Girls take note: Corn fiber can strengthen bones
Many older women suffer hip fractures, from which they may never fully recover. Thin and brittle bones can put them at risk for such breaks. And that risk may trace all of the way back to childhood. That’s when much of a woman’s bone is built up. Not surprisingly, girls are often told to consume plenty of milk and other sources of bone-building calcium. Now a study finds that teens and women could boost the value of that calcium even more by also eating foods rich in soluble corn fiber.
“You build about half of your adult bone mass in adolescence," says Connie Weaver. She heads nutrition science at Purdue University in West Lafayette, Ind. Once women hit menopause (typically between 45 and 52 years of age), their bones can rapidly lose mass (thin), she notes. So Weaver’s team led two new studies to look at the role soluble corn fiber might play in limiting that. Many processed foods already contain this fiber. These include protein bars, cereals and frozen desserts. It’s added to boost the fiber content of these foods.
For their study in 11- to 14-year-old girls, the researchers included the fiber in muffins and fruit drinks. The trial was divided into three parts. At some point, each of the 28 girls cycled through every 4-week phase. During those phases, the girls got drinks and muffins that provided either 0, 10 grams or 20 grams of extra corn fiber per day. The girls were free to exercise or eat anything else throughout the trial.
The researchers also fed the girls calcium along with their breakfasts and injected some of this mineral directly into their blood. The calcium in blood is completely absorbed by the body. But calcium in the diet is only partly absorbed as it passes through the gut. What isn’t taken up will be excreted in urine. By comparing the amounts of calcium in urine and blood, the researchers were able to calculate how much of this bone-building mineral each girl had absorbed in each phase of the trial.
This was a double blind study. That means that until the experiment ended, nobody — neither the participants nor the researchers — knew which phase of the trial a patient was in (and what fiber dose a girl was getting).
The researchers compared calcium absorption from the fiber-rich diets to the four-week phase when they got no bonus fiber. This showed that the girls absorbed around 13 percent more calcium during the bonus 10 and 20-grams-per-day phases. Moreover, their stool samples showed this was happening because gut microbes were breaking down this fiber into short-chain fatty acids. Those fatty acids are known to aid calcium uptake.
The findings appear in the July Journal of Nutrition.
Older women also benefit from this fiber
For the second trial, Weaver’s team recruited 14 post-menopausal women into a 50-day-long double-blind study. As with the girls, these women got calcium injections and foods with an extra 0, 10 or 20 grams of soluble corn fiber. And these participants, too, got similar benefits from the fiber. This research appeared online July 17 in the American Journal of Clinical Nutrition.
With an extra 10 grams of the fiber each day, the women lost 4.8 percent less calcium, as measured in their urine. Since that calcium comes from bone, this indicated the women were slowly losing bone mass with their regular diet. When the women got an extra 20 grams of corn fiber daily, they preserved even more of their bone — 7 percent more than when they were on their regular diet.
Weaver hopes the study will make women more aware of bone health. “Your choices —exercise and what you eat — matter for bones,” she says.
Jeri Nieves studies bone health at Columbia University in New York City. She says the new studies were well conducted. But although soluble corn fiber appears to be safe, she would not yet recommend people start adding high quantities of it to their diets. For that, we would need more studies.
She also would like to see studies try to confirm bone benefits, such as improvements in bone strength or density, from long-term consumption of this fiber.
(for more about Power Words, click here)
adolescence A transitional stage of physical and psychological development that begins at the onset of puberty, typically between the ages of 11 and 13, and ends with adulthood.
calcium A chemical element which is common in minerals of the Earth’s crust and in sea salt. It is also found in bone mineral and teeth, and can play a role in the movement of certain substances into and out of cells.
clinical (in medicine) A term that refers to diagnoses, treatments or experiments involving people.
density The measure how condensed an object is, found by dividing the mass by the volume.
diet The foods and liquids ingested by an animal to provide the nutrition it needs to grow and maintain health
double-blind study A study in which neither the participants nor their doctors (or other people administering the study) know who is receiving a potentially therapeutic treatment.
fatty acid A large molecule made of up chains of carbon and hydrogen atoms linked together. Fatty acids are chemical building blocks of fats in foods and the body.
fiber Something whose shape resembles a thread or filament of some kind. (in nutrition) Components of many fibrous plant-based foods. These so-called non-digestible fiber tends to come from cellulose, lignin, and pectin — all plant constituents that resist breakdown by the body’s digestive enzymes.
fracture (noun) A break. (verb) To break something and induce cracks or a splitting apart of something.
fruit A seed-containing reproductive organ in a plant.
journal (in science) A publication in which scientists share their research findings with the public. Some journals publish papers from all fields of science, technology, engineering and math, while others are specific to a single subject. The best journals are peer-reviewed: They send out all submitted articles to outside experts to be read and critiqued. The goal, here, is to prevent the publication of mistakes, fraud or sloppy work.
mass A number that shows how much an object resists speeding up and slowing down — basically a measure of how much matter that object is made from.
menopause The time in an older woman’s life that occurs following the permanent end of her menses (periods). It can occur at any point during a woman’s 40s or 50s, but is usually around age 51. It happens as the production and cycling of reproductive hormones wanes, ending her ability to bear children. And there may be symptoms that show up for months or years, such as hot flashes (where the body’s thermostat goes haywire and can lead to sweating for no reason), and emotional symptoms that can disrupt sleep, lower a woman’s energy level or trigger anxiety or sadness.
mineral The crystal-forming substances, such as quartz, apatite, or various carbonates, that make up rock. (in physiology) The same chemicals that are needed by the body to make and feed tissues to maintain health.
nutrition (adj. nutritious) The healthful components (nutrients) in the diet — such as proteins, fats, vitamins and minerals — that the body uses to grow and to fuel its processes.
online A term that refers to things that can be found or done on the Internet.
post-menopausal An adjective for the later stage in a woman's life, the years following menopause.
processed foods Foods purchased from a grocery story that are substantially different from the raw materials that went into them. Examples include most foods that come in cans, bottles, boxes or bags. Examples include breakfast cereals, frozen pizzas, canned tuna, jars of spaghetti sauce and dill pickles.
risk The chance or mathematical likelihood that some bad thing might happen. For instance, exposure to radiation poses a risk of cancer. Or the hazard — or peril — itself. Among cancer risks that the people faced were radiation and drinking water tainted with arsenic.
soluble Some chemical that is able to dissolve some liquid. The resulting combo becomes a solution.
stool (in medicine) Another name for feces.
JOURNAL: C.M. Whisner et al. Soluble corn fiber increases calcium absorption associated with shifts in the gut microbiome: A randomized dose-response trial in free-living pubertal females. The Journal of Nutrition. Vol. 146, July 2016, p. 1298. doi: 10.3945/jn.115.227256.
JOURNAL: S.A. Jakeman et al. Soluble corn fiber increases bone calcium retention in postmenopausal women in a dose-dependent manner: A randomized crossover trial. The American Journal of Clinical Nutrition. Published online July 17, 2016. doi:10.3945/ajcn.116.132761.