Wheat Flour

Wheat flour is produced by milling the dried kernels of wheat (Triticum aestivum). It is a foundational ingredient in bread, pasta, pastries, cereals, and countless processed foods across most food cultures. All-purpose wheat flour typically contains the endosperm only, with whole wheat flour retaining the bran and germ for higher fiber content. Refined wheat flour has the bran and germ removed during processing.

Wheat flour is approximately 70–75% carbohydrates (mostly starch), 8–15% protein (depending on wheat variety and flour type), and 1–2% fat. Refined wheat flour lacks the insoluble fiber and micronutrients present in whole grain versions. When consumed, wheat starch is broken down into glucose and absorbed into the bloodstream. Foods made from refined wheat flour—such as white bread—have a high glycemic index (GI approximately 70–75), meaning they raise blood sugar relatively quickly. Foods made from whole wheat flour tend to have a lower glycemic index (approximately 55–70, varying by product and preparation) due to fiber content, which slows glucose absorption and promotes satiety.

Blood Sugar and Glycemic Response

Refined wheat flour products cause relatively rapid increases in blood glucose and insulin, particularly when consumed without protein, fat, or fiber. Whole wheat flour produces a more gradual glycemic response due to its fiber content. Regular consumption of refined grain products is associated with increased risk of type 2 diabetes in observational studies, whereas whole grain consumption is linked to lower diabetes risk.

Gluten and Celiac Disease

Wheat contains gluten, a protein complex consisting of glutenin and gliadin that triggers an autoimmune intestinal response in people with celiac disease (affecting approximately 1% of the population). For regulatory and labeling purposes, the FDA defines 'gluten-free' as containing fewer than 20 parts per million (ppm) of gluten—a threshold considered safe for most people with celiac disease, though sensitivity varies among individuals. Non-celiac gluten sensitivity (NCGS) is less well-defined but may cause gastrointestinal or systemic symptoms in some people; prevalence is unclear. Wheat flour is unsuitable for anyone with diagnosed celiac disease or confirmed gluten sensitivity.

Portions and Tolerance

Wheat flour itself is not toxic and is safe for the general population at typical dietary levels. People without celiac disease or gluten sensitivity tolerate wheat flour in standard food portions without adverse effects. Those with type 2 diabetes or metabolic syndrome may benefit from choosing whole wheat flour or limiting refined wheat products to reduce blood sugar spikes. Individuals with irritable bowel syndrome (IBS) may experience bloating or gas from wheat in some cases, though wheat is not universally a trigger. A small proportion of people with IBS may be sensitive to wheat's fermentable carbohydrates (fructans), which are classified as high FODMAP in the short-chain carbohydrate framework.