the supplement companies and the media boost them to the skies for the obvious commercial reasons.

Doctors don't know everything, but your own physician is your best source of advice. He's "selling" care and expertise, not bottles of super-duper capsules.