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Spotlight
Fall 2010
on nutrition issues
What’s Inside
Did you know? p. 2, 8
In brief
p. 5
Q&A
p. 7
What’s new?
p. 10
Authors
Veronica Streeter, MAN, RD, is a
recent graduate of the Master of
Applied Nutrition program at the
University of Guelph. Veronica also
holds a Bachelor of Arts degree in
kinesiology from the University of
Western Ontario and a Bachelor of
Science degree with a specialization
in food and nutrition from Brescia
University College. She has
particular interests in nutrition
education and health promotion
and aims to work as a Registered
Dietitian in a community setting.
Vanessa Nagy is completing her
Master of Public Health degree in
community nutrition at the University
of Toronto and is on a work placement
in the Nutrition Department at
Dairy Farmers of Canada. She has
a particular interest in school and
child nutrition and looks forward to
working as a Registered Dietitian in a
community or public health setting.
Acknowledgement
Our special thanks go to Dr. Stuart
Phillips for providing an expert
review of this issue of Spotlight.
Dr. Phillips is a Professor and the
Associate Chair of Graduate Studies
in the Department of Kinesiology at
McMaster University and is a Fellow
of the American College of Sports
Medicine and the American College
of Nutrition. His research focuses
on factors that maintain, increase
or decrease skeletal muscle mass.
Dr. Phillips has published over 140
research manuscripts in the areas
of nutrition, exercise and body
composition; we thank him for
sharing his knowledge and expertise.
Protein Power: Protein’s Contribution to
the Reduction of Chronic Disease Risk
Synopsis
Diet and lifestyle modifications remain the cornerstone of chronic disease prevention
and management. A growing body of evidence suggests that a balanced diet that
includes adequate protein – characterized as protein intake above the Recommended
Dietary Allowance of 0.8 grams of protein per kilogram of body weight, but well
within the Acceptable Macronutrient Distribution Range for protein of 10% to 35%
of total dietary energy – contributes to overall health and reduces the risk of some
chronic diseases. Research also points to milk products in the reduction of risk for
some common chronic diseases, likely as a result of the multiple nutrient components
present in milk, including high-quality protein. Specifically, moderate consumption
of milk protein may reduce risk factors for heart disease by improving an individual’s
blood lipid profile and reducing blood pressure. Individuals at risk of or diagnosed
with type 2 diabetes may also benefit from this macronutrient via improved glycemic
regulation. Finally, milk protein consumption has advantages for body composition,
which is beneficial for individuals trying to maintain a healthy body weight, or elderly
individuals trying to prevent age-related muscle loss. These findings support the
promotion of dietary protein within the recommended Dietary Reference Intakes,
and are consistent with eating at least two, and up to four, daily servings of Milk and
Alternatives, as recommended in Eating Well with Canada’s Food Guide. Given the
aging Canadian population, the rising prevalence of obesity and the fact that heart
disease and type 2 diabetes are two of the most significant causes of morbidity and
mortality in Canada, optimizing protein intake, including adequate consumption of
milk products, is not only relevant to, but also timely for, improving the health of the
Canadian population.
Introduction
Chronic diseases are the major cause
of death and disability worldwide.1 In
Canada, chronic diseases are estimated
to account for approximately 89% of
all deaths.1 The economic impact of
premature deaths due to heart disease,
stroke and diabetes is substantial: in
2005 it was estimated that Canada lost
approximately $500 million in national
income as a result of premature deaths
from chronic diseases.2 However, at
least 80% of these premature deaths
could be prevented by modifying
individual lifestyle behaviours to include
a healthy, balanced diet and regular
physical activity.1
The promotion of behaviours that benefit health,
such as improved diet and increased physical activity,
is a cost-effective intervention that could slow the
spiralling cost of chronic disease in Canada. Scientific
research suggests that moderate consumption of protein,
within the Acceptable Macronutrient Distribution
Range (AMDR), can provide nutritional and metabolic
advantages that may prevent and manage chronic
diseases. The chronic diseases and conditions discussed
in this issue of Spotlight are cardiovascular disease,
type 2 diabetes, sarcopenia and obesity. Emerging
evidence suggests that adequate consumption of highquality milk protein reduces the risk of these common
chronic diseases. Additionally, dairy products are
important contributors to higher-protein diets, which
further prevent and manage chronic disease risk.
Did you know?
Milk Proteins
Cow’s milk represents a unique source of nutrients
that can act both independently and synergistically
with one another. Milk contains two types of protein:
whey (20%) and casein (80%). Both are high-quality
proteins, according to science-based rating scales,
and both contain all essential amino acids in
amounts sufficient to support the multiple roles of
protein in the body.3,4
According to the Protein Digestibility-Corrected
Amino Acid Score (PDCAAS), a method of measuring
protein quality based on availability of essential
amino acids as well as digestibility, milk provides
higher-quality protein than beef, soy or wheat.5
Because of its high quality, cow’s milk protein is
used as a standard reference protein to evaluate
the nutritive value of food proteins.6 Individual milk
proteins have been shown to exhibit a wide range
of beneficial functions that may play a role in the
prevention and management of chronic disease.
2 Spotlight Fall 2010
Cardiovascular Disease
The term cardiovascular disease describes a cluster of
diseases of the circulatory system; it is currently the
leading cause of death in adult Canadians.14 Ischemic
heart disease, or heart attack, is the most common
type of cardiovascular disease and affects both men
and women.15 The majority of cases of cardiovascular
disease stem from modifiable risk factors, including
lack of physical activity, poor diet, smoking, high blood
cholesterol, hypertension and, potentially, stress.15
Healthy eating, which includes sufficient dietary
protein consumption, assists in the reduction of
cardiovascular disease risk. In particular, some
components of milk proteins have been demonstrated
to reduce blood pressure, which can contribute to
lowering total estimated cardiovascular risk.16
The Evidence: Dietary Protein and
Cardiovascular Disease
An abnormal blood lipid profile consists of
elevated levels of low-density lipoprotein (LDL)
cholesterol, low levels of high-density lipoprotein
(HDL) cholesterol, and high levels of triglycerides,
a type of fat found in the blood.14 The Canadian
Cardiovascular Society recommends a diet reduced
in simple sugars and refined carbohydrates for the
prevention of cardiovascular disease in adults.17
Subsequent evidence suggests that replacing simple
carbohydrates with other macronutrients, such as
protein from lean meats, poultry and dairy products,
produces beneficial metabolic effects. Increasing
protein intake can reduce simple carbohydrate
consumption and contribute to weight loss.
In one study, the comparison of three types of
diets – high carbohydrate, high unsaturated fat and
high protein – revealed favourable changes from
baseline lipoproteins in all but the high-carbohydrate
diet.18 However, the high-protein diet also significantly
reduced the triglyceride concentration compared with
the other two diets.18 The authors proposed that this
further reduction in triglycerides by the high-protein
diet reveals that protein possesses a triglyceridelowering effect, beyond the result of its replacing
carbohydrates in the diet.18
Additional research supports the improvement of
individuals’ blood lipid profiles with a moderate increase
in protein intake, within the recommended AMDR, by
decreasing triglyceride concentration,19–22 increasing HDL
cholesterol22 and reducing LDL cholesterol.19,22 Finally,
further scientific evidence suggests that a moderate
increase in protein consumption, within the AMDR,
results in a decreased risk of coronary heart disease18 and
reduced estimated 10-year coronary heart disease risk.2
Hypertension, another modifiable risk factor,
plays a role in cardiovascular disease prevention
and management. The longitudinal CARDIA Study
concluded that protein intake was inversely associated
with average blood pressure in multiethnic groups
during seven years of follow-up.23 A meta-analysis
confirms this association.24 Emerging evidence suggests
that the protein component of milk has hypotensive
effects.16 Specifically, milk protein–derived peptides
can inhibit angiotensin-1 converting enzyme (ACE)
activity, a mechanism similar to the action of many
antihypertensive medications.16
Furthermore, the addition of whey protein, a
protein found in dairy products, to the diet has also
demonstrated significant blood pressure–decreasing
effects when compared to glucose controls. 25,26
Additionally, whey protein has produced significant
improvements in inflammatory markers and individual
vascular function.26 Therefore, milk, as a whole food,
has the potential to decrease blood pressure and should
be considered an essential component of the treatment
of hypertension.16 The Spring 2010 issue of Spotlight,
“Dietary Factors in the Prevention and Management of
Hypertension,” described the role of dairy products in
the Dietary Approaches to Stop Hypertension (DASH)
Diet, a highly advocated strategy for the prevention and
management of hypertension.
Type 2 Diabetes Mellitus
Type 2 diabetes is a chronic disease that develops
in stages. The onset is defined as insulin resistance,
which is the decreased ability of insulin to stimulate
muscle to clear glucose from the blood.27 In the later
stages of diabetes, the pancreas loses the ability to
secrete extra insulin in response to elevated levels of
blood glucose.27
Currently, more than three million Canadians
are living with diabetes; this number is expected to
grow to 3.7 million by 2020.28 The number of people
diagnosed with type 2 diabetes is increasing as a
result of the aging of the population, rising rates of
obesity and decreasing levels of physical activity.28
It is estimated that by 2020, the annual cost of
diabetes to the Canadian health-care system will
be approximately $16.9 billion.28
Lifestyle modifications, including adequate
physical activity, a balanced diet and achieving or
maintaining a healthy body weight, can prevent or
delay the onset of type 2 diabetes and help those
already diagnosed manage the disease. For example,
a protein-rich diet can reduce hyperglycemia after
meals, improve overall glucose control and decrease
glycated hemoglobin (a blood marker used to identify
the average plasma glucose over the previous three
months). Additionally, there is considerable evidence
that adequate consumption of milk products is
associated with a reduced risk of developing type 2
diabetes.29,30 Several components of milk products may
be responsible for reducing this risk. Recent evidence
supports the role of milk protein in improving glycemic
control and contributing to weight management.
The Bottom Line: Substantial evidence supports
the theory that replacing dietary carbohydrates with
protein, within the AMDR, lowers LDL cholesterol
and triglycerides, improves HDL cholesterol and
reduces blood pressure. In particular, the bioactive
peptides found in milk proteins have the potential
to significantly lower blood pressure; therefore, milk
products should be emphasized as part of a healthy
balanced diet to help lower cardiovascular disease risk.
Fall 2010
Spotlight
3
The Evidence: Dietary Protein and
Type 2 Diabetes Mellitus
Achieving optimal glycemic control is fundamental
to the management of diabetes. Both fasting and
post-prandial plasma glucose levels correlate with the
risk of complications and contribute to the measured
glycated hemoglobin value. 31 Emerging evidence
indicates that a short-term increase in dietary protein
consumption dramatically lowers glycated hemoglobin
concentration, which indicates improved glycemic
control.32,33 However, longer-term studies are required
to understand whether an increase in dietary protein
consumption also improves long-term glucose control
and decreases the glycated hemoglobin value.
The 2008 Canadian Diabetes Association Clinical
Practice Guidelines recommend a diet reduced in
simple sugars and refined carbohydrates, as do the
Canadian Cardiovascular Society Guidelines.17,34 The
guidelines do not provide suggestions as to which
macronutrients should replace refined carbohydrates,
but there are only two options: protein and fat. Recent
studies have compared the effects of replacing simple
carbohydrates with protein-rich foods in the diets
of individuals with type 2 diabetes and found less
variation in plasma glucose and plasma insulin with
this altered macronutrient intake. 32–34 Additionally,
strong evidence has established that dietary protein
intake improves post-prandial glycemic control in
healthy35–38 and insulin-resistant individuals,20 as well
as in individuals with type 2 diabetes.33,39
Milk proteins are associated with reduced postprandial glycemia.38 Specific mechanisms for these
metabolic outcomes are still being unravelled, but
evidence suggests that the ingestion of food protein
results in a significant increase in plasma insulin.40
Therefore, the replacement of refined carbohydrates
with protein-rich foods will result in a reduced glucose
response, not only because of the increased insulin
response from the protein source, but also owing to the
decreased ingestion of simple carbohydrates.
4 Spotlight Fall 2010
Food proteins differ in their capacity to stimulate
insulin release.41 In one study, whey protein, a fraction
of milk protein, demonstrated insulinotropic properties
above those demonstrated by other food sources, such
as cod and wheat gluten.41 These results indicate that
consumption of milk protein may stimulate insulin
activity and, therefore, that regularly consuming milk
with meals may reduce post-prandial glycemia. A full
review of the role of milk products in the prevention
and management of type 2 diabetes can be found in
the Spring 2009 issue of Spotlight, “Preventing and
Managing Type 2 Diabetes.”
The Bottom Line: Protein consumption, within the
AMDR, has been shown to increase glucose control
and insulin sensitivity in both healthy individuals
and those with insulin resistance or type 2
diabetes. Additionally, it appears that milk protein
has the potential to reduce post-prandial glycemia
and therefore that adequate consumption of milk
products should be encouraged.
In brief
Dietary Reference Intakes
The Dietary Reference Intakes are nutrient reference
guidelines that aim to ensure that Canadians and
Americans consume healthy, balanced diets.7 These
guidelines consist of standard recommendations,
including the Recommended Dietary Allowance
(RDA) and the Acceptable Macronutrient Distribution
Range (AMDR).7 The RDA is an estimate of the
minimum amount of a nutrient required to prevent
deficiency in most healthy people in a specific life
stage and gender group.7 The RDA for protein for
adults is 0.8 grams of protein per kilogram of body
weight per day.8
Some researchers have suggested that the RDA,
while useful for micronutrients, is not suitable for
macronutrients.9,10 Emerging scientific evidence
suggests that the optimal dietary protein intake is
greater than the RDA, particularly for the prevention
of chronic disease. This evidence further indicates that
this standard may be inappropriate for the Canadian
population.11,12 In contrast, the AMDR, expressed as
a percentage of total energy intake, is a range of
intakes determined to meet nutrient requirements and
that is also associated with a reduced risk of chronic
disease.8 Proponents of the latter are encouraging
clinicians to abandon the RDA – the minimum daily
requirement – and adopt the AMDR as the standard
for macronutrient consumption.9,10
The AMDR for protein is 10% to 35% of total daily
energy intake.8 Currently, Canadians consume an
average of 17% of their daily calories from protein,
or approximately 85 grams of protein per day.13
According to the AMDR, Canadians can safely
increase their protein intake to as much as 35% of
daily calories, or approximately 175 grams of protein
per day for an average man or 130 grams per day
for an average woman.
Sarcopenia
Sarcopenia is the process by which the body’s
lean muscle mass declines with age over time.42
Sarcopenia affects more men than women.42,43 Its
prevalence ranges from 20% to 30% in those over
60 years old and reaches 50% in those over 80.42 The
prevalence of sarcopenia will continue to increase
as the population ages. As sarcopenia increases, and
muscle strength decreases, it is reasonable to suspect
that the incidence of falls will increase, concordant
with a decrease in quality of life and reduced
functional independence, which can ultimately result
in institutionalization.44
Sarcopenia is not a chronic disease in itself;
however, it can be a catalyst for the development
of chronic diseases and conditions, including
cardiovascular disease, diabetes and obesity, owing
to muscle’s capacity for lipid oxidation, glucose
uptake and glucose storage.45 Behaviours associated
with the development of sarcopenia include
inadequate consumption of dietary protein and a
sedentary lifestyle.46 Given that muscle mass is harder
to build among the elderly because of a blunted
cellular response to strength training and dietary
protein, the role of high-quality, nutrient-dense
sources of dietary protein is especially important.47
The Evidence: The Role of Dietary
Protein in Preventing Sarcopenia
The importance of adequate protein consumption
in the prevention of sarcopenia is illustrated by a
longitudinal study that examined this association in
older, community-dwelling men and women. This
study found that individuals in the highest quintile
of protein intake (1.2 grams per kilogram of body
weight per day, 50% greater than the RDA) lost 40%
less lean mass than did individuals in the lowest
quintile of protein intake (0.8 g/kg/d, the protein
RDA).48 These results suggest that low protein intake
may be a modifiable risk factor for sarcopenia among
older adults.48
Fall 2010
Spotlight
5
Currently, many individuals aged 71 and older
have inadequate dietary protein intake.49 No
difference has been found between younger and
older individuals’ protein digestion and absorption,
but there is some disagreement over whether older
people can mount a robust increase in muscle
protein synthesis in response to a meal.50–52 This
finding indicates that, besides their blunted cellular
response to muscle hypertrophy and feeding, elderly
individuals may not be consuming enough dietary
protein or, more specifically, enough high-quality
protein, such as milk-based proteins that contain
leucine. Leucine is a branched-chain amino acid
that has been shown to be critically important
in stimulating muscle protein synthesis53 and is
required in larger amounts in older persons.54,55
As individuals age, their energy consumption
decreases. Moreover, recent research reports
that dietary protein requirements are inversely
proportional to energy intake,56 indicating that
elderly individuals likely need to consume larger
amounts of dietary protein to compensate for
their decreased energy intake. Additionally, recent
scientific evidence suggests that elderly people may
actually have a protein requirement that is higher
than the current RDA,11,12,43,46 providing further
support for the theory that many elderly individuals
consume inadequate amounts of protein and are at
high risk of becoming sarcopenic.
Research has established the optimum quantity
of dietary protein per meal to be 25 to 30 grams,
as this amount is sufficient to optimize protein
synthesis.57,58 In one study, consumption of more
than 30 grams of protein per meal did not result
in an increase in protein synthesis beyond what
was observed with consumption of 30 grams. 57
This finding was confirmed in a study comparing
younger and older participants, indicating that this
recommendation is not only practical for elderly
individuals, but also for the younger population.57
The quality of ingested protein should also be
considered in dietary recommendations.59 It has
been suggested that as a result of inadequate dietary
protein intake, the elderly should consume highquality protein sources, such as dairy proteins.
6 Spotlight Fall 2010
As mentioned, the Protein Digestibility-Corrected
Amino Acid Score (PDCAAS) is used to determine
protein quality.5 Milk-based products are a source of
high-quality protein, and have a PDCAAS of 121%
(values higher than 100% are truncated at 100%).5
More importantly, milk proteins also have a high
content of the amino acid leucine, which plays a
large role in stimulating muscle protein synthesis in
aging muscle.53–55
Eating Well with Canada’s Food Guide recommends
that adults over age 50 consume three servings of
Milk and Alternatives per day. However, currently
fewer than 30% of men and women in this age group
consume the recommended number of servings.13,60
Adequate milk product consumption in the elderly
is recommended not only for the high-quality
protein these foods contain, but also for their large
amounts of whey protein.46,59 This particular dairy
component is digested and absorbed more quickly
than soy protein and also stimulates muscle protein
synthesis better than soy protein. 3 The proteins
in milk, including casein and whey, also promote
the maintenance of lean muscle mass, another
important factor in the prevention of sarcopenia, which
can alleviate the risk of developing other chronic
diseases.3,61 Therefore, adequate consumption of Milk
and Alternatives by adults over age 50 is important
because these foods may play a role in decreasing the
risk of sarcopenia in this population.62
The Bottom Line: Currently, many older individuals
do not consume enough dietary protein or milk
products. Inadequate consumption of protein may
contribute to the decrease in muscle mass and the
increase in risk of chronic disease experienced by
older adults. Adequate consumption of milk protein
is particularly important owing to its high content of
both leucine and whey, both of which play large roles
in muscle protein synthesis in the elderly.
Health professionals can encourage sufficient
protein consumption in this population by stressing
the importance of consuming approximately 25 to
30 grams of high-quality protein at each meal and
three servings of Milk and Alternatives per day.
Q&A
Q: D
oes high dietary protein consumption have a
negative effect on bone health?
Q: Are higher-protein diets considered safe?
A:
A: Despite
this widely held belief, research strongly
suggests that individuals with high protein intakes
– up to approximately 2 grams per kilogram of
body weight – actually have better bone quality
when calcium intake is adequate (i.e., 1000 to 1200
milligrams per day).63 This is true throughout the
life cycle: adequate protein intake is associated
with high bone mineral density in teenaged girls
and in premenopausal women,64 and high dietary
protein consumption has been correlated with
reduced risk of hip fracture in both elderly men
and women.65
The misconception that high dietary protein
intakes lead to poor bone health came from early
studies that identified a correlation between
increased protein intake and increased urinary
calcium excretion.66,67 For example, the acid-ash
hypothesis theorizes that the consumption of
protein increases the acid load of the diet and
brings about the release of calcium from the
skeleton, leading to increased urine calcium and,
eventually, osteoporosis.68
However, current research does not support
the principles of the acid-ash hypothesis and suggests
that dietary protein actually increases intestinal
absorption of calcium. Therefore, excretion of
calcium in the urine may result from increased
gastrointestinal calcium absorption that results in
adequate calcium balance.66–68 Research completed
to date shows negative calcium balance depends
on dietary calcium intake, not protein intake.69
Moreover, Heaney and Layman suggest that optimal
protein intakes for bone health are likely higher
than currently recommended intakes, particularly
in the elderly.63 Research strongly supports adequate
amounts of both protein and calcium, two key
components of milk, for healthy bones.
he Dietary Reference Intakes report no
T
identifiable health risks associated with protein
consumption up to 35% of total energy intake in
healthy individuals.8,70 However, caution is advised
for individuals with renal disease as protein
consumption at the higher end of the AMDR is
contraindicated in such cases.71 Renal function
decreases with age; therefore, assessment of renal
function is recommended before older individuals
adopt a higher-protein diet.72
Q: S
hould I recommend protein supplements to
my clients to enhance their protein intakes?
A:
eople can easily meet their protein requirements
P
by consuming whole foods such as milk products,
eggs, nuts, legumes, lean meats, fish and poultry.
Consuming protein supplements may cause
adverse effects such as diarrhea and bloating.73 A
balanced diet, including whole, protein-rich foods,
is a healthier, less expensive and sufficient way to
meet individual protein requirements.74
ormation
nutrition inf
Fall 2010
Spotlight
7
Weight Management: A Key
to Preventing Chronic Disease
Excess body weight is a major risk factor for
chronic diseases, such as cardiovascular disease,
type 2 diabetes and metabolic syndrome.15,17,77,78
Maintaining optimal energy balance, which
includes both physical activity and healthy eating,
is a key prevention strategy.15,17,41,77,78 Adequate
protein consumption may enhance the benefits of
resistance-based physical activity, such as weight
lifting, by promoting accretion of lean muscle
mass47,79–81; it also plays an important role in healthy
eating through its effects on appetite.
Physical Activity
It is important for health professionals to motivate
clients to engage in regular exercise. Ideally, adults
should aim for 30 to 60 minutes of moderate physical
activity most days of the week, incorporating a mixture
of endurance, flexibility and weight-bearing activities.82
Regular exercise is beneficial not only for weight loss,
but also to assist with favourable body composition
changes, including the development and maintenance
of muscle mass.47
Additionally, the consumption of protein, including
milk protein, immediately after resistance exercise
may assist with protein synthesis and contribute to
the accretion of lean muscle mass.47,79–81 Lower-fat
milk has proven to be an effective drink to support
favourable body composition outcomes during
resistance training by stimulating muscle protein
synthesis in men83,84 and promoting lean-mass gain
and fat-mass loss in women.85
Weight loss is also often associated with bone loss.
In one study, consumption of a high-protein diet and
three daily servings of Milk and Alternatives during
a period of weight loss attenuated participants’ bone
mineral loss.86 Encouraging the consumption of milk
products after periods of physical activity and during
weight loss endeavours promotes the maintenance of
lean muscle mass and bone mass, thereby promoting
weight loss primarily of adipose tissue.61,86
Healthy Eating
In Your Practice
The 2006 Canadian Clinical Practice Guidelines for
the management and prevention of obesity conclude
that a moderate increase in protein consumption,
within the AMDR, may be advantageous for weight
loss.87 Dietary protein plays a role in body weight
regulation, partially through its effects on appetite.
Protein as a macronutrient has proven to be
significantly superior to both fat and carbohydrate
in producing satiety.88 Additionally, milk protein has
been demonstrated to be more effective than soy
protein at decreasing hunger.71,89
Timing of protein intake is important; scientific
research suggests that protein consumption at
breakfast decreases hunger and appetite throughout
the rest of the day.90,91 According to one study, the
consumption of protein-rich snacks, such as cheese,
should not promote weight gain because energy
intake appears to be regulated during subsequent
meals.92 In summary, milk protein’s ability to reduce
hunger 93,94 and increase satiety71,89 can produce
substantial decreases in caloric intake, resulting in
successful weight management.61
Nutrition therapy, including optimizing intake of
high-quality protein, can play an integral role in
reducing the risk of chronic disease. Protein-rich foods
are typically found in the Meat and Alternatives and
Milk and Alternatives food groups of Canada’s Food
Guide and include lean meats, fish, poultry, eggs,
cheese, yogurt, legumes and nuts (see Table 1).62,95
Milk in particular is an excellent source of highquality complete protein in a nutrient-rich package.5
In fact, given the nutrient density of milk, which
contains protein, calcium and vitamins D, B12 and A,
it is surprising that Canadians’ average consumption
of milk products is below recommendations13,60 ;
this food source of protein should be particularly
encouraged. The evidence-based AMDR recommends
10% to 35% of caloric intake from protein. 8
Currently, Canadians consume approximately
Table 1. Protein Content of Various Foods and Beverages96
Food Group
Meat and Alternatives
The Bottom Line: Consuming milk after resistance
exercise can stimulate muscle protein synthesis and
promote fat loss. Additionally, adequate protein in
the diet can contribute to body weight regulation
by helping to control appetite.
Did you know?
It is commonly believed that recreational athletes
have higher protein requirements than average
Canadians; however, studies show no benefit to
exercise or sport performance with consumption
of dietary protein in excess of the Acceptable
Macronutrient Distribution Range.75 Furthermore,
adequate dietary protein consumption can be
achieved with a balanced diet, without the use of
protein supplements.74–76
17% of their daily energy from protein sources.13,60
Therefore, Canadians can safely increase their
daily consumption of dietary protein; in fact, most
Canadians could double their protein intake and still
be safely within recommended guidelines.
A diet reduced in refined carbohydrates has been
recommended for individuals diagnosed with type 2
diabetes, obesity or cardiovascular disease.17,34,87
A wealth of research has demonstrated that replacing
carbohydrates in the diet with protein may have a
number of beneficial health effects. Consumption of
approximately 25 to 30 grams of dietary protein at
meals maximally stimulates protein synthesis.48
Encouraging your clients to consume a serving of
Milk and Alternatives at each meal will help them meet
the daily servings from this food group recommended
by Eating Well with Canada’s Food Guide and will also
ensure they are well on their way to consuming an
adequate amount of protein at each meal.
Milk and Alternatives
Grain Products
Vegetables and Fruit
Food
Protein Content, grams
Beef sirloin steak, 75 g
26
Tofu, firm, raw, 75 g
21
Pork tenderloin, 75 g
21
Chicken, skinless breast, 75 g
20
Tuna, canned light, 75 g
19
Eggs, whole cooked, 2 large
13
Kidney beans, boiled, 175 mL (¾ cup)
12
Lentils, boiled, 175 mL (¾ cup)
13
Almonds, 60 mL (¼ cup)
8
Cottage cheese, 125 mL (½ cup)
15
Cheddar cheese, 50 g (1¾ oz)
12
Milk, 250 mL (1 cup)
8
Yogurt, 175 mL (¾ cup)
8
Whole-wheat pasta, cooked, 125 mL (½ cup)
4
Whole-wheat bread, 1 slice
3
Brown rice, cooked, 125 mL (½ cup)
3
Oatmeal, prepared, 175 mL (¾ cup)
3
Potato, with skin, cooked, 125 mL (½ cup)
5
Broccoli, cooked, 125 mL (½ cup)
2
Butternut squash, cooked, 125 mL (½ cup)
1
Banana, raw, 1 medium
1
Apple juice, bottled, 125 mL (½ cup)
—
Bolded foods indicate high-quality, complete protein sources.
8 Spotlight Fall 2010
Fall 2010
Spotlight
9
References
What’s new?
Protein for Active Canadians
Be on the lookout in the new year for Protein for
Active Canadians and Protein – A Current Reference
for Fitness Professionals, a pair of resources being
developed by the Canadian Society for Exercise
Physiology and the Registered Dietitians at Dairy
Farmers of Canada. These
user-friendly
resources
ormation
nutrition inf
update fitness professionals on the most recent
scientific evidence and consensus on protein for
active Canadians. They also provide practical clientcentered tips and tools such as post-workout snack
and meal suggestions with good sources of protein
to support intakes adequate for good health and
physical activity.
Conclusion
Evidence has shown that in addition to reducing the
risk of obesity, adequate protein consumption, as
part of a balanced diet, may also help prevent and
manage other chronic diseases and conditions, such
as cardiovascular disease, diabetes and sarcopenia.
In particular, milk products are protein-rich foods
that may promote optimal body composition and
help prevent and manage chronic diseases.
Healthy eating patterns can include a wide range of
protein intakes – from 10% to 35% of total energy for
adults.8 Health professionals should encourage two to
four daily servings from the Milk and Alternatives
10 Spotlight Fall 2010
food group, depending on the client’s age, in
addition to promoting consumption of other
protein-rich foods, such as lean meats, beans,
fish, eggs and poultry to replace simple sugars
and refined carbohydrates, in accordance with the
2009 Cardiovascular Society Guidelines, the 2008
Canadian Diabetes Association Practice Guidelines
and Eating Well with Canada’s Food Guide.17,34,62 These
relevant and timely recommendations may help
reduce the risk of common chronic diseases in the
Canadian population.
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Fall 2010
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12 Spotlight Fall 2010