While scientists have not yet specifically looked into whether aspartame can cause constipation, some research indicates it may affect a person’s gut microbiota. However, the results are conflicting.

Aspartame is an artificial sweetener that manufacturers include in many low calorie beverages, foods, and other products.

Manufacturers widely use it today, and the Food and Drug Administration (FDA) has approved its use as a food additive. The FDA and other similar administrations worldwide have also established acceptable and safe daily intake levels of aspartame.

This article explores the possible gastrointestinal side effects of aspartame. It also discusses acceptable daily intake levels of aspartame, natural alternatives, and tips to help prevent constipation.

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The FDA states that aspartame is one of the most commonly studied food additives. Researchers have investigated the ingredient for potential side effects and concluded it is safe for use.

However, there appears to have been no formal research into whether aspartame consumption may cause constipation.

Several studies have investigated how sweeteners affect a person’s gut microbiota, which describes the trillions of bacteria and other microbes that live in their gut. Doctors refer to problems with a person’s gut microbiota as dysbiosis. These issues may lead to gut problems, which may include chronic constipation.

Scientists have studied how aspartame affects a person’s gut microbiota. However, several human and animal studies found different and conflicting results. Some studies found that aspartame did not affect the gut microbiota. Conversely, others found that it could influence how the gut worked and may affect the gut microbiota.

Another 2019 review of studies investigated research into the effects of several sweeteners on a person’s gut microbiota. However, the researchers could not find any data on these effects. They also noted that a person’s body rapidly breaks down and absorbs aspartame in the small intestines before it has a chance to reach the large intestine, which is where most of the gut microbiome resides.

For this reason, they stated it is hard to understand how aspartame influences a person’s gut microbiota. However, they noted that the artificial sweeteners saccharin and sucralose may affect the gut microbiota according to findings from several animal studies.

Aspartame and phenylketonuria (PKU)

The American Cancer Society (ACS) suggests researchers have not been able to conclusively link aspartame to any specific health problems, except for people with phenylketonuria (PKU).

PKU is a genetic disorder, meaning it is present from a person’s birth. If someone has PKU, their body cannot break down an amino acid called phenylalanine.

This amino acid is present in many foods. Aspartame also contains high levels of phenylalanine. Those with PKU need to avoid aspartame to help prevent harmful levels of phenylalanine from building up in their bodies.

The FDA establishes and monitors acceptable daily intake (ADI) levels for many food additives. An ADI is the amount of a substance a person can safely consume daily over their lifetime. Health experts usually express ADIs in milligrams (mg) of the substance a person can consume daily for each kilogram (kg) of their body weight.

The FDA’s ADI for aspartame is 50 mg for every kg of someone’s body weight. For someone weighing 60 kg, or 132 pounds (lb), this ADI equates to 75 packets of aspartame sweetener per day.

In 1984, the European Food Safety Authority established an ADI for aspartame of 40 mg per kg of a person’s body weight. A person with a body mass of 70 kg (154 lb) would need to drink at least 9–14 cans of diet soda every day to exceed this limit, according to the ACS.

People who usually consume synthetic sweeteners such as aspartame may wish to use natural sweeteners, such as stevia and monk fruit, which both have FDA approval for consumption.

Another option is honey. However, while it has a slightly lower glycemic index score than sugar, it can still raise a person’s blood sugar levels.

In contrast, research indicates that stevia and monk fruit are unlikely to affect a person’s blood sugar levels.

People can help prevent constipation by:

A healthcare professional may also recommend dietary supplements, over-the-counter laxative medications, or changes to prescription medications.

A person needs to speak with a doctor if constipation persists or worsens.

Aspartame is an artificial sweetener that manufacturers add to many beverages and foods. Scientists have carried out many studies into its potential side effects.

However, no specific research has determined whether aspartame can cause constipation, and research into its effects on gut microbiota is inconclusive.

People need to consider that the Food and Drug Administration (FDA) has approved aspartame as a food additive. However, it is unsuitable for people with PKU.

Additionally, other sweeteners, such as stevia extract, monk fruit extract, and honey, are available.

A person can take steps to prevent constipation, such as drinking plenty of liquids, eating more dietary fiber, and exercising regularly.