Nutrition/ Nutrients
What is nutrition, and why does it
matter?
- Macro-nutrients
- Micro-nutrients
- Vitamins
- Dietitian vs. nutritionist
Nutrition is the study of nutrients
in food, how the body uses them, and the relationship between diet, health, and
disease.
 |
Nutrients/Nutrients
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Nutritionists use ideas from
molecular biology, biochemistry, and genetics to understand how nutrients
affect the human body.
Nutrition also focuses on how people
can use dietary choices to reduce the risk of disease, what happens if a person
has too much or too little of a nutrient, and how allergies work.
Nutrients provide nourishment.
Proteins, carbohydrates, fat, vitamins, minerals, fiber, and water are all
nutrients. If people do not have the right balance of nutrients in their diet,
their risk of developing certain health conditions increases.
This article will explain the
different nutrients a person needs and why. It will also look at the role of
the dietitian and the nutritionist.
Macro-nutrients
Consuming the right balance of
nutrients can help maintain a healthful lifestyle.
Macronutrients are nutrients that
people need in relatively large quantities.
Carbohydrates
Sugar, starch, and fiber are types
of carbohydrates.
Sugars are simple carbs. The body
quickly breaks down and absorbs sugars and processed starch. They can provide
rapid energy, but they do not leave a person feeling full. They can also cause
a spike in blood sugar levels. Frequent sugar spikes increase the risk of type
2 diabetes and its complications.
Fiber is also a carbohydrate. The body breaks down some types of fiber and uses them for
energ; others are metabolized by gut bacteria, while other types pass through
the body.
Fiber and unprocessed starch are
complex carbs. It takes the body some time to break down and absorb complex
carbs. After eating fiber, a person will feel full for longer. Fiber may also
reduce the risk of diabetes, cardiovascular disease, and colorectal cancer.
Complex carbs are a more healthful choice than sugars and refined carbs.
Proteins
Proteins consist of amino acids,
which are organic compounds that occur naturally.
There are 20 amino acids. Some of
these are essential, which means people need to obtain them from food. The body
can make the others.
Some foods provide complete protein,
which means they contain all the essential amino acids the body needs. Other
foods contain various combinations of amino acids.
Most plant-based foods do not
contain complete protein, so a person who follows a vegan diet needs to eat a
range of foods throughout the day that provides the essential amino acids
Fats
Fats are essential for:
lubricating joints
helping organs produce hormones
enabling the body to absorb certain
vitamins
reducing inflammation
preserving brain health
Too much fat can lead to obesity,
high cholesterol, liver disease, and other health problems.
However, the type of fat a person
eats makes a difference. Unsaturated fats, such as olive oil, are more
healthful than saturated fats, which tend to come from animals.
Water
The adult human body is up to 60%
water, and it needs water for many processes. Water contains no calories,
and it does not provide energy.
Many people recommend consuming 2
liters, or 8 glasses, of water a day, but it can also come from dietary
sources, such as fruit and vegetables. Adequate hydration will result in pale
yellow urine.
Requirements will also depend on an
individual’s body size and age, environmental factors, activity levels, health
status, and so on.
Micro-nutrients
Micro-nutrients are essential in
small amounts. They include vitamins and minerals. Manufacturers sometimes add
these to foods. Examples include fortified cereals and rice.
Minerals
The body needs carbon, hydrogen,
oxygen, and nitrogen.
It also needs dietary minerals, such
as iron, potassium, and so on.
In most cases, a varied and balanced
diet will provide the minerals a person needs. If a deficiency occurs, a doctor
may recommend supplements.
Here are some of the
minerals the body needs to function well.
Potassium
Potassium is an electrolyte. It
enables the kidneys, the heart, the muscles, and the nerves to work properly.
The 2015–2020 Dietary Guidelines for Americans recommend that adults consume
4,700 milligrams (mg) of potassium each day.
Too little can lead to high blood
pressure, stroke, and kidney stones.
Too much may be harmful to people
with kidney disease.
Avocados, coconut water, bananas,
dried fruit, squash, beans, and lentils are good sources.
Sodium
Sodium is an electrolyte that helps:
maintain nerve and muscle function
regulate fluid levels in the body
Too little can lead to hyponatremia.
Symptoms include lethargy, confusion, and fatigue. Learn more here.
Too much can lead to high blood
pressure, which increases the risk of cardiovascular disease and stroke.
Table salt, which is made up of
sodium and chloride, is a popular condiment. However, most people consume too
much sodium, as it already occurs naturally in most foods.
Experts urge people not to add table
salt to their diet. Current guidelines recommend consuming no more than 2,300
mg of sodium a day, or around one teaspoon.
This recommendation includes both
naturally-occurring sources, as well as salt a person adds to their food.
People with high blood pressure or kidney disease should eat less.
Calcium
The body needs calcium to form bones
and teeth. It also supports the nervous system, cardiovascular health, and
other functions.
Too little can cause bones and teeth
to weaken. Symptoms of a severe deficiency include tingling in the fingers and
changes in heart rhythm, which can be life-threatening.
Too much can lead to constipation,
kidney stones, and reduced absorption of other minerals.
Current guidelines for adults
recommend consuming 1,000 mg a day, and 1,200 mg for women aged 51 and over.
Good sources include dairy products,
tofu, legumes,and green, leafy vegetables.
Phosphorus
Phosphorus is present in all body
cells and contributes to the health of the bones and teeth.
Too little phosphorus can lead to
bone diseases, affect appetite, muscle strength, and coordination. It can also
result in anemia, a higher risk of infection, burning or prickling sensations
in the skin, and confusion.
Too much in the diet is unlikely to
cause health problems though toxicity is possible from supplements,
medications, and phosphorus metabolism problems.
Adults should aim to consume around
700 mg of phosphorus each day. Good sources include dairy products, salmon,
lentils, and cashews.
Magnesium
Magnesium contributes to muscle and
nerve function. It helps regulate blood pressure and blood sugar levels, and it
enables the body to produce proteins, bone, and DNA.
Too little magnesium can eventually
lead to weakness, nausea, tiredness, restless legs, sleep conditions, and other
symptoms.
Too much can result in digestive
and, eventually, heart problems.
Nuts, spinach, and beans are good
sources of magnesium. Adult females need 320 mg of magnesium each day, and
adult males need 420 mg.
Zinc
Zinc plays a role in the health of
body cells, the immune system, wound healing, and the creation of proteins.
Too little can lead to hair loss,
skin sores, changes in taste or smell,and diarrhea, but this is rare.
Too much can lead to digestive
problems and headaches. Click here to learn more.
Adult females need 8 mg of zinc a
day, and adult males need 11 mg. Dietary sources include oysters, beef,
fortified breakfast cereals, and baked beans. For more on dietary sources of
zinc, click here.
Iron
Iron is crucial for the formation of
red blood cells, which carry oxygen to all parts of the body. It also plays a
role in forming connective tissue and creating hormones.
Too little can result in anemia,
including digestive issues, weakness, and difficulty thinking. Learn more here
about iron deficiency.
Too much can lead to digestive
problems, and very high levels can be fatal.
Good sources include fortified
cereals, beef liver, lentils, spinach, and tofu. Adults need 8 mg of iron a
day, but females need 18 mg during their reproductive years.
Manganese
The body uses manganese to produce
energy, it plays a role in blood clotting, and it supports the immune system.
Too little can result in weak bones
in children, skin rashes in men, and mood changes in women.
Too much can lead to tremors, muscle
spasms, and other symptoms, but only with very high amounts.
Mussels, hazelnuts, brown rice,
chickpeas, and spinach all provide manganese. Male adults need 2.3 mg of
manganese each day, and females need 1.8 mg..
Copper
Copper helps the body make energy
and produce connective tissues and blood vessels.
Too little copper can lead to
tiredness, patches of light skin, high cholesterol, and connective tissue
disorders. This is rare.
Too much copper can result in liver
damage, abdominal pain, nausea, and diarrhea. Too much copper also reduces the
absorption of zinc.
Good sources include beef liver,
oysters, potatoes, mushrooms, sesame seeds, and sunflower seeds. Adults need
900 micrograms (mcg) of copper each day.
Selenium
Selenium is made up of over 24
selenoproteins, and it plays a crucial role in reproductive and thyroid health.
As an antioxidant, it can also prevent cell damage.
Too much selenium can cause garlic
breath, diarrhea, irritability, skin rashes, brittle hair or nails, and other
symptoms.
Too little can result in heart
disease, infertility in men, and arthritis.
Adults need 55 mcg of selenium a
day.
Brazil nuts are an excellent source
of selenium. Other plant sources include spinach, oatmeal, and baked beans.
Tuna, ham, and enriched macaroni are all excellent sources.
Vitamins
Eating a variety of healthful foods
can provide the body with different vitamins.
People need small amounts of various
vitamins. Some of these, such as vitamin C, are also antioxidants. This means
they help protect cells from damage by removing toxic molecules, known as free
radicals, from the body.
Vitamins can be:
Water-soluble: The eight B vitamins and vitamin C
Fat-soluble: Vitamins A, D, E, and K
Water soluble vitamins
People need to consume water-soluble
vitamins regularly because the body removes them more quickly, and it cannot
store them easily.
Vitamin
|
Effect
of too little
|
Effect
of too much
|
Sources
|
B-1 (thiamin)
|
Beriberi
Wernicke-Korsakoff syndrome
|
Unclear,
as the body excretes it in the urine.
|
Fortified
cereals and rice, pork, trout, black beans
|
B-2
(riboflavin)
|
Hormonal
problems, skin disorders, swelling in the mouth and throat
|
Unclear,
as the body excretes it in the urine.
|
Beef
liver, breakfast cereal, oats, yogurt, mushrooms, almonds
|
B-3 (niacin)
|
Pellagra,
including skin changes, red tongue, digestive and neurological symptoms
|
Facial
flushing, burning, itching, headaches, rashes, and dizziness
|
Beef
liver, chicken breast, brown rice, fortified cereals, peanuts.
|
B-5 (pantothenic
acid)
|
Numbness
and burning in hands and feet, fatigue, stomach pain
|
Digestive
problems at high doses.
|
Breakfast
cereal, beef liver, shiitake mushroom, sunflower seeds
|
B-6 (pyridoxamine,
pyridoxal)
|
Anemia, itchy rash,
skin changes, swollen tongue
|
Nerve
damage, loss of muscle control
|
Chickpeas,
beef liver, tuna, chicken breast, fortified cereals, potatoes
|
B-7 (biotin)
|
Hair
loss, rashes around the eyes and other body openings, conjunctivitis
|
Unclear
|
Beef
liver, egg, salmon, sunflower seeds, sweet potato
|
Weakness,
fatigue, difficulty focusing, heart palpitations, shortness of breath
|
May
increase cancer risk
|
Beef
liver, spinach, black-eyed peas, fortified cereal, asparagus
|
|
B-12
(cobalamins)
|
Anemia,
fatigue, constipation, weight loss, neurological changes
|
No
adverse effects reported
|
Clams,
beef liver, fortified yeasts, plant milks, and breakfast cereals, some oily
fish.
|
Vitamin
C (ascorbic acid)
|
Scurvy,
including fatigue, skin rash, gum inflammation, poor wound healing
|
Nausea,
diarrhea, stomach cramps
|
Citrus
fruits, berries, red and green peppers, kiwi fruit, broccoli, baked potatoes,
fortified juices.
|
Fat-soluble vitamins
Fat-soluble vitamins
The body absorbs fat-soluble
vitamins through the intestines with the help of fats (lipids). The body can
store them and does not remove them quickly. People who follow a low-fat diet
may not be able to absorb enough of these vitamins. If too many build up,
problems can arise.
Vitamin
|
Effect
of too little
|
Effect
of too much
|
Sources
|
|
Vitamin
A (retinoids)
|
Night
blindness
|
Pressure
on the brain, nausea, dizziness, skin irritation, joint and bone pain, orange
pigmented skin color
|
Sweet
potato, beef liver, spinach, and other dark leafy greens, carrots, winter
squash
|
|
Vitamin
D
|
Poor
bone formation and weak bones
|
Anorexia,
weight loss, changes in heart rhythm, damage to cardiovascular system and
kidneys
|
Sunlight
exposure plus dietary sources: cod liver oil, oily fish, dairy products,
fortified juices
|
|
Vitamin
E
|
Peripheral neuropathy,
retinopathy, reduced immune response
|
May
reduce the ability of blood to clot
|
Wheatgerm,
nuts, seeds, sunflower and safflower oil, spinach
|
|
Vitamin
K
|
Bleeding
and hemorrhaging in severe cases
|
No
adverse effects but it may interact with blood thinners and other drugs
|
Leafy,
green vegetables, soybeans, edamame, okra, natto
|
Antioxidants
Some nutrients also act as
antioxidants. These may be vitamins, minerals, proteins, or other types of
molecules. They help the body remove toxic substances known as free radicals,
or reactive oxygen species. If too many of these substances remain in the body,
cell damage and disease can result.
Dietitian vs. nutritionist
A registered dietitian nutritionist
(RD or RDN) studies food, nutrition, and dietetics. To become a registered
dietitian, a person needs to attend an accredited university, follow an approved
curriculum, complete a rigorous internship, pass a licensure exam, and complete
75 or more continuing education hours every 5 years. Dietitians work in private
and public healthcare, education, corporate wellness, research, and the food
industry
A nutritionist learns about
nutrition through self-study or formal education, but they do not meet the
requirements to use the titles RD or RDN. Nutritionists often work in the food
industry and in food science and technology.
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