On Nutrition
It’s an often-repeated nutrition fact: Most people in the U.S. aren’t eating enough fiber. Depending on age and sex, adults need 21 to 38 grams per day, but only 4% meet those recommendations. Most adults consume about half the recommended amount, even though fiber-rich diets have numerous health benefits, including better gut health, and reduced risk of heart disease, diabetes and some forms of cancer.
If you know you could stand to up your fiber game, but those health benefits haven’t felt sufficiently motivating, here’s a new reason — microplastics. It seems that everywhere you turn, there’s more bad news about microplastics, and scientists have detected them in human blood, saliva, and multiple organs and tissues, including the heart and brain.
Research on potential health impacts of microplastics is in the very early stages, but it appears they may contribute to inflammation, an impaired immune system, and cell and organ damage. While some microplastics are intentionally created for products such as facial scrubs and toothpastes, most come from the breakdown of plastic products, including plastic bags and single-use containers, synthetic textiles, paint and tires. Like it or not, microplastics are ubiquitous in our environment, in the air we breathe, the food we eat and the water we drink.
How can you counteract that reality? Making sure you’re eating enough fiber is one place to start. It’s long been known that dietary fiber can help usher unwanted substances out of our intestines so we can excrete them, and emerging research suggests this is also true with microplastics. Also, consuming adequate fiber can improve the health and integrity of the intestinal lining, which may prevent microplastics from passing through the intestinal wall and into our blood, tissues and organs.
Fiber is found in fruits, vegetables, whole grains and pulses (dry beans, lentils, chickpeas and dry peas), and all these foods offer a wealth of additional nutrients we need for good health. One of the easiest ways to up fiber intake is to add more pulses — a half cup has almost 8 grams of fiber, compared with less than 2 grams in a half-cup of brown rice — which also serve as a source of protein. In its scientific report, the 2025 Dietary Guidelines Advisory Committee recommended increasing intake of pulses to as much as three cups per week, in lieu of some servings of starchy vegetables and possibly animal-based protein.
Ready to start upping your fiber intake? Start slowly. Increasing dietary fiber from any source has the potential to create some digestive discomfort or distress. We have gut microorganisms that specialize in digesting fiber, and if your intake is low, there can be an adjustment period while your microbe population shifts to accommodate the changes.
Fiber may help mitigate your exposure to microplastics, but you can also take steps to reduce your exposure. The best thing you can do is to stop microwaving food in plastic containers. From there, you can opt for reusable stainless steel or glass water bottles whenever possible and transition to glass food storage containers and wood or bamboo cutting boards. There’s been concern about the impact of plastic cooking utensils, but we actively degrade the surface of plastic cutting boards every time we use them.
The idea of plastic particles in our brains — and elsewhere — is weird, scary, maybe even gross. We can’t turn back time, but by eating more fiber and reducing our use of plastic in the kitchen, we can make choices that may benefit our health and the environment in countless ways.
Carrie Dennett: CarrieOnNutrition@gmail.com. CarrieOnNutrition@gmail.com; on Instagram: @CarrieDennett. Carrie Dennett, MPH, RDN is a registered dietitian nutritionist at Nutrition By Carrie, and author of “Healthy For Your Life: A non-diet approach to optimal well-being.” Visit her at nutritionbycarrie.com.