- Researchers recently studied the effects of peanuts, herbs, and spices, including cinnamon, ginger, cumin, and turmeric, on the gut microbiome in two separate studies.
- They found that peanuts, like herbs and spices, increased levels of certain gut bacteria after just 4 to 6 weeks of adding them to a typical American diet.
- They noted that more research is needed to understand the implications of their findings and the possible health benefits of having more gut bacteria.
Diet influences the types of bacteria that live in the gut. These bacteria are linked to multiple measures of health, including glycemic controlwhich is important for regulating blood sugar levels,
Meanwhile, a systematic review of nut consumption found that almonds, walnuts, hazelnuts and pistachios increase the diversity of intestinal bacteria. However, until now, no studies have examined the effects of peanuts on the microbiome.
Further study of the effects of dietary agents such as herbs, spices, and peanuts on gut bacteria could help inform preventive healthcare strategies and therapy.
Researchers recently conducted two studies investigating how peanut, herb, and spice consumption affects the gut microbiome. They found that all three ingredients increased the diversity of gut bacteria after just 4 to 6 weeks of consumption.
The studies were published in
To investigate the effects of herbs and spices on the microbiome, the researchers recruited 54 adults with an average age of 45 years. All participants were overweight or obese and had at least one other cardiovascular risk factor, such as elevated glucose or triglycerides.
The researchers provided 48 participants with the same diet for four weeks along with one of three doses of spices and herbs: 0.5 g per day, 3.3 g per day, or 6.6 grams per day.
Participants ate all three amounts of herbs and spices for four weeks with a two-week “washout” period in between. Spices included cinnamon, ginger, cumin, turmeric, rosemary, oregano, basil, and thyme.
They provided stool samples at the beginning of the study and at the end of each diet period.
The researchers found that consuming 3.3 grams or 6.6 grams of herbs or spices per day increased levels of Ruminococcaceae bacteria.
The highest levels of Ruminococcaceae bacteria were observed among those who consumed the highest levels of herbs and spices.
For the peanut study, the researchers recruited 50 adults who had elevated fasting glucose levels and were overweight or obese.
They asked the participants to consume 28 grams of peanuts or crackers and cheese every day as an evening snack.
All participants tested both diets for six weeks with a four-week washout period in between. The researchers collected fecal samples from the participants at the beginning of the study and at the end of each dietary intervention.
They found that those who ate peanuts had higher levels of Ruminococcaceae bacteria in their fecal samples than those who ate crackers and cheese.
They further noted that those who ate peanuts also had higher levels of the Roseburia bacteria than at the start of the study.
Studies suggest that Roseburia is related to weight loss and reduced glucose intolerance.
When asked about the health benefits of Ruminococcaceae, Dr. Lona Sandónassociate professor in the Department of Clinical Nutrition, School of Health Professions at UT Southwestern Medical Center, who was not involved in the study, said today’s medical news that the studies did not specifically look at the health benefits of these ingredients.
“However, it appears that Ruminococcaceae increase bacteria that produce butyrate, a short-chain fatty acid that, when produced in higher amounts, can help control appetite, balance energy, and improve blood glucose,” he said. Dr Sandon.
It is not yet entirely clear how peanuts and herbs might increase the diversity of the gut microbiome.
“In addition to being a source of protein and healthy fats, peanuts are also a source of fiber. Bacteria in the gut feed on fiber. With more fiber in the diet, more bacteria and a greater variety of bacteria can thrive in the gut,” said Dr. Sandon.
“As for herbs and spices, the theory is that polyphenols, the chemicals found in herbs and spices and also in foods like dark cocoa, wine, grapes, berries, and cherries, provide a food source or help create an environment in the gut that supports the growth of a greater variety of bacteria.”
“Polyphenols [in peanuts, herbs, and spices] They are known to promote health in a number of ways, such as reducing the risk of cancer or reducing inflammation. It may be that the way they work to promote health is through changes in the gut microbiome.”
— Dr. Lona Sandón
The researchers concluded that adding small amounts of peanuts, herbs, or spices to the diet could increase the abundance of certain gut bacteria.
However, the researchers noted that more research is needed to learn how a greater abundance of these bacteria might affect overall health.
When asked about study limitations, Dr. Sandon noted small sample sizes and short study durations.
“[This makes] makes it hard to conclude what might happen in the long run. Furthermore, the studies were not looking specifically for health effects, but were looking to determine how the change in diet affected the microbiome. We cannot draw conclusions about health impacts from these findings,” he said.
MNT also spoke with Dr. Dana Ellis Hunnes, an assistant professor at the UCLA Fielding School of Public Health, who was not involved in the study. Dr. Hunnes is also the author of Recipe for survival: what you can do to live a healthier and more environmentally friendly life.
He noted that another limitation of the studies is their narrow focus, that is, only on peanuts rather than a broader variety of nuts or legumes.
“I would love to see a future study that looks at the overall quality of the diet and not just a specific food or nutrient, also known as ‘nutritional reductionism’ or nutritionism,” he said.
He also noted that the studies were funded by the industries themselves: The Peanut Institute, a nonprofit organization that encourages healthy lifestyles that include the consumption of peanuts, and the McCormick spice and herb company.
“[This doesn’t mean the [studies are bad]it just means they have an interest in the results,” he said.
