There is significant recent research that confirms that whole wheat foods can promote gut health, decrease inflammation and reduce the risk of colon cancer.
Whole wheat reduces inflammation
This has been illustrated in a new clinical study published in the American Journal of Nutrition.
The researchers, from the University of Naples, tested 80 people who were overweight or obese. They also had a low consumption of fruits and vegetables. (Hmm, what a shock.)
The subjects were split randomly into two groups. One group was given whole wheat foods that replaced their previous refined wheat foods. The other continued eating refined wheat foods.
The study lasted eight weeks. Blood, urine and feces of the subjects were analyzed before, during and after the study. The subjects were also tested for other physiological measures.
The group that ate the whole wheat foods had significantly reduced inflammation within the gut. This was determined by reduced tumor necrosis factor-alpha levels (TNF-a) along with increased interleukin-10 levels. Lower TNF-a levels illustrate reduced inflammation. Increased IL-10 levels indicate increased gut immunity.
The subjects who ate the whole wheat also had reduced plasminogen activator inhibitor 1, which illustrates a lower degree of artery inflammation.
Whole wheat increases probiotics and decreases clostridium
Those eating the whole wheat foods also experienced an increase in the lactobacilli colonies and bacteriodes colonies. This means their probiotic colonies grew.
This was accompanied by an increase in dihydroferulic acid in the blood and ferulic acid in the feces. Both indicate a better adjusted microbiome, which results in reduced inflammation throughout the body.
Furthermore, the research found those on the whole wheat diet had reduced colonies of Clostridium species. Clostridium is associated with numerous inflammatory gut conditions, including irritable bowel syndrome and others.
Whole wheat improves microbiome
Eight weeks is certainly too short to see permanent changes in the gut’s microbiome. However, one of the more important changes within the digestive tracts of the subjects was in fact their microbiome.
In these eight short weeks, the researchers found increased levels of the microbiome type called Bacteroidetes. This microbiome is seen in greater numbers among healthier people. People with less inflammation. And people with less obesity.
Mice studies have confirmed this relationship between the microbiome groups, bacteroidetes and firmicutes. The firmicutes type tends to increase fat storage and calorie extraction.
The issue appears to be related to a gene called TLR5, which apparently identifies bacteria in the gut. In the absence of bacteria – or in the absence of the gene itself as found in mice studies – excessive appetite results. This produces an increased risk of obesity.
Apparently, firmicutes microbiome also results in greater energy extraction. This means more calories are being extracted from the foods.
Brain inflammation, microbiome and diet
As long as we’re talking microbiome, I should probably mention a very new study. This is a mice study. I am not a fan of mice studies not only because of the cruelty aspect, but because mice have metabolic differences with humans. Mice study findings are thus not always appropriate when applied to humans.
This particular study found that mice fed a high-fat diet had a worsening of their gut microbiome. They had greater gut permeability (leaky gut). They also produce greater inflammation factors in the gut. And increased inflammation in the brain.
While again we cannot necessarily apply this to humans, it may indicate that diets with higher fat content produce greater brain inflammation.
This news, however, is really not news because many studies on humans have shown that the Mediterranean Diet reduces inflammation and the risk of dementia and other neuroinflammatory diseases. The Med diet of course is a lower-fat diet. But its primary benefit is that it consists of better types of fats. Fats such as monounsaturates and omega-3 fats.
Wheat, diet and our microbiome
You probably thought this article was going to be only about wheat. Sorry about that. The point of laying out this research is that our diet directly affects our gut bacteria. And our gut bacteria affect our levels of inflammation. Not only in the gut. But in the brain. And the rest of the body.
As I discussed in another article about our probiotics, whole wheat feeds certain types of probiotics in our gut. These include certain species of lactobacilli but also bifidobacteria. The latter of which also happen to live in our colon and reduce the risk of colon cancer.
This prebiotic ingredient of whole wheat is called arabinoxylan oligosaccharide. Oligosaccharides are complex prebiotic molecules that feed our gut bacteria. This is what the “O” stands for in FOS, TOS and GOS prebiotics.
Because arabinoxylan is part of the outer shell of the wheat berry, it is mostly absent in refined wheat foods.
Worse, refined wheat foods will have an extraordinary amount of gluten. As a proportion of gluten to arabinoxylan, a very great amount of gluten.
The prebiotic called arabinoxylan oligosaccharide promotes the growth of probiotic (good) bacteria. Several studies have shown certain gut probiotics reduce levels of colon-cancer related enzymes such as beta-glucosidase and beta-glucuronidase.
As to whether the anti-cancer benefits of wheat come from its prebiotic content or its alkylresorcinol content has not been fully determined. It is likely to be both.
The bottom line is that when looked at from a larger perspective, whole grain wheat is a healthy food.
The funny thing is, about those gut bacteria that secrete the enzymes that break down gluten into harmless amino acids: They also happen to feed off of the arabinoxylans in the whole wheat.
Wheat and colon cancer
Researchers from the Danish Cancer Society Research Center in Copenhagen followed 1,372 colorectal cancer patients together with 1,372 matched healthy persons. The study was part of the European Prospective Investigation into Cancer and Nutrition.
To confirm whole grain wheat and rye consumption the researchers measured blood levels of alkylresorcinols – phenolic lipids consumed almost exclusively from the bran of cereal grasses wheat and rye.
The researchers found that those with the highest 25% of alkylresorcinols in their bloodstream had a 52% lower incidence of distal colon cancer, with the lowest risk ranging from a 72% lower incidence.
Furthermore, among Scandinavians, higher levels of alkylresorcinols had a 27% reduced incidence of all types of colon cancer.
Furthermore, their research found that among populations that ate greater amounts of alkylresorcinols – notably Central Europe and Scandinavian countries – there was a clear relationship. This of course means that it isn’t about eating a few meals here and there with whole wheat and rye: Rather, it is about consistently including whole grains in the diet.
The researchers stated this clearly:
“Plasma alkylresorcinols concentrations were associated with colon and distal colon cancer only in Central Europe and Scandinavia (ie, areas where alkylresorcinol levels were higher).”
Those areas where “alkylresorcinol levels were higher” relate to regions where more whole-grain wheats are consumed. Other regions of Europe and among many other western countries, wheat products consumed are primarily from white (refined) flours, which contain little alkylresorcinol content.
Other studies confirm whole wheat helps prevent colon cancer
This is not the first study to correlate reduced colon cancer incidence with the consumption of whole-grain wheat. A larger study from the Danish Cancer Society Research Center followed 108,000 Danish, Swedish, and Norwegian persons for eleven years. From this population 1,123 were diagnosed with colorectal cancer during the 11 years.
As the researchers analyzed their diets, they found that the consistent (daily) consumption of whole-grain wheat foods, including whole-grain breads and cereals resulted in a 44% lower incidence of colorectal cancer among the population studied.
They did not find the same correlation among greater consumption of whole-grain oats.
How do whole wheat and rye produce anti-cancer benefits?
One component, as mentioned above, is alkylresorcinol content. These are phenol lipids – a sort of fat – that are found mainly in the outer layers (such as the pericarp) of the bran of kernels of Triticum aestivum (wheat) and Triticum durum (durum wheat which is used to make pasta) as well as Secale cereale (rye). Rice has been found to contain alkylresorcinols but rice’s alkylresorcinols are contained in the strands not the kernels.
The research has shown that alkylresorcinols have numerous biological effects, including curbing mutagenic activity and inhibiting carcinogenic enzymes in the gut. They also have been shown to have antifungal activities.
Scientific References
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