What are the Nutrients in Kiwi? Explaining Calories, Vitamins, and Health Benefits [Comprehensive Nutrient Guide]

Kiwi is appealing for its sweet and sour taste and vibrant cross-section.
Available year-round and easy to eat by simply cutting in half and scooping with a spoon, it is popular across generations as a convenient addition to both desserts and breakfast.

Kiwi contains a well-balanced mix of nutrients, including vitamin C, dietary fiber, folate, and potassium. Furthermore, it is a nutrient-dense fruit that also contains components such as actinidin, a protein-degrading enzyme, and lutein, a type of carotenoid.

In this article, we will explain in detail the nutrients contained in kiwi, their expected benefits, and recommended ways to eat and store them.

What is Kiwi? Introducing its Characteristics, Varieties, and Nutrition

Kiwi is a vine plant in the Actinidiaceae family, and it is said to have originated along the Yangtze River in China. Originally called the "Chinese gooseberry," it came to be commonly known as "kiwifruit" because its appearance resembled the "kiwi bird," the national bird of New Zealand.

Kiwi Varieties

In stores, the following two types are widely popular (*1, 2). When we talk about "kiwi" on the dinner table, it generally refers to the green-fleshed variety.

• Green-fleshed variety (Hayward): The most widely consumed variety in the world. It has a lot of fuzz, a refreshing tartness, and is high in dietary fiber.

• Yellow-fleshed variety (Gold Kiwi / Hort16A): A variety developed in New Zealand. The flesh is yellow, has a strong sweetness, and is rich in vitamin C (*1, 2, 3).

Nutritional Components of Kiwi (per 100g of green-fleshed variety)

• Energy: 51kcal

• Water: 84.7g

• Protein: 1.0g

• Fat: 0.2g

• Carbohydrates: 13.4g (Sugars 10.8g)

• Vitamin C: 71mg

• Folate: 37μg

• Potassium: 300mg

• Calcium: 14mg

• Dietary Fiber: 2.6g

*The edible portion of one kiwi is approximately 80–100g.

Main Nutrients and Expected Benefits

Kiwi contains a wide range of nutrients, including vitamin C, dietary fiber, folate, and potassium, as well as components like actinidin and lutein. Let's look at the function of each.

Vitamin C

Kiwi is a fruit rich in vitamin C (*3, 4, 5). Green varieties contain 71mg per 100g, and yellow varieties contain about 140mg per 100g, which is more than strawberries (about 62mg) or Satsuma mandarins (about 32mg). Vitamin C is a nutrient with strong antioxidant properties that is said to support immune function and is involved in maintaining the health of skin and mucous membranes. Because it is a nutrient that tends to be lacking, kiwi is a reliable way to easily supplement it.

Dietary Fiber

Kiwi contains dietary fiber, and green varieties have a high amount among fruits. There is 2.6g per 100g of green kiwi, which is more than apples (about 1.9g) or mandarins (about 1.0g) (*3, 6, 7). It contains both water-soluble and insoluble dietary fiber, which are nutrients said to help regulate the intestinal environment and improve bowel movements. It is an easy way to supplement components that tend to be lacking in daily diets.

Folate

Folate is a water-soluble B vitamin that is involved in cell production and DNA synthesis. It is especially necessary from before pregnancy through the early stages of pregnancy, and is said to be involved in reducing the risk of neural tube defects in babies (*3, 8, 9, 10, 11).

Potassium

This is a mineral expected to help promote the excretion of excess sodium in the body and maintain normal blood pressure (*3, 12).
Japanese people tend to have a high salt intake, so potassium, which helps with its excretion, is considered a nutrient to be actively consumed. It is also essential for combating swelling and maintaining muscle and nerve function.

Actinidin

Actinidin is a protein-degrading enzyme found in abundance in kiwi. It has the same function as enzymes found in pineapple and ginger, and has been used in cooking to tenderize meat. In recent years,

its role in aiding the digestion of dietary protein has been studied, and the possibility that it supports digestion, especially after eating meat or fish, has been reported (*13).

Lutein

Lutein is a type of carotenoid (phytochemical) found in green and yellow vegetables and fruits, and is a component said to have antioxidant properties (*14, 15, 19). Research is being conducted on its role in
protecting the eyes from oxidative stress caused by blue light and other factors, and its involvement in maintaining eye health.

Recommended Ways to Eat Kiwi

Kiwi is a fruit often eaten raw, but adding a little extra effort can expand the ways you enjoy it. Here are some recommended ways to eat it to make the most of its nutrients (*16).

Eating it raw as is (★★★)

Components sensitive to heat, such as water-soluble vitamin C, can be consumed without waste by eating it raw. The convenience of just cutting it in half and scooping it out with a spoon is also a plus.

Pairing with yogurt or smoothies (★★★)

The sweet and sour flavor pairs well with yogurt. Making it into a smoothie allows you to consume dietary fiber and vitamins all at once, making it easy to incorporate into your breakfast.

Use agar when making jelly (★★☆)

The actinidin contained in kiwi breaks down the proteins in gelatin, so if added raw, it may not set well and can cause water separation. Either heat it before using or use agar so that even raw kiwi will set nicely.

How to store kiwi

Storage methods for kiwi change before and after it is fully ripe.
Here are some storage tips to keep them delicious.

Storage before ripening (post-harvest ripening)

While they are hard, let them ripen at room temperature. Place them in a plastic bag or similar container and keep them out of direct sunlight. They are ready to eat when the bottom and stem ends become slightly soft and you can feel some elasticity when holding them (※17,18).

Storage after ripening

Once they are ready to eat, wrap each one in a paper towel and store them in a plastic bag or freezer bag in the refrigerator.

Freezing

If you cannot eat them right away, you can also freeze them. The guideline is about 1 month, but because the taste and texture are prone to change it is recommended to use them in juices or smoothies.

Even with freezing, the nutritional value is relatively preserved, but since the flavor and vitamin C gradually decrease the longer they are stored, it is recommended to eat them as soon as possible.

Summary

Kiwi is a highly nutritious fruit that contains vitamin C, dietary fiber, folic acid, and potassium, as well as the protein-digesting enzyme actinidin and lutein.

It is also low in calories and easy to eat—just cut it in half and scoop it out with a spoon. Eating it as is allows you to get vitamin C without waste. Why not add a kiwi to your daily meals or snacks?

Frequently Asked Questions (Q&A)

Q1. How much kiwi should I eat per day?
A. Generally, one per day (about 80–100g of edible portion) is considered a good guideline.
While it is an easy way to supplement vitamin C and other nutrients, it also contains carbohydrates, so it is recommended to incorporate it as a daily habit while being mindful not to overeat.

Q2. How can I make hard kiwi ready to eat faster?
A. Placing them in a plastic bag with an apple or banana and leaving them at room temperature will help them ripen faster. This is because the ethylene gas released by apples and bananas promotes ripening. It should be ready to eat in a few days to a week when you can feel some elasticity when holding it.

Q3. Can I eat kiwi with the skin on?

Yes. If you wash it well, you can eat it with the skin on.
The skin is rich in nutrients, containing plenty of dietary fiber, polyphenols, and vitamin E. However, if the fuzz bothers you, you can scrub it off, or choose varieties with less fuzz like gold kiwi to make it easier to eat.

Q4. Is there a nutritional difference between gold kiwi and green kiwi?
A. Yes, there is a difference.
Generally, gold kiwi tends to contain more vitamin C, while green kiwi tends to contain more dietary fiber For example, per 100g, green kiwi has about 71mg of vitamin C, while gold kiwi has about 140mg.
On the other hand, green kiwi contains slightly more dietary fiber. Both are highly nutritious fruits, so you can choose based on your preferences and goals.

Q5. When is the best time to eat kiwi, morning or night?

A. Breakfast is a great time to supplement vitamin C and dietary fiber, but there is no problem with eating it at night. It is more important to incorporate it into your daily diet consistently rather than focusing on the time of day.