Educational information, not medical advice — ask your doctor or midwife.
Nance is a small golden-yellow fruit from a tropical tree, Byrsonima crassifolia. The tree grows from Mexico and the Caribbean down into Brazil. The fruit is eaten as food far more often than it is used as medicine.
The taste is tart, oily and strong. People eat it fresh, or turn it into juice, jam, ice cream and liqueur. Frozen pulp is sold in Latin food shops around the world.
In folk medicine, the bark and leaves matter more than the fruit. Both are very high in tannins, the dry, bitter compounds found in strong tea and oak bark.
Here is the honest verdict. As a food, nance is safe for most people and rich in vitamin C. As a medicine, human evidence is almost absent.
Long use in tradition is not proof that something works. It is also not proof that it is safe. Both of those points apply to nance bark and leaf remedies throughout this page.
No one has shown how nance works in people, because the trials have not been done. Almost all of the research sits in test tubes and rodents.
In lab tests, nance extracts soak up free radicals. That is an antioxidant effect, and many fruits show it. Whether it changes anything inside your body is unknown.
In test tubes, bark extracts have slowed the growth of some bacteria and yeasts. That is not the same as treating an infection in a person.
In rats and mice, some extracts lowered blood sugar. These findings are early. They have not been repeated in human trials.
The old use for diarrhoea has a simple rationale. Tannins bind proteins and make tissue feel tight and dry. This astringent effect is well described in the lab, but it has not been tested for nance in people.
Most readers will meet nance as food, not as a supplement.
Common forms: - Fresh fruit, sold loose in local markets - Frozen pulp, used for juice and smoothies - Bottled juice and agua de nance - Jams, candied fruit and ice cream - Nance in syrup, in jars - Licor de nance, a sweet fruit liqueur
Traditional medicine forms: - Bark decoction, boiled and drunk or used as a wash - Leaf tea - Bark rinses for the mouth or skin
Supplement capsules of nance bark or fruit extract exist, but they are uncommon. Their strength is rarely stated in a way you can check.
Nance has been eaten and used across Latin America for a very long time. Archaeological remains place the fruit in Mesoamerican diets well before the colonial era.
Folk healers in Mexico, Guatemala, Costa Rica and Panama used bark decoctions far more than the fruit. The bark was given for diarrhoea and stomach complaints.
Bark washes were also applied to skin sores and used as a rinse after childbirth. Some communities used the bark as a dye and a tanning agent, which fits its high tannin content.
Ethnobotanical surveys in the twentieth century recorded these uses repeatedly. The records describe what people did. They do not test whether it helped.
Stop and see a doctor if any of these happen.
- Diarrhoea that lasts more than two days in an adult, or one day in a child - Diarrhoea with blood, black stools or a fever - Signs of dehydration: dizziness, very dark urine, passing little urine - Belly pain that is severe or keeps getting worse - A rash, itching or swelling of the lips, tongue or face after eating nance - Trouble breathing after eating nance; this needs emergency care straight away
If you have diabetes and your blood sugar readings change after starting nance products, tell your doctor.
In the United States, the European Union and across Latin America, nance is an ordinary food. Fruit, pulp and juice are sold freely. Bark or leaf supplements are not approved as medicines, and no health claim for them has been accepted by the FDA or by European regulators.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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