The new guidelines do not recommend a diet rich in fiber, but rather that you eat more kiwi – and more.
In one, researchers examined 75 clinical trials to formulate recommendations about foods, drinks and supplements for chronic constipation in adults.
Since constipation means different things to different people, they used a very broad definition of constipation. This covered what patients considered to be constipation, as well as the definitions of constipation used in clinical trials. Chronic constipation is generally when someone passes few, hard stools over a period of at least three months.
Researchers produced 59 recommendations. However, they said most of the recommendations were based on low-quality evidence. Therefore, this article explores only the strongest advice.
Why kiwi? How many per day?
The researchers recommended eating two to three kiwis a dayfor at least four weeks to improve constipation. Whether it’s green kiwi or gold kiwi, the evidence clearly shows that both can help.
But how? There are several reasons.
A fiber in kiwi swells a lot when mixed with watermore than the fiber in apples. This swelling helps make the stool bulkier, making it easier to pass through the intestine.
Eat the whole fruit, including the shellprovides more fiber than eating just the pulp, but eating kiwi without the skin is perfectly acceptable.
Green kiwi contains an enzyme called actinidina which helps the body digest proteins in the stomach and small intestine. This can help with constipation, making food proteins softer and easier to pass through the intestine.
Kiwifruit contains a type of crystal called it’s crazy. These are believed to increase the production of mucus in the intestine, lubricating it and helping the passage of stool.
Eating kiwifruit may also result in a reduction in species of methane-producing bacteria, which have been linked to constipation.
Mineral water and magnesium
Researchers have reported the benefits of drink mineral water. They suggested drinking 0.5–1.5 liters per day (approximately two to six cups) of mineral water for two to six weeks.
Why? Mineral water often contains magnesiumwhich acts as a laxative. In fact, magnesium oxide is often used as a dietary supplement for chronic constipation.
The guidelines confirmed that the Magnesium oxide can help soften stool and increase bowel frequency. Researchers recommended taking 0.5–1.5 g per day for at least four weeks.
But this may not be appropriate for everyone. For example, people with kidney disease should be careful. Magnesium supplements may also interact with other medications.
Rye bread
Researchers cited studies showing that rye bread relieves constipation more than white bread or common laxatives.
Recommended six to eight slices a day of rye bread for at least three weeks.
But this is simply not realistic for many people. And, as rye contains gluten, this would not be appropriate for people with celiac disease.
A high-fiber diet may not be necessary after all
There was a big surprise in the guidelines.
The researchers said there was a lack of solid evidence for generic high-fiber diets in treating constipation when people consume at least 25 g of fiber per day.
Here’s the reason. Researchers were only able to find one randomized controlled trial – the gold standard for testing interventions such as a change in diet – in which a high-fiber diet (25–30 g/day) was compared with a low-fiber diet (15–20 g/day).
This essay did not show any benefit of a high-fiber diet in improving constipation. People on the low-fiber diet passed less gas and felt less bloated than people on the high-fiber diet.
This doesn’t mean fiber doesn’t help with constipation.. There is good evidence that Supplementing the diet with more fiber helps with chronic constipation.
A high-fiber diet is generally a key part of national dietary guidelines. For example, the Dietary Guidelines for Americans recommend that some adults have a dietary fiber intake of at least 28 g per day. There are certainly health benefits, such as lower cholesterol and blood sugar levels, when following a high-fiber diet.
But we now know that it is not necessary to relieve chronic constipation.
