U.S. Code of Federal Regulations § 137.165 (a) on enriched flour specifies that it must

contains in each pound 2.9 milligrams of thiamin, 1.8 milligrams of riboflavin, 24 milligrams of niacin, 0.7 milligrams of folic acid, and 20 milligrams of iron.

Why are not vitamin E, vitamin B₆, magnesium, potassium, and protein required to be added? These nutrients are removed in the refining process, too:
Whole Grain Council

  • 5
    I’m voting to close this question because why a law prescibes something and not something else is politics - Lawmaker said so is all we need to know in law.
    – Trish
    Commented Nov 19, 2023 at 23:59
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    @Trish Legislators base (or at least should base) their laws off of reason; law is not arbitrary.
    – Geremia
    Commented Nov 20, 2023 at 0:10
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    @Geremia "Legislators base (or at least should base) their laws off of reason; law is not arbitrary." Oh my summer child. If that were true, we'd live in much better world.
    – ohwilleke
    Commented Nov 20, 2023 at 0:18
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    @ohwilleke Some laws are conventions (driving on the right side of the road, for example), but laws regarding food processing would seem not to be conventions but based on nutritional science.
    – Geremia
    Commented Nov 20, 2023 at 1:47
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    @Trish firstly, as we’ve discussed before in the past, the distinction is hardly that clear cut. Secondly, why do you care and what actually motivates you so eagerly to invoke that point every time it seems possibly applicable? Without even having read the one that has been posted, I can imagine several good and informative answers being given to this and I look forward to reading them. What is gained by shutting a good question down? Commented Nov 20, 2023 at 1:55

1 Answer 1


The fortification of flour began during World War II as a way to address malnourishment in new draftees and volunteers for military service. But, the linked FDA regulation in question was adopted in 1977. It was always limited to micronutrients, as opposed to macronutrients like protein and fiber. By the 1970s, enrichment of flour was a matter of considerable controversy spelled out in the historical account below which also identifies the criteria to decide which nutrients will be enriched which were applied at the time:

In the 1930s and 1940s specific deficiency disease syndromes were first identified and documented in the United States (Foltz et al., 1944; McLester, 1939; Williams et al., 1943). Based on this new science, in 1940 the Committee on Food and Nutrition (now the Food and Nutrition Board [FNB]) recommended the addition of thiamin, niacin, riboflavin, and iron to flour (NRC, 1974). About that time FDA first established a standard of identity for enriched flour that identified specific nutrients and amounts required for addition to any flour labeled as “enriched” in order to improve the nutritional status of the population (FDA, 1941). The approach of using a standard of identity, which establishes the specific type and level of fortification required for particular staple food to be labeled as enriched, has remained a key aspect of fortification regulations and policy in the United States. These standards have been amended over the years, but they continue as the basis for the addition of thiamin, niacin, riboflavin, folic acid, and iron to enriched flour, with the addition of calcium as optional.

Concurrent with these activities, the nutritional status of Americans was being questioned as a result of the poor nutritional status of young men enlisting for service during World War II. These concerns led to the National Nutrition Conference for Defense in May 1941, convened by President Roosevelt. An outcome of this conference was the recommendation for flour and bread enrichment using the existing standards developed by FDA (Quick and Murphy, 1982).

Although the original FDA standard was not amended to include bread for several years, the enrichment of bread began in 1941 as a result of discussions among FNB, AMA, FDA, and the American Bakers Association. The voluntary cooperation of bakery-associated industries led to 75 percent of the white bread in the United States being fortified by the middle of 1942 (Quick and Murphy 1982). The first War Food Order, enacted in 1943, stated that all flour sold for interstate commerce would be enriched according to FDA standards. This order was later repealed in 1946, but was followed in 1952 with official standards of identity for enriched bread (FDA, 1952a, 1952b). Under this new regulation, fortification of flour and bread products was not mandatory, but if a product was labeled as “enriched” it was required to meet the standards of identity described in the regulation.

FDA made a decision in the 1940s that it would not require mandatory fortification for any food product; this policy is still in place. For every standard of identity for which there is an enriched version of a food, there is a corresponding standard of identify for an unenriched version. Prior to 1990 individual states could enact laws that addressed fortification of products sold within their boundaries. For example, by the time the enriched bread standard was finally promulgated by FDA in 1952, the enrichment of flour and bread was mandatory in 26 states (Hutt, 1984). The National Labeling Education Act of 1990 provided for federal preemption of standards of identity, however, thus nullifying these state laws.

Since the 1950s standards of identify have been issued for the fortification of food, such as oleomargarine and rice and other cereal grains, and have been proposed for formulated meal replacements. The most recent standard of identity change for these products was the regulation, effective in January 1998, regarding folate. To meet the standard of identify for most breads, flours, corn meals, rice, noodles, macaroni, and other grain products labeled as enriched, folic acid is to be added at the level of 0.43 mg to 1.4 mg/lb of product. This decision reflects an overall approach within the United States that incorporates six underlying principles first presented in a joint statement of FNB and the Council on Foods and Nutrition of AMA (NRC/AMA, 1968):

  • The intake of the nutrient, in the absence of fortification, is below the desirable level in the diets of a significant number of people.

  • The food from which the nutrient is to be derived is likely to be consumed in quantities that will make a significant contribution to the diet of the population in need.

  • The addition of the nutrient is unlikely to create an imbalance of essential nutrients.

  • The nutrient added is stable under proper conditions of storage and use.

  • The nutrient is physiologically available from the food to which it will be added.

  • There is a reasonable assurance against intake sufficiently in excess to be toxic.

Fortification Policies and Regulations Since the 1960s

In the 1960s FDA proposed a more restrictive regulatory approach in response to increased fortification of food that it feared might lead to overfortification. These were the first major regulatory changes related to food fortification that had been proposed since 1941. In 1962 FDA proposed to limit fortification to only nutrients essential to human health and appropriate for supplementation. The agency listed 12 essential nutrients with a suitable range for their supplementation and 11 nutrients that were considered essential but not appropriate for supplementation because signs of deficiency only occurred under experimental situations (Hutt, 1980, 1984). The previous year FDA had brought legal action against New Dextra Brand Fortified Cane Sugar claiming in part that the sugar's labeling was misleading because its 19 added nutrients inherently claimed that it was more nutritious than other sugars and that the nutrients were present in sufficient amounts to significantly improve the diet. Another element of the legal action claimed that sugar was an inappropriate vehicle for fortification. FDA's “misbranding” approach was not upheld in the U.S. District Court, and the U.S. Court of Appeals agreed. The court held that FDA had no legal authority to prohibit food fortification unless it can be shown to be unsafe. The United States District Court concluded (as upheld by the United States Court of Appeals):

"The basic flaw in the Government's case against the product is that it is seeking, under the guise of misbranding charges, to prohibit the sale of a food in the marketplace simply because it is not in sympathy with its use. But the Government's position is clearly untenable. The provisions of the Federal Food, Drug, and Cosmetic Act did not vest in the Food and Drug Administration or any other federal agency the power to determine what foods should be included in the American diet; this is the function of the marketplace…."

Still attempting to reduce indiscriminant food fortification and dietary supplement products, in 1966 the FDA proposed to limit the number of food products that could be fortified to eight classes and to specify the nutrients that could be used with each class. This proposed regulation was worded in the context of two new standards of identity: one for vitamin and mineral dietary supplements and the other for a limited number of food products (FDA, 1966). FDA convened public hearings on these proposed regulations in 1968 and 1969 (Hutt, 1980). This proposed regulation and a subsequent proposal in 1974 of general rules governing the addition of nutrients to food, along with provisions to enforce the rules (FDA, 1974), were eventually abandoned due to objections and comments in public hearings and due to other events.

Two events in particular changed the course of FDA's regulatory approach in the 1960s and 1970s: President Nixon's White House Conference on Food, Nutrition and Health in 1969 and Congress's enactment of the new Section 411 of the Food, Drug, and Cosmetic Act (FD&C) in 1976. The White House Conference issued a report that recommended fortification of existing and new food products to reduce malnutrition, which was in many ways the opposite of the 1966 FDA proposed regulation (Hutt, 1980; WHC, 1970). After FDA published regulations based on its 1968 and 1969 hearings, Congress was persuaded in 1976 to amend the FD&C Act to limit FDA's authority over vitamin and mineral supplements. This amendment explicitly prohibited FDA from imposing maximum limits on the potency of any vitamin or mineral in a dietary supplement in tablet, capsule, or small measured liquid form except for safety reasons. The 1976 statute also prohibited FDA from limiting the combination or number of safe nutrients in a dietary supplement (21 U.S.C. §350). The FDA Modernization Act of 1997 extended this to include dietary supplements in food form (P.L. 105-115). When FDA attempted to limit the amount of vitamin A and vitamin D fortification by declaring any level higher than 150 percent of the U.S. Recommended Daily Allowances (US RDAs) to be a prescription drug, this approach was also struck down by the courts.

Current Fortification Policies

In 1943, due to the heightened interest in fortified food, FDA issued a policy statement (which has never been withdrawn) on the addition of nutritive ingredients to food. In this policy FDA stated that implicit in fortification is the promise to consumers that the fortified food, through its fortificants, contributes substantially to the nutritional well being of the individual who consumes usual amounts of the food. This aspect of the policy was rejected by the courts in the New Dextra Sugar case and by the 1976 vitamin-mineral amendments to the FD&C Act. The FDA policy also said that the specific nutrient deficiencies in the diet of the general population and population subgroups, the overall place of the food item in the diet of this population, and the effectiveness and suitability of the food vehicle should determine the type and amount of nutrients to be added to food. This policy further affirmed the importance of natural food in the diet, endorsed the restoration of nutrients lost during food processing, and indicated that it was appropriate, in some instances, to fortify processed food above restoration amounts and to fortify unprocessed food in order to correct deficiencies if the food in question is a particularly effective vehicle for fortification (Hutt, 1980, 1984).

In 1974 FDA proposed regulations that moved beyond the standard of identity approach and included a more comprehensive view-point of the addition of nutrients to food (FDA, 1974). In 1980 these views were published not as regulations, but as a policy statement that manufacturers “… are urged to follow if they elect to add nutrients to a manufactured or processed food” (FDA, 1980, p. 6314). The policy was codified in 21 C.F.R. 104.20 (FDA, 1980). This policy is the current statement of the agency regarding fortification. It is important to note that this statement, as a policy, it is not enforceable.

Of key relevance to this report, the codified policy includes situations and conditions in which the fortification of food with the nutrients listed in the policy is considered appropriate:

  1. … to correct a dietary insufficiency that is recognized by the scientific community to exist and known to result in nutrient deficiency disease … ; 2) … to restore such nutrient(s) to a level(s) representative of the food prior to storage, handling and processing … ; 3) … in proportion to the total caloric content of the food, to balance the vitamin, mineral, and protein content …; and 4) … that replaces traditional food in the diet to avoid nutritional inferiority … (FDA, 1980, p. 6323)

In the codified policy there are a number of qualifications listed with each condition of fortification. For example, the policy recommends that vitamins, minerals, and protein be added in proportion to the total caloric content of the food for which the stated caloric reference value is “… per 100 kilocalories based on a 2,000-kilocalorie total intake as a daily standard …” (FDA, 1980). This section includes a listing of the nutrients the policy recommends as appropriate to add as fortificants and cites the US RDAs as the reference standards for amounts of nutrients to be added per 100 kilocalories. The FDA fortification policy thus recommends using the same reference standards for fortification that are used for the nutrition labeling of food.

The policy includes statements that nutrients added to food should be stable, physiologically available, present at a level that will not led to excess intake, suitable for fortification purposes, and acceptable in terms of food safety regulations. The policy concludes with links to food labeling in that it specifies that claims and statements on the label cannot be false or misleading. Another point mentioned in the fortification policy is that FDA “does not consider it appropriate to fortify” fresh produce, meat, poultry, or fish products, sugars, or snack foods (e.g., candies and carbonated beverages).

Historically the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS) has followed an unwritten policy prohibiting indiscriminant fortification of the products it regulates (Post, 2002). In 1980 it adopted FDA's policy guidelines on the addition of nutrients to food (21 C.F.R.104.20). In 1982 an FSIS review of the policy concluded that the food it regulated would continue to follow FDA policy guidelines (Quick and Murphy, 1982). Meat and poultry regulations do, however, permit some limited addition of nutrients for specific purposes, such as the addition of ascorbic acid (vitamin C) to accelerate the curing process and the addition of thiamin hydrochloride for flavoring. With the exception of margarine, there are no FSIS food standards that permit or require the addition of nutrients (Post, 2002). The diversity of food products in the marketplace that fall under FSIS regulation has grown, and FSIS has found that products may contain label claims for fortification that are not addressed by the 1980 guidelines (Post, 2002). FSIS has made some accommodation for these food products by allowing label statements about nutrients contributed by fortified ingredients approved by FDA (e.g., calcium-enriched egg noodles) (Post, 2002).

I suspect, but do not know, that vitamin E, vitamin B₆, magnesium, potassium were excluded from the enrichment requirements because a documented problem with specific diseases caused by deficiencies in this vitamins and minerals was not well documented in the general public at the time that the list of vitamins and minerals to be enriched was established. Also, notably, the initial list from World War II was focused on malnourishment in young adult male potential military recruits. This seems to still be the case.

For example:

Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitamin E, can cause nerve problems.

Vitamin E was also initially understood as a prenatal vitamin issue.

Dietary deficiency in Vitamin B6 is also rare.

Magnesium deficiency is most often found in hospitalized people, people who are starving generally, and alcoholics, rather than the general public.

Potassium deficiency due to not "eating a diet with enough potassium-containing foods or fasting can cause the gradual onset of hypokalemia. This is a rare cause and may occur in those with anorexia nervosa or those on a ketogenic diet."

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