Kiwi, scientifically known as Actinidia deliciosa, is a nutrient-dense fruit that has garnered significant attention for its impressive health benefits. Originating from China and now widely cultivated in countries like New Zealand and the United States, kiwi is celebrated for its high vitamin C content, potent antioxidants, and a variety of essential nutrients. This small, fuzzy fruit is not only delicious but also offers a multitude of health advantages, including improved heart health, enhanced digestive function, and boosted immune response. Backed by extensive scientific research, the health benefits of kiwi extend far beyond its vitamin C content, making it a valuable addition to a balanced diet.

What is Kiwi ?

Kiwi is a nutrient-dense fruit native to China and widely cultivated in New Zealand and other parts of the world. It is renowned for its high vitamin C content, dietary fiber, iron, carotenoids, and antioxidants, which contribute to various health benefits such as lowering blood pressure, improving wound healing, and enhancing bowel health. The green-fleshed variety, Actinidia deliciosa cv. Hayward, retains chlorophyll during maturation, which gives it its characteristic color and distinguishes it from other Actinidia species that lose chlorophyll and develop yellow or orange hues. Kiwifruit has also been studied for its potential in enzymatic debridement of acute burn wounds, showing promising results in faster eschar separation and wound healing in animal models. Additionally, regular consumption of green kiwifruit has been linked to the maintenance of normal defecation, making it beneficial for digestive health. The fruit’s rich chemical composition, including polyphenols, flavonoids, and dietary fibers, further enhances its antioxidant and anti-inflammatory properties, making it a valuable component of a healthy diet.

Nutritional Profile of Kiwi

Kiwifruit is an excellent source of various essential vitamins, minerals, fiber, and antioxidants. Here is a detailed nutritional profile of kiwifruit:

Vitamins

• Vitamin C: Kiwifruit is an outstanding source of vitamin C, providing around 83% of the daily value in just one 3.5 oz. (100g) serving. Vitamin C is a powerful antioxidant that supports immune function and collagen production.
• Vitamin K: One kiwifruit provides around 34% of the daily vitamin K needs. Vitamin K is essential for blood clotting and bone health.
• Vitamin E: Kiwifruit contains a good amount of vitamin E, with one serving providing around 9% of the daily value. Vitamin E is a fat-soluble antioxidant that supports immune function and skin health.

Minerals

• Potassium: Kiwifruit is a rich source of potassium, containing 312mg per 100g serving, which is around 4% of the daily needs. Potassium is important for blood pressure regulation and heart health.
• Magnesium: One serving of kiwifruit provides 17mg of magnesium, around 4% of the daily requirement. Magnesium is involved in energy production and muscle function.

Fiber

Kiwifruit is a good source of dietary fiber, containing around 3g of fiber per 100g serving. The fiber in kiwifruit is a mix of soluble and insoluble types, which can aid digestion and promote feelings of fullness.

Antioxidants

In addition to vitamins C and E, kiwifruit contains various other antioxidant compounds like flavonoids, carotenoids (lutein and zeaxanthin), and chlorophyll. These antioxidants help neutralize free radicals and may offer protection against chronic diseases.

Science backed health benefits of Kiwi

Kiwifruit is a nutrient-dense superfood that packs a powerful punch of health benefits. This fuzzy, green fruit has long been celebrated for its exceptional vitamin C content, but recent scientific research has unveiled a myriad of other health-promoting properties. From boosting immunity and aiding digestion to supporting cardiovascular health and even promoting better sleep, the humble kiwi is a true nutritional powerhouse. In this article, we’ll explore the science-backed health benefits of this remarkable fruit, backed by credible research studies and expert insights.

1. Improved Gastrointestinal Comfort

Kiwifruit has been found to be a natural remedy for improving gastrointestinal (GI) comfort and function. Consuming two green kiwifruits daily can significantly alleviate symptoms of constipation, such as increasing the frequency of complete spontaneous bowel movements and improving stool consistency. Moreover, kiwifruit consumption has been associated with a reduction in abdominal pain, indigestion, and reflux, leading to an overall improvement in GI comfort. The beneficial effects of kiwifruit on GI health are attributed to its high fiber content, which aids in promoting regular bowel movements, and the presence of various bioactive compounds, including actinidin, a proteolytic enzyme that may enhance protein digestion.

What Research Says?

• Study shows that kiwi can help with stomach comfort. One study looked at how kiwi with actinidin (a type of kiwi called ‘Hayward’) affects digestion after a protein-rich meal in healthy men. The study showed that even though it didn’t speed up digestion, eating ‘Hayward’ kiwi made people feel less bloated and more comfortable. This means the enzyme actinidin in green kiwi might be important for easing stomach discomfort.
• Actinidin in kiwifruit helps with stomach digestion. Research on young rats showed that actinidin from green kiwifruit made the digestion of proteins like beef and soy faster. It also sped up how quickly food left the stomach. The study found that actinidin might make protein digestion and stomach emptying better, leading to improved digestion.
• Kiwifruit can help with bowel problems, especially for people who are constipated. A study showed that older adults who ate kiwifruit often had better bowel movements. They had bigger, softer stools and went to the bathroom more often. Another research looked at green kiwifruit extract in capsules for constipation in healthy people. This study didn’t see big changes with the extract. But other studies using the whole fruit did show benefits. This suggests that eating more or the whole fruit might work better.
• Eating kiwifruit can help your gut bacteria. A study with healthy rats found that eating the flesh and skin of kiwifruit made their gut bacteria more varied and rich. The study also saw less bad bacteria and more good ones like Lactobacillus and Barnesiella. These changes in the gut bacteria can lead to better gut health and comfort.

2. Beneficial for Cardiovascular Health

Kiwifruit has been found to offer potential benefits for cardiovascular health due to its unique nutritional composition. Regular consumption of kiwifruit can help lower blood pressure levels, a major risk factor for heart disease. This effect is attributed to the high potassium content and the presence of bioactive compounds like vitamin C and polyphenols, which may improve endothelial function and reduce oxidative stress on blood vessels. Additionally, kiwifruit has been shown to inhibit platelet aggregation, thereby reducing the risk of thrombosis and atherosclerosis, particularly in individuals with elevated risk factors like smoking. The fiber, antioxidants, and favorable nutrient profile of kiwifruit may also contribute to improved lipid profiles and overall cardiovascular health by lowering total cholesterol, triglycerides, and LDL (bad) cholesterol while increasing HDL (good) cholesterol levels. 

What Research Says?

• Kiwi fruit is known for having more vitamin C than many other fruits. It also has a lot of dietary fiber, potassium, vitamin E, and antioxidants like lutein and zeaxanthin. Together, these nutrients make kiwi fruit good for your health.
• Kiwi has antioxidants like vitamin C, choline, lutein, and zeaxanthin. They are important because they fight off free radicals. This helps lower stress and swelling in the body, which can cause heart diseases. The skin of the kiwi is especially good for you because it has a lot of these healthy antioxidants.

3. Enhance wound healing

Kiwifruit has been found to possess remarkable wound-healing properties, as evidenced by several scientific studies. The presence of proteolytic enzymes like actinidin, along with high levels of vitamin C and other antioxidants, contributes to the wound-healing potential of kiwifruit. Topical application of kiwifruit extract can significantly accelerate the healing process of chronic wounds, such as bedsores, by promoting the formation of granulation tissue, collagen deposition, and angiogenesis (new blood vessel growth). Additionally, kiwifruit extract has been demonstrated to enhance the proliferation and migration of human gingival fibroblasts, which play a crucial role in oral wound healing. The antibacterial and debridement properties of kiwifruit further aid in preventing infection and removing necrotic tissue, facilitating the healing process.

What Research Says?

• Kiwifruit may help with wound healing. In a study, rats with serious burn wounds got better quicker when treated with fresh kiwifruit. Their wounds healed faster than those in the control group. The kiwifruit-treated wounds were fully healed by Day 20, which was sooner than the others. This suggests that kiwifruit can speed up healing.
• Kiwifruit has been shown to fight bacteria and help new blood vessels grow in medical studies. One study looked at people with stage 2-3 bedsores on their lower back. It found that kiwifruit extract made the sores smaller and helped form more collagen and new tissue. The study also saw more blood vessel growth in those treated with kiwifruit, which means better wound healing by improving blood flow and tissue repair. In a similar way, another study on foot ulcers in diabetic patients showed that kiwifruit extract helped heal wounds better, including making them smaller and helping new tissue grow. However, it didn’t seem to fight bacteria in this case.
• Scientists have studied how kiwifruit helps heal wounds at the cell and molecule levels. They found that kiwifruit extract makes human gum cells live longer, grow more, and move better, which is important for healing wounds. Also, the extract helped grow new blood vessels in chicken embryos, showing it can help with blood flow and fixing tissue.
• Study on rats with skin wounds show that kiwifruit helps wounds heal faster. Wounds treated with kiwifruit healed quicker, were stronger, and closed more than those not treated with it. This means kiwifruit may speed up healing and make the healed area tougher.
• Kiwifruit has a lot of good stuff in it like vitamin C, actinidin (an enzyme that breaks down proteins), and antioxidants. These help heal wounds by lowering oxidative stress, making more collagen, and helping tissue repair itself. A detailed review of kiwifruit’s plant-based chemicals and health effects shows it could be useful for healing wounds and other health benefits.

4. Good for Immune Function and Respiratory Health

Kiwifruit is an excellent source of vitamin C, which plays a crucial role in supporting immune function and respiratory health. Consuming kiwifruit can help increase plasma vitamin C levels and improve the function of immune cells like neutrophils, which are essential for fighting off infections. Additionally, the high vitamin C content in kiwifruit has been linked to potential benefits for respiratory health, such as reducing the severity and duration of upper respiratory tract infection symptoms and improving lung function in individuals with asthma. The antioxidant and anti-inflammatory properties of vitamin C, along with other bioactive compounds present in kiwifruit, may contribute to its ability to support a healthy immune system and protect against respiratory issues. Incorporating kiwifruit into a balanced diet can be an effective way to boost vitamin C intake and potentially enhance immune function and respiratory health.

What Research Says?

• Kiwifruit is packed with important nutrients like vitamins C and E, folate, carotenoids, and polyphenols. These help keep your immune system strong and ease infection symptoms. The green kiwifruit (Actinidia deliciosa) and the gold one (Actinidia chinensis) have lots of vitamin C. They have more than many other fruits, including strawberries and oranges.
• Eating kiwifruit often can help your immune system. Kiwifruit has a lot of vitamin C, which helps different parts of the immune system work better. It also has vitamin E and polyphenols, which are antioxidants that reduce oxidative stress. This is important for keeping your immune system healthy.

5. Helps manage glucose levels

Kiwifruit has shown promising potential in managing glucose levels and mitigating the effects of diabetes, according to several scientific studies. Extracts from kiwifruit leaves and fruits exhibit anti-hyperglycemic activity, effectively reducing elevated blood glucose levels in animal models of diabetes. The bioactive compounds present in kiwifruit, such as polyphenols, flavonoids, and dietary fibers, are believed to contribute to this beneficial effect by improving insulin secretion, enhancing glucose uptake by cells, and inhibiting enzymes involved in carbohydrate digestion. Additionally, kiwifruit extracts have been found to possess antioxidant properties, which may help alleviate oxidative stress associated with diabetes and protect pancreatic beta cells from glucose toxicity. Furthermore, kiwifruit consumption may aid in regulating lipid metabolism and reducing inflammation, both of which are crucial factors in the management of diabetes and its complications .

What Research Says?

• Kiwi fruit helps fight diabetes mostly because of its fibers. These fibers change the gut bacteria in a good way. This can help rats with type 2 diabetes caused by a high-fat diet and a certain drug. The fibers make rats weigh less, feel fuller, and have lower blood sugar. They also help with insulin resistance, inflammation, and fat levels in the blood. Kiwi’s power against diabetes is connected to better gut bacteria and more short-chain fatty acids. Different types of kiwi fibers affect different helpful bacteria and fatty acids.
• Kiwi fruit’s methanol extract can block the α-glucosidase enzyme better than acarbose, a common diabetes drug. This means kiwi might help lower blood sugar after meals and be a strong natural option for diabetes control.
• Kiwi fruit has a lot of antioxidants that help fight inflammation and cell damage, which are common problems in Type 2 Diabetes (T2DM). Research shows that kiwi extract can improve liver and kidney function, reduce inflammation, protect against oxidative damage, and prevent cell death in diabetic rats. It does this by helping insulin work better and blocking an enzyme called PTEN with compounds like syringic acid, P-coumaric acid, caffeic acid, and ferulic acid.
• Kiwi fruit helps control blood sugar and has many other health benefits. It’s full of vitamin C, fiber, iron, and nutrients like choline, lutein, and zeaxanthin. These help lower blood pressure, heal wounds faster, and make your gut healthier. Kiwi’s antioxidants fight off free radicals, which can stop diseases and inflammation.

6. Improved sleep quality

The fruit’s high content of serotonin and antioxidants, such as vitamin C and polyphenols, plays a crucial role in enhancing sleep onset, duration, and efficiency. Consuming two kiwifruits one hour before bedtime for four weeks led to a 35.4% reduction in sleep onset latency, a 28.9% decrease in waking time after sleep onset, and a 13.4% increase in total sleep time. Additionally, sleep efficiency improved by 5.41%, and subjective sleep quality scores significantly increased. 

What Research Says?

• A study looked at how extracts from the peels of green and gold kiwifruit affect sleep in mice. The results showed that giving these extracts to the mice made them fall asleep faster and sleep longer. This effect grew stronger with higher doses. The part of the extracts called ethyl acetate (EA) worked the best to increase sleep time. This was linked to the amount of flavonoids in it. The way these extracts help with sleep is similar to how a common sleep medicine, diazepam, works. They both act on the same brain system, which involves GABA, a brain chemical.
• A study looked at how eating kiwifruit affects sleep and recovery in top athletes. They ate two medium green kiwifruits (Actinidia deliciosa) one hour before bedtime for four weeks. The findings showed that their sleep got better, with higher PSQI global scores and sleep quality scores. They also had less stress from life and sports. Plus, they slept longer, woke up less at night, and found it easier to fall asleep again if they did wake up.

7. Beneficial for Skin Health

Kiwifruit offers numerous benefits for maintaining healthy and radiant skin. Its high vitamin C content acts as a potent antioxidant, protecting the skin from oxidative stress and premature aging caused by free radicals. Additionally, the presence of vitamin E in kiwifruit helps to nourish and moisturize the skin, improving its texture and preventing dryness. The fruit is also rich in omega-3 fatty acids, which contribute to skin elasticity and suppleness, reducing the appearance of fine lines and wrinkles. Furthermore, kiwifruit contains enzymes like actinidin that possess natural exfoliating properties, aiding in the removal of dead skin cells and promoting a brighter complexion. The antibacterial and anti-inflammatory compounds found in kiwifruit can also help in treating acne and other skin conditions.

What Research Says?

• Kiwifruit has lots of vitamins, minerals, and antioxidants that are good for your health. It’s full of vitamin C, tocopherols, and phenolic compounds, especially in the skin. These help stop free radicals, which protects your skin from damage and swelling.
• Kiwifruit polysaccharides help skin cells grow and make more collagen. This is key for fixing and renewing skin. They boost growth signals and energy in cells, which leads to more ATP creation and cell growth. So, kiwifruit stuff could help heal skin and make it smoother.
• Kiwifruit might help heal wounds faster. A rat study showed that putting fresh kiwifruit on burn wounds sped up healing. It worked better than not using anything. Kiwifruit could be a good natural treatment for burns.
• Kiwifruit’s anti-inflammatory qualities come from its rich amount of phenolic compounds. These help lower inflammation and protect cells, which is good for keeping skin healthy. Also, kiwifruit’s antioxidants guard the skin against harm from things like sunlight and pollution.
• Eating kiwifruit can help your gut health, which is good for your skin. A healthy gut helps you absorb nutrients better and lowers inflammation in your body, making your skin healthier. Research shows that eating kiwifruit makes good gut bacteria grow and reduces bad bacteria, helping your overall health.

8. Helps in Weight Management

Kiwi is an excellent fruit for weight management due to its low calorie and high fiber content. A single kiwi fruit contains only around 42 calories but packs an impressive 2.1 grams of fiber. This fiber helps promote feelings of fullness and satiety, preventing overeating and unnecessary calorie intake. Additionally, kiwis have a low glycemic index, meaning they don’t cause rapid spikes in blood sugar levels that can lead to increased hunger and cravings. The high vitamin C content in kiwis may also aid in fat metabolism, further supporting weight loss efforts. Incorporating kiwis into a balanced diet can be a tasty and nutritious way to support a healthy weight.

What Research Says?

• Kiwifruit is full of vitamin C, fiber, iron, and nutrients like choline, lutein, and zeaxanthin. These help lower blood pressure, heal wounds, control blood sugar, and keep your bowels healthy. The antioxidants in kiwifruit fight off free radicals, which can stop diseases and inflammation.
• Kiwifruit seed oil, or KSO, can help reduce swelling inside the body. A study with obese mice that ate a lot of fat showed that KSO made the levels of certain swelling-related substances go down. These substances include TNF-α, IL-6, IL-1β, COX-2, and iNOS. Lowering swelling is important because long-term swelling often goes along with obesity and problems with how the body uses food for energy.

How to Incorporate Kiwi into Your Diet

Here are some tips for selecting and storing kiwi, as well as creative ways to add kiwi to your meals and snacks:

Tips for Selecting and Storing Kiwi

When selecting kiwis, look for fruits that are plump and slightly soft to the touch, but not mushy. The skin should be fuzzy and free of blemishes or wrinkles. Avoid kiwis that are hard as rocks, as they may be underripe.Unripe kiwis can be left to ripen at room temperature for a few days. To speed up the ripening process, place them in a paper bag with an apple or banana. Once ripe, kiwis can be stored in the refrigerator for up to 2 weeks. Ripe kiwis can also be frozen for later use. Simply peel, slice, and arrange the kiwi pieces on a baking sheet. Once frozen, transfer them to an airtight container or freezer bag. Frozen kiwi slices are great for smoothies or can be thawed and used in other recipes.

Creative Ways to Add Kiwi to Meals and Snacks

Breakfast and Brunch

• Top your yogurt, oatmeal, or chia pudding with diced kiwi for a burst of flavor and nutrition.
• Make a tropical smoothie bowl with kiwi, mango, pineapple, and coconut milk.
• Bake kiwi into muffins or bread for a moist and flavorful treat.

Salads and Sides

• Add diced kiwi to green salads or fruit salads for a refreshing twist.
• Make a kiwi salsa by combining diced kiwi, red onion, jalapeño, cilantro, and lime juice. Serve with grilled fish or chicken.
• Grill or sauté kiwi slices and serve them as a side dish with savory meats or fish.

Beverages

• Blend kiwi into smoothies or juices for a tangy and refreshing drink.
• Make a kiwi lemonade by combining kiwi puree, lemon juice, and sweetener.
• Muddle kiwi slices and mint leaves for a unique cocktail or mocktail.

Desserts

• Top pavlova or meringue with whipped cream and sliced kiwi.
• Make a kiwi sorbet or granita for a light and refreshing treat.
• Bake a kiwi tart or galette with a buttery crust and custard filling.

Conclusion

Kiwifruit is a true superfood packed with an impressive array of health benefits backed by scientific research. Its high vitamin C, fiber, and antioxidant content contribute to improved immune function, cardiovascular health, wound healing, and skin health. Additionally, kiwifruit’s unique enzymes and bioactive compounds aid in digestive comfort, glucose management, and weight control. With its delightful taste and versatility in various dishes, incorporating kiwifruit into a balanced diet can be a simple yet effective way to enhance overall well-being and potentially reduce the risk of chronic diseases.

ADDITIONAL RESOURCES

Here is a list of US organizations related to research on berries and fruits, along with their short descriptions and URLs:

1. American Society for Horticultural Science (ASHS)

ASHS promotes and encourages national and international interest in scientific research and education in horticulture in all its branches.

2. The Fruit Tree Planting Foundation (FTPF)

FTPF is dedicated to planting fruitful trees and plants to alleviate world hunger, combat global warming, strengthen communities, and improve the surrounding air, soil, and water.

3. International Society for Horticultural Science (ISHS)

Although international, ISHS has a significant US presence and promotes research, education, and the dissemination of knowledge in all branches of horticulture.

4. University of California Agriculture and Natural Resources (UC ANR)

UC ANR conducts research and extends knowledge in agriculture, including studies on various fruits and berries.

5. North American Raspberry & Blackberry Association (NARBA)

NARBA supports the growth and development of the raspberry and blackberry industry through research, education, and promotion.

6. California Strawberry Commission

The California Strawberry Commission conducts research to improve strawberry farming practices and fruit quality, as well as promoting the health benefits of strawberries.

7. Citrus Research and Development Foundation (CRDF)

CRDF supports research and development activities to protect and improve the citrus industry, including studies on fruit diseases, pest management, and horticultural practices.

Recommendations for books on Kiwi fruit

Here are some recommendations for books on research about Kiwi fruit, along with their links:

1. “Kiwi Fruit: The Genus Actinidia” by Hongwen Huang

This comprehensive book covers various aspects of kiwi fruit, including its biology, cultivation, genetics, and breeding.

2. “Kiwifruit: Science and Management” edited by Harvey Ferguson, Roger B. H. Wills, and Gordon R. Price

This book provides an extensive overview of kiwifruit science and management, including production techniques, pest control, and post-harvest handling.

3. “Kiwifruit: The Comprehensive Assessment of Economic Impact and Disease Management” by Mark S. Hoddle

This book focuses on the economic impact of kiwifruit production and the management of diseases affecting kiwifruit crops.

4. “Kiwifruit Growing and Handling” by Eric J. T. Melville

This practical guide covers all aspects of growing and handling kiwifruit, including cultivation techniques, harvesting, and storage.

5. “The Kiwifruit Genome” edited by Raffaele Testolin, Michael P. Davey, and Riccardo Velasco

This book provides detailed information on the genetic research and genomic advancements related to kiwifruit, offering insights into breeding and biotechnology.

FAQS

1. What are the key nutrients found in kiwi fruit?
   Kiwi is an excellent source of vitamin C, vitamin K, vitamin E, folate, and potassium. It also contains fiber, copper, and antioxidants like lutein and zeaxanthin.
2. How can kiwi benefit digestive health?
   The fiber, actinidin enzyme, and prebiotics in kiwi can aid digestion by promoting regular bowel movements, improving protein digestion, and supporting a healthy gut microbiome.
3. Does kiwi have anti-inflammatory properties?
   Yes, the antioxidants like vitamin C and vitamin E in kiwi may help reduce inflammation in the body.
4. Can kiwi support heart health?
   Kiwi’s potassium content may help regulate blood pressure, while its fiber and antioxidants could potentially lower cholesterol and triglyceride levels, reducing heart disease risk.
5. How might kiwi benefit the immune system?
   The high vitamin C content, along with other antioxidants in kiwi, may enhance immune function and reduce the severity of respiratory infections.
6. Can kiwi promote healthy skin?
   The vitamin C in kiwi is essential for collagen production, which may improve skin elasticity and reduce wrinkles. Its vitamin E may also benefit skin health.
7. Does kiwi have any benefits during pregnancy?
   The folate in kiwi is important for fetal development and may help reduce the risk of neural tube defects during pregnancy.
8. Can kiwi aid in weight management?
   As a low-calorie, high-fiber fruit, kiwi may promote feelings of fullness and support weight loss or maintenance when included in a balanced diet.
9. How might kiwi benefit bone health?
   Kiwi contains vitamin K, which plays a role in bone metabolism, as well as magnesium and other nutrients that support bone density.
10. Can kiwi improve sleep quality?
    Some research suggests that the antioxidants, serotonin, and folate in kiwi may help improve sleep quality and recovery in certain populations.

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