Quick answer

Three fruits contain well-studied digestive enzymes: pineapple (bromelain), unripe papaya (papain) and green kiwifruit (actinidin). All three break down protein. In 12 older adults eating 100 g of beef, green kiwifruit made amino acids rise faster in the blood, but did not change the total absorbed.^1,2,3

Key facts

Bromelain is found in both the stem and the fruit of the pineapple plant.¹
Papain and chymopapain are present in unripe papaya, not in the ripe fruit.²
Gold kiwifruit of the Hort 16A variety has no actinidin; green Hayward kiwifruit does.³
The pancreas and the lining of the small intestine make the enzymes that break down fat, protein, starch and sugars.^4,5

Which foods contain digestive enzymes

Pineapple contains bromelain, a group of enzymes that break down protein, in both its stem and its fruit.^1,6

Unripe papaya contains the protein-cutting enzymes papain and chymopapain. NIH's LactMed database notes that they are not present in the ripe fruit.²

Green kiwifruit contains actinidin, an enzyme that breaks down protein. Gold kiwifruit of the Hort 16A variety has none.^3,7

Fruits with protein-cutting enzymes^1,2,3,8
Food	Enzyme	Where it is found	Worth knowing
Pineapple	Bromelain	Stem and fruit	Also sold as a supplement
Papaya	Papain and chymopapain	Unripe fruit and the tree's latex	Not present in ripe fruit
Green kiwifruit	Actinidin	The fruit	Absent from Hort 16A gold kiwifruit

Ripeness matters for papaya. A ripe papaya from the shop is still good food, but according to LactMed it is not a source of papain. The enzyme sits in the green fruit and in the milky latex of the tree.^2,8

What eating them was found to do

In 12 healthy older adults eating 100 g of beef, green kiwifruit with actinidin made essential amino acids rise faster in the blood than gold kiwifruit without it. The total amount absorbed and the measures of protein use did not differ.³

Before that trial, the case for kiwifruit rested on laboratory digestion models and studies in pigs. They showed actinidin speeding up the breakdown of proteins from milk, meat, fish, eggs, legumes and cereals in the stomach, and a pig study with the enzyme switched off showed actinidin was responsible.⁷

The human result was narrower than the laboratory one: amino acids arrived sooner, not in larger amounts. The participants also ate two kiwifruit a day for two weeks before each test, which is more than an occasional fruit with dinner.³

We found no trial testing whether eating pineapple or papaya with a meal changes digestion in people. Bromelain has been studied as a supplement and as a medicine applied to the skin, not as a fruit eaten with meals.¹

Your body makes its own

The pancreas makes enzymes that break down fat, protein and starch, and enzymes in the lining of the small intestine finish splitting sugars so they can be absorbed.^4,5

All three fruits above carry protein-cutting enzymes, which cover only one part of that work. For milk sugar and bean sugars, the enzymes with human evidence are lactase and alpha-galactosidase, studied as supplements at stated strengths.^9,10

Allergy warnings

Allergic reactions to papaya are not uncommon, and cross-reactions with latex and kiwi have occurred. In one series, 11 people with latex allergy had severe reactions to papaya, and papain was named among papaya's most allergenic proteins.^2,8

Actinidin is itself a major kiwifruit allergen. In simulated digestion it still bound allergy antibodies almost as strongly as before, one reason kiwifruit can trigger allergy in both children and adults.¹¹

Bromelain supplements come from the pineapple plant, so a pineapple allergy is a reason to avoid them, and allergic reactions to bromelain have been reported.^1,12

Questions people ask

Is ripe papaya a good source of papain?

No. NIH's LactMed database notes that papain and chymopapain are present before papaya ripens but not in the ripe fruit.²

Do I need enzyme-rich foods to digest a meal?

Your pancreas and small intestine make the enzymes for fat, protein, starch and sugars. In the one human trial of an enzyme-rich fruit, green kiwifruit changed how fast amino acids appeared in the blood, not how much was absorbed.^3,4,5

Which kiwifruit has the enzyme?

Green kiwifruit of the Hayward variety contains actinidin. The Hort 16A gold kiwifruit used as the comparison in the human trial has none.³

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Sources

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.