Peanuts, herbs and spices for a healthy gut: Penn State studies reveal microbiome boost

02 Dec 2022 --- Two separate studies out of Penn State University have shown that adding peanuts and herbs and spices to the average American diet can increase the abundance of gut bacteria associated with better health. 

The research found that adding a daily ounce of peanuts or about a teaspoon of herbs and spices to diets may affect the composition of gut bacteria – an indicator of overall health.

The human gut microbiome is a collection of trillions of microorganisms that live inside the intestinal tract. The bacteria there can affect nearly all systems of the body, including metabolism and the building and maintaining of the immune system.

“Research has shown that people who have a lot of different microbes have better health and a better diet than those who don’t have much bacterial diversity,” says Penny M. Kris-Etherton, Evan Pugh University Professor of Nutritional Sciences at Penn State.

Inside the studies
For the peanut study, which was published in the journal Clinical Nutrition, Kris-Etherton and her colleagues compared the effects of snacking on 28 grams of peanuts per day versus a higher carbohydrate snack – crackers and cheese.

At the end of six weeks, participants who ate the peanut snack showed an increased abundance of Ruminococcaceae, a group of bacteria linked to healthy liver metabolism and immune function.Participants who ate peanuts showed increased Ruminococcaceae, a group of bacteria linked to healthy liver metabolism and immune function.

In the herbs and spices study, which was published in The Journal of Nutrition, scientists analyzed the impact of adding blends of herbs and spices – such as cinnamon, ginger, cumin, turmeric, rosemary, oregano, basil and thyme – to the controlled diets of participants at risk for cardiovascular disease.

The team examined three doses – about 1/8 teaspoon per day, a little more than 3/4 teaspoon per day and about 1 1/2 teaspoon per day. At the end of four weeks, participants showed an increase in gut bacteria diversity, including an increase in Ruminococcaceae, most notably with the medium and high doses of herbs and spices.

“It’s such a simple thing that people can do,” notes Kris-Etherton. “The average American diet is far from ideal, so I think everyone could benefit by adding herbs and spices. It’s also a way of decreasing sodium in your diet but flavoring foods in a way that makes them palatable and, in fact, delicious. Taste is really a top criterion for why people choose the foods they do.”

Gut microbiota and health
In both studies, the increase in Ruminococcaceae and bacterial diversity was viewed positively, as scientists continue to learn more about the connection between the gut microbiota and a spectrum of health factors – from blood pressure to weight. However, Kris-Etherton points out that more research is needed to understand all of the implications.

“We need a lot more research on the microbiome to see what its proper place is in terms of overall health.”

In related news, researchers revealed that just four weeks of eating mixed tree nuts could have positive effects on mood, memory and overall thinking capability. This same study and others also found that eating nuts can help to modulate metabolites, bacteria and microbes in the gut.

Edited by Joshua Poole