Tired? Depressed? Always under the weather? You might not be getting the right amount
of these vitamins and minerals.
Today’s average restaurant meal is more than four times larger than in the 1950s, and
according to the Centers for Disease Control and Prevention (CDC), adults are, on average, 26
pounds heavier. Despite the embarrassing abundance of food, many Americans still
unknowingly suffer from nutrient deficiencies. Whether from vapid calories (hello, junk food),
chemical-induced deficiencies, a lack of a variety, or any number of other factors, some of us
just aren’t getting what we need.
The CDC’s Second Nutrition Report, an assessment of diet and nutrition in the U.S. population,
concludes that there are a number of specific nutrients lacking in the American diet. Not only
can nutrient deficiencies have long-lasting health effects, they can make you feel rotten. Here
are some of the more common vitamins and minerals lacking in our diets, deficiencies that can
cause an array of symptoms, from poor memory and bleeding gums to impaired work
productivity and depression.
1. Vitamin B12
Vitamin B12 is naturally found in many animal products, including fish, meat, poultry, eggs and
dairy items; it is generally not found in plant foods. Fortunately for vegans, fortified breakfast
cereals and some nutritional yeast products also contain vitamin B12. The vitamin is required for
proper red blood cell formation, neurological function and DNA synthesis. Deficiency of this
important vitamin is common, affecting up to 15 percent of the general population.
The Recommended Daily Allowance (RDA) for males and females over the age of 14 is 2.4
Symptoms of vitamin B12 deficiency include megaloblastic anemia, fatigue, weakness,
constipation, loss of appetite and weight loss. Neurological problems like numbness and tingling
in the hands and feet can also occur. Other symptoms include difficulty maintaining balance,
depression, confusion, dementia, poor memory and soreness of the mouth or tongue. Vitamin
B12 has also been linked to Alzheimer’s disease.
2. Vitamin C
Most animals are able to synthesize vitamin C internally, but not humans; we need to get it from
our food — lest we end up like the scurvy-ravaged sailors of lore. Citrus fruits, tomatoes, tomato
juice and potatoes are major sources of vitamin C in the American diet. Other good contributors
include red and green peppers, kiwi, broccoli, strawberries, Brussels sprouts and cantaloupe.
Vitamin C is not naturally found in grains, but it is added to some fortified breakfast cereals.
The body uses vitamin C for the biosynthesis of collagen, L-carnitine and certain
neurotransmitters, and it is also involved in protein metabolism. In addition to its biosynthetic
and antioxidant functions, vitamin C plays an important role in immune function and improves
the absorption of nonheme iron. The RDA for adults over 19 is 90 milligrams (mg) for males and
75 mg for females.
Vitamin C deficiency causes scurvy, the symptoms of which include fatigue, malaise,
inflammation of the gums, loosening or loss of teeth, joint pain, and poor wound healing.
Although scurvy is no longer the scourge it once was, but narrowly chosen diets and bulimia
among teens has created a scurvy resurgence. It can also afflict alcoholics or older people
whose ability to absorb vitamin C has diminished from excessive medications or poor eating
3. Vitamin D
Not many foods naturally contain Vitamin D. Fatty fish like salmon, tuna, mackerel, and fish liver
oils are the best natural food sources. To a lesser extent, vitamin D is also found in beef liver,
cheese, egg yolks and mushrooms. Fortified foods offer Americans most of the vitamin D they
consume. Since the 1930s, nearly all of the U.S. milk supply has been fortified with 100
International units (IU) per serving. Breakfast cereals are also commonly fortified with vitamin D.
And fortunately, our clever bodies make vitamin D when skin is exposed to sunlight; most
people meet at least some of their vitamin D needs this way.
Vitamin D regulates calcium in the body and helps it to maintain strong bones. It is involved in
healthy muscle movement, the nervous system relies on it, and it improves immune function as
well as helping to reduce inflammation. The RDA for vitamin D is 600 IU for males and females
between 19 and 70 years.
In children, vitamin D deficiency causes rickets, which has become less common since the
1930s but does still occur. With rickets, the bones become soft and bend. In adults, vitamin D
deficiency leads to osteomalacia, causing bone pain and muscle weakness. Vitamin D
deficiency has also been linked to daytime sleepiness.
Iodine is a mineral found in ocean fish, seaweed, shrimp, and other seafood, as well as dairy
products and products made from grains. Produce also contains iodine, although levels in fruits
and vegetables depend on the soil they were grown in.
Iodine is used by the body to produce thyroid hormones that work to control other essential
functions. Thyroid hormones are also required for proper bone and brain development during
pregnancy and infancy. The RDA for those 14 years and older is 150 mcg.
Iodine deficiency during fetal and early-childhood development is a leading cause of brain
impairments in much of the world. In adults, mild-to-moderate iodine deficiency can cause
goiter, as well as impaired mental function and work productivity. Chronic iodine deficiency may
be associated with an increased risk of some forms of thyroid cancer.
According to the World Health Organization, iron deficiency is the number one nutritional
disorder in the world. Dietary iron comes in two forms, heme and nonheme. Heme iron is found
in red meats, fish and poultry; nonheme iron is found in plants, like lentils and beans. Nonheme
iron is the form that is added to enriched and fortified foods. Animal-derived iron is absorbed
better than nonheme iron, but most dietary iron is nonheme iron. (Read more about iron for
Iron is essential for proper body functions. It helps transport oxygen to the cells, aids in blood
cell creation, supports protein structures in the body and other important functions. The RDA for
iron is 8 mg for males age 19-51, and 18 mg for females 19-51. For both males and females
over 51, the RDA is 8 mg.
Symptoms of iron deficiency can include fatigue and weakness, poor work and school
performance, slow cognitive and social development during childhood, difficulty maintaining
body temperature, decreased immune function, increased susceptibility to infection, and
inflamed tongue. (Read one writer’s experience with iron and overwhelming fatigue here.)
Magnesium is found in legumes, nuts, whole grains and vegetables, but American magnesium
levels have dropped by half in the last century due to changes in agriculture and diet. Most
Americans do not get the recommended amounts of magnesium, according to the experts.
Magnesium helps the body regulate more than 325 enzymes and plays an important role in
organizing many bodily functions like muscle control, electrical impulses, energy production and
the elimination of harmful toxins. The RDA for males 19-30 is 400 mg, and 420 mg for males 31
and over. Females 19-30 should aim for 310 mg; those 31 and over should get 320 mg.
Early signs of magnesium deficiency include loss of appetite, nausea, vomiting, fatigue and
weakness. As magnesium deficiency worsens, numbness, tingling, muscle contractions and
cramps, seizures, personality changes, abnormal heart rhythms and coronary spasms can
occur. One prominent study revealed that a magnesium-rich diet may lower stroke risk.
Zinc is abundant in oysters, red meat, poultry and fortified breakfast cereals. Beans, nuts, whole
grains and dairy products also provide some zinc, but beans and grains have compounds that
keep zinc from being fully absorbed by the body. Because of this, vegetarians may need to eat
twice as much zinc than what is recommended.
Zinc is important for helping the immune system battle bacteria and viruses. It also helps in the
production of cells and during pregnancy and infancy; in childhood, zinc helps the body to
develop correctly. Zinc helps wounds heal properly and plays a role in taste and smell. The RDA
for zinc is 11 mg for adult men and 8 mg for adult women.
Symptoms of zinc deficiency include slow growth in infants and children, delayed sexual
development in adolescents and impotence in men. Too little zinc can also be to blame for hair
loss, diarrhea, eye and skin sores, loss of appetite, problems with wound healing, decreased
ability to taste food, and lower alertness levels.
Note that some nutrients have upper limits as well, and overusing supplements can lead to
adverse effects. (Also, some supplements can interfere with prescribed medications.) If you
think you may be suffering from a nutrient deficiency, consult with your physician before loading
up on supplements.