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Some plants may help us reduce high blood pressure and celery may be one of them. But celery also contains relatively high levels of sodium for a vegetable—about 100 mg of sodium in one cup (~130 g) of chopped celery. Even though it’s relatively high in sodium, it also contains other compounds like NBP, the compound primarily responsible for celery’s taste and aroma, which can relax the smooth muscles that line blood vessels, potentially resulting in lower blood pressure. And there are other compounds in celery that likely have antihypertensive effects, but those are all based on rodent studies—and indeed, celery seed appears to lower blood pressure in hypertensive rats. But what about humans?
You don’t know until you put celery seed to the test, or in this case, celery seed extract, in a randomized, triple-blind, placebo-controlled, cross-over, clinical trial. After four weeks of taking the celery seed extract, systolic blood pressure dropped by at least 10 points, and diastolic blood pressure by about 8 points. But the whole celery seed equivalent would be way more than people could eat.
Is there anything a more modest sprinkle of celery seed a day might help with? Look at this: “Treatment of women’s sexual dysfunction using Apium graveolens L. Fruit (celery seed): A double-blind, randomized, placebo-controlled clinical trial.” And this study used a culinary-friendly dose of celery seed—about 500 mg or about ¼ tsp per capsule, three times per day. At the end of six weeks, there was a significant improvement in the self-reported female sexual functioning among those eating celery seeds, with significant improvements across multiple measures within just three weeks.
What about celery juice? There was a case report of a man who juiced a bunch of celery every day and had a drop in blood pressure and what appeared to be a nonrandomized controlled trial in which an undisclosed amount of celery juice seemed to help. A review concluded that celery can be considered an antihypertensive agent, but the quality of evidence seems slight. What’s the downside though?
Well, celery seed is generally considered safe, and a safety evaluation was performed in the blood pressure trial that indicated so, but maybe not for everybody. Here is a case report of someone who had been taking about two tablespoons of dried celery leaves a day, and it seemed to cause overactive thyroid gland activity; the same happened to this woman who had been taking celery extract powder for weight loss. She did lose 57 pounds (26 kg) in 78 days, but that was likely because the celery extract led to hyperthyroidism. That is not a healthy way to lose weight, risking side effects with names like thyrotoxic paralysis.
Celery is also an allergen for some, often called “pollen-related food allergy.” People who are allergic to some pollens are more likely to have an allergy to celery, such as what happened in this rare case of severe anaphylactic shock after consumption of raw celery. Some only get allergic reactions to celery if they eat it before exercising. Heating celery eradicates symptoms for about 50 percent of people with a celery allergy, but those who react to raw celery also react when it’s dried.
Even if you don’t have a celery allergy, here’s a warning for those who eat a lot of celery, celery juice, or celeriac (celery root). There are compounds called psoralens in the celery/parsnip/parsley family that can make you sensitive to sunlight. Farmworkers can suffer from a condition known as celery blisters when handling plants without skin protection in the sun. Even grocery store workers who go from the produce aisle to the tanning salon can get into trouble. These compounds can make their way into our skin from the inside out as well, and they are not destroyed by cooking. Too much time in the sun after commencing a “celery soup diet” or spending time on a tanning bed an hour after eating just one large celery root may be enough to result in a serious blistering burn.
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