Travel & Lifestyle: How Dietary Fiber Can Help Your Longevity

Carbohydrates have long been seen as the villain — the macronutrient worth fearing and restricting — while another reigns supreme as the “healthier” option in the given cultural moment. Today, that’d be protein.

This perspective and the resulting constraints don’t come without problems. “If we are just focusing on one specific [nutrient] without looking at the bigger picture, then we will end up having some blind spots,” said Abby Chan, an anti-diet registered dietitian. “If we’re only focusing on protein, unless it’s plant-based, we’re going to be limiting the overall diet quality and variety that we’re taking in.”

It’s time to reframe. Carbohydrates are essential to your body’s proper functioning, as they’re broken down into glucose, the primary energy source for your cells, tissues, brain, muscles and other organs. And new research shows that certain types of carbs may be linked with healthy aging.

The investigation, published in JAMA Network Open, looked at the midlife diets of more than 47,500 women in the 1980s, as well as their health outcomes roughly 30 years later, using data from Nurses’ Health Study questionnaires. Of the studied population, 7.8% met the definition of “healthy aging.” These women lived to age 70 and were free from 11 major chronic diseases, had no memory or physical function impairments, and had good mental health.

Carbohydrates were one of the most influential factors. Consuming more total carbohydrates and more “high-quality” carbs (from foods like whole grains, fruits, vegetables and legumes) during midlife was positively linked with healthy aging. On the flip side, consuming more “refined” carbs (from added sugars, refined grains like white flour, etc.) was linked with lower odds of healthy aging.

“We’ve all heard that different carbohydrates can affect health differently, whether for weight, energy or blood sugar levels,” Andres Ardisson Korat, the lead author of the study, said in a press release. “But rather than just look at the immediate effects of these macronutrients, we wanted to understand what they might mean for good health 30 years later. Our findings suggest that carbohydrate quality may be an important factor in healthy aging.”

It sounds ground-breaking, but according to Chan, the research simply adds to a growing list of studies showing that dietary fiber — a type of carbohydrate — is king.

“When we look overall at any sort of nutrition research, or if we’re comparing specific diets or things like that, the thing that typically always rings true is the fiber content of it,” Chan explained. “From an overall metabolic standpoint, from a cardiovascular standpoint, from just an overall health metric standpoint, fiber is going to be the one thing that’s going to be health-promoting in every single area.”

Fiber helps keep your bowel movements regular and feeds the beneficial bacteria (read: probiotics) that make up your gut microbiome, among other perks, said registered dietician Cary Kreutzer, an instructional professor of clinical gerontology and pediatrics at the USC Leonard Davis School of Gerontology. It’s also linked with reduced risk of cardiovascular disease and colon cancer and some improvements in cognitive function.

“If we don’t have fiber, then we’re going to be lacking and missing out on some of those really huge benefits,” Chan said. Getting your fill of carbs from fiber-rich whole grains, fruits and vegetables, beans and legumes, and nuts and seeds means you’ll also score essential vitamins and minerals (think: iron, B vitamins) that are health-promoting, she noted.

Though the study was produced by researchers affiliated with renowned institutions like Tufts University and Harvard T.H. Chan School of Public Health, there are some limitations to keep in mind. The study population was only female nurses, who were predominantly white and well-educated, so the findings may not be generalized to a more diverse population. The data also show connections — not clear cause and effect. “I think one of the issues with it is that when we’re looking at big cohorts of data like that, we can’t put people in a vacuum; we can’t put them in a room for 20 years,” Chan said. “So I would say it’s more of an associative effect.”

It’s important to consider how access might play a role in the results, too. “Is it, basically, the economic and financial and time privilege of those individuals that’s also creating some more of these positive health outcomes that we’re seeing, or is it just the whole grains? Obviously, in a longitudinal cohort study, we can’t really specifically study that,” Chan said.

Considering the well-studied benefits of fiber, however, it’s worth prioritizing in your diet. Fewer than 10% of Americans get the recommended amount of fiber each day (14 grams per 1,000 calories). To Chan, one of the simplest ways to amp up your intake is to flip your mindset. Ask yourself, “What can I add to my plate that’s beneficial?” rather than, “What can I cut out that’s ‘bad’?”

“When we look at our relationship with food, the more that we focus on what we shouldn’t be doing, the more we end up only thinking about that, and it becomes hyper-restrictive, and then we end up feeling guilty about the decisions that we make,” Chan said. Seek out ways to incorporate another fruit into your breakfast, veggie into your midday snack or whole grain (e.g., barley, farro, brown rice, quinoa) into your dinner.

Practice “eating the rainbow,” incorporating a mix of colorful plant-based foods into your meals to nab carbs, fiber and a variety of micronutrients, and look at food labels so you have a better idea of how much fiber you’re getting each day, Kreutzer suggested. Of course, chronic health conditions are multifactorial, and prioritizing fiber-rich foods is just one element of prevention. If you’re able, regularly meet with your health care provider to check your blood pressure, cholesterol and other metrics, she recommends.

Changing your eating habits can feel overwhelming and, to some middle-aged folks, too late to make a difference. But making small tweaks now could have a big impact on your health down the line. “I think many people think, ‘What’s going to happen to me is going to happen to me, and I don’t have control,’” Kreutzer said. “I think people need to know that they can make those changes now, and it potentially can add years to their life.”