Dietary fiber has received a lot of attention in food research over the past couple of decades. That’s because fiber from plants provide a lot of health benefits.
These fiber benefits include better heart health, boosting our probiotic populations, reducing cancer risk and others.
Now we can add to the list another benefit of dietary plant fiber: reducing inflammation. But this benefit confers most to not just any type of fiber.
Fiber studied for inflammation
Scientists from the Columbia University School of Public Health, Harvard Medical School and others studied the relationship between dietary fiber consumption and inflammation reduction among older adults.
The research followed 4,125 adults who were 65 years old or older. The participants completed food frequency questionnaires. They were also tested for inflammation. Blood tests were given and inflammation markers were measured.
The most notable inflammation marker tested was C-reactive protein, also called CRP. Another inflammation marker tested is called interleukin 1 receptor antagonist, also called IL-1Ra. This helps block a pro-inflammatory cytokine called IL1beta.
The researchers found that greater consumption of fiber was associated with a dramatic reduction in cardiovascular disease. The researchers assumed this also related to inflammation reduction, because heart disease is linked to inflammation.
Indeed, each increase in total fiber consumption by 5 grams per day was found to reduce C-reactive protein by 5 percent, and reduced IL1Ra by 4 percent.
A certain type of fiber reduces inflammation further
But they found that only a certain type of dietary fiber was directly linked to significantly lower inflammation. This type of fiber is called cereal fiber.
The researchers found that cereal fiber reduced inflammation significantly. An increase of cereal fiber by 5 grams per day resulted in a reduction of CRP by 12 percent and 10 percent of IL-1RA.
When the researchers broke apart the other types of fiber, it found that cereal fiber accounted for most of the inflammation reduction.
The research also found that much of the heart health benefit of the different fibers come from the cereal fiber.
What is cereal fiber?
When you hear the word “cereal” you likely think about breakfast cereal. But while breakfast cereal typically contains cereal fiber, the word accounts for more sources of fiber.
The word “cereal” is derived from the Roman goddess of the harvest called Ceres.
Cereal fiber relates to fiber that comes from plants that are referred to as “cereal grasses.” Cereal grasses include:
- Corn
- Barley
- Durum
- Einkorn
- Fonio
- Kamut
- Millet
- Oats
- Rice
- Rye
- Spelt
- Sorghum
- Teff
- Triticale
- Wheat
These are distinguished from the pseudocereal foods such as quinoa, chia and buckwheat.
Cereal grasses produce food by producing kernels. These kernels are also often referred to as grains. A grain contains an endosperm, a germ and bran. The bran is the outside sheath. When the sheath is included, the good is referred to as a whole grain.
Cereal grains are prebiotic
One of the fundamental benefits of cereal grains is their prebiotic potential. Prebiotic means they feed our body’s probiotic populations.
The study discussed above said this about the inflammation result:
“These findings on source of fiber could partly explain the discrepancy in the results from prebiotic intervention trials that seek to reduce inflammation because the prebiotics are from different sources. Similarly, differences in the source of fiber intake in specific populations (eg, low cereal fiber intake and high vegetable fiber intake) may also help explain differences in risk for a particular disease affected by inflammation.”
What they are referring to are studies showing that some prebiotics have been shown to reduce inflammation. But the result has not been prebiotics across the board, as indicated by a 2017 review study from Brazil. This study showed that out of 10 studies that tested inflammation against prebiotics, six studies showed that prebiotics reduced inflammation. And the other four studies did not show significant reduction.
An example of that later case was a study that showed that FOS prebiotics (fructo-oligosaccharides) did not significantly reduce inflammation markers such as CRP or IL1beta.
But cereal grains are also significantly prebiotic. For example, a 2021 study from China’s Center for Disease Control and Prevention tested 210 people. They had them consume either 80 grams of oats or rice per day for 45 days. Then they tested their probiotic levels in the gut along with their cholesterol levels.
The researchers found significant increases in a number of healthy probiotic species including Bifidobacteria and Roseburia species.
The prebiotics also reduced their cholesterol levels, as indicated in many other studies.
The bottom line is that whole grains like wheat, barley, corn, oats, rice and others provide food for those probiotic species that help our bodies reduce inflammation.
REFERENCES:
Shivakoti R, Biggs ML, Djoussé L, Durda PJ, Kizer JR, Psaty B, Reiner AP, Tracy RP, Siscovick D, Mukamal KJ. Intake and Sources of Dietary Fiber, Inflammation, and Cardiovascular Disease in Older US Adults. JAMA Netw Open. 2022 Mar 1;5(3):e225012. doi: 10.1001/jamanetworkopen.2022.5012.
Fernandes R, do Rosario VA, Mocellin MC, Kuntz MGF, Trindade EBSM. Effects of inulin-type fructans, galacto-oligosaccharides and related synbiotics on inflammatory markers in adult patients with overweight or obesity: A systematic review. Clin Nutr. 2017 Oct;36(5):1197-1206. doi: 10.1016/j.clnu.2016.10.003.
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