A new study published in Molecular Nutrition & Food Research shows that certain everyday foods might play a big role in keeping older adults healthy. The secret? Polyphenols—natural compounds found in fruits, green tea, and even dark chocolate.
This research, led by Professor Cristina Andrés-Lacueva and her team, followed more than 50 volunteers aged 65 and older.
Over eight weeks, participants ate a diet rich in polyphenol-containing foods like apples, pomegranates, blueberries, dark chocolate, and green tea. The scientists wanted to see how this diet affected a substance in the blood called indole 3-propionic acid (IPA).
IPA is made when certain gut bacteria break down tryptophan, an amino acid found in many foods. It’s not something you get directly from what you eat—it’s something your body produces with the help of gut bacteria.
IPA is important because it has antioxidant, anti-inflammatory, and brain-protective properties. It also helps keep your gut lining strong, which is essential for good digestion and immune health.
After the eight-week diet, the researchers found something exciting: people who ate more polyphenol-rich foods had much higher levels of IPA in their blood. Not only that, but they also had lower levels of inflammation and noticeable changes in their gut bacteria.
One group of bacteria, known as Bacteroidales, was particularly affected. These bacteria may play a key role in helping the body make IPA.
However, not everyone in the study saw the same benefits. Older adults who had kidney disease didn’t show the same rise in IPA levels. The researchers believe this might be due to differences in the types of bacteria living in their guts.
This is important because people with kidney problems usually have lower IPA levels, which has been linked to faster kidney decline and worsening health.
Tomás Meroño, another lead researcher in the study, says that finding ways to increase IPA naturally through diet could have long-term health benefits. Boosting IPA might help slow aging and prevent chronic illnesses like kidney disease or other inflammation-related problems.
This study is a good reminder that what we eat doesn’t just feed us—it also feeds the trillions of microbes in our gut. These microbes, in turn, produce compounds that can protect our bodies from disease and help us stay healthy as we age.
This study adds to the growing evidence that healthy aging isn’t just about cutting calories or avoiding certain foods—it’s also about eating the right kinds of foods that support our gut health.
Polyphenols, found in many fruits, vegetables, tea, and dark chocolate, seem to act like “fuel” for good gut bacteria. These bacteria turn that fuel into IPA, a powerful substance that may help lower inflammation, protect brain function, and keep our digestive systems strong.
The fact that older adults without kidney disease showed clear improvements is promising. It suggests that simply eating more of these polyphenol-rich foods could be a simple, low-cost way to stay healthier longer.
However, it also shows that people with existing health conditions, like kidney disease, may need more targeted help—perhaps combining diet changes with medical treatments or probiotics to restore balance in the gut.
What’s exciting is that these foods are common and easy to include in your daily life. A cup of green tea, a few pieces of dark chocolate, and a handful of berries or an apple could do more than just taste good—they might help your body produce more of the helpful compounds it needs to fight aging and inflammation.
More research is still needed, especially in people with different health conditions. But this study gives strong support to the idea that smart food choices can directly impact how well we age. If you’re over 65—or care for someone who is—consider making these small changes to the diet. They could add up to better health and quality of life.
If you’re interested in inflammation, you might also want to read studies on what causes it in bowel diseases and how vitamins like B and D could help reduce it. You’ll also find research showing which common foods can trigger inflammation, and which ones—like polyphenol-rich fruits—can help reduce it.
The full research findings are available in Molecular Nutrition & Food Research.
If you care about nutrition, please read studies about the harm of vitamin D deficiency you need to know, and does eating potatoes increase your blood pressure?
For more information about health, please see recent studies about unhealthy habits that may increase high blood pressure risk, and results showing MIND diet may reduce risk of vision loss disease.
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