Can whole grains improve your microbiome?

RGBstock photo- sundstrom

When it comes to health news, everywhere you turn you hear about the health promoting effects of a healthy microbiome – those trillions of beneficial bacteria in your gut. Research is showing that the health perks may extend from head to toe including risks for many chronic diseases and may even have an impact on mood and mental health.

So how do you change or improve your microbiome?

If anyone tells you it’s a simple matter such as simply popping a probiotic, tune them out. Instead be aware that there are many issues to consider including antibiotic use and food choices. And one simple way to start, is to switch from refined grains to whole grains. (A quick recap on definitions: a probiotic is a food or supplement containing live bacteria while s prebiotic, such as whole grains, are foods that stimulate the growth of healthy bacteria and are the food of choice for healthy bacteria to flourish).

But recent headlines may have you believing otherwise. “Brown bread might not be any better than white bread after all” and “Is whole wheat bread healthier? It depends on the person, study suggests.” The study published in the journal, Cell Metabolism, looked at the impact of white versus sourdough whole wheat bread on a number of different factors including the participants’ blood sugars, fat and cholesterol levels and found no difference between the breads. There were two test weeks for subjects- one for the white bread and the other for the whole wheat. The 20-subject investigation also measured the makeup of the their microbiomes before, during, and after the study and concluded that different people react differently, even to the same foods. The investigators stated that findings could help tell people “which foods are a better fit for them, based on their microbiomes.”

But don’t pitch your whole grains because of this study. At first glance, when I was interviewed by CTV News about the study, I wondered about the study design and why the researchers didn’t include other grains. Those such as barley and oats, besides having more soluble fibre and therefore, a lower glycemic index and more blood cholesterol- lowering effects, are known to have greater prebiotic potential than wheat, the grain of choice for the study. There were other issues to consider as well such as it seems that there were only three tests meals of each kind of bread each week, hardly enough to have an impact on the microbiome.

You also have to wonder about the validity of the research especially when you consider that the scientists who designed the study are consultants to a company that sells kits to evaluate the purchaser’s stools and genetic makeup. Their website states ,”DayTwo analyzes your microbiome to predict blood sugar responses to thousands of different foods.” Hmmmm

A recent CNN article, by scientist Tim Spector, showed there’s more than genes to consider when you look at the bacteria in your gut. In the article, What a hunter-gatherer diet does to the body in just three days, the author whose microbiome had already been shown to be quite healthy, describes his intensive three days of eating like a hunter gatherer during his stay at his research camp. He measured his gut microbes before heading to Tanzania, during his stay and after his return to the UK. He describes his fibre-packed diet of wild foods as well as his daily routine. When his stool samples were tested following the 3 days, his gut microbal diversity increased a whopping 20%. Unfortunately shortly after his return, Spector’s gut returned to his pre-Africa trip in just a few days.

But new research, using randomized controlled feeding of study subjects comparing whole grains to refined ones shows that you don’t need to go to Africa to improve your gut bacteria. I’ll have the research for you in my next post – including why controlled feedings are key to providing valid research findings.

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Categories: Nutrition News

Author:Rosie Schwartz

Rosie Schwartz is a Toronto-based consulting dietitian and writer.

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