Nutrition and Physical Activity: Fueling the Active Individual
President's Council on Physical Fitness and Sports
Guest Author:
Melinda M. Manore, PhD, RD, FACSM, Department of Nutrition and Food Management, Orgeon State University, Corvaillis, OR 97331
Co-edited by:
Drs. Charles B. Corbin and Robert P. Pangrazi, Arizona State University, and Dr. Deborah Young, University of Maryland
Introduction
There is no doubt that the type, amount, composition, and timing of food intake can dramatically affect exercise performance,
recovery from exercise, body weight and composition, and health. When exercise or physical work increase to more than 1 hour per
day, the importance of adequate energy and nutrient intakes becomes more critical. As the American public becomes more
concerned with health and health issues, the interest in nutrition and physical activity has increased. This interest in health has also
heightened the sale of supplements, herbal preparations, and weight loss products, all aimed at improving health, preventing or
curing disease, improving sport performance, and changing body composition and weight. Sorting through this supplement soup is
difficult because supplement manufacturers frequently make unsubstantiated claims about their products, leaving the consumer to
sort the fact from the fiction. As stated in the 2000 Position Statement on Nutrition and Athletic Performance, published by the
American Dietetic Association (ADA), Dietitians of Canada, and the American College of Sports Medicine (ACSM), any active
individual “who wants to optimize health and exercise performance needs to follow good nutrition and hydration practices, use
supplements and ergogenic aids carefully, minimize severe weight loss practices, and eat a variety of foods in adequate amounts” (ADA, 2000).
Recently, the Food and Nutrition Board (FNB) of the Institute of Medicine (IOM) published new dietary reference intake (DRIs)
for energy, macronutrients (protein, fat, and carbohydrate) (IOM, 2002). They have also published new DRIs for micronutrients
(vitamins and minerals) and related compounds (IOM, 1997, 1998, 2000, 2001). These DRIs are a set of reference values for
energy and specific nutrients designed to be used as guidelines for making dietary recommendations to individuals or groups of
individuals. For the first time, the specific needs of active individuals were considered
for energy and some nutrients. The dietary recommendations summarized in this
paper are based on extensive research in the area of nutrition and physical activity, and
four current national and international publications (listed below) related to thenutritional needs of active individuals. These four publications are the Position
Statement on Nutrition and Athletic Performance mentioned above (ADA, 2000), the
IOM’s report for energy, macronutrients (2002), the 2003 International Olympic
Committee’s (IOC) Consensus Statement on Sport Nutrition (Burke, 2003), and the
accompanying research articles (Burke et al., 2004; Coyle, 2004; Hargreaves et al.,
2004; Loucks, 2004; Maughan et al., 2004; Shirreffs et al., 2004; Tipton & Wolfe,
2004) recently published in the Journal of Sport Science in 2004. These recommendations
are general in nature, since energy and nutrient needs can vary greatly depending on
the age, gender, exercise training intensity and duration, health issues, and the sport in
which one participates. This paper will address the current energy, macronutrient and
fluid needs of active individuals, while briefly addressing micronutrients and
supplements and specific nutrition and fluid recommendations for before, during and
after exercise.
Energy Needs
Active individuals need more energy (calories) each day than their sedentary
counterparts – assuming individuals are the same age, body size and participate in
similar non-physically active daily activities. Exercise requires energy to fuel and
repair the muscles, thus, meeting one’s energy needs to maintain body weight should
be a priority for any athlete or active individual. Energy balance is achieved when the
energy consumed (sum of energy from food, supplements and fluids) equals energy
expenditure (sum of all the energy expended by the body in movement or to maintain
body functions) (Swinburn & Ravussin, 1993). Knowing whether one is in energy
balance is simple: weight is maintained. If energy intake does not cover the costs of
energy expenditure, then weight and muscle mass are lost, and the ability to perform strenuous exercise typically declines. Although weight loss is
the goal of many Americans, weight loss in an active
individual who is currently at a healthy body weight can
decrease exercise performance and the health benefits
associated with exercise training. When energy intake is
restricted, fat and muscle mass will be utilized for energy to
fuel the body, and the loss of muscle mass will result in the
loss of strength and endurance. Additionally, chronically low
energy intake usually results in poor nutrient intakes,
including carbohydrate, protein, vitamins and minerals.
Exactly how much energy an active individual needs each
day will depend on a number of factors, including age,
gender, body size, level and intensity of physical activity and
activities of daily living. The Food and Nutrition Board of
the IOM (2002) reviewed the energy needs of active and
very active individuals and provided some general
recommendations based on age and body size. In general,
active individuals walk between ~6-10 mi/d, while very
active individuals walk >10 mi/d at 2-4 mph. For example,
for a 30-year old male weighing 72.2 kg (160 pounds) and
having a body mass index (BMI) of 24.99 (kg/m2), the
estimated energy needs are 2,959 and 3,434 kcal/d for active
and very active individuals, respectively. For a 30-year old
women weighing 68 kg (150 pounds) and having a BMI of
24.99 (kg/m2), the estimated energy needs are 2,477 and
2,807 kcal/d for active and very active individuals,
respectively. Thus, the first goal of an active individual is to
maintain adequate energy intake to assure that a healthy body
weight is maintained. Although this seems like a simple task,
there are many active individuals who find this difficult to
do. For these individuals, a dietary plan that assures meals
and snacks are not skipped will improve energy intake and
help maintain weight. Finally, energy needs typically
decrease with age, so even if activity levels do not change,
the amount of energy required to maintain body weight will
decrease. For this reason, body weight typically increases
with age, even if activity levels remain constant.
Eating to achieve or maintain a healthy body weight
and body composition
Although active individuals typically have body weights that
are within normal ranges for their height (BMI 19-25 kg/m2),
it is not unusual for them to want to change their body
weight (e.g., either increase or decrease) to meet the
demands of their sport or their own perception of an “ideal
weight.”Weight change should be accomplished slowly
during a period when the individual is not participating in
competitive events. If weight gain is desired, this can be
accomplished by adding ~500-1000 kcal/d into the diet per
day, while participating in strength training exercises to
assure that the extra energy consumed is contributing to
muscle mass and not fat gain (ADA, 2000; Thompson & Manore, 2000). Increases in muscle mass usually occur
slowly and depend on a number of factors, including one’s
genetic make-up, degree of positive energy balance that has
occurred, amount of rest received, and the type of exercise
training program being used (Manore & Thompson, 2000).
Any diet for weight loss should result in a gradual decrease
in weight (~1-2 pound/wk or 0.5-1.0 kg/wk) and maximize
fat loss, while preserving lean tissues (ADA, 2000). If energy restriction is too severe, the nutritional quality of the diet is compromised, lean tissue is lost, and the ability to exercise
decreases. In addition, severe energy restriction can lead to
preoccupation with food, loss of motivation, and the inability
to stay on the diet (Thompson & Manore, 2000; Manore,
1999b, 2000). In order to remain physical active while
dieting, the diet needs to provide adequate carbohydrate for
glycogen replacement and enough protein for the
maintenance and repair of lean tissue. For these reasons,
experts do not recommend fad diets that restrict energy too
severely (typically <1800 kcal/d for women; <2000 kcal/d
for men) or eliminate food groups (e.g., little or no
carbohydrate; restricted to eating only certain foods) for
active individuals.
Before beginning a weight loss diet, an active individual
needs to identify what constitutes a realistic healthy body
weight for his/her activity level. This decision should be
made based on past dieting experiences, type of activity
engaged in, the social setting around work and home,
genetics (family size and shape), health risk factors, and
psychological issues. A healthy weight is one that can be
realistically maintained, allows for positive advances in
exercise performance, minimizes the risk of injury or illness,
is consistent with long-term good health, and reduces the risk
factors for chronic disease (ADA, 2000; IOM, 2002). If an
unrealistic weight goal is set, there is a high probability of
failure, which has a number of emotional and psychological
outcomes. Unfortunately, failure to meet weight loss goals in
some sports can result in severe consequences, such as being
cut from the team, restricted participation, or elimination
from competition. These situations can result in active
individuals chronically dieting to maintain a lower than
healthy body weight, which can lead to disordered eating and
in severe cases a clinical eating disorder. Nutritional
strategies for identification, intervention and treatment of
eating disorders in athletes have been presented elsewhere
(ADA, 1994; Beals, 2004; Sungot-Borgen, 1998).
Dieting for weight loss in active women and girls can be
especially problematic, especially if weight is already within
medical norms. Low energy intake combined with high
energy output contributes to the development of menstrual
dysfunction in women, which is characterized by a
significant decrease in reproductive hormones and disruption
of the normal menstrual cycle (Harber, 2000; Loucks, 2004;
Manore, 2002). The decrease in reproductive hormones,
especially estrogen, can lead to loss of (or failure to gain)
bone mass in young female athletes and active adult women.
This pattern of low energy intake can put them at risk for one
or more of the disorders in the female athlete triad
(amenorrhea, disordered eating, osteoporosis) (ACSM, 1997).
Macronutrient Requirements For Exercise
Carbohydrate, protein and fat are important nutrients for
active individuals, but the amounts of these macronutrients
needed will depend on an individual’s exercise intensity,
duration and frequency, the type of exercise engaged in, and
their health, body size, age and gender. Macronutrient
recommendations for those engaged in daily physical activity
are given below and in Table 1.
Table 1.
Dietary Reference Intakes (DRIs) for macronutrients and
recommendations for active individuals
| Nutrient |
New Guidelines –
2002 |
Old Guidelines –
1989 |
Guidelines for
Active Individuals |
| Carbohydrate |
45-65% of total
energy |
≥ 50% of total
energy |
The amount of
carbohydrate required
for moderate intensity
exercise is 5-7 g/kg
body weight; 7-12 g/kg
body weight for high
intensity endurance
activities. |
| Protein |
10-35% of total
energy;
0.8 g/kg of body
weight |
10-15% of total
energy;
0.8 g/kg of
body weight |
Protein requirements are
typically higher in active
individuals. Recommendations range from 1.2-1.7 g of protein/kg body
weight. This level of protein
typically represents
15% of total energy. |
| Fat |
20-35% of total
energy |
≤ 30% of total
energy |
Fat intakes between 20-35%. Carbohydrate and
protein needs should be
met first. |
1IOM, 2002. 2FNB, 1989. 3Burke et al., 2004; Tipton and Wolfe, 2004.
Carbohydrate needs
The mix of fuel (protein, fat, carbohydrate) burned during
exercise depends primarily on the intensity and duration of
the exercise performed, one’s level of fitness, and prior
nutritional status. All other conditions being equal, as
exercise intensity increases the use of carbohydrate for
energy will also increase (Brooks & Mercier, 1994; Brooks& Trimmer, 1995). The duration of exercise also changes
substrates use. As duration of exercise increases (e.g., from
60 to 120 min), muscle glycogen becomes depleted, causing
the body to draw on circulating blood glucose as a source of
carbohydrate. If blood glucose cannot be maintained within
physiological range during exercise, the ability to perform
intensity exercise will decrease (Coyle et al., 1986). Fat can
be used as a source of energy over a wide range of exercise
intensities; however, the proportion of energy contributed by
fat decreases as exercise intensity increases. In these
circumstances, carbohydrate becomes the dominant fuel
source while the contribution from fat decreases (Bergman et
al., 1999). Protein can also be used for energy at rest and
during exercise; however, in well-fed individuals it probably
provides <5% of the energy expended (El-Khoury et al.,
1997; Phillips et al., 1993). As the duration of exercise
increases, the energy contribution of protein may increase to
maintain blood glucose. The amount of carbohydrate, fat andprotein used for energy during
exercise will also depend on when
exercise occurs relative to the last
meal and the level exercise intensity
performed. For example, when
subjects are tested after an overnight
fast, the contribution of fat to the
energy pool is greater than when
these same individuals are tested
after a meal (Bergman and Brooks,
1999). In both situations, the
exercise performed was moderate
(~50% of VO2max). For higher
intensity exercise (>65% of
VO2max) neither prior feeding nor
exercise training significantly altered
fuel used (Bergman & Brooks,
1999).
Currently there is no research
available suggesting that active
healthy individuals need
significantly different proportions of
energy from carbohydrate, protein
and fat than those proposed in the
2002 IOM report from the Food and
Nutrition Board on Dietary
Reference Intakes: Energy,
Carbohydrate, Fiber, Fat, Fatty
Acids, Cholesterol, Protein and
Amino Acids (45-65% of energy
from carbohydrate, 10-35% of
energy from protein, and 20-35% of
energy from fat). This report
determined an Acceptable
Macronutrient Distribution Range
(AMDR), which is defined as arange of intakes that are associated with reduced risk of
chronic disease, while providing adequate intakes of
essential nutrients. These new AMDRs for the
macronutrients are very broad and allow for developing
flexible dietary recommendations across a variety of activity
levels, body sizes, food preferences, and health-related
dietary issues.
Although high carbohydrate diets (>65% of energy intake)
have been advocated in the past for endurance athletes, the
use of proportions in making dietary recommendations for
active individuals is generally not practical (ADA, 2000). It
is more helpful to make macronutrient recommendations for
protein and carbohydrate based on body size (e.g., gram/kg
body weight). For example, if energy intake is 5000 kcal/d
for an active adult male, even a diet containing 50% of the
energy from carbohydrate will provide 625 g of carbohydrate
(~9 g/kg for a 70 kg body weight person). This level of
carbohydrate is adequate to maintain muscle glycogen stores
for a highly active individual (Coyle, 1995). Similarly, if
protein intakes in this diet were as low as 10% of energy
intake, absolute protein intake (125 g/d; 1.8 g/kg) would
easily meet the protein recommendations for athletes (1.2-1.7
g/d or 84-119 g in a 70 kg body weight person, see protein
section below). Conversely, when energy intakes are low
(≤ 1800 kcal/d) even a diet providing 60% of the energyfrom carbohydrate may not maintain optimal carbohydrate
stores (≤ 5 g/kg in a 55-kg body weight person) in an active
individual. In general, it is recommended that active
individuals doing moderate duration/low-intensity physical
activity consume 5-7 g/kg of carbohydrate per day. If exercise
is intense and heavy endurance training is being done, then
7-12 g/kg of carbohydrate per day is recommended (Burke et
al., 2004). Thus, dietary carbohydrate recommendations for
the active individual will depend on the level of physical
activity being performed.
Protein needs
Active individuals often think that they need to consume
high protein diets to cover the building and repair of their
muscle tissue. Although not reflected in the new IOM report
on energy and macronutrients (2002), exercise physiologists
and sport nutritionists generally agree that exercise increases
the need for protein (g/kg body weight) (ADA, 2000; Tipton& Wolfe, 2004). Exercise may increase the need for protein
in three ways: 1) increased need for protein to repair
exercise-induced damage to muscle fibers; 2) support gains
in muscle mass that occur with exercise; and 3) provide
energy source during exercise (Lemon, 1998). How much
additional protein is needed may depend on the type of
exercise performed (endurance vs. resistance), the intensity
and duration of the activity, body composition (e.g., kg of
lean tissue mass), and whether weight loss is being
attempted.
Lemon (1998, 2000) examined the research on the protein
needs of athletes and recommends 1.2-1.4 g/kg body
weight/day for individuals participating in endurance sports
and 1.6-1.8 g/kg body weight/day for those involved in
resistance or speed exercise. The higher protein
recommendations for individuals participating in resistance
training allows for the accumulation and maintenance of lean
tissue (Lemon, 1998, 2000; Tarnopolsky et al., 1992).
Although these recommendations are higher than the current
RDA for protein (0.8 g/kg body weight) (IOM, 2002), they
do not typically exceed the habitual protein intakes of most
active individuals. As illustrated earlier, if energy intake is
3000-5000 kcal/d for a 70 kg active male, a diet providing
10% of energy from protein would contain 75-115 g of
protein per day or 1.1-1.8 g/kg of protein for this individual.
In reality, this individual would probably consume closer to
15% of energy from protein. Thus, there is usually little need
to recommend that active individuals consume more protein.
Increasing protein intakes beyond the recommended level is
unlikely to result in additional increases in lean tissue, since
there is a limit to the rate at which protein tissue can be
accrued (Lemon, 1998, 2000). Those individuals at greatest
risk for low protein intakes are active individuals who restrict
energy intake for weight loss or follow vegetarian diets,
especially active women (Manore, 1999a, 2002).
Fat needs
Over the years the amounts and types of fat recommended
for good health have changed, which is frustrating and
confusing for the consumer. Dietary recommendations for
active individuals have typically focused on getting adequate
intakes of carbohydrate and protein, and keeping fat intake to 25-30% of energy intake, which is within the new AMDR for
fat (20-35% of energy). Although fat is seen by many
individuals as something to avoid, fat is a necessary
component of a normal diet. Fat provides energy and
essential elements for cell membranes, and is associated with
the intakes of the fat-soluble vitamins E, A and D. However,
the type of fat consumed is important since the long-term
negative effects of high saturated fat diets on health are well
known. In addition, low fat intakes (<15-17% of energy) are
generally not recommended for active individuals (Horvath
et al., 2000a, 2000b), since they are reported to decrease
energy and nutrient intakes and exercise performance.
Currently, there appear to be no health benefits to consuming
a very low fat diet (<15% of energy from fat) in healthy
individuals compared to more moderate fat intakes (Dreon et
al., 1999). Thus, unless there is some medical reason for
restricting fat, dietary intakes should be within the AMDR
for fat.
The new IOM report for macronutrients (2002) also gives
recommendations for the types of fat to be included in the
diet. These recommendations apply to all individuals,
regardless of activity level. Diets should be low in saturated
and trans fats, while providing adequate amounts of essential
fatty acids (linoleic and a-linolenic acids). The essential fatty
acids are required to make a number of potent biological
compounds within the body that help regulate blood clotting,
blood pressure, heart rate and the immune response. Linoleic
acid is found in vegetable and nut oils (e.g., sunflower,
safflower, corn, soy, peanut oil) and it is recommended that
adult men consume 14-17 g/day and adult women consume
11-12 g/day. Americans appear to get adequate amounts of
linoleic acid, due to the high amount of salad dressings, salad
oils, margarine, and mayonnaise-based foods they consume.
The second essential fatty acid, a-linolenic acid, is found
primarily in leafy green vegetables, walnuts, soy oil and
foods, canola oil, and fish products and fish oils. Americans
are most likely to have low intakes of this essential fatty acid.
The recommended intakes for a-linolenic is 1.6 g/day for
adult men and 1.1 g/day for adult women. If active
individuals consume very low fat diets (<15% of energy),
getting adequate amounts of the essential fatty acids can be a
problem (Horvath et al., 2000a).
Research has also examined the impact of high fat diets (40-70% of energy intake) on fat utilization during exercise and
athletic performance (Muoio et al., 1994; Lambert et al.,
1994). It was hypothesized that consuming a high fat diet
would enhance fat oxidation and utilization during exercise.
Unfortunately, most individuals cannot tolerate these high fat
levels for long, nor can health professionals recommend
them for long-term health; thus, there is little support for
recommending these diets to active individuals (Jeukendrup & Saris, 1998).
Hydration
It is well-documented in the research literature that exercise
performance is optimal when athletes and active individuals
maintain fluid balance during exercise (Coyle, 2004).
Conversely, exercise performance is impaired with
progressive dehydration (Barr et al., 1999; McConnell et al.,
1997; Walsh et al., 1994), which can eventually lead topotentially life-threatening heat injury if action is not taken
(Noakes, 1993). Thus, it is imperative that all active
individuals attempt to remain well hydrated. The ACSM and
the National Athletic Trainers’ Association (NATA) have
position statements that provide comprehensive overviews of
the research and recommendations on maintaining hydration
before, during and after exercise (ACSM, 1996a; Casa et al.,
2002). Active individuals exercising in special environmental
conditions (heat, cold, altitude) need to take extra
precautions to remain hydrated (ACSM 1996a; Brinkley et
al., 2002; Freund & Sawka, 1996).
Maintaining water and electrolyte balance
Maintaining fluid and electrolyte balance means that active
individuals need to replace the water and electrolytes lost in
sweat. This requires that active individuals, regardless of age,
strive to hydrate well before exercise, drink fluids throughout
exercise, and rehydrate once exercise is over. As outlined by
ACSM and NATA (ACSM, 1996a; Casa et al., 2000),
generous amounts of fluids should be consumed 24-h before
exercise and 400-600 mL of fluid should be consumed 2-h
before exercise. During exercise, active individuals should
attempt to drink ~150-350 mL (6-12 oz) of fluid every 15-20
minutes. If exercise is of long duration (usually >1 h) or
occurs in a hot environment, sport drinks containing
carbohydrate and sodium should be used. When exercise is
over most active individuals have some level of dehydration.
Drinking enough fluids to cover 150% of the weight lost
during exercise may be needed to replace fluids lost in sweat
and urine (Shirreffs et al., 1996). This fluid can be part of the
post-exercise meal, which should also contain sodium, either
in the food or beverages, since diuresis occurs when only
plain water is ingested (Maughan & Leiper, 1995; Maughan
et al., 1996; Shirreffs et al., 2004). Sodium helps the
rehydration process by maintaining plasma osmolality and
the desire to drink.
Micronutrient Requirements For Exercise
Micronutrients, such as vitamins and minerals, play an
important role in maintaining the health of the active
individual. They are involved in energy production, synthesis
of hemoglobin for the production of red blood cells,
maintenance of bone health, adequate immune function,
building and repair of muscle tissue, and the protection of
body tissues from oxidative damage (Manore & Thompson,
2000; ADA, 2000). There are a number of ways that exercise
is hypothesized to alter the need for vitamins and minerals.
For example, exercise stresses many of the metabolic
pathways in which these micronutrients are required, while
exercise training may cause muscle biochemical adaptations
that increase micronutrient needs. Exercise may also increase
the turnover and loss of micronutrients from the body, and
the need for these micronutrients to repair and maintain the
higher lean tissue mass of the active individual (ADA, 2000).
It is assumed that the current DRIs are appropriate for
athletes and active individuals, unless otherwise stated (IOM
1997,1998, 2000. 2001). Those individuals at the greatest
risk of poor micronutrient status are those individuals who
restrict energy intake or use severe weight loss practices,
eliminate one or more of the food groups from their diet, or who restrict or eliminate one or more food groups from the
diet (e.g., no or little carbohydrate or fat). Individuals
participating in these types of eating behaviors may need to
use a multivitamin or mineral supplement to improve overall
micronutrient status. Current discussions of the micronutrient
needs and supplement issues of active individuals are
covered elsewhere (Manore, 2000, 2002; Manore &
Thompson, 2000; Maughan et al., 2004; Powers et al., 2004;
Spriet & Gibala, 2004)
Eating for good health and exercise performance
Compared to their sedentary counterparts, the diet of an
active individual requires additional fluid to cover sweat
losses, energy to fuel physical activity, protein for building
and repair of muscle tissue, and carbohydrate for the
replacement of muscle glycogen. In some cases the need for
other nutrients also increases (e.g., B-complex, antioxidant
vitamins, iron). As more energy is consumed to cover the
cost of exercise, it is assumed the intake of these other
nutrients will also increase. Thus, as energy requirements
increase, the first goal should be to consume nutrient-dense
carbohydrate-based food groups (e.g., whole grain breads
and cereals, vegetables, and fruits) and lean protein sources
(e.g., lean meats, fish, poultry, dairy, legumes). The aim
should be to increase energy intake to maintain weight using
nutrient-dense foods that will also provide vitamins and
minerals, instead of meeting additional energy needs with
high-fat and sugar foods. This is especially true for active
individuals who are small (low BMIs) or have lower energy
needs.
Timing of food intake is also important for active
individuals. Eating sensibly before exercise assures that there
is enough energy to fuel the exercise event, while eating after
exercise will help refuel the body. We know that being wellfed
before exercise can improve performance (ADA, 2000),
and that the post-exercise meal helps replace muscle
glycogen and repair muscle tissue damage (Burke et al.,
1996). Depending on the sport, eating or using a sport drink
during exercise can also improve performance and delay time
to fatigue (McConnell et al., 1996). Active individuals, who
exercise more than once per day, may need to time eating
around exercise, use sport drinks during exercise, and make
sure that meals are not skipped (Benardot & Thompson,
1999). Specific recommendations for what to eat and drink
before, during and after exercise have been discussed in
detail elsewhere (Burke et al., 2004; Hargreaves et al., 2004;
ADA, 2000; Manore & Thompson, 2000).
Supplements
Nearly 25% of Americans use dietary supplements daily and
~35-40% use them occasionally. For individuals engaged in
physical activity, the estimates are as high as 50-100%
(Sobal & Marquart, 1994). This high use of supplements has
created a 14 billion-dollar industry, which constantly
bombards consumers with advertisements for their products
(Sarubin, 2000). It is not surprising that the American
consumer is very confused about whether they should use
vitamin or mineral supplements, how much to take, and
which product to buy. Unfortunately, there is no
governmental body that regulates dietary supplements and verifies that what is on the label is also in the bottle. In
addition, there is little or no regulation as to the claims made
on the bottle. The Dietary Supplement Health and Education
Act of 1994 allows supplement manufacturers to make
claims regarding the effect of products on the structure and
function of the body, as long as they do not claim to “diagnose, mitigate, treat, cure or prevent” a specific disease
(103rd Congress, 1994). This allows supplement
manufacturers to make a “broad” range of health statements
for their supplements, which may or may not be accurate and
substantiated by clinical research. Thus, the consumer is left
with the task of evaluating the product and the claims of the
product.
How does the consumer know which supplement to buy or
recommend? Listed below are some general guidelines an
active individual can follow when selecting a supplement.
- Use a multivitamin/ mineral supplement that contains
micronutrients in amounts close to recommended amounts
(e.g., one-a-day type supplements). This approach helps
avoid nutrient-nutrient interactions or reaching toxic levels
of any one nutrient. However, most multivitamin/mineral
supplements do not contain the recommended amount for
some minerals, such as calcium. For individuals who avoid
or cannot use dairy products, a major source of calcium in
the US diet, calcium supplements or calcium-fortified
foods may need to be used. Look for supplements that
provide ~50-100% of the Daily Value (DV) or
Recommended Dietary Allowance (RDA), and avoid those
that provide many times the recommended amounts.
- Use individual supplements sparingly unless warranted
due to a health problem or a lack of the nutrient in the diet.
Individuals should avoid the 5-10 pill/day routine. Using large doses of vitamins and minerals will increase the risk
of nutrient-nutrient interactions and may lead to toxic
effects. Some supplements can also interfere with
prescription and over-the-counter medications, so keeping
closer to the RDA or DV will help avoid these pitfalls.
- Select supplements from a reputable, well-established company and look for supplements that carry the US
Pharmacopoeia (USP) or National Formulary (NF)
notation. These notations mean that the manufacturer has
voluntarily complied with a strict set of standards
regarding product purity, strength, packaging, labeling and
weight variation. The Food and Drug Association (FDA)
does not inspect vitamin and mineral supplements, so
using supplements from a reputable company will help
assure that you get what is listed on the label.
Summary
We now know that what you eat and drink can significantly
impact health and exercise performance. The active
individual needs to make sure they consume enough energy
to maintain a healthy body weight for their activity level and
sport, while reducing risks of chronic disease. Active
individuals need more carbohydrate and protein than
sedentary individuals, and should not restrict fat intake too
severely. Keeping well-hydrated and replacing fluids lost
during exercise is also a key part of feeling good and
performing at one’s best. Active individuals dieting for
weight loss may need to supplement, but in general
supplements should be used with caution and after careful
examination of the diet.
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_________________________________________________________________
| Title: |
Nutrition and Physical Activity: Fueling the Active Individual |
| Author: |
Manore, M.M. |
| Publisher: |
President's Council on Physical Fitness and Sports |
| Source: |
President's Council on Physical Fitness and Sports Research Digest (Bloomington, Ind.) |
| Volume (Issue): |
5(1) |
| Date: |
Mar 2004 |
| Page: |
1-8 |
| SIRC Article #: |
S-964997 |
This material has been copied under license from the Publisher. Any resale for profit or further copying is strictly prohibited.
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