Can Kiwi Actually Help Alleviate Constipation?

Kiwi has a laxative effect that can effectively treat constipation without causing bloating.

When stool is hard and occurs no more than three times a week, accompanied by abdominal discomfort, it is classified as chronic constipation. Developed countries have a high prevalence of this condition, affecting around 17-27% of the population. Women and elderly people are more susceptible to it than men and young people, and a sedentary lifestyle, lack of fiber and fluids in the diet, and stress are all contributing factors.

While there are various laxatives and supplements that can increase bowel movement frequency and soften the stool, they can cause abdominal pain, bloating, and diarrhea with frequent use. For this reason, chronic constipation is often treated by incorporating natural laxative foods into the diet. The European Food Safety Authority recommends the consumption of kiwi as an effective treatment option.

What can be the benefits of kiwi for constipation?

Kiwi fruit originates from the woody vine of the actinidia, which flourishes in subtropical climates like Greece, Italy, and New Zealand. As a berry with a thin skin, juicy flesh, and edible seeds, kiwi is known from a botanical standpoint. While kiwi fruits can come in green, yellow, or red, only the first two types are frequently stocked in stores.

Scientists have yet to determine the exact mechanism by which kiwi fruit helps treat chronic constipation. However, they suggest that several components of the fruit play a role in enhancing peristalsis, softening stool, accelerating digestion, and supporting intestinal microflora.

The most valuable component of kiwi fruit is fiber, which has been extensively studied and clinically proven to effectively treat chronic constipation. Fiber can be classified as either soluble or insoluble, with the soluble form making up one-third of the total fiber in kiwi fruit. This type of fiber is easily digested and nourishes the intestinal bacteria necessary for regular bowel movements. The remaining fiber in kiwi fruit is insoluble, passing through the intestines mostly unchanged and forming soft fecal masses.

Plant fibers present in kiwi fruit have the ability to retain water, causing them to increase in volume up to three times their original size. As the fiber, saturated with water, enters the intestine, it increases the volume of feces, leading to softer stool. Moreover, kiwi fruit fiber has been found to swell one and a half times more than psyllium, a fiber with a known laxative effect, and six times more than apple plant fibers.

Apart from fiber, other micronutrients present in kiwi fruit may also contribute to its laxative effect.

Actinidin

As an active digestive enzyme, actinidin is responsible for breaking down food proteins and improving stomach emptying. Furthermore, it has been found to ease spasms in the large intestine, facilitating the smooth passage of food through the digestive system.

Polyphenols

Polyphenols are a group of chemical compounds that play a crucial role in protecting plants from harmful external factors. In addition to this, they serve as a valuable food source for gut bifido- and lactobacilli, which actively participate in the digestive process.

Calcium oxalate needle-like crystals

Calcium oxalate needle-like crystals present in kiwi fruit have been found to nourish gut microbiota. These crystals, upon coming into contact with the intestinal surface, stimulate the production of mucus, which is a protein necessary for the smooth passage of feces.

Although the effects of these substances have only been studied in animal experiments, scientists believe that they play a crucial role in kiwi’s laxative activity. However, further research is necessary to validate this hypothesis.

What science says about the benefits of kiwi for constipation

Two key clinical studies evaluated the effectiveness of kiwi in treating constipation today.

In 2022, researchers from New Zealand published the results of the first double-blind randomized crossover study. The study selected 184 volunteers aged 18 to 65 with normal weight and without severe chronic diseases, including gastrointestinal diseases.

The researchers divided the participants into two groups. The first group ate two ripe kiwis every day for a month, while the second group took psyllium, a fiber supplement with clinically proven laxative activity.

After a month, the researchers compared the effects of kiwi and psyllium. The volunteers who ate kiwi experienced a reduction in abdominal discomfort, and their frequency of bowel movements per week increased by 1.53 times. This result is significant enough to consider kiwi beneficial for constipation. On the other hand, the group of volunteers taking psyllium did not experience an increase in the frequency of bowel movements for everyone. Some participants also reported that their gastrointestinal discomfort did not go away.

In 2021, American scientists published the results of the second study. The study compared the effect of kiwi and psyllium on the well-being of adult patients diagnosed with chronic constipation over the course of a month. Prunes with proven laxative effects were also included in the trials. All participants were divided into three groups: the first group was given kiwi twice a day, the second group took 12 grams of psyllium, and the third group ate 100 grams of prunes per day.

When the experiment concluded, all volunteers reported an increase in the frequency of bowel movements. Participants who ate kiwi, however, reported less complaints about side effects such as bloating.

The journal “Pharmacology of the Future” published a review of all available clinical studies on kiwi in 2021. The authors of the scientific paper concluded that experiments involving volunteers provide compelling evidence of the benefits of kiwi for chronic constipation.

In the same year, nutrition experts from the European Food Safety Authority recognized that clinical trials have shown a causal relationship between the consumption of kiwi and maintaining normal bowel movements. The experts stated that kiwi can be considered a beneficial food for constipation.

How to eat kiwi to normalize bowel movements

If a person does not have allergies or food intolerance, they can eat two ripe kiwi fruits of any color without skin every day to alleviate constipation. This amounts to approximately 200 grams of pulp. Eating four fruits is also possible without the risk of diarrhea. However, it is not yet known what will happen if you regularly consume more than four kiwi fruits.

It is essential to note that consuming kiwi fruit daily eases mild constipation. But, it is not a medicinal laxative. If someone is suffering from severe and regular constipation that does not improve with dietary changes, it is necessary to consult a doctor rather than rely on kiwi.