Rice bran is the thin outer layer of a rice grain, removed during milling to produce the white rice most people eat. It makes up only 6 to 7% of the total grain by weight, but it contains a disproportionate share of the grain’s nutrients, healthy fats, and fiber. What looks like milling waste is actually one of the most nutrient-dense parts of the rice kernel, and it’s used in everything from cooking and supplements to animal feed and skincare.
Where Rice Bran Sits on the Grain
A whole rice grain has three main parts: the outer husk, the bran layer, and the starchy white endosperm at the center. The bran itself isn’t a single membrane. It’s made up of several sub-layers: the pericarp (the outermost skin), a seed coat beneath it, a thin layer called the nucellus, and finally the aleurone layer, which sits closest to the starchy core. The tiny germ, or embryo, of the grain is also removed along with the bran during milling.
When rice is processed into brown rice, only the husk is removed, leaving the bran intact. That’s why brown rice has its characteristic tan color, chewier texture, and higher nutritional value. Milling it further strips the bran away, producing white rice and generating rice bran as a byproduct. Globally, rice milling produces millions of tons of bran each year, most of it in Asia.
Nutritional Profile
Rice bran is unusually rich in fiber, fat, protein, and B vitamins for a grain component. Per 100 grams of crude rice bran, you get roughly 21 grams of dietary fiber, 13 grams of protein, and about 21 grams of fat. That fat content is what makes rice bran so calorie-dense compared to the starchy endosperm, and it’s also what creates the storage challenges discussed below.
The B-vitamin content is striking. A 100-gram serving provides 2.75 mg of thiamine (B1), 34 mg of niacin (B3), 4.07 mg of vitamin B6, and 7.39 mg of pantothenic acid (B5). It also delivers 781 mg of magnesium, a mineral many people don’t get enough of. These nutrients are largely absent from white rice, which is why white rice in many countries is artificially fortified after milling.
How It Compares to Wheat Bran
People often compare rice bran to wheat bran, and the two differ more than you might expect. Wheat bran is much higher in insoluble fiber, the kind that adds bulk and helps with regularity, at about 49% compared to rice bran’s 24%. Rice bran, on the other hand, has nearly double the soluble fiber of wheat bran (2.7% versus 1.5%). Soluble fiber is the type linked to cholesterol reduction and steadier blood sugar levels.
Rice bran also has significantly more fat and a wider range of bioactive compounds. It’s the better source of magnesium and several B vitamins, while wheat bran tends to be the go-to for pure fiber content. For people with gluten sensitivity, rice bran has the obvious advantage of being naturally gluten-free.
Bioactive Compounds and Heart Health
What sets rice bran apart from most grain byproducts is a compound found almost exclusively in rice: a potent antioxidant that works through multiple pathways to lower cholesterol. It blocks cholesterol absorption in the gut, increases the body’s excretion of bile acids (which forces the liver to use up more cholesterol), and inhibits one of the key enzymes involved in cholesterol production, the same enzyme targeted by statin medications.
The clinical evidence is promising. One randomized, double-blind, placebo-controlled trial found that supplementation over three months reduced LDL (“bad”) cholesterol by 19.3% and increased HDL (“good”) cholesterol by 29.3% in adults with mildly elevated cholesterol. Animal studies have shown similar effects, with reduced blood triglycerides and lower overall fat synthesis. Some of these benefits appear to work through changes in gut bacteria, which influence how the body processes amino acids and lipids.
Rice bran also contains compounds that influence arterial health directly, acting on the inflammatory and oxidative pathways involved in plaque buildup. This combination of cholesterol-lowering and anti-inflammatory properties is why rice bran oil has gained popularity as a cooking oil in parts of Asia.
Uses in Skincare
Rice bran has a long history in East Asian skincare, and modern research has started to explain why. The bran contains a mix of antioxidants, healthy fats, and plant compounds that protect skin from UV damage and pollution by neutralizing the reactive molecules that accelerate aging. Rice bran extract has been shown to strengthen the skin’s lipid barrier, reducing water loss and improving hydration and smoothness.
In laboratory studies, rice bran extract boosted the production of type I collagen in skin cells and increased elastin content in skin tissue. Mice treated with the extract showed a 10% increase in skin collagen and more than a 10% improvement in skin moisture and elasticity compared to untreated groups. Fermented versions of the extract have also shown the ability to reduce melanin production and suppress inflammatory signaling, making them useful for uneven skin tone and inflammatory skin conditions.
Use in Animal Feed
The vast majority of rice bran produced globally goes into animal feed rather than human food. It’s a cost-effective energy source for livestock, particularly in rice-growing regions where it’s abundant. In dairy cows, full-fat rice bran serves as a concentrated fat source that can increase milk yield, milk fat content, and body weight. Calves supplemented with defatted rice bran gain more weight than unsupplemented calves.
In horses, rice bran has been a staple in high-energy feed formulations for decades, particularly in Australia. Its energy density, between 14.3 and 15.5 megajoules per kilogram of dry matter, makes it useful for performance animals that need calorie-dense feed without excessive bulk. One consideration for livestock producers is that the fat in full-fat rice bran can interfere with fiber digestion, so defatted versions are sometimes preferred when the goal is better forage utilization rather than raw calorie supplementation.
Why It Spoils Quickly
The biggest challenge with rice bran is that it goes rancid fast. In the intact grain, the fat-digesting enzymes (lipases) are concentrated in the seed coat while the oil is stored separately in the aleurone layer and germ. Milling breaks this separation. The enzymes immediately contact the oil and start breaking it down into free fatty acids, producing off-flavors and reducing nutritional quality. Mold and bacteria on the grain surface accelerate the process further.
Without stabilization, rice bran can become rancid within hours to days of milling. This is the main reason rice bran has historically been treated as waste rather than food. Stabilization typically involves heat treatment to deactivate the lipase enzymes. Extrusion, where the bran is pushed through a heated chamber, is the most common method. Temperatures between 120 and 130°C for as little as 20 to 30 seconds are enough to inactivate the enzymes. Dry heating at 120°C for 30 minutes achieves a similar result. Once stabilized, rice bran can be stored for months and used in food products.
If you’re buying rice bran for cooking or supplementation, look for products labeled “stabilized.” Unstabilized rice bran will taste bitter and lose its nutritional value rapidly.
Arsenic Considerations
Rice is known to accumulate arsenic from soil and water more readily than most grains, and the bran layer tends to concentrate it more than the inner starchy portion. The FDA has conducted risk assessments on arsenic in rice products, focusing on the long-term cancer risks to the lungs and bladder from inorganic arsenic exposure. The agency has set action levels for arsenic in infant rice cereals, which are the products of greatest concern because of the vulnerability of young children.
For adults eating rice bran in moderate amounts, this is generally not a major concern. But if you’re consuming rice bran daily as a supplement, it’s worth choosing products from manufacturers that test for heavy metals, and varying your grain sources rather than relying exclusively on rice-based products.