Recent research about fiber has brought healthy complex carbs back into the news. It seems that in addition to being heart healthy and helping to keep cholesterol in check, it's really good for your brain. Here's a look at what the new research says plus some other surprising health benefits of eating a diet rich in fiber.

It delays brain aging

A woman holds a bowls of raspberries One cup of raspberries has eight grams of fiber, making this delicious fruit super healthy for the brain. (Photo: GrashAlex/Shutterstock)

Based on research that showed older mice that consumed high-fiber diets had reduced rates of inflammation in their guts, scientists did a "genetic analysis of inflammatory markers" on humans and looked at the immune cell in the brain known as microglia. Researchers have found that "a high-fiber diet reduced inflammation in the brain's microglia," according to Medical News Today. Inflammation in microglia can cause a decline in memory and cognitive abilities as we age. Human diets rich in fiber can keep microglia inflammation down and may be helpful in combating dementia or Alzheimer's.

It decreases your risk of diverticulitis

Raw, sliced sweet potatoes Adding fiber-rich sweet potatoes to your diet can help prevent diverticulitis. (Photo: mama_mia/Shutterstock)

Diverticulitis occurs when pouches in the lining of the intestine, known as diverticula, become inflamed. Diverticula often develop as people get older. When the diverticula are inflamed, it can cause abdominal pain, nausea, diarrhea or constipation. According to WebMD, a diet rich in fiber may both soften and add bulk to the stool, making it easier to pass through the colon, decreasing the risk of the diverticula becoming inflamed.

It promotes healthy gut bacteria

Mexican black beans Black beans contain a lot of fructan, a high-fiber natural carb that's particularly helpful in promoting gut health. (Photo: Zoeytoja/Shutterstock)

The research that found fiber is good for the brain was based on research that showed fiber is good for the gut in mice. Fiber "feeds the billions of bacteria in our gut," as reported in The New York Times, and when our gut bacteria is happy, they help to keep the intestines and immune system working well. The mice that were fed low-fiber diets developed inflamed intestines, put on weight, and had higher blood sugar levels. While it was the healthy gut bacteria that kept these problems from occurring in some mice, it was the high-fiber diet that led to the healthy gut bacteria.

It promotes healthy bones

Avocado toast If you want to start your day by helping your bones, add some avocado to your breakfast. It has five grams of fiber per half cup. (Photo: zi3000/Shutterstock)

Here's another benefit that we don't automatically associate with a high-fiber diet: healthier joints and bones. Care2 reports that "eating more fiber may help prevent rheumatoid arthritis and build stronger bones." But, it's not the fiber that directly affects the joints and the bones; it's the healthy gut bacteria fed by the fiber that can keep us from developing health problems with rheumatoid arthritis or osteoporosis.

It prevents hemorrhoid pain

A bearded man bites into an apple Apples are high in fiber, but to get the most fiber out of an apple to help avoid hemorrhoid flareups, eat the skin, too. (Photo: Glayan/Shutterstock)

If you're susceptible to hemorrhoid flareups, it's important to add fiber to your diet, according to Harvard Health Publishing. Adding fiber to your diet can help to soften the stool; a softer stool is less likely to aggravate hemorrhoids as it passes by them, which can cause pain or bleeding. During an active flare-up of hemorrhoids, fiber pills may be necessary to quicken the process, but eating a steady diet of fiber-rich foods can keep the flare-ups from happening in the first place.

Notice that various forms of the word "inflamed" pops up frequently in almost all of these health benefits. Perhaps what's more of a surprise here isn't how fiber is good for you, but how fiber is good for gut bacteria and how healthy gut bacteria keeps inflammation down.

That's something to remember the next time you're deciding between an apple and a glass of fruit juice.

Robin Shreeves ( @rshreeves ) focuses on food from a family perspective from her home base in New Jersey.

5 surprising ways fiber is good for you
Fiber does more than keep your heart healthy and help you manage your weight.