Return to story

Curb digestive woes with a high-fiber diet

August 20, 2006 5:31 am

Readers want to know how much fiber is enough, and whether soy is worth eating.

Q I know we need 25 to 35 grams of fiber a day. But how does a person determine what is exactly right? Is there an age or weight variable? What is the drawback to getting too much fiber?

--J.L., King George

AEating more fiber can help you avoid constipation and diverticulitis. It even reduces cholesterol levels and the risk of diabetes, according to the National Academy of Sciences.

People who eat more fiber are more likely to be normal weight than overweight, according to a study in the Journal of the American Dietetic Association this summer.

And healthy people who ate more than 35 grams of fiber daily for a year had better digestion. They reported less constipation and heartburn and no worse symptoms of gas and bloating than their peers. That's according to the Women's Healthy Eating and Living Study.

Talk with your doctor about fiber if you have digestive problems.

Generally, babies are the only people who don't need fiber. Breast milk has everything newborns need, and it doesn't have fiber. When a baby reaches 6 months old and starts eating solid foods along with breast milk (or formula), it's good to offer pureed vegetables and fruits, which have some fiber.

Children and adults need about 14 grams of fiber for every 1,000 calories they eat, which translates to 25 to 38 grams for most adults. National surveys show Americans eat half that amount.

If people choose high-fiber foods and adjust portions to their hunger level, they will naturally get enough fiber, without counting or doing math.

If that's too vague for you, aim for about two fist-size portions of high-fiber foods per meal. Whole grains, fruits, vegetables, beans and nuts are all rich in fiber.

Remember that refined foods like white bread, white rice, regular pasta, mashed potatoes, juice and sweets are low-fiber foods, so don't overdo them.

Balance your meal with a palm-size portion of low-fiber but protein-rich food, such as meat, chicken, fish, eggs, cheese, yogurt, milk or soy.

It's hard to overdo fiber from foods, so the National Academy of Sciences has not set any limits on fiber.

QI want to thank you again for all the nutrition tips you gave me in [the] spring--I have lost another 10 pounds and am down to 200 now instead of 210! I may try some more weight loss and get to 190.

I started using soy products about two years ago, and from what I read, it was good for your health! I recently read that there was no advantage to using soy. Was this a serious article or just an effort to kill the popularity of soy?

--Rachael Cubbage, Stafford

Note: Cubbage was featured in a story by me on April 30 that was part of a series of articles on people who kept food diaries, and sought my advice, in hopes of improving their eating habits.

ACongratulations on all your hard work! I remember that you are battling heart disease, high blood pressure and diabetes.

Studies show that you can improve your health and sometimes reduce the need for medicines with even a 5 percent to 10 percent weight loss, which would be 10 to 20 pounds. (But don't adjust your meds unless your doctor approves.) At any rate, it sounds like you are taking good care of yourself.

As for soy, scientists hotly debate it. We know soy is a source of high-quality, heart-healthy protein and has been shown to reduce cholesterol levels. For menopausal women, soy may reduce the length of hot flashes. It's not clear if soy actually strengthens bones or prevents cancer--there is some evidence that if soy is protective, it may be more so if eaten in adolescence. We just don't know.

Despite Internet rumors, it's not necessary for people with thyroid problems to avoid soy foods, according to the journal Thyroid.

In general, healthy people can safely enjoy soy foods and reduce their cholesterol levels.

Soy comes from soybeans. Asian cooks traditionally use soy foods such as soy sauce, miso soup, tempeh and tofu. Soy also is popular in vegetarian versions of familiar American foods such as soymilk, veggie burgers and soy hot dogs.

Soy foods are fine, according to the American Cancer Society. I don't recommend soy supplements, though, because they have much higher levels of natural isoflavones.

Researchers aren't sure if they prevent or increase cancer risks at these high doses. Hopefully, we will find the answer in the next few years.

The bottom line is that soy does have health benefits. It's just wise to realize that it isn't a miracle fix for heart disease, high cholesterol or any other problem.

If you like it, by all means keep eating it.

JENNIFER MOTL, a registered dietitian, welcomes reader questions via her Web site, brighteating.com, or mailed to Nutrition, The Free Lance-Star, 616 Amelia St., Fredericksburg, Va. 22401.