Guava leaf, like many other herbs, has an amazing array of qualities, and it seems to be able to do amazing things. It can stop diarrhea and has saved many lives across the world. Especially in impoverished countries, and in regions where modern health care is either not accessible, or it is not affordable (or both). There are constituents in guava leaf that attack pathogens. It’s antibacterial. Guava leaf can regulate blood glucose levels. It can help make you thin! It can even allow you to drink as much as you want and not have (many) repercussions the next day!

Read more

Many of you have been writing to ask how to make guava leaf tea, so I figured I would make it a new post.  There are two methods available when making medicinal herbal teas: Infusions and Decoctions.  Infusions are made by starting with boiling water, and letting the herbs soak for 10-20 minutes.  To make an herbal decoction, you add your herbal material to cold water, heat it to boiling, then simmer for 20 minutes or more.  Decoctions are more often used with root and bark material because medicinal qualities are more difficult to extract.

For guava leaf tea, you can use either method – to ensure the maximum amount of phytochemicals are extracted, simmer for a minimum of 10 minutes.  If using dried leaves, add a couple teaspoons per each 8oz water to start, then alter to personal taste.  If using fresh leaves you need to add more (maybe 2-4tsp), as the leaves will not be as concentrated and still contain a great deal of water.

These methods may be used for a variety of medicinal teas, but be sure to research your ingredients.  Guava leaf has not been shown to have any toxicity, so making a very strong guava leaf tea is ok.  The same cannot be said for all herbs.  As always, make sure to discuss all herbal uses with a medical professional to asses medication interactions and health concerns.

Cheers to your health, everyone, and I appreciate your comments and questions.  Keep them coming!

In October, the Bangkok Post ran an article suggesting people use guava leaves, along with mangosteen skin, the outer part of makham pom  (Indian gooseberry), si siad (Acacia catechu) trunk, maak or betel fruit, and phlu leaves to help prevent fungal infection following the worst flooding in Thailand’s history.  Read the article here.

Originally inherited from the Aztec in Mesoamerica, guava leaves have a long history in Guatemala as a useful, and sometimes lifesaving, tool for battling diarrhea and intestinal discomfort.  They are listed alongside 15 other plants in “Plants used in Guatemala for the treatment of gastrointestinal disorders,” published in the Journal of Ethnopharmacology, in 1993.

 

This paper “reports the in vitro studies [studies done in a petri dish] of the activity of 16 plant extracts against pathogenic enterobacteria (31).  The researchers start out with a list of 408 plants; they narrow the list down to 34 plants which are deemed worthy of further study.  Of these 34 plants, 16 are chosen for “confirmation” of antibacterial activity against E coli, Salmonella enteritidis, and Shigella flexneri pathogens.  Guava leaf (Psydium guajava) turns out to be one of three plants (out of the 16) that inhibits growth of all three kinds of bacteria.

For a majority of these plants, the most effective extraction agent for antibacterial activity is ethanol.  Ethanol extract, acetone extract, and n-hexane extracts of each plant are tested and compared for effectiveness.  For guava leaf, the acetone extract proved most effective for antibacterial activity.

In Guatemala, guava leaf is used for diarrhea, dysentery, stomach pain, leucorrhea (a condition of unusual vaginal discharge), and a variety skin infections.

To access this article, please click here.

 

According to Indian folklore, “it is believed that the leaves of this plant [guava] can cure jaundice within three days” (305).  The use of guava leaves is reported to be widespread in the Mangalore district of Karnataka, in Southwest India, for the cure of jaundice.  Scientists in the area decided to verify the use of guava leaves for jaundice and other liver diseases by conducting a study on the hepatoprotective (liver protection) properties of guava leaves.

The study on the hepatoprotective effects of guava leaf extract was conducted at the Krupanidhi College of Pharmacy in Bangalore, India.  Researchers collected fresh leaves from guava trees in the Koramangala area in Bangalore.  They crushed them, and boiled the leaves in water for one hour.  They filtered out the solids, and evaporated the water, leaving a powdered guava leaf extract.  Rats were used as study subjects.

Analysis of the extract showed that it contained carbohydrates, tannins, flavanoids, saponins, steriods, protiens and amino acids.

Researchers found that the extract showed good liver protective activities; the effect produced by the higher doses of guava leaf extract (500mg/kg) was similar to that produced by Silymarin, a well-known hepatoprotective agnet.  Furthermore, the guava leaf extract prevented an increase in liver weight in rats, something Silymarin does not do.

“In conclusion,” the researchers stated, “the aqueous extract of Psidium guajava Linn. leaves [guava leaves] showed good hepatoprotective activity in CCI4 induced acute and chronic liver damage, PCM induced liver damage and TAA induced liver necrosis.  The hepatoprotective activity may be due to the antioxidant effect of the plant” (310).  In other words, guava leaves can help protect the liver.  Guava leaf tea or guava leaf extract seems to be able to help prevent damage, or help to treat damage already done.

For a link to the full article, please click here.

In the journal Nutrition and Cancer, an article on the “Action Mechanism and Signal Pathways of Psidium guajava L. Aqueous Extract in Killing Prostate Cancer LNCaP Cells” was published in 2010.  The study comes out of Taiwan, a country which makes frequent use of guava leaves for a variety of ailements.

In the article, an ”aqueous extract of Psidium guajava L budding leaves (PE) has been shown to possess anti-prostate cancer activity in a cell line model” (260).  The researchers reported that they were drawn to study guava leaves’ effect on prostate cancer cells after conducting a study which showed that guava leaves were “potent anti-glycative agents” (261); this action was ascribed to the unusual free radical scavenging and anti-oxidative capabilities of guava leaf polyphenols.  The effects of glycation can result in the formation of irreversible advanced glycation end products (AGE’s), which are associated with many progressive diseases and can also trigger cancer formation.  Since guava leaves showed strong anti-glycative properties, the scientists chose to study the leaves’ action against an abundant form of prostate cancer, LNCap: Lymph node-metastasis prostate cancer.

They performed tests both in vitro (petri dish) and in vivo (in mice).  In vitro, they found that guava leaves were cytotoxic on the cancer cells, and that the leaves ”arrested cell cycle of LNCaP cells…[guava leaves] inhibited LNCaP cell growth and proliferation by preventing the cells from entering the S phase, and…TUNEL assay also confirmed the apoptic mechanism induced by [guava leaves]” (265).

In vivo, “although no significant difference in body weight was observed among the tumor-implanted [mice], the size of the tumors in the untreated mice was much larger when compared to tumor sizes in the guava leaf-treated mice at week 6 of the study.

“Conclusively,” the authors state, “[guava leaf] is a potent anticancer agent, acting through both cytotoxic and apoptotic action mechanisms; therfore, it [can feasably be used] as a potential adjuvant anti-prostate cancer therapy, in particular, for anti-androgen-responsive PCa” (268).

Click here for access to the full article.

 

Active.com lists guava fruit as a superfood alongside sardines, blueberries and flaxseed.

To follow the link, click here.

This article was published in 2008 with research conducted at National Taiwan University.  Scientists set out to evaluate the “antihyperglycemic effect of guava leaf extracts in diabetic rats.” 

As stated in previous posts, diabetes mellitus is a type of metabolic disorder, characterized by hyperglycemia (high blood sugar), and deficiencies in in insulin secretion and/or insulin action.  Type 2 Diabetes is the most common type of diabetes.  According to this article, Type 2 Diabetes is expected to affect more than 365 million people worldwide by the year 2030.

People in both Japan and Taiwan boil guava leaves in water and drink the extract as a folk medicine for diabetes, and researchers decided to test the efficacy of this treatment in Type 2 Diabetic rats.  They found that “diabetic rats that received oral guava leaf extracts showed lower blood glucose levels” (p. 1460), and the lowering of blood glucose levels was dose-dependent.  So, higher doses of guava leaf extract resulted in lower blood glucose readings. 

Researchers concluded that “guava leaf extracts may relieve hyperglycemia in diabetic rats.  Guava leaf extracts also stimulate[d] glucose utilization in liver tissues.”  They found that through a variety of possible mechanisms/pathways, guava leaf extract “resulted in a decrease in the blood glucose level in diabetic rats.”

To access the full article, click here

          The World Health Organization (WHO) categorizes diabetes as a top preventable killer worldwide – Type 2 diabetes, arising commonly from excess body weight and inactivity, comprises 90% of diagnosed diabetics.  In 2004, an estimated 3.4 million people died from blood sugar related consequences, and WHO predicts that death from diabetes will double by 2030.  Eighty percent of these deaths will occur in low-to-middle income countries.

          These are sobering statistics.  However, there is a silver lining illuminating these dark clouds.  Type 2 diabetes is both manageable, and highly preventable.  Guava leaves can, and do, play an important role in diabetes management and prevention.  The Japanese Ministry of Health, Labor and Welfare has published a list of “Foods For Specific Health Uses,” or FOSHU.  This list includes a commercial (pre-packaged) form of guava leaf tea, called Bansoureicha, made by Yakult Honsha.    

          In 2010 Yakult Honsha published a clinical study utilizing guava leaf tea in Nutrition & Metabolism, “Anti-hyperglycemic and anti-hyperlipidemic effects of guava leaf extract.”  In the study, they reviewed “evidence regarding the anti-hyperglycemic activities and safety of GvEx (guava leaf extract) and Guava Leaf Tea in vitro [petri dish], as well as in animal models and several clinical trials.”  They also described “the efficacy and safety of Guava Leaf Tea in pre-diabetic and diabetic patients with T2DM (Type 2 Diabetes Mellitus).”[i]

          In a clinical trial involving twenty hospitalized patients with T2DM, guava leaf tea was given to patients 2 hours after mealtime, after postprandial glucose levels had been allowed to elevate.  The elevated level was “significantly reduced with a single administration of guava leaf tea.”   

          In a continuation of the clinical study, they tested guava leaf tea’s effectiveness over a twelve-week period.  They found that “insulin resistance significantly decreased in all subjects.  Moreover…serum levels of total cholesterol and triglycerides significantly decreased in the subjects with hypercholesterolemia (high cholesterol) and hypertriglycemia (high triglyceride levels).”

          What does this all mean?  Guava leaf use should be more widespread as a tool to help combat a worldwide leading cause of malady, both in developed and undeveloped countries.  As the article states, “the consecutive ingestion of guava leaf tea [or guava leaf extract] with every meal is expected to benefit pre-diabetic and diabetic patients as an aliment therapy in both developed and undeveloped countries.”  Yakault Honsha’s motives are for people to buy and drink their product every day, but any form of guava leaf will have the same wonderful benefits. 

          Look for more reviews on scientific articles about guava leaf to come!  

       To read the full article, click here

---

Deguchi et. Al. “Anti-hyperglycemic and anti-hyperlipidemic effects of guava leaf extract,” Nutrition and Metabolism, 2010, 7:9.

Blogger/author Sushma Joshi’s compelling thoughts on the gap between “modern” and “traditional” medicine in Nepal:

Last Tuesday, Kalpana Dhimal (28), hung herself after she couldn’t afford health care for her infant daughter. The baby died a day later. “Poverty-stricken mom hangs self,” was the headline of a national daily. According to the same report, the child was running a 105 degree fever. The nursing home demanded Rs.1,700 per day. Like many women, she didn’t ask her husband or family for the money. She chose to die instead.

Joshi’s article mentions the use of guava leaves to treat epilepsy. Read the full article here.

Did you know… That we can make a difference?

The American Heart Association’s Go Red For Women^® works every day to fund research and fight this killer so that more women can be saved. But they need our help. Please celebrate National Wear Red Day^® on Friday, February 4, or any day to raise awareness about heart disease among women, and the funds to ensure the research that could save a woman’s life
won’t have to be denied.

The American Heart Association uses all revenues from local and national Go Red For Women activities, like National Wear Red Day, to support awareness, research, education and community programs to benefit women. These funds help women by offering educational programs, advancing women’s understanding about their risk for heart disease and providing tools and motivation to help women reduce their risk to protect their health.

It is their mission and belief that together we can make a difference. This February we can join their mission, raise funds and rally support to fight this silent killer.