Lesson 1

A closer look

Conventional White Flour on Grocery Store Shelves

Picking up a bag of bread flour or all-purpose flour is convenient, but refined white flour is different from whole-grain flour. A wheat kernel has three main parts:

To make refined white flour, milling removes most of the bran and germ and keeps primarily the endosperm. Those outer parts contain oils that can shorten flour’s storage life, so removing them helps flour keep longer. Enriched flour may then have specific vitamins and minerals added back.

What changes

What Is Lost?

When the bran and germ are removed, the flour loses much of the grain’s naturally occurring:

• Dietary fiber
• Natural oils
• Vitamin E and B vitamins
• Minerals such as magnesium, zinc, phosphorus, potassium, manganese, and selenium
• Antioxidants and other plant compounds

The refined flour that remains is made mostly of starch and protein. Its structure can work well for baking, but it is no longer the complete grain.

A label you may see

What About “Enriched” Flour?

Many refined flours are labeled enriched. After the bran and germ are removed, manufacturers add back a specified group of nutrients. In the United States, enriched flour includes thiamin (vitamin B₁), riboflavin (B₂), niacin (B₃), iron, and folic acid.

Enrichment helps restore those specific nutrients, but it does not put the bran and germ back into the flour or restore all of the grain’s fiber, natural oils, and other plant compounds.

A change in the way flour was made

How Modern Milling Changed Our Bread

White flour existed long before modern roller mills. In the late 1800s, steel roller milling spread through the United States and made it easier to separate the bran and germ from the endosperm. By the 1870s and 1880s, this technology was helping mills produce refined white flour on a much larger scale. The change made white flour more widely available.

The bran and germ contain fiber, minerals, B vitamins, natural oils, vitamin E, and other nutrients. The endosperm is the largest part of the kernel and contains mostly starch and protein; refined white flour is made primarily from this part. Removing the oil-rich germ helped flour keep longer. Whole wheat flour, when used without sifting, keeps the bran, germ, and endosperm together.

For more on the history of milling in Minneapolis, see the Minnesota Historical Society’s flour milling history.

Sue Becker’s connection

Nutrient Deficiencies and Pellagra

Sue Becker discusses the history of milling alongside several nutrient-deficiency conditions. These conditions have specific causes; the history is not evidence that refined wheat flour alone caused them.

In the early 1900s, pellagra became a major public-health problem in the American South. It was associated with poverty and restricted diets that often relied heavily on corn products and lacked a variety of nutrient-rich foods. Refined wheat flour by itself did not cause the epidemic. Beginning in 1914, physician Joseph Goldberger’s research showed that improving the diet could prevent pellagra.

Read the National Institutes of Health history of Goldberger and pellagra.

Pellagra’s Four D’s

Death is the fourth D and a possible outcome when pellagra is left untreated. For a plain-language overview, see the Cleveland Clinic’s guide to pellagra.

Hear Sue Becker discuss this history in Episode 205, “The Deception of Enrichment—The Demise of Real Bread”. Her discussion of pellagra and the four D’s begins around 6½ minutes. There is also a Sue Becker interview about milling, bran, germ, and flour history.

Enrichment over time

What Was Added Back—and When?

In 1941, the United States established an enrichment standard for refined flour that added four nutrients:

• Thiamine (vitamin B₁)
• Riboflavin (vitamin B₂)
• Niacin (vitamin B₃)
• Iron

That was about 60–70 years after roller milling began expanding in the United States. Enrichment helped address nutrient deficiencies, but it did not put the whole bran and germ back into refined flour. Read the National Academies history of flour enrichment.

In 1998, folic acid (vitamin B₉) became the fifth required nutrient in enriched cereal-grain products. This was 57 years after the original enrichment standard and was intended to reduce the risk of neural tube birth defects. Learn more from the National Institutes of Health folate fact sheet.