Editor's Note: This article is a reprint. It was originally published November 14, 2016.
Mostly everyone in the U.S. has heard of a guava. Many have never tasted one, however, with all the apples, bananas and grapes available. But like virtually every other plant-based food, besides being delicious, this one has its own set of health qualities, and they’re quite impressive.
From the Myrtle family, guavas are common as shade trees, because they can grow to more than 30 feet high in South and Central America, indicating they like a warm climate. In Florida, where they’re more like 20 feet high, it’s advised that growth be curtailed because they’re invasive.
Guava trees are grown in Malaysia, Vietnam, Hawaii, Peru, Mexico, China, India and the extreme Southern U.S. They can have a single trunk or several to create a canopy, with flowers that look like a tiny, white firework explosion, and oval or teardrop-shaped leaves.
With a different name in every port (such as “amrood” in India), the exterior of the pale green, pink or white, round or oval fruits (considered berries by botanists) depends on the variety. Inside, they’re generally one of the same colors, with small, edible brown seeds. The taste is sweet to tart, similar to both a pear and a strawberry.
Guavas are used in desserts and smoothies, as well as sauces and savory dishes, but what’s added determines how good they are for you. Prepared so they’re both tasty and healthy, they impart dramatic improvement in a number of diseases and disorders.
And like so many other foods, eating them fresh brings about the most extraordinary benefits. Additionally, unlike other exotic fruits, guavas are seldom sprayed with pesticides and other chemicals.1
Nutrients in Guavas Improve Immunity
Guavas contain several nutrients your body can’t do without. In every 1-cup serving you get 21% of the recommended dietary allowance (RDA) of vitamin A and 20% each of potassium (about the same amount as a banana) and folate.
While that’s impressive, it’s the vitamin C that outstrips the others to a staggering degree: Each serving imparts 628% of this bacteria-buster, so it’s no surprise that it fights disease so powerfully. Guavas are even recommended for dengue fever.2
The same serving size nets 20% of the RDA of folate, which is good for brain health and crucial for ensuring a healthy nervous system for unborn babies. Those nutritive benefits translate to the prevention and treatment of numerous diseases through improved immune function.3
Traditional uses for guava over centuries included alleviating pain from toothaches and canker sores4 and helping wounds heal when the juice is applied topically. Guavas were said to treat epilepsy and convulsions by making them less frequent.
Guavas Improve Skin, Fight Coughs and Colds
The astringents in guavas, particularly fruits that are not quite ripe, help treat acne and smoothen the texture of your skin. This benefit comes through both eating them and rinsing your skin with an emulsion of the pulp, juice and leaves, which serves to tighten, tone and detoxify.5
In fact, studies show guavas work even better for this purpose than the leading lotions, creams and potions. Guavas also prevent wrinkles and slow other signs of aging while removing dead skin cells and brightening your complexion.6
It’s predominantly vitamins A, B and C together that pass along these benefits, along with potassium, as they all have antioxidant properties. The vitamin C combined with biotin also remedies hair loss. Vitamin C is one reason traditional treatments for coughs and colds in Mexico, South America and India relied heavily on guavas.
However, it’s important to note that it was the juice from immature guavas, not the ripe fruit, because ripe guava is said to make respiratory and cold problems worse. Not-quite-ripe guavas relieve symptoms such as sore throat while reducing mucus in the respiratory tract, and also inhibit microbial activity from spreading germs.
Fiber — One of the Most Important Guava Nutrients
Most of the fiber in guava is insoluble fiber,7 which means it’s more adept at moving waste through your colon than most other foods. This is important for staving off bowel trouble, such as constipation and even colon cancer.
Guavas have been useful as a folk medicine to treat both diarrhea and dysentery. Astringents contained in raw guava fruits, as well as their leaves, make your gums feel “tighter” and your mouth fresher. This same effect takes place in your bowels due to alkaline content, which is both antibacterial and disinfectant.
Dysentery, which involves microbial growth, is inhibited while excess mucus is eradicated from your intestines. The vitamin C in guavas, as well as potassium and carotenoids, support the digestive system and are useful for improving hemorrhoids and symptoms of gastroenteritis.
At the same time, constipation takes a back seat when you eat guavas, in part because of laxatives in the seeds, whether they’re chewed or eaten whole. The seeds are responsible for some of the most advantageous health benefits. Both the seeds and skin contain carotenoids, glycosides and other phenolic and flavonoid elements.
You may have heard that “death starts in the colon.” That’s because constipation is linked to more than 70 different ailments, so getting rid of waste quickly is critical. Fiber also helps your body retain water, improving bowel movements by flushing everything through. Guavas also help your body by regulating your metabolism and aiding in the absorption of all those minerals and vitamins.
Fiber in Guavas Positively Affects Your Blood Pressure and Heart Health
By keeping your blood from thickening too much, guava consumption lowers your blood pressure. A study in India involved 120 participants with high blood pressure who were given guava to eat before meals for 12 weeks. This brought about an overall decrease in study subjects’ blood pressure levels. They also had higher intakes of total and soluble fiber as well as vitamins and minerals.8
Heart health is another benefit of eating this tropical fruit, and in several ways. Antioxidants play an important part, as they zap free radicals that cause oxidative stress and damage. One study reported that the leaves “inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production, lipid peroxidation and cell death.”9
The potassium and fiber content also support cardiovascular health by lowering blood pressure and reducing the risk of stroke, which is closely interrelated with your heart function.10
Fiber in Guavas Linked to Lowering Blood Sugar
Fiber also balances the sugar your body absorbs, which lowers the risk of either a spike or drop in glucose and insulin levels. A clinical study indicated that drinking tea made from guava leaves lowered the blood sugar levels of 19 people and was effective for up to two hours.11
Further testing by the same group in Japan, using 20 participants with Type 2 diabetes, revealed that when study participants drank guava-leaf tea after a meal, their blood sugar levels dropped by more than 10%.
Multiple animal and test-tube studies have shown guava extract to decrease blood sugar levels, improve its control in the long term and reduce insulin resistance. One study observed:12
“Although PG [Psidium guajava leaves] is known for its beneficial role in diabetes mellitus, for the first time we report its potential in the management of lifelong pathologies arising from high fructose intake initiated during developmental years.”
Guava Consumption and Cancer Prevention
If anything can be proven to be a dramatic game-changer in a plant-based food, its effect on cancer will do it. Not wanting to disappoint, guavas have been shown to have dramatically positive results in cancer studies, by inhibiting cancer cell growth and metastasis, in particular.
Lycopene works with flavonoids, lutein, quercetin and cryptoxanthin to inhibit the growth of cancer cells. According to Organic Facts:
“There have been numerous studies done ... on guava’s effects primarily on prostate cancer, breast cancer and oral cancers. Guava leaf oil is extremely successful as an anti-proliferative substance, and has actually been shown to be more effective than some leading modern medicines in reducing cancerous growth.
Guavas are also rich in lycopene, a powerful antioxidant that has been shown to be wildly successful in reducing prostate cancer risk. That same antioxidant has also shown to inhibit the growth of breast cancer cells, although further human trials need to be done.”13
Guavas have been shown to lower the risk of cancer of the skin, colon and lungs.14 A study in the Journal of Functional Foods15 also mentions apoptosis in gastric cancer cell proliferation.
Other Health Problems That Guavas Help Improve
All the other nutrients in this exotic fruit certainly don’t go to waste. Your body uses them to fight disease and help you in numerous ways:
- Thyroid — Copper, another mineral found in abundance in guavas, has the ability to regulate your thyroid metabolism in two ways — production and absorption. It helps regulate hormones throughout your body and optimizes the function of your organs.
- Eyesight — Vitamin A, or retinol, one of the most prominent nutrients in guavas, is known for its ability to improve eyesight, and in several different ways. It’s been shown to improve cataracts, macular degeneration and other maladies affecting your vision, and even reverse damage that’s already been done.
- Scurvy — Also known as the “scourge of sailors,” vitamin C is the only treatment for this condition. Luckily, the vitamin C in guavas eclipses even that of most citrus fruits. Guavas contain around 125 milligrams (mg),16 while oranges have 69.7 mg,17 grapefruits have 31.2 mg18 and lemons around 34.4 mg.19
- Brain health — Vitamin B3 (niacin) and vitamin B6 (pyridoxine) improve the function of the nerves of your brain, which in turn increases blood flow and stimulates cognitive function, improving your ability to focus.
- Weight loss — The roughage from fiber is one of the reasons why guavas are good for anyone wanting to slim down. They’re also very filling, which translates to eating less, and contain less sugar in comparison to fruits like apples and grapes.20
Painful Menstrual Cramps Relieved by Eating Guavas
Dysmenorrhea is the medical term for the painful menstrual cramps women experience during their period, a problem that affects more than a few. But studies show guava consumption helps relieve the pain.
In one study, 197 women with this problem were given 6 mg of guava leaf extract every day, which reduced the pain even more than conventional treatments.21 Researchers determined that pain relief comes about via the “spasmolytic” or spasm-lowering effect the extract has on the uterus.22