Tuesday, November 22, 2011

Hibiscus Tea (Roselle) - Flor de Jamaica & Lowering Blood Pressure

I usually tend to write about teas, herbs, and other beverages that I especially like, but this time I thought I'd share one that I do not particularly like, although a large number of others seem to love it. And while I may not like it, I find it very interesting because of the overwhelming scientific evidence that it can be effective at treating high blood pressure. This drink is hibiscus tea, an herbal tea made from the calyces (sepals) of the roselle plant (Hibiscus sabdariffa). Pictured here is an iced glass of this beverage:

Hibiscus tea goes by many names, in part because it is widely consumed in so many different countries and cultures. In Egypt, this drink is often referred to as karkadé(كَركَديه‎) which is just Arabic for hibiscus, and in much of Latin America it is called Jamaica, short for agua de flor de Jamaica.

The picture above shows the roselle plant, used to produce this herb. It is widely cultivated in hot, tropical climates, such as Egypt and Nigeria. On RateTea, you can find listings of different sources of hibiscus, including both tea companies selling it as an herbal tea, and herb companies selling it as a bulk herb.

Why I don't like hibiscus: sourness, cooked vegetable aroma:

Hibiscus produces the most sour herbal infusion of any herb that I've tried. It is even more sour than many fruits. Because of its intense sour flavor, it is often blended with other herbs, and, whether it is consumed on its own, or in blends, it is typically sweetened, often heavily so. I tend not to like sour qualities, and hibiscus is over the top on the sourness for me.

I also am not crazy about the aroma of hibiscus. In some respects its aroma is rather fruity or berry-like, and I like these qualities, but I also find that it has a strong cooked vegetable or cooked fruit aroma, much like what your home will smell like if you've been making large quantities of jam. I find this smell mildly unpleasant, and this is another reason I'm not a fan of hibiscus.

But you may love it...I find that most people like both sourness and jam more than I do!

Hibiscus is a common ingredient in herbal blends and flavored teas:

Even if you may not be aware of it, it is highly likely that you actually have consumed hibiscus in some form or another. Hibiscus is one of the most common ingredients in herbal teas, including the Celestial Seasonings Zinger® series, where it serves both to impart a deep purple-red color, and to add sourness to a blend. As you can expect, I don't particularly like these blends. The only mainstream commercial blend that contains hibiscus as a main ingredient, that I actually enjoy, is Bigelow's Sweet Dreams. Hibiscus is also sometimes blended with tea; I've tried a black tea blend with hibiscus; I wasn't a huge fan of it.

Hibiscus and Hypertension (High Blood Pressure):

I've researched a fair amount about the medicinal uses and health properties of various herbs, and hibiscus was one herb that stood out in that it has an overwhelming amount of strong evidence supporting its efficacy for treating a specific, rather serious health condition: hypertension (or high blood pressure). Not only has hibiscus been found to be effective at lowering blood pressure in multiple controlled clinical trials, but it has even been compared to a number of different prescription antihypertensive drugs, and it was found to be as effective as one of them. Furthermore, unlike prescription medications used to treat hypertension, hibiscus was found to have a complete absence of strong or serious side effects. As something that has been widely consumed as a beverage for hundreds of years, it seems absurd that people would take one of these medications without first trying hibiscus, especially in cases of milder hypertension. If you want citations to these studies you can find citations and some more detailed discussion of these studies on RateTea's page on hibiscus tea.

One of my motivations for sharing this post is to get the word out about hibiscus. Hypertension is a widespread problem in America, and most of us probably know at least a few people who are suffering from this condition. It certainly cannot hurt to try regularly drinking a few cups of this herb to lower your blood pressure before trying out a potentially riskier prescription drug. If you choose to drink it in herbal tea form, however, be careful about how much sugar you add, as high-sugar diets can contribute to or worsen hypertension.

Hibiscus may also have some other health properties, although these have been less extensively studied, and only have suggestive support, mostly from animal studies. These properties include an antipyretic (fever-lowering) effect, protection against liver damage, and lowering of cholesterol.

Do you like hibiscus?

I'd be curious to hear from other people...do you feel similarly about this herb as I do, or do you actually enjoy it? Did you know about these studies on hypertension? Would you take an herb like this one, before taking prescription medication?


  1. I'm an oddball - I like the flavor of hibiscus steeped on it's own. It's like a fruit stew. I don't particularly enjoy it in blends because it tends to overpower everything. It's better as one ingredient.

    As for the other question, there's something important that struck me:

    First, the studies you reference on the other site that you're saying support hibiscus actually are referring to "tolerance" as the aspect where it excels - that's a different medical concept than efficacy. Naturally-occuring compounds will of course be better tolerated (which simply means they produce less side effects) - but if someone's blood pressure is not under good control, it can be dangerous to recommend someone delay using a prescribed medication.

    Lisinopril is mentioned in the other article as the drug that was shown to still be more effective - but people may or may not be aware that Lisinopril uses a natural ingredient as well - snake venom. The same ingredient that stops the mouse's heart when the snake bites down, just in a much more diluted form, it de-constricts the vessels quickly. If someone's battling chronic high blood pressure, they need the fast-acting efficacy of a med like Lisinopril.

    To illustrate the same idea: Asthmatics were precribed coffee as a treatment at the turn of the 20th century because the caffeine caused an adrenaline rush to help delay the air sacs from constricting, but caffeine leaves the body very quickly so it wasn't a cure. Over time, they've developed steroids and bronchodilators that do a better job of sustaining that effect and keeping people feeling better long-term.

    Hibiscus may have a mild effect on blood pressure, but it's my understanding that you would have to be drinking it continuously over 24 hours in order for it to be a real "treatment" of any sort, even mildly.

    Bottom line - it's not really a question of using it "before" or "in lieu" of a properly presribed medication - hibiscus can be enjoyed as a complement to it. The risks of not getting hypertension treated sustainably are more serious than the headache or fainting side effects that might happen with Lisinopril.

    Very nice article - thought-provoking!

  2. The articles cited on that page establish clinically-significant efficacy, although lower than the stronger, modern drugs. For example, Hibiscus sabdariffa extract was found equally effective as Captopril. Captopril is a relatively old drug, and is now in use mainly because its patent has expired and it is available as a generic, but it also has common side-effects. It seems pretty common sense that, given the outcome of that one study, hibiscus is likely to be a much safer alternative for people who would be on that particular medication, or for people who take it but have had an adverse reaction.

    Also, when I said "before", I was thinking along the lines of the first study cited, in which hibiscus tea (not an extract) was found to produce a change in mildly hypertensive or pre-hypertensive people.

    I do not consider self-treatment as a substitute for professional medical advice when people face serious life-threatening conditions, but I do want to encourage people to consider adding this beverage to their toolbox. Most cases of hypertension in America are cases of mild, chronic hypertension caused by lifestyle factors. And I do think that, in general, many doctors in America are too quick to push pills, and many patients too quick to pop pills, when they are not always necessary and are not always the safest result.

    Perhaps in the end it is all a moot point...when I really think hard about hypertension, I think a bigger issue is diet, lifestyle, and stress level. But that's a whole other beast. I merely wanted to write a post about this particular herb, as I found it interesting how strong the scientific evidence was, from the few studies that have been done on it. Many herbs have only weakly suggestive or inconclusive evidence supporting their use. Here, the evidence of an effect is very solid. And who knows, with further research, if hibiscus could be developed into a more potent treatment...if it is truly 100% tolerable at the doses used, and if it has a dose-dependent effect, then there's potential for greater efficacy.

  3. I love hibiscus. I don't make it at home though. As healthy as it is, I assume a lot of sugar should be added to make it tasty. I used to love a sugar preserved hibiscus snack from Trader Joe's. Too bad they discontinued it!

  4. Trader Joe's actually has a history of discontinuing many of my favorite products. Fortunately though, they added back their 70% cocoa-content pound plus (500g) bar of chocolate, only a few months after discontinuing it in a local store here. I told the people that it was a major draw to the store (which was true). But they've also discontinued a type of beer, type of shampoo, tangerine juice, and a wide variety of other things that I used to buy regularly and in quantity. But that's a bit irrelevant!

  5. Hi Alex, I know this is an old post. In your hand you are holding two hibiscus roselles.
    i am interested in acquiring the 'white' one.
    Do you still have access to the plant?


    1. The photo isn't me, but...no, unfortunately, I don't have access to these plants. Where I live, though, there are native hibiscus plants (not the ones here), Hibiscus laevis. I don't know if they can be used in tea, but they're native, and very beautiful. They grow only in wetlands and you can only grow them in a garden if you have wet conditions.

  6. Alex, I love hibiscus, commonly called sorrel in Jamaica.
    I would love to be able to have seeds to the "white" one you are holding in your hand.
    Do you still have access to the plant?