05/01/2015 03:39 pm ET Updated May 01, 2016

Whole Grains: Dietary Angel or Demon?

Whole grains. Should we eat them or not?

Controversy abounds. On the one hand, whole grains have a long history of inclusion in healthy eating programs and have been a dietary staple in traditional cultures for millennia. Indeed, national institutions such as the American Heart Association recommend whole grains as an essential part of a healthy diet.

On the other hand, some experts are calling into question whether or not whole grains are really all they're literally cracked up to be.

As I discussed in my recent HuffPost blog about gluten, there is reason to believe that gluten sensitivity is more common than we used to think, and that for those who are sensitive, consuming these whole grains can be detrimental to their health.

But it's not just wheat and its gluten-containing brethren that have come under scrutiny. Some suggest that whole grains are simply altogether unnecessary, that we didn't eat them in Paleolithic times, don't need them, their relatively high carb count may drive weight and health problems, and that they may even contain compounds (e.g., phytates and lectins) that are toxic to the human gut and are by and large genetically-modified organisms (GMOs).

So what's the truth about whole grains? Are they a dietary angel or demon?

Let's look to the research to see what science really tells us about these ancient staples of the human diet.

The Wide World of Grain

There is ample evidence that low-glycemic load whole grains (like oats, quinoa, teff, brown rice, and buckwheat) when eaten in moderation are not only a healthy part of the human diet, but reduce your risk of illness -- particularly cardiovascular problems -- and enhance gut microbiome health and biodiversity due to their prebiotic effects.

A recently-published study bears out the heart-protective effects of whole grains. Investigators at the Harvard School of Public Health examined data on whole grain intake and mortality in 74,341 women in the Nurse's Health Study and 43,744 men in the Health Professional's Follow-up Study -- two of the largest cohort health studies ever published. What they found was impressive. Each daily serving of whole grains correlated with a 5 percent reduction in all-cause mortality (ACM) and a 9 percent reduction in cardiovascular disease (CVD) mortality. Replacing a daily serving of refined grains with whole grains led to a 4 percent and 8 percent reduction in ACM and death from CVD respectively, and that replacing a serving of red meat with whole grains lead to a 10 percent reduction in ACM and a 20 percent reduction in CVD mortality.

We also know that whole grains provide an important source of food for the gut microbiome and thus have prebiotic effects. As we continue to learn more about the gut microbiome's impact on our health, it's becoming clear that the biodiversity of your inner ecology is an important factor in your overall health and has an impact on weight as well, as I spell out in my upcoming book The Gut Balance Revolution.

Indeed, some whole grains are veritable superfoods. Oats, for example, contain 4 grams of protein, 3.6 grams of satiating dietary fiber, and only 12 net grams of carbs per serving making them ideal for weight loss. The fiber in oats helps keep blood glucose levels stable over time -- a fact that has implications for those with blood sugar control issues and weight problems and can lower blood pressure.

Quinoa, another nutritional superstar, is high in protein, contains a good dose of fiber (5 grams per serving), has a low glycemic load, and has a satiating effect -- the highest among the gluten-free grains.

While it is true that some whole grains do contain compounds that can be toxic, these are either easily removed (by washing) or only need to be avoided under special circumstances. For example, quinoa is coated with saponin, a potential toxic, bitter tasting chemical. All you have to do is wash it before you cook it, and you're safe. It's also high in oxalates, so if you have kidney stones you shouldn't eat it. But for the rest of us this ancient whole grains is a superfood we can and should enjoy.

To my knowledge there is no research to suggest that whole grains are toxic or inflammatory to the human gut except is special circumstances -- like gluten is in CD patients. And while it's true that the caveman did not consume a lot of whole grains, the fact they have been with us for millennia and are considered an important part of some of the healthiest diets in the world (the Mediterranean and Baltic Sea Diets, for example) lends credence to the idea that they are not only harmless but essential for achieving optimal health.

Despite these facts, only about 5 percent of Americans get the recommended minimum amount of whole grains each day (five 28 gram servings or the equivalent of about a cup of oats). So it's likely you aren't getting enough and should consider adding more whole grains to your diet.

In my next post I will give you some tips on selecting and consuming grains.