Rice bran is the outer coating of a rice grain, removed during milling to produce white rice. It makes up only 6 to 7 percent of the grain’s total weight, but it contains a disproportionate share of the grain’s nutrients: healthy fats, fiber, protein, and a range of antioxidants. Most people encounter rice bran as an oil, a supplement, or an ingredient in animal feed, though it’s increasingly showing up in health foods and skincare products.
Where Rice Bran Sits on the Grain
A whole rice grain has several layers. The outermost is the hull (or husk), which is inedible and removed first. Beneath that sits the bran, a thin but nutrient-dense shell made up of four sub-layers: the pericarp, seed coat, nucellus, and aleurone. Beneath the bran is the starchy endosperm, which is what you eat as white rice. Brown rice still has its bran intact, which is why it’s darker, chewier, and more nutritious than white rice.
When mills strip the bran away, the resulting byproduct is a fine, tan-colored powder with a slightly nutty flavor. Globally, rice milling generates millions of tons of this byproduct every year, and only a fraction of it ends up in human food.
Nutritional Profile
Per 100 grams, raw rice bran contains about 316 calories, 13 grams of protein, 21 grams of dietary fiber, and roughly 21 grams of fat. That fat content is worth a closer look. Only about 4 grams are saturated; the rest splits nearly evenly between monounsaturated fat (7.5 grams) and polyunsaturated fat (7.5 grams), a ratio that’s generally favorable for heart health.
Rice bran is also rich in B vitamins, magnesium, manganese, and phosphorus. But what sets it apart from other grain byproducts is its collection of bioactive compounds, particularly one called gamma-oryzanol, a mixture of antioxidants found almost exclusively in rice bran. These compounds are a major reason rice bran oil has attracted interest in nutrition research.
Heart Health and Cholesterol
The most studied health benefit of rice bran relates to cholesterol. In clinical trials, rice bran oil reduced LDL (“bad”) cholesterol by about 7 percent in moderately hypercholesterolemic adults, without lowering HDL (“good”) cholesterol. Interestingly, defatted rice bran (the fiber left after the oil is extracted) did not have the same effect. The cholesterol-lowering action comes from compounds in the oil itself, not the fiber.
A randomized controlled trial focusing on gamma-oryzanol found even larger reductions. Participants consuming rice bran oil with higher concentrations of gamma-oryzanol saw LDL drop by up to 12 percent, along with significant improvements in antioxidant capacity. These effects suggest that rice bran oil may help reduce cardiovascular risk factors, particularly for people with elevated cholesterol.
Blood Sugar and Gut Health
Rice bran’s fiber and phenolic compounds also influence blood sugar. In animal studies, the phenolic compounds bound to rice bran fiber activated insulin signaling pathways in muscle tissue, helping cells absorb glucose more effectively. These same compounds shifted the composition of gut bacteria, encouraging the growth of species that produce butyrate, a short-chain fatty acid that supports gut lining health and may improve metabolic function. Human research in this area is still limited, but the mechanisms are consistent with what’s known about high-fiber, polyphenol-rich diets.
Skin and Cosmetic Uses
Rice bran has a long history in East Asian skincare, and modern research has started to validate some of those uses. The bran contains phenolic compounds, squalene (a natural moisturizer), and other plant compounds that show anti-aging, anti-inflammatory, and photoprotective properties in lab and clinical testing. Rice bran extracts appear in serums, moisturizers, and cleansers marketed for skin brightening and UV protection. Rice bran oil’s light texture and mild scent also make it a practical carrier oil in cosmetic formulations.
Rice Bran Oil for Cooking
Refined rice bran oil has a smoke point of about 232°C (450°F), which places it among the better options for high-heat cooking like stir-frying and deep frying. It has a clean, neutral flavor that doesn’t overpower food. In parts of Asia, particularly India and Japan, it’s a staple cooking oil. Its fatty acid profile is similar to peanut oil but with the added benefit of gamma-oryzanol and other antioxidants that aren’t present in most other cooking oils.
The Rancidity Problem
Fresh rice bran has a serious practical limitation: it goes bad fast. The bran contains 15 to 20 percent oil by weight, and it’s also loaded with enzymes called lipases that immediately start breaking down that fat once milling exposes it to air. Free fatty acids accumulate within hours, producing off-flavors and reducing nutritional value. Without treatment, raw rice bran becomes rancid in days.
This is why stabilization is essential. Heat treatment (using steam, dry heat, or microwave energy) deactivates the lipase enzymes and extends shelf life to roughly six months. If you buy rice bran as a food product, it should be labeled as stabilized. Unstabilized rice bran is typically diverted to animal feed or oil extraction, where rancidity matters less.
Phytic Acid and Mineral Absorption
Rice bran contains high levels of phytic acid, ranging from about 1,800 to 3,200 milligrams per 100 grams depending on the variety. Phytic acid binds to minerals like calcium, iron, and zinc in the digestive tract, reducing how much your body can absorb. The inhibitory effect is strongest for calcium, followed by iron and then zinc. This is one reason why diets very high in unprocessed bran can sometimes contribute to mineral deficiencies, particularly in populations that rely heavily on rice as a staple and have limited dietary diversity.
Soaking, fermenting, or sprouting can reduce phytic acid levels. If you’re adding rice bran to smoothies or baked goods as a fiber supplement, this is worth keeping in mind, though moderate amounts in the context of a varied diet are unlikely to cause problems.
Arsenic Concentrations
One safety consideration that often gets overlooked: arsenic in rice accumulates preferentially in the bran. Rice bran contains 72 to 98 percent more inorganic arsenic than the white rice endosperm, and that increase is predominantly the more toxic inorganic form. This is the same reason brown rice has higher arsenic levels than white rice. For most people eating rice bran occasionally, this isn’t a major concern, but it’s relevant for anyone consuming large amounts of rice bran daily, or for products intended for infants and young children, who are more sensitive to arsenic exposure.