Don’t confuse the message when it comes to fibre supplements and mineral absorption

Supplements work best if people take them—and directing patients to change the timing of taking fibre or mineral supplements might mean they forget to, one expert said. A common practice is to advise patients to wait a few hours between taking oral medication and fibre supplements, with an example is in the patient-focused Harvard Health publication. This same caveat is often given when it comes to mineral supplements.But there’s little clinical evidence supporting that advice, said Dr. Ines Pinto-Sanchez, a gastroenterologist at the digestive diseases clinic at Hamilton Health Sciences and associate professor of medicine at McMaster University in Hamilton, Ont.As fibre travels down the gastrointestinal tract, it traps various molecules, including sugars and fats, Dr. Pinto-Sanchez said. “It is true that other nutrients, for example iron, zinc, copper, may get trapped in this process.” But studies suggest that it might not have a clinically significant effect. A meta-analysis published in Critical Reviews in Food Science and Nutrition examined the effect of dietary fibre on iron absorption. It found no correlation between the consumption of dietary fibre and markers of iron absorption, such as hemoglobin or fractional iron absorption.This means that even if fibre traps some of the iron, “it’s not very clear if it has a clinically meaningful outcome.” Studies examining this issue are complicated because of so many factors at play. Other compounds in the diet can also either interfere with mineral absorption (e.g., phytates) or aid in mineral absorption (e.g., vitamin C). Telling patients to wait two- to three- hours between taking a mineral supplement and a fibre supplement (or consuming dietary fibre) could be problematic because then patients forget to take the second supplement. “Many patients get fixated in that separation and then they forget,” said Dr. Pinto-Sanchez.The benefits of fibre supplementation or increaing dietary fibre far outweigh any risk of limiting mineral absorption, Dr. Pinto-Sanchez said. There are numerous types of dietary fibre and fibre supplements and they provide various digestive, metabolic and cardiovascular benefits. Ideally, patients eat whole foods to profit from both the fibre and the minerals in those foods, said Jedid-Jah Blom, a registered dietitian at the digestive disease clinic at Hamilton Health Sciences. If patients are taking fibre supplements, they should take them with adequate fluids. “You always have to drink an extra glass of water with that,” Blom said.Some physicians may still suggest patients take mineral and fibre supplements at different times. Dr. Michelle Sholzberg, a hematologist at St. Michael’s Hospital in Toronto and associate professor at University of Toronto, said she would recommend taking a fibre supplement in the morning, and iron supplements at night. “There are a lot of things and medications, including fibre supplements, that can interfere with iron absorption,” she said “Yes, I would recommend that people avoid taking them at the same time.” she said. The iron needs in pregnancy are particularly important. Dr. Sholzberg said she advises patients taking prenatal supplements at a different time than iron supplements, because calcium and magnesium in the prenatal supplements interfere with iron absorption.

Don’t confuse the message when it comes to fibre supplements and mineral absorption

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