Gram for gram, guava has more vitamin C than any other food among the 90 we compare: 228 mg per 100 g, against 53 mg in an orange. A single guava (55 g) has 126 mg and an orange (131 g) about 70 mg, so the guava wins fruit for fruit too. The amount varies a lot, though. Plant scientist Julia Morton reports that most of the vitamin sits in the skin and firm flesh, and that nearly ripe fruit can hold 350 to 450 mg per 100 g against 50 to 100 mg in fully ripe, soft fruit.
Guava is also one of only 9 foods in our database with measured lycopene, the red pigment best known from tomatoes. USDA lists 5,204 µg per 100 g, along with 5.4 g of fiber, for just 68 calories. In a small trial, bite-size pieces of guava had a glycemic index of 29, which is low.
A guava is botanically a berry from a tree in the myrtle family, and its flesh runs from off-white to deep pink. The fruit is little studied in people, and a good share of the research uses leaf extract or leaf tea instead. Every card about a leaf product or an extract says so, and the studies of the fruit itself come first.
Health benefits of guava
The top findings from 22 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Higher hemoglobin and less anemia in childrenGuava added to a school meal for 7 months raised hemoglobin by 3.7 g/L and cut anemia by 51% in Indian children. A preschool trial (25 g of guava a day) also raised hemoglobin and ferritin, a marker of iron stores.
- ★More iron absorbed from a meal with guavaWith a rice meal, 100 g of guava raised iron absorption from 9.7 to 23.9% in girls and from 8.6 to 19.2% in boys. It measured one meal in 16 adolescents, not iron status over time.
- ★Low glycemic index in healthy adultsBite-size guava had a glycemic index of 29 and guava puree 47, both low. The glycemic index is a score for how fast a food raises blood sugar; this was a small trial of 19 healthy adults.
- ★Less gum inflammation after 14 days without brushing200 g of guava a day limited the rise in gum inflammation over 14 days without tooth cleaning (0.10 against 0.87 on water). Vitamin C alone helped too, and this does not show that guava treats gum disease.
- ★Less platelet clumping after one guava juiceIn 30 healthy volunteers, one 500 mL drink of guava juice reduced platelet (blood clotting cell) clumping triggered by collagen, but not by ADP. It was a single drink, so long-term effects are unknown.
All 22 studies, strongest evidence first
A school meal of mungbean dal with fresh guava for 7 months raised hemoglobin by 3.7 g/L and cut anemia by 51% in Indian children
Randomized trial in 200 children aged 6 to 10 (46% anemic) in rural Haryana, comparing dal with guava (about 170 mg of vitamin C) against dal alone. Body iron stores did not improve significantly, and the 56% drop in iron-deficiency anemia was not statistically significant. The authors report no conflicts of interest.
Adding 25 g of guava to a preschool meal for 140 days raised hemoglobin and ferritin and lowered iron deficiency in young children
Cluster-randomized trial in 399 children aged 24 to 48 months in 28 preschools in India, with guava, banana or cucumber added to the meal. Acute respiratory infections were also less common in the guava group, while cognitive development and growth did not change. The trial was not blinded.
Eating guava for 12 weeks lowered blood pressure by 9.0/8.0 mm Hg and total cholesterol by 9.9% in people with high blood pressure
Randomized, single-blind trial in patients with essential hypertension: 61 ate guava, preferably before meals, and 59 did not. Triglycerides fell 7.7% and HDL cholesterol rose 8.0% compared with the other group. The abstract does not give the amount of guava eaten. The lead author’s other trials from this period were the subject of a 2005 BMJ investigation into suspected research fraud, so treat this result with caution.
0.5 to 1 kg of guava a day for 4 weeks lowered blood pressure by 7.5/8.5 mm Hg in people with high blood pressure
Randomized, single-blind trial in 145 patients, of whom 72 ate a soluble-fiber, potassium-rich diet with guava and 73 kept their usual diet. Total cholesterol fell 7.9% and triglycerides 7.0%, while the rise in HDL cholesterol was not significant. That is a large amount of fruit for a month. The lead author’s other trials from this period were the subject of a 2005 BMJ investigation into suspected research fraud, so treat this result with caution.
300 mL of guava juice with a meal for 10 weeks raised hemoglobin by 0.64 g/dL more than a placebo juice in anemic schoolchildren
Placebo-controlled trial in 95 anemic Tarahumara children aged 6 to 9 in northern Mexico; the juice gave about 200 mg of vitamin C. The main analysis covered the 33 children who were iron deficient, and their ferritin did not differ significantly. The authors call the effect marginal.
A guava jelly drink for 8 weeks improved working memory and perceived stress in healthy adults at the higher dose
Pilot placebo-controlled trial with 25 people per group, aged 20 to 40, who drank 86 g a day of a jelly drink holding 36.6% or 73.2% guava juice with mint syrup. The lower dose changed brain-wave measures and an anxiety score. This was a flavored product, not whole fruit, and a small pilot.
400 g of ripe guava a day for 6 weeks lowered blood pressure and BMI in healthy students, but blood sugar and cholesterol rose when it was eaten with the peel
Randomized study in 45 healthy medical students, 15 in each group: guava with peel, guava without peel, or none. Peeled guava lowered total cholesterol, triglycerides and LDL, while its fall in fasting glucose was not significant. The abstract gives no group averages.
200 g of guava a day limited the rise in gum inflammation during 14 days without tooth cleaning (index up 0.10, against 0.87 on water)
Randomized trial in young nonsmoking adults who took 200 g of guava, 200 mg of vitamin C or water daily while gingivitis was provoked on purpose. Vitamin C alone also limited the rise (0.24), and the guava group built up less plaque than the water group. It does not show that guava treats gum disease.
A guava fruit extract in a glucose drink lowered the blood sugar rise at 30 and 90 minutes in healthy adults
Randomized trial in 31 healthy young adults, using a supercritical CO2 extract of guava fruit, not the whole fruit. At 30 minutes the rise was 1.96 mmol/L against 2.60 with plain glucose, and insulin was not significantly lower. A supplement company paid the salary of one author, and the extract lost strength with storage and repeated freezing.
One 500 mL drink of fresh guava juice reduced platelet clumping, heart rate and blood pressure in healthy volunteers
Randomized trial in 30 healthy volunteers, 10 per group, who drank guava juice, yam bean juice or water. Clumping triggered by collagen fell but clumping triggered by ADP did not, and dietary nitrate did not explain guava’s effect. It was a single drink, so long-term effects are unknown.
Bite-size guava had a glycemic index of 29 and guava puree 47, both low
Randomized crossover trial in 19 healthy adults in Singapore (9 older, 10 younger) who ate guava or papaya as bite-size pieces or puree, compared with pure glucose. All forms were low glycemic index, but older adults had a bigger blood sugar rise than younger ones. It was a small trial in healthy people.
100 g of guava with a rice meal raised iron absorption from 9.7 to 23.9% in girls and from 8.6 to 19.2% in boys
Isotope study in 16 adolescents aged 13 to 15 from two residential schools in India. The meal with guava had 20 times more vitamin C, and zinc absorption did not change. It measured absorption from a single meal, not iron status over time.
After 200 g of fresh guava, quercetin metabolites were the most abundant flavonoids in blood and urine
Study in healthy volunteers who ate 200 g of guava, pineapple or pomelo after a flavonoid-free diet. Metabolites first appeared after 2 hours and peaked at 6 hours, and about 900 µg of quercetin metabolites left in the urine over 24 hours. It measured absorption, not health effects.
Guava juice lowered blood glucose in healthy volunteers and in people with maturity-onset diabetes, as it did in mice
Short report from Taiwan that also tested guava juice in normal and diabetic mice. The effect in people was shorter and weaker than that of the diabetes drugs chlorpropamide and metformin. The abstract gives no group sizes, so treat it as a preliminary finding.
Guava leaf extract, 1 g a day for 12 weeks, eased knee pain and stiffness more than placebo (a leaf extract, not the fruit)
Double-blind pilot trial in Japanese adults with knee pain, using a leaf extract. Pain and stiffness scores and a visual pain scale were lower than on placebo at week 12. The abstract gives no group sizes, and the authors work for Kao Corporation.
Older Thai adults who ate guava had about half the odds of frailty (0.52)
Cross-sectional study of 350 older adults in northern Thailand using a food questionnaire and a frailty test. The adjusted 95% range was 0.28 to 0.96. A snapshot like this cannot show that guava prevents frailty, though lab tests found more flavonoids and antioxidant capacity in guava than in banana.
Adolescent girls who did not eat guava had 3.8 times the risk of low serum iron
Cross-sectional study of 85 girls in Pune, India, using food questionnaires and blood tests; 28.2% had anemia and 65.9% were iron deficient. The range was wide (1.1 to 9.4), and the study cannot separate guava from other habits.
Guava fruit and leaf extracts blocked up to 80% of glucose transport in gut cells, and lowered blood glucose in mice
Cell and mouse study of extracts of guava fruit and leaf, not whole fruit eaten by people. Blood glucose in mice fell about fourfold. Two authors work at PM International AG.
Guava fruit given to diabetic rats for 4 weeks lowered blood sugar in a dose-dependent way
Study in rats whose insulin-producing cells were damaged with streptozotocin and that received guava at 125 or 250 mg/kg. Guava protected pancreatic cells from oxidative damage and restored antioxidant enzyme activity. This was in rats, not people.
Diets with 1 to 5% red guava for 8 weeks improved blood sugar control and lowered inflammation markers in diabetic mice
Study in mice made diabetic with streptozotocin and fed red-fleshed guava. Insulin resistance, triglycerides, cholesterol, C-reactive protein and TNF-alpha improved compared with untreated diabetic mice. This was in mice, not people.
A lycopene-rich extract of red guava killed breast cancer cells in a dish at doses that spared mouse fibroblast cells
Lab study of an extract that was 20% lycopene by dry weight. After 72 hours the dose that halved viability was about 6 µg/mL for MCF-7 breast cancer cells and about 912 for the fibroblasts. Cells in a dish say little about eating guava.
Guava leaf tea inhibited drug-processing enzymes less than grapefruit juice did in lab tests and did not change warfarin’s effect in rats
Lab and rat study of guava leaf tea, not the fruit, by researchers at the tea maker Yakult. Leaf polyphenols, but not the whole leaf extract, inhibited some enzymes, and rats given the extract for 90 days showed no change in liver enzyme expression. It was not tested in people.
Who should be careful with guava
Most people can eat guava freely. Take a little care if one of these applies:
- Irritable bowel syndrome. Monash University tested guava at two stages: a serving of well-ripened guava was low in FODMAPs, while the same serving of unripe guava was high. If you react to FODMAPs, choose ripe fruit.
- Leaf tea and extracts. These are a different product from the fruit and are sold to curb the blood sugar rise after meals. If you take diabetes medicine or warfarin, ask your clinic before using them regularly. A lab and rat study found little sign of drug interaction, but it was not tested in people.
How to choose, store and eat guava
- Ripeness: guava is eaten at two stages, mature green with white flesh and a taste like a sweet apple, or fully ripe and soft. Monash found ripe guava low in FODMAPs and unripe guava high.
- Whole or puree: bite-size guava had a glycemic index of 29 and puree 47 in 19 adults, so pieces are the gentler choice for blood sugar.
- Skin on or off: Morton reports the vitamin C is concentrated in the skin and firm flesh, but in one trial of 45 students, 400 g a day with the peel went with higher blood sugar and cholesterol, and without it with lower.
Ripe, soft guava keeps for about a week in the fridge at 5 to 8°C (41 to 46°F), and its shelf life at room temperature is also about 7 days. Green or partly ripe fruit can be harmed by cold, with pitted skin and a failure to ripen, so let it ripen on the counter first.
Sources
- The mysterious case of the guava. Monash University FODMAP blog. 2016.
- Paull RE, Chen CC. Guava: postharvest quality-maintenance guidelines. University of Hawaiʻi, CTAHR. 2014.
- Morton J. Guava. In: Fruits of Warm Climates. 1987. Purdue University NewCROP.
- Tey SL, Lee DEM, Henry CJ. Fruit form influences postprandial glycemic response in elderly and young adults. J Nutr Health Aging. 2017.
- Kumari S, Rakavi R, Mangaraj M. Effect of guava in blood glucose and lipid profile in healthy human subjects: a randomized controlled study. J Clin Diagn Res. 2016.
- Kaneko K, Suzuki K, Iwadate-Iwata E, et al. Evaluation of food-drug interaction of guava leaf tea. Phytother Res. 2013.
- Deguchi Y, Miyazaki K. Anti-hyperglycemic and anti-hyperlipidemic effects of guava leaf extract. Nutr Metab (Lond). 2010.
History of guava
Guava has been used by people in the Americas for thousands of years, yet where it was first tamed is still debated. A 2024 genetic study of 215 plants from 11 countries pointed to Brazilian Amazonia as the probable origin of domestication, with the tree spreading from there to the Peruvian Andes, northern South America, Central America and Mexico. Older accounts placed its home in southern Mexico and Central America.
The English word comes from the Taíno guayabo, passed on through Spanish guayaba, and has been in English since the mid-16th century. Morton notes the tree was already in the West Indies by 1526. Spanish and Portuguese colonizers then carried it to the East Indies and Guam, and the Philippine name bayabas is a corruption of the Spanish word.
Guava reached Hawaii apparently in the early 1800s and was reportedly brought to southern Florida in 1847. By 1886 it was common over more than half of Florida, and the first commercial planting there followed in 1912. In 1947 Hawaii began shipping frozen guava juice and puree to processors on the US mainland.
People have long used more than the fruit. Roots, bark, leaves and unripe fruit served as astringents for diarrhea, and the wood was turned into spinning tops in Guatemala. During World War II, guava powder holding 2,500 to 3,000 mg of vitamin C was added to military rations. A single fruit holds 112 to 535 hard seeds.
Today guava is a huge crop. In 2024 the FAO listed 62.2 million tonnes of guavas, mangoes and mangosteens together, with India producing 27.8 million tonnes, about 45% of the total.
Sources
- Arévalo-Marín E, Casas A, Alvarado-Sizzo H, et al. Genetic analyses and dispersal patterns unveil the Amazonian origin of guava domestication. Sci Rep. 2024.
- Morton J. Guava. In: Fruits of Warm Climates. 1987. Purdue University NewCROP.
- Guava. Wikipedia.
Frequently asked questions about guava
Is guava good for you?
For most people, yes. Raw guava has 5.4 g of fiber and 228 mg of vitamin C per 100 g for 68 calories. In two trials guava added to children’s meals raised hemoglobin, and two older trials found lower blood pressure, though both were single-blind and one used 0.5 to 1 kg a day. None of the findings here reaches strong evidence.
Does guava have more vitamin C than an orange?
Yes, about four times as much by weight. Raw guava has 228 mg of vitamin C per 100 g against 53 mg in a raw orange. Per fruit, a guava (55 g) has 126 mg, or 140% of the daily value, and an orange (131 g) has about 70 mg, or 77%. Amounts vary with variety and ripeness.
Can you eat guava skin?
Yes, the skin was eaten in research: healthy students ate 400 g a day of ripe guava with the peel for 6 weeks in one trial. Morton reports that the vitamin C is concentrated in the skin and firm flesh. In that trial, peeled guava lowered total cholesterol and triglycerides, while unpeeled guava was followed by higher fasting glucose and cholesterol, so the evidence is mixed and small.
Is guava good for diabetes?
It can fit, but the evidence in people with diabetes is thin. Bite-size guava had a glycemic index of 29 and puree 47, both low, in 19 healthy adults. A 1983 Taiwanese report found guava juice lowered blood glucose in people with maturity-onset diabetes, and a guava fruit extract lowered the blood sugar rise after a glucose drink in 31 healthy adults. Check portions and choices with your care team.
Does guava lower blood pressure or cholesterol?
Two older trials say yes, but the evidence is weak. In 145 patients with high blood pressure, 0.5 to 1 kg of guava a day for 4 weeks lowered pressure by 7.5/8.5 mm Hg. In another trial, 12 weeks of guava lowered it by 9.0/8.0 mm Hg and total cholesterol by 9.9%. Both were single-blind, both came from one research group whose other trials the BMJ later questioned, and no newer trial has repeated them.
Does guava help with iron deficiency?
It can help your body absorb iron from other foods, because of its vitamin C. Guava itself has little iron, 0.26 mg per 100 g. In 200 Indian children, guava with a mungbean meal raised hemoglobin by 3.7 g/L and cut anemia by 51%, though not iron stores. In adolescents, 100 g of guava raised iron absorption from a rice meal from 9.7 to 23.9% in girls.
How many calories and how much fiber are in a guava?
One guava (55 g) has 37 calories and 3 g of fiber. Per 100 g that is 68 calories and 5.4 g of fiber, with 2.6 g of protein and 8.9 g of sugars. Net carbs give 55% of the calories, fiber 16%, protein 16% and fat 13%.
Is guava leaf tea good for you?
The evidence is limited, and it is a different product from the fruit. In Japan a guava leaf tea is approved as a food for specified health uses to curb the blood sugar rise after meals, according to a review by the tea maker’s researchers. In a 12-week pilot, 1 g a day of leaf extract eased knee pain compared with placebo. If you take diabetes medicine or warfarin, ask your clinic first.