Wheat Bran & Wheat Germ: Nutrients, What Research Shows and Safety

Wheat bran and wheat germ are two parts of the wheat kernel (Triticum aestivum, grass family Poaceae) that are removed when white flour is made. Bran is the outer layer, very high in fiber. Germ is the small seed embryo, higher in protein and fat. They are sold as flakes or flour-like meal to stir into cereal, yogurt and baking. This page covers both as foods, and keeps them apart from whole wheat berries (whole wheat), whole-wheat bread and from supplements and hype. Both come from wheat, so gluten and wheat allergy come first below.

Read this first

• Gluten and wheat allergy: wheat is one of the grains that contain gluten (with barley and rye), and wheat is on the MedlinePlus list of the most common food allergens. [10] [11] People with celiac disease or a wheat allergy should not eat wheat bran or germ unless their clinician says so. For trouble breathing or swelling of the face, lips or throat, call 911 (or your local emergency number). [11]
• Fiber side effects: wheat bran is very high in fiber (42.8 g per 100 g, USDA). [1] MedlinePlus says raising fiber too fast can cause gas, bloating and cramps. [15]
• Kidney stones and kidney disease: NIDDK names wheat bran among foods people with calcium oxalate stones may want to cut back on. [6] Bran and germ are also high in phosphorus and potassium (USDA). [1] [2] Ask your kidney team.
• Young children: the CDC lists plain wheat germ as a choking hazard for infants and young children. [9]
• Evidence in one line: wheat bran probably helps stool frequency modestly in people with constipation, based on small, mixed, mostly low-quality trials; we found no solid trials for wheat germ. [3] [4] [7]

What is in it (USDA values)

The first table is for wheat bran, crude (USDA FoodData Central item 169722, SR Legacy). [1] The serving column is 1 ounce (28.35 g), a stated weight we computed from the 100 g values. USDA's own household portion is 1 cup, 58 g, which is much more than people usually stir into a meal. [1]

The second table is for wheat germ, crude (USDA item 168892). [2] The serving column is again 1 ounce (28.35 g), computed; USDA's household portion is 1 cup, 115 g. [2] We did not read how USDA defines "crude" for this item, and toasted wheat germ is a different product that is not in our file.

% Daily Value uses the FDA 2016 Daily Values; values vary with the wheat variety, where it grew and how it was milled. The serving figures are the 100 g values multiplied by 0.2835. USDA lists no vitamin E value for the germ item in our file, although other studies report vitamin E compounds in wheat germ.

Plant compounds: a lab study of wheat germ oil measured fats that are mostly unsaturated (linoleic acid about 59% of the fat) and vitamin E compounds called tocopherols. [8] A 2026 review of wheat compounds (phenolic acids, flavonoids and lignans) says most of the supporting evidence comes from cell and animal studies and calls for rigorous human trials. [16]

What research says

Eaten as food vs taken as an extract. The bran trial gave 20 g a day of bran, and we did not read how it was taken. We did not find trials of wheat germ extracts. Wheat germ oil is a separate product that we did not assess for health effects.

How much is a normal serving

USDA household portions in our files are 1 cup of bran (58 g, about 125 kcal) and 1 cup of germ (115 g, about 414 kcal), which are large amounts for a topping. [1] [2] The table uses a stated 1 ounce (28.35 g). The 2025-2030 Dietary Guidelines for Americans set a goal of 2 to 4 servings of whole grains a day; the page we read did not define a serving of bran or germ. [18] The NHS gives 30 g of fibre a day as the aim for adults, and says most adults eat about 20 g. [19] These are official figures, not a prescription. Increase fiber slowly. [15]

Safety, allergy and medicines

• Celiac disease, gluten and wheat sensitivity: NIDDK says gluten occurs naturally in wheat, barley and rye. [10] Bran and germ come from wheat; we did not find a source on whether any given bran or germ product is low in gluten, so people with celiac disease should assume they contain it unless the package says "gluten-free" (fewer than 20 parts per million, per the FDA rule that NIDDK describes). [10] A 2025 review of non-coeliac wheat sensitivity says self-reported rates are often above 10%, but blinded challenges confirm it in typically under 30% of cases, and that fructans (a type of fermentable carbohydrate) and other wheat proteins are implicated as triggers. [12] See gluten and celiac basics.
• Wheat allergy: wheat is on the MedlinePlus list of the most common food allergens. Signs include hives, swelling of the mouth or throat, vomiting and trouble breathing. For anaphylaxis, call 911 and use prescribed epinephrine. [11]
• Fiber side effects: gas, bloating and cramps if fiber rises too quickly. [15] In the pooled analysis of fiber trials in constipation, flatulence was higher with fiber. [3]
• Oxalate and kidney stones: NIDDK (page reviewed May 2017) lists wheat bran among foods that people who have had calcium oxalate stones may want to cut back on, and says to ask a health professional how much oxalate to eat. [6]
• Kidney disease: wheat bran has 1,013 mg of phosphorus and 1,182 mg of potassium per 100 g; wheat germ has 842 mg and 892 mg. [1] [2] NIDDK advises people with kidney disease to limit added phosphorus and to follow their kidney team's potassium advice. [14]
• Choking: the CDC lists "plain wheat germ" and whole grain kernels among grain products to avoid for infants and young children. [9]
• Raw flour: FDA says never to eat or taste raw flour, dough or batter, because flour is a raw product that can carry E. coli and Salmonella. [13] That page is about flour; it does not name bran or germ. Stir bran or germ into foods you cook or bake, or follow the package.
• Phytates (mineral absorption): we did not find, in the sources we read, a clear result on how much the phytates in bran reduce mineral absorption in a normal mixed diet. See antinutrients in whole grains.
• Medicines, pregnancy and breastfeeding: we did not find a medicine interaction or a pregnancy warning for wheat bran or germ in the sources we read. If you take several medicines, ask a pharmacist.

Choosing, storing and food safety

• Wheat germ goes rancid. A lab study found it is very prone to deterioration because of its unsaturated fats and its own enzymes; untreated germ reached its spoilage limit in under four days under hot, humid test conditions. [8] Buy small amounts, keep them sealed and use them soon, and throw away germ that smells bitter or stale. The study did not test home refrigeration, so we do not give a storage time.
• Keep bran and germ dry; WHO says moldy grain can form with poor storage, and that moldy, discolored or shriveled grain should be discarded. [17]
• Check the label for added sugar or salt in flavored products; the USDA values here are for plain bran and germ. [1] [2]

Related pages

• Whole wheat
• Whole-wheat bread
• Oat bran
• How much fiber per day, and fiber side effects
• Gluten, celiac disease and gluten sensitivity basics
• Foods and kidney disease: potassium and oxalates