Every day, your body produces skin, muscle, and bone. It churns out rich red
blood that carries nutrients and oxygen to remote outposts, and it sends nerve
signals skipping along thousands of miles of brain and body pathways. It also
formulates chemical messengers that shuttle from one organ to another, issuing
the instructions that help sustain your life.
But to do all this, your body requires some raw materials. These include at
least 30 vitamins, minerals, and dietary components that your body needs but
cannot manufacture on its own in sufficient amounts.
Vitamins and minerals are considered essential nutrients—because acting in
concert, they perform hundreds of roles in the body. They help shore up bones,
heal wounds, and bolster your immune system. They also convert food into
energy, and repair cellular damage.
But trying to keep track of what all these vitamins and minerals do can be
confusing. Read enough articles on the topic, and your eyes may swim with the alphabet-soup
references to these nutrients, which are known mainly be their initials (such
as vitamins A,B,C,D,E, and K—to name just a few).
In this article, you’ll gain a better understanding of what these vitamins
and minerals actually do in the body and why you want to make sure you’re
getting enough of them.
Micronutrients with a big role in the body
Vitamins and minerals are often called micronutrients because your body
needs only tiny amounts of them. Yet failing to get even those small quantities
virtually guarantees disease. Here are a few examples of diseases that can
result from vitamin deficiencies:
- Scurvy. Old-time sailors
learned that living for months without fresh fruits or vegetables — the
main sources of vitamin C — causes the bleeding gums and listlessness of
scurvy.
- Blindness. In some
developing countries, people still become blind from vitamin A deficiency.
- Rickets. A deficiency in
vitamin D can cause rickets, a condition marked by soft, weak bones that
can lead to skeletal deformities such as bowed legs. Partly to combat
rickets, the U.S. has fortified milk with vitamin D since the 1930s.
Just as a lack of key micronutrients can cause substantial harm to your
body, getting sufficient quantities can provide a substantial benefit. Some examples
of these benefits:
- Strong bones. A
combination of calcium, vitamin D, vitamin K, magnesium, and phosphorus
protects your bones against fractures.
- Prevents birth defects.
Taking folic acid supplements early in pregnancy helps prevent brain and
spinal birth defects in offspring.
- Healthy teeth. The mineral
fluoride not only helps bone formation but also keeps dental cavities from
starting or worsening.
The difference between vitamins and minerals
Although they are all considered micronutrients, vitamins and minerals
differ in basic ways. Vitamins are organic and can be broken down by heat, air,
or acid. Minerals are inorganic and hold on to their chemical structure.
So why does this matter? It means the minerals in soil and water easily find
their way into your body through the plants, fish, animals, and fluids you
consume. But it’s tougher to shuttle vitamins from food and other sources into
your body because cooking, storage, and simple exposure to air can inactivate
these more fragile compounds.
Interacting—in good ways and bad
Many micronutrients interact. Vitamin D enables your body to pluck calcium
from food sources passing through your digestive tract rather than harvesting
it from your bones. Vitamin C helps you absorb iron.
The interplay of micronutrients isn’t always cooperative, however. For
example, vitamin C blocks your body’s ability to assimilate the essential
mineral copper. And even a minor overload of the mineral manganese can worsen
iron deficiency.
A closer look at water-soluble vitamins
Water-soluble vitamins are packed into the watery portions of the foods you
eat. They are absorbed directly into the bloodstream as food is broken down
during digestion or as a supplement dissolves.
Because much of your body consists of water, many of the water-soluble
vitamins circulate easily in your body. Your kidneys continuously regulate
levels of water-soluble vitamins, shunting excesses out of the body in your
urine.
Water-soluble vitamins
(Click on the links below for more information from the Harvard School of
Public Health nutrition source website)
B vitamins
- Biotin
(vitamin B7)
- Folic
acid (folate, vitamin B9)
- Niacin
(vitamin B3)
- Pantothenic
acid (vitamin B5
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- Riboflavin
(vitamin B2)
- Thiamin
(vitamin B1)
- Vitamin
B6
- Vitamin
B12
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Vitamin C
What they do
Although water-soluble vitamins have many tasks in the body, one of the most
important is helping to free the energy found in the food you eat. Others help
keep tissues healthy. Here are some examples of how different vitamins help you
maintain health:
- Release energy. Several B
vitamins are key components of certain coenzymes (molecules that aid
enzymes) that help release energy from food.
- Produce energy. Thiamin,
riboflavin, niacin, pantothenic acid, and biotin engage in energy
production.
- Build proteins and cells.
Vitamins B6, B12, and folic acid metabolize amino acids (the building
blocks of proteins) and help cells multiply.
- Make collagen. One of many
roles played by vitamin C is to help make collagen, which knits together
wounds, supports blood vessel walls, and forms a base for teeth and bones.
Words to the wise
Contrary to popular belief, some water-soluble vitamins can stay in the body
for long periods of time. You probably have several years’ supply of vitamin
B12 in your liver. And even folic acid and vitamin C stores can last more than
a couple of days.
Generally, though, water-soluble vitamins should be replenished every few
days.
Just be aware that there is a small risk that consuming large amounts of some
of these micronutrients through supplements may be quite harmful. For example,
very high doses of B6 — many times the recommended amount of 1.3 milligrams
(mg) per day for adults — can damage nerves, causing numbness and muscle
weakness.
A closer look at fat-soluble vitamins
Rather than slipping easily into the bloodstream like most water-soluble
vitamins, fat-soluble vitamins gain entry to the blood via lymph channels in
the intestinal wall (see illustration). Many fat-soluble vitamins travel
through the body only under escort by proteins that act as carriers.
Absorption of fat-soluble vitamins
- Food
containing fat-soluble vitamins is ingested.
- The food
is digested by stomach acid and then travels to the small intestine, where
it is digested further. Bile is needed for the absorption of fat-soluble
vitamins. This substance, which is produced in the liver, flows into the
small intestine, where it breaks down fats. Nutrients are then absorbed
through the wall of the small intestine.
- Upon
absorption, the fat-soluble vitamins enter the lymph vessels before making
their way into the bloodstream. In most cases, fat-soluble vitamins must be coupled with a protein in order to travel through the body.
- These
vitamins are used throughout the body, but excesses are stored in the liver
and fat tissues.
- As
additional amounts of these vitamins are needed, your body taps into the
reserves, releasing them into the bloodstream from the liver.
Fatty foods and oils are reservoirs for the four fat-soluble vitamins.
Within your body, fat tissues and the liver act as the main holding pens for
these vitamins and release them as needed.
To some extent, you can think of these vitamins as time-release
micronutrients. It’s possible to consume them every now and again, perhaps in
doses weeks or months apart rather than daily, and still get your fill. Your
body squirrels away the excess and doles it out gradually to meet your needs.
Fat-soluble vitamins
(Click on the links below for more information from the Harvard School of
Public Health nutrition source website)
What they do
Together this vitamin quartet helps keep your eyes, skin, lungs,
gastrointestinal tract, and nervous system in good repair. Here are some of the
other essential roles these vitamins play:
- Build bones. Bone
formation would be impossible without vitamins A, D, and K.
- Protect vision. Vitamin A
also helps keep cells healthy and protects your vision.
- Interact favorably. Without
vitamin E, your body would have difficulty absorbing and storing vitamin
A.
- Protect the body. Vitamin
E also acts as an antioxidant (a compound that helps protect the body
against damage from unstable molecules).
Words to the wise
Because fat-soluble vitamins are stored in your body for long
periods, toxic levels can build up. This is most likely to happen if you take
supplements. It’s very rare to get too much of a vitamin just from food.
A closer look at major minerals
The body needs, and stores, fairly large amounts of the major minerals.
These minerals are no more important to your health than the trace minerals;
they’re just present in your body in greater amounts.
Major minerals travel through the body in various ways. Potassium, for
example, is quickly absorbed into the bloodstream, where it circulates freely
and is excreted by the kidneys, much like a water-soluble vitamin. Calcium is
more like a fat-soluble vitamin because it requires a carrier for absorption and
transport.
Major minerals
- Calcium
- Chloride
- Magnesium
- Phosphorus
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What they do
One of the key tasks of major minerals is to maintain the proper balance of
water in the body. Sodium, chloride, and potassium take the lead in doing this.
Three other major minerals — calcium, phosphorus, and magnesium — are important
for healthy bones. Sulfur helps stabilize protein structures, including some of
those that make up hair, skin, and nails.
Words to the wise
Having too much of one major mineral can result in a deficiency of another.
These sorts of imbalances are usually caused by overloads from supplements, not
food sources. Here are two examples:
- Salt overload. Calcium
binds with excess sodium in the body and is excreted when the body senses
that sodium levels must be lowered. That means that if you ingest too much
sodium through table salt or processed foods, you could end up losing
needed calcium as your body rids itself of the surplus sodium.
- Excess phosphorus.
Likewise, too much phosphorus can hamper your ability to absorb magnesium.
A closer look at trace minerals
A thimble could easily contain the distillation of all the trace minerals
normally found in your body. Yet their contributions are just as essential as
those of major minerals such as calcium and phosphorus, which each account for
more than a pound of your body weight.
Trace minerals
- Chromium
- Copper
- Fluoride
- Iodine
- Iron
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- Manganese
- Molybdenum
- Selenium
- Zinc
|
What they do
Trace minerals carry out a diverse set of tasks. Here are a few examples:
- Iron is
best known for ferrying oxygen throughout the body.
- Fluoride
strengthens bones and wards off tooth decay.
- Zinc
helps blood clot, is essential for taste and smell, and bolsters the
immune response.
- Copper
helps form several enzymes, one of which assists with iron metabolism and
the creation of hemoglobin, which carries oxygen in the blood.
The other trace minerals perform equally vital jobs, such as helping to
block damage to body cells and forming parts of key enzymes or enhancing their
activity.
Words to the wise
Trace minerals interact with one another, sometimes in ways that can trigger
imbalances. Too much of one can cause or contribute to a deficiency of another.
Here are some examples:
- A minor
overload of manganese can exacerbate iron deficiency. Having too little
can also cause problems.
- When the
body has too little iodine, thyroid hormone production slows, causing
sluggishness and weight gain as well as other health concerns. The problem
worsens if the body also has too little selenium.
The difference between “just enough” and “too much” of the trace
minerals is often tiny. Generally, food is a safe source of trace minerals, but
if you take supplements, it’s important to make sure you’re not exceeding safe
levels.
A closer look at antioxidants
Antioxidant is a catchall term for any compound that can counteract unstable
molecules such as free radicals that damage DNA, cell membranes, and other parts
of cells.
Your body cells naturally produce plenty of antioxidants to put on patrol.
The foods you eat — and, perhaps, some of the supplements you take — are
another source of antioxidant compounds. Carotenoids (such as lycopene in
tomatoes and lutein in kale) and flavonoids (such as anthocyanins in
blueberries, quercetin in apples and onions, and catechins in green tea) are
antioxidants. The vitamins C and E and the mineral selenium also have
antioxidant properties.
Why free radicals may be harmful
Free radicals are a natural byproduct of energy metabolism and are also
generated by ultraviolet rays, tobacco smoke, and air pollution. They lack a
full complement of electrons, which makes them unstable, so they steal
electrons from other molecules, damaging those molecules in the process.
Free radicals have a well-deserved reputation for causing cellular damage.
But they can be helpful, too. When immune system cells muster to fight
intruders, the oxygen they use spins off an army of free radicals that destroys
viruses, bacteria, and damaged body cells in an oxidative burst. Vitamin C can
then disarm the free radicals.
How antioxidants may help
Antioxidants are able to neutralize marauders such as free radicals by
giving up some of their own electrons. When a vitamin C or E molecule makes
this sacrifice, it may allow a crucial protein, gene, or cell membrane to
escape damage. This helps break a chain reaction that can affect many other
cells.
It is important to recognize that the term “antioxidant” reflects a chemical
property rather than a specific nutritional property. Each of the nutrients
that has antioxidant properties also has numerous other aspects and should be
considered individually. The context is also important — in some settings, for
example, vitamin C is an antioxidant, and in others it can be a pro-oxidant.
Words to the wise
Articles and advertisements have touted antioxidants as a way to help slow
aging, fend off heart disease, improve flagging vision, and curb cancer. And
laboratory studies and many large-scale observational trials (the type that
query people about their eating habits and supplement use and then track their
disease patterns) have noted benefits from diets rich in certain antioxidants
and, in some cases, from
antioxidant supplements.
But results from randomized controlled trials (in which people are assigned
to take specific nutrients or a placebo) have failed to back up many of these
claims. One study that pooled results from 68 randomized trials with over
230,000 participants found that people who were given vitamin E, beta carotene,
and vitamin A had a higher risk of death than those who took a placebo. There
appeared to be no effect from vitamin C pills and a small reduction in
mortality from selenium, but further research on these nutrients is needed.
These findings suggest little overall benefit of the antioxidants in pill
form. On the other hand, many studies show that people who consume higher
levels of these antioxidants in food have a lower risk of many diseases
Source : http://www.helpguide.org/harvard/vitamins_and_minerals.htm