Nec­es­sary roughage

Fiber has slipped un­der diet-trend radar re­cently, but it’s still cru­cial to good health

Northwest Arkansas Democrat-Gazette - - STYLE - DAVID TEM­PLE­TON

Di­etary fiber is so 20th cen­tury.

Im­por­tant re­search pub­lished and widely pub­li­cized in the 1970s, ’80s and ’90s high­lighted fiber’s role in re­duc­ing the risk of heart dis­ease, Type 2 di­a­betes, gas­troin­testi­nal dis­or­ders in­clud­ing di­ver­ti­c­uli­tis, and some can­cers — all while help­ing to con­trol weight. Save the world with fiber.

Here in the 21st cen­tury, fiber no longer gets the at­ten­tion it once com­manded — save for the oc­ca­sional fiber bar com­mer­cial. The spot­light now has shifted to the long list of plant foods in­clud­ing whole grains, nuts, fruits and veg­eta­bles that con­tain di­etary fiber.

The prob­lem is, peo­ple never go to restau­rants and or­der fiber nuggets, or buy a bag of frozen in­di­gestible roughage at the gro­cery store. By eat­ing more fruits, veg­eta­bles, legumes and whole grains, peo­ple, by de­fault, in­crease fiber con­sump­tion.

And, yet, the U.S. Depart­ment of Agri­cul­ture still des­ig­nates di­etary fiber as “a nu­tri­ent of con­cern.” The av­er­age con­sump­tion rate of 14 to 16 grams a day is not the rec­om­mended lev­els of 25 grams for women and 33 grams for men. Fewer than 10 per­cent of Amer­i­cans con­sume the rec­om­mended lev­els.

Some sources sug­gest 50 grams a day, twice the cur­rently rec­om­mended lev­els, which would re­flect the lev­els at­tained by whole-plants-munch­ing ve­gans. For ex­am­ple, a

2015 study led by Stephen O’Keefe, a pro­fes­sor of medicine at the Univer­sity of Pitts­burgh School of Medicine, showed re­duc­tions in colon can­cer among South Africans who reg­u­larly con­sumed 50 grams of fiber daily vs. the 10-gram level of black Amer­i­cans, who

also were con­sum­ing ex­cess lev­els of meat and fat.

Peo­ple also con­tinue to ig­nore the cho­rus of mes­sages from sci­en­tists, health of­fi­cials and gov­ern­ment agen­cies that Amer­i­cans need more di­etary fiber.

“It’s a good topic to bring to the sur­face that’s flipped be­low the radar screen and needs to be pulled up again,” said David J. Jenk­ins, who holds the hon­orific po­si­tion of “univer­sity pro­fes­sor” at the Univer­sity of Toronto. He de­vel­oped the Glycemic In­dex, which as­signs num­bers to foods to give con­sumers a way to tell slower-act­ing “good carbs” (such as veg­eta­bles and whole grains, which keep blood sugar sta­ble) from the faster “bad carbs” (such as white bread and re­fined su­gars, which cause blood sugar to shoot up).

Peo­ple shouldn’t be think­ing of eat­ing a cer­tain num­ber of grams of fiber, he says. “They should be think­ing about eat­ing more fiber-rich foods.”


Once you eat car­bo­hy­drates, pro­teins and fats, the body uses them or ends up own­ing them as fat cells. But you only rent the fiber that bulks up food with­out adding calo­ries.

It serves as a gas­troin­testi­nal cleaner that car­ries out de­bris when its in­testi­nal jour­ney is com­pleted.

Too lit­tle fiber causes con­sti­pa­tion — “the most com­mon gas­troin­testi­nal com­plaint

in the United States, and con­sump­tion of fiber seems to re­lieve and pre­vent con­sti­pa­tion,” states a re­port by the Har­vard T.H. Chan School of Pub­lic Health.

In the past two years, var­i­ous stud­ies have shown other ben­e­fits of di­etary fiber.

One study con­firmed di­etary fiber to be a pri­mary method of pre­ven­tion for car­dio­vas­cu­lar dis­ease with re­duc­tions in sys­tolic blood pres­sure — the higher num­ber — and lower choles­terol lev­els, es­pe­cially LDL choles­terol, of­ten de­scribed as bad choles­terol.

A Jan­uary 2016 study in the Jour­nal of Di­a­betes In­ves­ti­ga­tion found higher in­take of fruits and var­i­ous veg­eta­bles, es­pe­cially berries and green leafy veg­eta­bles, with fiber as a key fac­tor in low­er­ing risk for Type 2 di­a­betes. In June 2016, a study found that di­etary fiber po­ten­tially could help in­flam­ma­tory bowel dis­ease. A meta-anal­y­sis of re­search in Jan­uary found that high fiber in­take re­duces the risk of pan­cre­atic can­cer.

In De­cem­ber, an­other study found an as­so­ci­a­tion be­tween di­etary fiber con­sump­tion and an over­all re­duced risk of breast can­cer, par­tic­u­larly in post­menopausal women.

Joanne Slavin, a reg­is­tered di­eti­tian and pro­fes­sor of food science and nu­tri­tion at the Univer­sity of Min­ne­sota, preaches the ben­e­fits of fiber-rich foods. She headed the Car­bo­hy­drate Com­mit­tee and served on the pro­tein sub­com­mit­tee for the U.S. Depart­ment of Agri­cul­ture 2010 Di­etary Guide­lines Sci­en­tific Ad­vi­sory Com­mit­tee. She says the rec­om­mended 25 daily grams of fiber for women likely will be in­creased even­tu­ally to 28 grams — twice the av­er­age con­sump­tion.

But reach­ing such lev­els re­quires con­scious ef­fort.

“So, def­i­nitely there is a lack of fiber in the diet,” she said. “Most plant foods only have 1 to 3 grams of fiber, so un­less you eat a lot, it is dif­fi­cult to con­sume 25 grams per day.”

She said, how­ever, that calo­rie in­take in the United

States is de­clin­ing (in pop­u­la­tion­wide statis­tics, not nec­es­sar­ily among in­di­vid­u­als), along with ap­par­ent sta­bi­liza­tion of the obe­sity epi­demic. That’s good news. The down­side is that fewer calo­ries most likely also mean de­clin­ing fiber con­sump­tion.

“So any tools to help with weight loss or avoid­ance of weight gain — such as high fiber di­ets — are im­por­tant mes­sages,” she said.

Only plant-based foods con­tain di­etary fiber.

Choles­terol ex­ists only in an­i­mal-based foods, in­clud­ing dairy, meat and eggs. To com­plete the cy­cle, sol­u­ble fiber from plant foods works in the hu­man gut to elim­i­nate choles­terol in­gested from an­i­mal-based foods.


A rel­a­tively new branch of nu­tri­tion science re­search is at­tempt­ing to un­der­stand the com­pli­cated bio­chem­istry of the gut “microbiome” — the mi­croflora, which in­clude nu­mer­ous types of bac­te­ria, liv­ing within the hu­man di­ges­tive tract. Where once upon

a time all “bac­te­ria” were as­sumed to be pathogens to be com­bated, to­day’s views have evolved to con­sider most of the mi­crobes we live with as friendly.

A large part of hu­man stool is bac­te­ria gen­er­ated by fiber, which is an in­di­gestible car­bo­hy­drate that serves as bac­te­rial food. Friendly and un­friendly bac­te­ria feed on foods we eat, with the im­mune sys­tem also in­volved as bor­der con­trol, work­ing to pre­vent tox­ins and pathogens from get­ting into the liver or blood­stream.

So health­ful foods can be re­de­fined as those that feed our friendly bac­te­ria.

Fiber also serves as an in­testi­nal bouncer, ush­er­ing tox­ins, pathogens and choles­terol out the back door, var­i­ous gov­ern­ment and re­search sources re­port.

“We are very in­ter­ested in the ef­fects of fiber on the gut — stool weight, changes in the gut, mi­croflora and tol­er­ance to dif­fer­ent fibers,” said Slavin, who holds a Ph.D. in nu­tri­tional sciences.


Fiber sup­ple­ments such as Me­ta­mu­cil con­tain psyl­lium, a fiber that serves as a lax­a­tive while low­er­ing blood lipids (choles­terol), she said. Eat­ing plants pro­vides the full reg­i­men of fiber, an­tiox­i­dants, vi­ta­mins and min­er­als, among other nutri­ents.

While fiber bars con­tain in­ulin, an­other good fiber found in chicory roots and agave, she cau­tioned that they also in­clude added sugar and fat, with high calo­ries.

“So they might be a good choice as an in­dul­gent treat,” she said. “But it’s im­por­tant to get rec­om­mended amounts of legumes, whole grains, veg­eta­bles and fruits, too.”

Re­searchers nowa­days bat­tle over whether fiber is health­ier in nat­u­ral or re­fined form, with pectin, the fiber in ap­ples, ac­tu­ally show­ing more health­ful ben­e­fits when re­fined into the gummy gel found in jams, Jenk­ins said.

Still, an ap­ple eaten off the tree re­mains a health­ful source of fiber.

And in the end, he said, it comes down to advising peo­ple to eat foods with fiber, rather than fiber it­self. Af­ter all, this is the 21st cen­tury.

“We should eat more fiber, but peo­ple don’t ac­tu­ally eat fiber,” he said. “They eat bread and beans. You should eat a serv­ing of beans every day. Eat oat bran with berries and nuts for break­fast. Cut out the white flour and have whole wheat in­stead and have an ap­ple a day to keep the doc­tor away. If you do that, you will get more use­ful amounts of fiber and could get some­thing in the or­der of 25 to 30 grams.”

Arkansas Demo­crat-Gazette/NIKKI DAWES

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