An avocado a day keeps poor gut health away, study reveals

URBANA, Ill. — Avocados are called a superfood with good reason. Studies show the nutrient-packed fruit is good for the heart, cholesterol, weight loss, and even the brain. Now a new study finds avocados also have a positive effect on gut health. Researchers from the University of Illinois say adding avocado to just one meal a day can improve the diversity of microbes in the gut and the healthy substances they create.

“We know eating avocados helps you feel full and reduces blood cholesterol concentration, but we did not know how it influences the gut microbes, and the metabolites the microbes produce,” says lead author and U of I graduate student Sharon Thompson in a university release.

The study adds avocados are high in dietary fiber and monounsaturated fat. Researchers discovered that eating the fruit daily creates a greater number of gut microbes which break down fiber. Compounds called metabolites these microbes create also support gut health.

“Avocado consumption reduced bile acids and increased short chain fatty acids. These changes correlate with beneficial health outcomes,” Thompson explains.

‘Fats and fiber in avocados positively affect gut microbiota’

The study examined 163 adults between 25 and 45 years-old who all fall into the category of overweight or obese. Each person had one meal a day replaced at either breakfast, lunch, or dinner. Part of the group had avocado with this test meal, while a control group had a similar meal that didn’t include avocado.

While other studies focus on avocado’s weight loss effects, the U of I team only focused on changes to the gastrointestinal microbiota. Researchers allowed the participants to keep eating their normal diet throughout the study with the exception of that one avocado meal each day.

Study authors took blood, urine, and stool samples from the participants for 12 weeks. Each person in the study also recorded what they ate every four weeks and how much of the test meal they ate during each sitting.

“Our goal was to test the hypothesis that the fats and the fiber in avocados positively affect the gut microbiota. We also wanted to explore the relationships between gut microbes and health outcomes,” says senior author Hannah Holscher.

Different fats have different effects

The results reveal that although avocados are rich in fat and participants eating the fruit consumed more calories, they also excreted more fat than the control group.

“Greater fat excretion means the research participants were absorbing less energy from the foods that they were eating. This was likely because of reductions in bile acids, which are molecules our digestion system secretes that allow us to absorb fat. We found that the amount of bile acids in stool was lower and the amount of fat in the stool was higher in the avocado group,” Holscher explains.

Researchers add that different types of fat have different effects on the human microbiome. The monounsaturated fat of an avocado is a heart-healthy variety, according to the team. The senior author says the fact that the fruit contains soluble fiber is also important for digestive health. A medium avocado contains between 12 and 16 grams of the 28 to 34 grams of fiber health experts recommend a person eats each day.

“Less than 5% of Americans eat enough fiber. Most people consume around 12 to 16 grams of fiber per day. Thus, incorporating avocados in your diet can help get you closer to meeting the fiber recommendation,” Holscher notes.

‘A win-win for gut microbes’

While eating fiber is good for the whole body, researchers conclude it’s especially vital for a healthy microbiome.

“We can’t break down dietary fibers, but certain gut microbes can. When we consume dietary fiber, it’s a win-win for gut microbes and for us,” Holscher contends. “Just like we think about heart-healthy meals, we need to also be thinking about gut healthy meals and how to feed the microbiota.”

The study notes that, on average, Americans don’t usually get enough micronutrients like potassium and fiber from their normal diets. Avocados offer a way to get both energy and nutrients from one densely packed food source.

“It’s just a really nicely packaged fruit that contains nutrients that are important for health. Our work shows we can add benefits to gut health to that list,” the assistant professor of nutrition adds.

The study appears in the Journal of Nutrition.

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