Can whole grains improve your microbiome? Part 2

In my last post, I provided insight into a recent study on breads which went against the grain of current thinking about prebiotic foods. These are plant foods containing indigestible carbohydrates that stimulate and feed the growth of beneficial bacteria in your gut. I promised you more info on the latest research on whole grains and their potential impact on your microbiome (what the entire collection of bacteria is called).

In the scientific investigation, published in two separate papers in the American Journal of Clinical Nutrition, the 81 subjects were provided with meals containing either whole grains (mainly whole wheat) or refined grains for a total of 6 weeks. The meals were prepared so that there were no changes in the weight of the participants as this could have an impact on the results. The carefully planned meals – what I referred to as “controlled feedings” – a major factor that was missing in the study showing no difference between whole grain and refined bread.

Good research means that you don’t allow for unknown factors to throw off your findings. So, for example, if participants who are assigned refined grains are eating lentils and chick peas on a daily basis and the ones in the whole grain group are only eating iceberg lettuce as their vegetable, then the results could be completely unreliable. That’s why controlled feedings make all the difference in studies like this.

The researchers also measured a number of elements at both the beginning and the end of the study including the stool weight- the fat, bacteria, and energy contained – the metabolic rate of participants along with their appetites and immune and inflammatory factors in the blood.

The results showed that consuming whole grains increased the resting metabolic rate (the calorie burning capacity of the individual), led to calorie losses in the feces, increased stool bulk and had a beneficial effect on the bacteria found in the stools as well as on certain aspects of the immune function. However, there were no effects on when it came to intestinal inflammation, blood sugar regulation, or appetite.

But it’s also important to keep in mind just how much in the way of whole grains were included in the study. It was only 16 grams per 1,000 calories consumed. That’s the equivalent of just one slice of whole grain bread or 1/3 cup of a cooked whole grain such as brown rice, whole wheat pasta or barley. So a study subject might have had the equivalent of 2/3 to 1 cup of cooked whole wheat pasta as their whole grain through the entire day. That’s not a whole lot when assessing the impact.

The accompanying editorial in the American Journal of Clinical Nutrition suggests that these results may explain some of the past observational research showing the benefits of whole grains going hand in hand with easier weight management. With observational research, you can only see that people who ate whole grains were also the individuals less likely to gain weight but you can’t show cause and effect. But with clinical studies such as the controlled feeding trials, you can.

But here’s an issue. In order to have an impact, the whole grain eating needs to be consistent. The CNN African- wild food study I pointed to in my last post showed that.

The good news is that even if you eat out on a regular basis, whole grains are becoming menu staples at eateries, from fine dining establishments to fast food chains. At an Oldways Whole Grains Council conference I attended, “Whole Grains Away from Home (Whole Grains in Foodservice, the Next Frontier)” in Chicago, experts revealed that putting whole grains on the menu, besides offering the health benefits (both human and planetary) more and more patrons are looking for, it also helps the bottom line in terms of food costs. Instead of a large steak, putting a smaller one on the menu atop a bed of whole grains saves money and is more in keeping with what diners may be looking for.

While leading chefs are creating whole grain offerings with choices such as farro, freekah and black rice, you can now select brown rice and quinoa even at many chain eateries. Grain bowls are now taking their place alongside sandwiches and salads for quick meal and burgers are also getting a makeover. You can now find variations, rather than being only meat or soy-based, comprised of various mixtures. For example, at Locol Cheeseburg, a fast food shop in Los Angeles and Oakland, the burger is a blend of beef, tofu, seaweed and sprouted grains for a lighter texture. On the east coast at Superiority Burger in New York City, an East Village vegetarian fast-food spot, their sliders are made with millet, wheat groats, quinoa or whatever grain is available.

Yes, eating whole grains consistently can help to promote a healthier microbiome. But it’s only one piece of the strategy. Get your fill of other plant foods such as pulses, fruits, vegetables and nuts and seeds too.


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Categories: Food Trends, Nutrition News

Author:Rosie Schwartz

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

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