Download The Power of Protein: More Than Muscle Building

The Power of Protein:
More Than Muscle Building
K
Why all the hype about protein lately?
Most people think of protein as slabs of meat that athletes,
body builders and strength trainers down regularly to build
muscle. Recent research has shown dietary protein has a much
broader list of benefits—from weight loss, satiety and healthy
aging to blood sugar control and diabetes management.
Many
1-2
experts, in fact, think our consumption of this important
nutrient should be higher than the Recommended Dietary
Allowance (RDA), which is based on the minimum needed
to replace daily losses.
Protein has truly become the Nutrient of the Decade.
Continue reading to find out more about protein, separate
the truth from the hype, figure out how much is needed and
learn what foods are good sources.
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What exactly IS protein?
Protein is an essential macronutrient,
along with fat and carbohydrate, that
our bodies need each day. It is part
of every cell, tissue and organ in our
bodies. It is made up of 20 amino
acids, or building blocks. Nine of these
amino acids are considered essential—
we need to get them from our diets
because our bodies cannot make them.
We need amino acids from the
protein in the foods we eat to build
and maintain bones, muscles and skin.
Other important functions of protein
include making enzymes, hormones and
antibodies; maintaining fluid, electrolytes
and acid-base balance; and providing
energy and glucose (sugar) to our
bodies.
If we don’t get enough protein, and
specifically enough of the 9 essential
amino acids, we can become protein
deficient, causing problems in all of
these areas. In addition, because the
body doesn’t have a way to store
protein as it does fat and carbohydrate,
we need to consume adequate protein
every day.
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HealthyEating.org
The Power of Protein
Where do we find it?
Protein is distributed widely in our food supply. The USDA
defines the protein group as all foods made from meat,
poultry, seafood, beans and peas, eggs, processed soy
products, nuts and seeds … but protein is found in other
food groups as well. For example, the Milk & Milk Products
food group contributes about one-fifth of our total daily
protein intake.1 Grains also provide some protein, and even
vegetables have small amounts of protein that round out a
balanced diet.
The majority of our protein comes from animal sources.
Americans ages 50 and above get almost two-thirds of
their protein from animal foods: 40 percent from meat, 18
percent from milk and milk products and 4 percent from
eggs.2
So, in a well-balanced diet that includes foods from all food
groups, it is fairly easy to get the protein we need on a
daily basis. Strict vegetarians (vegans) who do not eat meat
or dairy products may have a hard time consuming enough
protein and might need to eat more calories to get the
same amount of protein. Ovo-lacto vegetarians who
consume dairy and eggs generally can get enough protein
through beans, nuts, eggs and milk and milk products.
See the Tips section below for ways to optimize protein
intake or read “Tips for Vegetarians” on the USDA’s www.
ChooseMyPlate.gov website to get more ideas.
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Are there different
types of protein?
The quality of protein varies
depending on the food source and
the type and amount of amino
acids that it provides. Animal-based
protein such as from lean meat,
eggs and milk and milk products
contains all the essential amino acids
in the ratio needed by our bodies, is
easily digestible and is considered a
“complete” protein source.3
Plant protein is generally considered
lower quality as it often lacks
certain essential amino acids and
contains components that impair
absorption. Plants are characterized
as an “incomplete” source of protein,
making it necessary to eat a variety
to provide the complementary
amino acids the body needs. It was
once thought that this variety had to
be consumed at one meal in order
for the body to effectively use the
protein; now, however, it is believed
that complementary protein can be
consumed over the course of the
day. Read “Tips to Help You Make
Wise Choices from the Protein Foods
Group” on the www.ChooseMyPlate.
gov website for good protein food
choices.
Protein Sources
Whey protein powder
Amount
1 oz
Lean beef, pork or poultry* 3 oz
Protein (g)
22
18-20
Seafood and fish*
3 oz
16
Greek-style yogurt
1 container
(6 oz)
12
Beans* and lentils
¼ cup
12
Nuts*
¼ cup
10
Milk
1 cup
8
Quinoa 1 cup
8
Traditional yogurt
1 container
(6 oz)
Cheese
1 oz
7
Eggs 1 each
6
Tofu
3 oz
6
Whole-wheat bread
1 slice
4
7-8
All values are from USDA National Nutrient Database for
Standard Reference 2011: http://ndb.nal.usda.gov.
* Value shown is the average of different cuts/types of that
food item (e.g., “lean beef ” is the average of round roast,
top round and top sirloin).
How do we know if we are
getting enough protein?
The RDA for protein is 0.8 grams per
kilogram body weight per day. This is about
45 grams/day for a 125-pound person; 70
grams/day for a 190-pound person. Most
Americans meet this minimum protein
requirement easily through their daily
diets. However, some groups—such as
athletes, older adults and those on weightloss diets—may benefit from increasing
their intake beyond the minimum levels to
take advantage of protein’s other health
effects. Online protein calculators4 can help
determine how much protein is needed
every day.
The Institute of Medicine provides a range
of protein intake of 10 to 35 percent of
calories from protein. On a 2000-kilocalorie
diet, this is 50 to 175 grams per day,
much higher than the minimum level set
by the RDA. The average American only
gets 16 percent of their calories from
protein,5 which is at the lower end of the
recommended range.
The table on the left shows some good
sources of protein and how many grams
each food contains.
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The Power of Protein
We’re hearing a lot about high-protein diets.
Just what are the benefits?
While past research has focused on the muscle building and sports
performance aspects of protein, more recent focus has been in other
areas.
Satiety/weight
A multitude of studies has shown that dietary protein may help with
weight management and obesity prevention by increasing satiety.6
Moderately high protein diets have also been shown to help with
weight maintenance after significant weight is lost.7
Healthy aging
Sarcopenia—the decrease in muscle mass and performance that
occurs with aging—occurs in up to 45 percent of older men and 26
percent of older women. Various studies suggest that diets higher
in protein can help minimize muscle loss and prevent frailty, helping
people live longer and more independent lives as they age.8 A higherprotein diet combined with resistance exercise has also been shown
to help build healthy muscles and support weight management in
older adults.9
Diabetes management and blood sugar control
A variety of studies has shown that high-protein diets can be
helpful in controlling blood sugar levels, as well as improving heart
disease risk in people with diabetes.10 Currently about 12 percent
of American adults have diabetes, and an additional 35 percent have
pre-diabetes.11 With the increasing incidence of overweight and
obesity in the United States, these levels are expected to rise much
higher in the coming years. Diabetes is a major risk factor for heart
disease and stroke.
Bone health
Most people think of calcium and vitamin D for bone health. Protein
is also important in building and maintaining strong bones. Many
studies show that dietary protein may positively impact bone health,
particularly when calcium intakes are adequate. This effect may be
through increasing muscle mass or calcium absorption, or through
hormonal effects on bone. The amount and timing of protein intake
on bone health, however, is unclear and needs more research.12
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Does the timing
of protein intake
matter?
While it may be easy to get
the total amount of protein in
our daily diet, it is harder to
get the distribution of protein
throughout the day that is best
for our bodies. New research
shows that it is best to spread
our protein intake evenly
over our meals and snacks to
help our bodies use it most
efficiently. The Tips section
below shows how to do this.
Some experts suggest getting
20 to 30 grams of protein at
each meal or snack.
Most Americans get almost half
of their protein at dinner, about
one-quarter at lunch and the
remainder at breakfast and
snacks. We can use the table
above to count how much
protein we are getting at each
meal and see where to make
improvements.
Tips
Getting enough of the right kinds of protein throughout the day
Get the day off to a strong start by making sure to get the first
dose of protein at breakfast. Add an egg to a bagel, nuts to cereal,
peanut butter to a slice of toast, a scoop of whey protein powder to
oatmeal or a scoop of Greek yogurt to granola.
ä
Make sure every meal and snack contains some protein. This will
help to feel full longer, reduce “swings” in blood sugar, improve bone
health and reap the many other rewards protein provides!
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Focus on high quality sources of protein—lean meats, beans, nuts
and nut butters, eggs, milk, cheese and yogurt. While vegetables and
grains contain small amounts of protein, they are generally lacking in
specific amino acids, making them a less complete protein source.
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If cost is a factor in food choices, consider dairy, beans, eggs and
certain nuts as inexpensive protein sources. Fish, lentils, tofu, seeds
and veggie burgers can also add variety to the diet beyond solely
meat-based options.
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Experiment with “newer” protein sources such as quinoa, amaranth and whey
protein powder for a change in routine.
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Read more about getting protein throughout the day in the article “Protein: Make
the Shift from Dinner to Daytime” on the www.healthyeating.org website.
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The Power of Protein
References
1.
2.
3.
Dairy Research Institute—NHANES 2003-2006; Age
2+ Years. From: World Dairy Summit 2012 Presentation:
Dairy Nutrition and Environmental Sustainability: Setting
the Record Straight. Original source: http://www.cdc.
gov/nchs/nhanes.htm
Berner LA, Becker G, Wise M, Doi J. Characterization
of Dietary Protein Among Older Adults in the United
States: Amount, Animal Sources and Meal Patterns.
JAND 2013;113:809-815.
FAO 2013. Dietary Protein Equality Evaluation
in Human Nutrition: Report of an FAO Expert
Consultation, FAO Food and Nutrition Paper 92. Rome:
FAO.
4.
http://www.healthcalculators.org/calculators/protein.asp
Accessed Jan 29, 2014.
5.
Centers for Disease Control and Prevention. FastStats;
Diet and Nutrition; NHANES 2007-10. http://www.cdc.
gov/nchs/fastats/diet.htm. Accessed Jan 29, 2014.
6.
Westerterp-Plantenga MS, Lemmens SG, Westerterp
KR. Dietary Protein: Its Role in Satiety, Energetics, Weight
Loss and Health. Br J Nutr. 2012 Aug;108 Suppl 2:S10512.
7.
Westerterp-Plantenga MS, Lejeune MP, Nijs I, van Ooijen
M, Kovacs EM. High Protein Intake Sustains Weight
Maintenance after Body Weight Loss in Humans. Int J
Obes Relat Metab Disord. 2004 Jan;28(1):57-64.
8.
Beasley JM, Shikany JM, Thomson CA. The Role of
Dietary Protein Intake in the Prevention of Sarcopenia
of Aging. Nutr Clin Pract. 2013 Dec;28(6):684-90.
9.
Fry CS, Rasmussen BB. Skeletal Muscle Protein Balance
and Metabolism in the Elderly. Curr Aging Sci. 2011
Dec;4(3):260-8.
10. Ajala O, English P, Pinkney J. Systematic Review and
Meta-analysis of Different Dietary Approaches to the
Management of Type 2 Diabetes. Am J ClinNutr. 2013
Mar;97(3):505-16.
11. U.S. Dept of Health and Human Services. National
Diabetes Information Clearinghouse. http://diabetes.
niddk.nih.gov/dm/pubs/statistics/#fast Accessed Jan 29,
2014.
12. Mangano KM, Sahni S, Kerstetter JE. Dietary Protein
is Beneficial to Bone Health Under Conditions of
Adequate Calcium Intake: An Update on Clinical
Research. Curr Opin Clin Nutr Metab Care. 2014
Jan;17(1):69-74.
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