Corn Flakes Nutrition Calculator — Fortified Iron, Stripped Fiber & What Processing Changes

Corn flakes (FDC 174648 — plain, fortified) contain 28.9mg iron per 100g (161% DV) — an astonishing number that exceeds even liver (6.5mg) and dwarfs spinach (2.7mg). But this iron is entirely from fortification — elemental iron powder is added during manufacturing. Unfortified corn has approximately 2.7mg iron per 100g, and the processing into flakes retains only about 0.5-1mg ^[1][3].

A single cup of corn flakes (~30g) provides 8.7mg iron (48% DV) — which sounds remarkably high for a 107-calorie serving. The fortification uses reduced iron (elemental iron powder), which has different absorption characteristics than naturally occurring iron in foods. Research has examined the bioavailability of different iron fortification forms, finding that elemental iron is absorbed at lower rates than ferrous sulfate or naturally occurring non-heme iron ^[1][3].

Similarly, folate at 675mcg per 100g (169% DV) is from folic acid fortification — natural corn contributes approximately 19mcg. Vitamin A at 463mcg RAE (51% DV), vitamin B12 at 4.77mcg (199% DV), niacin at 15.6mg (98% DV), and thiamine at 1.17mg (98% DV) are all fortified additions. Remove the fortification, and corn flakes would be nutritionally sparse ^[1].

Whole corn (yellow, raw) has 7.3g fiber per 100g from its bran, germ, and endosperm. Corn flakes retain only 0.7g fiber per 100g — a 90% reduction. The processing sequence — degermination (removing the germ), milling (removing bran), cooking in sugar/salt syrup, flaking under pressure rollers, and toasting — systematically strips every fiber-containing structure ^[1][3].

A cup of corn flakes (~30g) delivers just 0.2g fiber (1% DV) — nutritionally negligible. For comparison: the same 30g of plain oats would provide 3.0g fiber (11% DV), and 30g of bran flakes provides 5.4g fiber (19% DV). Corn flakes are among the lowest-fiber commercially available breakfast cereals ^[1].

The germ and bran that are removed contain not just fiber but also the natural oils, B vitamins, and minerals of corn. This is why corn flakes require such heavy fortification — the processing removes the naturally nutritious parts of the grain, and manufacturers add synthetic versions back. Whole-grain corn cereals exist but are a different product category ^[1][3].

Corn flakes contain 729mg sodium per 100g (32% DV) — the highest among common breakfast cereals. Granola has 26mg, plain oats 6mg, and even muesli has just 248mg. A single cup (~30g) delivers 219mg sodium (10% DV), and a typical 1.5-cup bowl reaches 328mg sodium (14% DV) — before adding milk (which adds another 50-80mg) ^[1].

The sodium comes from salt added during the cooking/flavoring stage of manufacturing. Raw degermed corn has about 1mg sodium per 100g — virtually all 729mg is added. Some brands offer 'reduced sodium' versions at approximately 400-500mg per 100g, but these are still high relative to other cereal categories ^[1].

For people tracking sodium intake, the corn flakes + milk combination (378-410mg per typical serving) contributes 16-18% DV from a single breakfast item. Combined with toast and butter (~200mg) or a glass of juice, a typical breakfast with corn flakes can easily reach 600-700mg sodium — one-quarter to one-third of the recommended 2,300mg daily limit ^[1][3].

Corn flakes have a glycemic index (GI) of approximately 81 (on the 0-100 glucose scale) — classified as high-GI. This is higher than white bread (~75), table sugar (~63-65), and significantly above rolled oats (~55) or muesli (~57). The high GI results from the processing: flaking under high pressure gelatinizes the starch, making it rapidly digestible ^[3].

Total carbohydrates at 84.09g per 100g with only 0.7g fiber means nearly all carbs are digestible — the glycemic load (GL) per cup serving (~30g) is approximately 20 (moderate-high). The refined corn starch in each flake is essentially pre-processed for rapid digestion. Adding milk (which contains protein and fat) modestly lowers the meal's overall glycemic response compared to eating dry corn flakes ^[1][3].

For nutrition journaling: a cup of corn flakes with ½ cup whole milk has approximately 182 calories (107 + 75), 6g protein, 31g carbs, 4.1g fat, and 0.2g fiber from the cereal. The low protein and fiber content means this meal has limited sustained satiety compared to oatmeal (which provides 5g protein, 4g fiber, and a GI of ~55 for the same calorie range) ^[1].

Frosted corn flakes have 37g sugar per 100g vs plain's 8g — a 29g increase from the sugar coating. Calories rise modestly from 357 to 378 kcal per 100g (a 6% increase), because the sugar coating replaces some of the corn starch gram-for-gram rather than purely adding on top ^[1].

A cup of frosted corn flakes (~33g) has 12.2g sugar — about 3 teaspoons — before any additions. With milk and a banana, sugar reaches approximately 23g per breakfast. Plain corn flakes with the same additions have about 14g — still significant from the banana and milk lactose ^[1].

Other nutritional changes from frosting: protein drops from 7.0 to 4.4g per 100g (sugar displaces some corn mass), sodium decreases slightly to 600mg (some salt displaced by sugar), and all fortification nutrients decrease by 15-20% proportionally. The fiber remains essentially identical at 0.6g — the sugar coating does not add or remove fiber ^[1].