Clearing PFAS

How fiber might be the unsung hero against these forever chemicals

If you’ve spent the last few years swapping non-stick pans for cast iron, side eyeing fast food wrappers, and scrolling past the anxiety inducing headlines about “forever chemicals”… you’re not alone.

Per- and polyfluoroalkyl substances (PFAS for short) are a large family of fluorinated compounds that show up in everyday products such as non-stick cookware, stain-resistant fabrics, food contact paper, and firefighting foams. Because the carbon-fluorine bond is one of the strongest in organic chemistry, these chemicals resist heat, water, and biological breakdown. Once they reach the human body, they stay: common members like PFOA and PFOS persist for roughly two to six years, while PFHxS can remain even longer. In practical terms, the PFAS used to waterproof a jacket ten years ago can still be measurable in blood — a durability that has earned them the nickname “forever chemicals.”

The clinical worry isn’t theoretical. Across dozens of epidemiologic cohorts, higher PFAS burdens have been consistently linked to a vast list of health concerns:

Sufficient evidence of an association:

• Decreased antibody response to routine vaccinations (a marker of immune suppression)

• Dyslipidemia, especially higher total and LDL cholesterol

• Reduced infant and fetal growth (lower birth-weight/length)

• Increased risk of kidney (renal-cell) cancer in adults

Limited or suggestive evidence of an association:

• Breast cancer in adults

• Liver enzyme elevations

• Pregnancy-induced hypertension and pre-eclampsia

• Testicular cancer in adults

• Thyroid disease and dysfunction

• Ulcerative colitis

Public health fixes are under way like new federal drinking water standards and more states banning PFAS-laden foams, but remediation takes time and blood levels decline at a glacial pace. Clinicians have toyed with pharmacologic shortcuts like cholestyramine, a type of binder used for stubborn hyperlipidemia which can also bind to PFAS in the intestine and drags them out. But at the same time, long term use of this binder can leave patients constipated and vitamin-depleted.

So when a team of Canadian and U.S. researchers reported this spring that a simple oat β-glucan drink trimmed circulating PFAS after just four weeks (no prescriptions, no side effects!), this feels like a huge win in the war against PFAS.

Inside the Oat-Fiber Trial

The study, a secondary analysis of a double-blind cholesterol trial registered as NCT03911427, enrolled seventy-two middle-aged Canadian men battling elevated LDL. For a month each participant mixed three sachets of powder into water daily, drinking one with each meal. Half of the powders delivered rice starch and a tiny bit of fiber; the others supplied about eight grams of total fiber, including three grams of oat β-glucan (the same gelling polysaccharide credited with oatmeal’s heart-healthy benefits).

Researchers froze serum samples on day 0 and day 28, running a panel of seventeen PFAS congeners. In the control group (the low fiber rice starch powder), nothing budged. In the β-glucan group, the heavy hitters of PFAS (PFOS, PFOA, PFHxS, PFNA, PFDA, and even stubborn PFUnDA) dropped by meaningful margins, some more than ten percent in a single month!

Though the cohort was small and male only (shocking), the magnitude of the results impressed toxicologists because long-chain PFAS ordinarily tick downward only a few percent per year through natural renal filtration.

How did this oat concoction do it? Think of the oat fiber β-glucan as a soft, sticky sponge. When it mixes with water in your gut, it swells into a gel that grabs onto bile acids — the digestive “soap” your liver releases after you eat. PFAS molecules like to ride on these same bile acids. Once the gel locks onto the bile, it drags the PFAS along for the ride all the way to the toilet, instead of letting them cycle back into your bloodstream. It’s the same basic trick doctors use with the drug cholestyramine, just delivered by a bowl of oats instead of a chalky prescription powder.

Animal data back the mechanism too. In mice loaded with PFOS, β-glucan supplements accelerated fecal elimination and lightened liver triglyceride stores.

Still, critics had concerns: four weeks doesn’t confirm long term plateau effects and oat fiber was tested against a low-fiber placebo rather than ordinary North American diets (which quite frankly don’t hit recommended daily fiber intake anyway). But these two concerns raises the question: how much fiber would real humans need to eat in order to duplicate, or even exceeed, the pilot’s success?

The Fiber Gap and How to Close It

The Institute of Medicine’s Adequate Intake stands at 25 grams of total fiber for adult women and 38 grams for adult men. Yet NHANES data put the U.S. median around fifteen grams, meaning most of us operate at barely half the recommended amount.

The oat drink volunteers added only 6-8 grams of extra fiber, nudging their daily total toward but still shy of the official target. This is powerful evidence that even a modest increase in fiber consumption can impact PFAS. Nutritionist now wonder whether meeting the full RDA, especially with soluble fiber varieties, might double or triple that clearance of PFAS.

Food Sources of Fiber

Soluble, viscous (gel-forming)

• Oats & barley (β-glucan)

• Psyllium husk

• Beans & lentils

• Apples, pears, citrus flesh (pectin)

• Chia & flaxseed (mucilage)

• Okra, eggplant

Soluble, non-viscous (prebiotic)

• Inulin-rich chicory root, Jerusalem artichoke

• Garlic, leeks, onions

• Green bananas & plantains (resistant starch type 2)

• Cooked then cooled potatoes, rice or pasta (resistant starch type 3)

Insoluble

• Whole wheat bread

• Brown rice, quinoa, millet

• Nuts & seeds (almonds, walnuts, pumpkin seeds, etc)

• Carrot, beet, and sweet potatos

• Leafy greens, broccoli, cauliflower, celery

I always recommend adding a variety of different type of fibers into your diet to get the maximum health benefits. For your cheat sheet on what these different types of fibers help do: soluble viscous fibers help bind PFAS, insoluble fibers add stool bulk for better bowel movements and constipation prevention, and prebiotic fibers feed beneficial short-chain-fatty-acid–producing bacteria in the gut.

How to Pack in Fiber

• Overnight chia-oat pudding
  Rolled oats (β-glucan = soluble viscous + fermentable) stirred with chia seeds (soluble viscous mucilage + insoluble hull) in your milk of choice; refrigerate overnight and finish with berries for extra fermentable pectin.

• Green-banana cinnamon smoothie
  Blend one peeled green banana (resistant starch 2 = soluble non-viscous + fermentable) with almond butter, milk, protein powder, and a teaspoon of psyllium husk (soluble viscous).

• Lentil-barley stew
  Simmer green lentils (GOS = fermentable) and pearled barley (β-glucan) with tomatoes, carrots, and spinach; finish with lemon juice. The mix delivers viscous, non-viscous, fermentable, and plenty of insoluble vegetable fiber.

• Cooled potato–mustard salad
  Boil diced red potatoes, chill overnight to generate resistant starch 3 (soluble non-viscous + fermentable), then toss with Dijon, olive oil, and any other ingredients you love in a potato salad.

• Psyllium-flax breakfast waffle
  Add 1 Tbsp psyllium husk (soluble viscous) and 2 Tbsp ground flax (fermentable plus insoluble lignin) to your favorite waffle batter. Serve with a smear of almond butter and sliced apple for more pectin.

• Berry–pear crumble with oat-nut topping
  Bake mixed berries and diced pear (pectin-rich, fermentable) under a crumble of oat flour, rolled oats, chopped walnuts, and a touch of psyllium. Delivers viscous gel, fermentable pectin, and insoluble nut bran.

• Watermelon, Mint & Barley Tabbouleh

  Swap the traditional bulgur for quick cooking pearl barley (β-glucan = soluble viscous + fermentable). Fold chilled barley into diced watermelon, cucumber, chopped mint, and parsley. Dress with lemon and olive oil. The fruit adds fermentable pectin; the cucumber skins contribute insoluble crunch.

Where We Go From Here

Larger randomized trials are under way — one funded by the U.S. Department of Defense, keen to protect service members stationed on bases with PFAS-laced groundwater. Another trial by a European consortium exploring whether barley β-glucan can match or surpass its oat sibling.

These results can take time and the systemic changes will probably crawl by at a snail’s pace. I always advocate for making these beneficial health changes even if the data isn’t concrete — because even if it comes out that no, fiber doesn’t make that much of an impact on PFAS detox, we still know that there’s an incredible list of health benefits still associated with it.

We know higher fiber intake is associated with: steady blood sugar, healthy cholesterol and lipid ranges, food for gut bacteria that produce anti-inflammatory short-chain fatty acids, keeps digestion moving smoothly, and aiding in phase 3 detoxification of estrogen metabolites. All across the board it’s a win-win to increase fiber intake, and now there’s a chance it might hold a key to the ever pressing PFAS dilemma.