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Whole Grains: Under-Sung Antioxidant Stars Get a Boost
9/17/2007
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Whole grains inhibit inflammation and reduce related health risks; their overlooked, abundant antioxidants are the likely reason

by Craig Weatherby


Carbohydrates have taken a beating lately, being blamed for promoting obesity and diabetes.


Indeed, refined grains like white flour and corn starch appear to increase the risk of chronic diseases.


Corn beats spinach in antioxidant face-off

Research reported at the 2002 American Institute for Cancer Research International Conference startled many by showing that, compared with fruits and vegetables, whole grains contain as much or more of the powerful polyphenol antioxidants that make preventive-health headlines.


These findings have since been confimed by similar research, but remain under-reported.


The antioxidants concentrated in the kernel and bran of whole grains have gone unseen because researchers typically measure only the “free” forms, which are immediately absorbed into the bloodstream. They didn’t even look for the “bound” forms, which get released by intestinal bacteria during digestion.


A team from Cornell University noted that on average, “free” form polyphenol antioxidants constitute 76 percent of the total polyphenols in common fruits and vegetables, while “free” polyphenols account for less than one percent of the total in whole grains (Adom KK, Liu RH 2002).


It’s no wonder, then, that the amount and activity of antioxidants in whole grains has been vastly underestimated.


In fact, the Cornell group discovered that the total antioxidant activity in all three types of whole foodsfruits, vegetables, and whole grainsis similar.


They assigned various foods a rating, based on a standard measure of antioxidant capacity (micromoles of vitamin C equivalent per gram), with these eye-opening results:


Corn = 181

Apple = 98

Spinach = 81

Broccoli = 80

Whole wheat = 77

Oats = 75

Banana = 65

Brown rice = 56


Remember, these findings apply only to the whole, unrefined version of these grains, not to corn starch, white flour, or white rice.

But people who eat whole-grain foods frequently are much less prone to develop metabolic syndrome and they are about one-third less likely to get heart disease or diabetes, compared to those who rarely eat whole grain foods.


The findings of a study from Harvard University, reported earlier this year, affirmed these cardiac benefits, by showing that people who eat a bowl of wholegrain cereal every day reduce their risk of heart failure by 27 percent.


It’s not as though the benefits of whole grains were news, with even the conservative Dietary Guidelines for Americans recommending three servings of whole-grain products daily.


But anti-grain prejudice persists, chiefly among advocates of Atkins-style high-protein diets, who advise us to avoid grain-based foods and seek our carbs from vegetables.


And advocates of the Paleolithic diet, dominated by greens, fruits, nuts, fish and grass-fed meats, hold a parallel position. They believe that we should stick closely to the diets to which our bodies adapted over many millennia, before the advent of cultivated grains.


(We agree with the Paleolithic approach when it comes to shifting our fat intake to the primal “omega-ratio”: an approximate four to one omega-6/omega-3 intake ratio, versus the average Americans' 30 to one omega-6/omega-3 intake ratio.)


Both groups of grain-doubters have some evidence and logic to back their positions.


And there’s nothing wrong with eating veggies in place of grains... provided you can get enough carbs from veggies and fruits to keep from feeling hungry and to keep your glucose-fueled brain running.


But the grain-averse seem unaware of the results of recent research, which revealed that unrefined wheat, corn, barley, and rye are amazingly rich in polyphenolsthe class of antioxidants found in colorful fruits and vegetables, tea, cocoa proven to help prevent premature aging and major diseases.


(For the details, see our “Corn beats spinach” sidebar. Buckwheat is also high in antioxidants, but it’s actually a fruit seed related to rhubarb … not a grain at all)


It turns out that whole grainseven cornrival colorful fruits and vegetables in terms of antioxidant content.


We’ve had clues to the antioxidant potential of whole grains, thanks to epidemiologic studies indicating that intake of whole grains reduces inflammatory chemicals in the blood.


(Refined grains raise blood levels of these same “inflammatory markers”, because they contain nothing much aside from starch, which spikes blood sugar levels: an effect known to induce inflammation.)


One short-term clinical study even showed reductions in oxidative stress and inflammatory factors in subjects consuming lots of whole grains (Jang Y et al 2001).


That outcome was one researchers would expect to see in people eating abundant amounts of polyphenol antioxidants, which act as anti-inflammatory influences on genetic switches in our cells.


The results of a recent study lend strong support to the preventive-health potential of whole, unrefined grains, and affirm that their antioxidants are essential to their benefits.


The new findings apply only to whole grains and whole grain flours, because virtually all of the antioxidants in grains occur in the outer layers, which get stripped off during the milling of grain into white flour.


Let’s take a look at the grain-boosting research.


Whole-grainy diets may reduce inflammation-related deaths

Intriguing findings flow from a recent analysis of data from the famed Iowa Women’s Health Study, in which researchers followed 27,312 postmenopausal women (between 55 to 69 years old) for 17 years.


For the new study, Dr. David Jacobs, Jr. and colleagues from University of Minnesota joined with researchers from the University of Oslo, Norway to study data from the Iowa investigation.


Compared with women who rarely or never ate whole-grain foods, those who consumed whole grain foods often were much less likely to die from an inflammation-related problem.


And these results came despite that fact that they excluded two major inflammation-related conditions: cardiovascular disease and diabetes.

They excluded these big diseases to see whether whole grains would positively impact risk of dying from diseases affected positively by antioxidant, anti-inflammatory agents like the polyphenols in whole grains but indifferent to high fiber intake.


The researchers defined eight categories of inflammation-related disease that can lead to death, including infectious, nervous system, endocrine (hormonal/glandular), nutritional, metabolic, respiratory system (e.g., asthma), digestive system (e.g., Crohn’s and IBS), skin (e.g., psoriasis, eczema), musculoskeletal (e.g., rheumatoid arthritis, scleroderma), and genito-urinary diseases.


These were the remarkable reductions in risk of inflammation-related death recorded in women who reported various levels of whole grain consumption:

  • 4 to 7 servings per week = 31 percent risk reduction
  • 7.5 to 10.5 servings per week = 21 percent risk reduction
  • 11 to 18.5 servings per week = 36 percent risk reduction
  • 19 servings per week = 34 percent risk reduction

The authors noted that a variety of antioxidants and other phytochemicals in whole grains directly or indirectly inhibit oxidative stress caused by free radicals, which both induce and are generated by inflammation.


Unsurprisingly, they hypothesized that the most likely explanation for the protective effects of whole grains resulted from reductions in oxidative stress and inflammation brought about by the antioxidants in whole grains.


So by all means, enjoy berries and red peppers… but have some oatmeal under the former and some wheat berries with the latter. Bon appetit!



Sources

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