Many medical organizations advise against
routine supplementation of vitamins and minerals (citing
“safety concerns,” lack of evidence of benefit,” or
that they are simply “unnecessary”) and recommend a
focus on acquiring nutrients from the diet. Which, for
the most part, is a good suggestion: no combination
of supplemental vitamins, minerals, or other nutrients
could possibly emulate the diversity of known (and
unknown) beneficial compounds found in the diet.
However, general dismissals of dietary supplements
often fail to acknowledge the significant portion of
micronutrients in the average diet that may come from
the fortification of foodstuffs. Food fortification (addition
of nutrients to foodstuffs for commercial benefit
or as a part of public health policy) has been credited
for the eradication of several diseases of nutrient deficiency
in the U.S.
If both fortification and supplementation similarly
involve the addition of vitamins or minerals to the diet
(often achieved using the exact same chemical “additives”),
why is there such a disparity in the perceptions
of each?
In the United States, foods were being fortified
even before the concept of recommended daily intake
had been established. Beginning with the addition of
iodine to table salt in the 1920s to stem the prevalence
of goiter, the enrichment of common dietary foodstuffs
with vitamins or minerals became the preferred
means to abate nutrient deficiency epidemics through
the 1930s, such as pellegra (vitamin B3 deficiency) in
the South, and rickets (vitamin D deficiency) in the
Northeast. Around this time, one-third of Americans
had poor diets, with over 10 percent showing signs
of vitamin deficiency. This frequency of nutrient deficiency
motivated the creation of the first recommended
daily allowances (RDAs) for iron, calcium,
vitamins A, B1, B2, B3, C, and D by the Committee on
Food and Nutrition of the National Research Council
(the predecessor to the modern Food and Nutrition
Board). RDAs served as the guidance for fortification
of low-cost “staple” foodstuffs; by the end of the
1950s, breads, flour, pasta, cornmeal, and white rice
(enriched with iron, vitamins B1, 2, and 3), as well as
milk (enriched with vitamin D and optionally vitamin
A) all had formal standards for fortification that were
encouraged and regulated by the FDA. Folic acid was
added to the list of grain product enrichments in 1996,
as a measure for the prevention of neural tube defects.
This addition represented a change in paradigm for
the FDA, in which they considered the benefits of fortification
for a small, poorly-defined group (women who
may be pregnant), over the potential for excessive intake
by the rest of the population.
Nowadays, fortified foods are prevalent in the
American food supply. Fortification of foods is no longer
only by government encouragement or mandate,
but often provides a competitive advantage for food
manufacturers, and has expanded to include nearly all essential and several non-essential nutrients (such as phytosterols, or fatty acids
from fish oil). Ready-to-eat cereals and
vitamin-C fortified drinks are the largest
contributors of fortified nutrients to the
U.S. food supply. Ninety-two percent of
breakfast cereals are fortified, and contribute
up to 30 percent of the daily intake
of many vitamins and minerals for adults
and children; many cereals are fortified up
to 100 percent of nearly all the essential
vitamins and minerals.
While food fortification has been
viewed by some as a nutritional triumph
(and to be fair, it has resulted in significant
decreases in several nutrient deficiency
diseases that were common in the early
twentieth century), individual supplementation
with vitamins or minerals has at
best been deemed unnecessary without
underlying deficiency, and at worst been
called potentially hazardous. So what are
the differences between supplementation
and fortification, which makes one more
acceptable than the other?
In reality, there is little difference between
these two schemes for improving
nutrient intake. Food fortification uses
many of the same ingredients as supplements;
comparing the ingredient lists
on a cereal box and multivitamin bottle
will reveal several of the same chemical
compounds. Baking these vitamins or
minerals into a loaf of bread doesn’t make
them any more effective than if they were
compressed into a tablet. While there is
a pervasive assumption that “food nutrients”
are more effective than “supplemental
nutrients,” this theory is of little
relevance to the added vitamins and
minerals of fortified foods. The argument
that supplemental vitamins or minerals
may lead to unnecessarily high, potentially
detrimental daily nutrient intakes may
have some merit (one could imagine it is
probably easier to “overdose” on multivitamins
than to eat a dangerous amount
of fortified bran flakes), although excessive
vitamin intake is also possible through
fortified foods (the possible link between
long-term excessive folic acid intake and
the risk of colon cancer is a recent concern).
Unfortunately, many organizations
do not recognize the parity between the
fortification and supplementation, or simply
fail to acknowledge that a substantial
portion of nutrients from a “healthy diet”
(even diets based on their own recommendations)
may actually be supplemental
(“fortified”). For example, consider the
TLC diet, the heart-healthy eating plan recommended
by the American Heart Association
in its Third Report of the National
Cholesterol Education Program. The TLC
plan meets most conventional definitions
of “healthy eating,” it encourages a diet
low in calories and saturated fats, high
in fiber, fruits, and vegetables. Looking
at the sample TLC menus, however, one
begins to realize a significant percentage
of several essential nutrients comes from
fortification, and not necessarily from the
foods themselves. In one menu (“Traditional
American Cuisine”), for example,
almost half of the iron, B1, B2 and B3,
40 percent of the folate and calcium,
and all of the vitamin D may come from
fortified foods (including enriched flour
products, rice, milk, and calcium-fortified
orange juice), based on analysis of the
menu choices using the USDA National
Nutrient Database for Standard Reference.
Without fortification, these meals
could be deficient for all but one of the
above nutrients.
Therefore, the blanket characterization
of dietary supplements as “unnecessary”
really ignores the prevalence of supplemental
vitamins (“food fortification”) in
the diet. Whether as an added food ingredient,
capsule, or tablet, supplemental
vitamins can, and have, played a recognized
role in prevention of disease, when
their intakes are properly balanced. Take
any statements to the contrary with a
grain of (iodized) salt.