The Nutritional Needs of Athletes
Tommy Boone
Professor and Chair
Director, Exercise Physiology Laboratories
Department of Exercise Physiology
The College of St. Scholastica
Duluth, MN 55811
Sadly, as we now find ourselves in the
21st century, some (certainly not all) exercise physiologists find themselves
in disagreement with the marketing practices of the sport nutrition supplement
industry. If it were not for their unethical and (possibly) illegal
performance-related claims, all the evils that have come to associate with
the dietary supplement industry would not exist. The following analysis
should lead the reader to a clear understanding of the problems created
by individuals who hide behind inadequate science. Understandably,
my statement is strong but based on concrete facts. Tucked securely
within this article are statements supported by experts who know what they
are talking about. There is no need for the reader to believe me
or to think that I have a particular bias against sports nutrition.
I’m committed only to the truth, and to an alternative thinking.
If we are unable to find a balanced perspective regarding exercise nutrition,
the claim that exercise physiologists make about professionalism will be
questioned. It is just a matter of time. It is the responsibility
of the exercise physiologist to be “…proactive in providing in providing
the public with clear and accurate guidance regarding the efficacy of products
that claim to provide structural or functional benefits.” [1, p. 525]
This is one of the most difficult subjects
to write about because of the exercise physiologists I know who are exercise
nutritionists. Time and again, I asked myself whether I’m making
matters worse, whether there are exercise physiologists who would agree
with me, and whether the ASEP members will be able to understand that critical
reflection is a hallmark of professionalism. I will return to this
point later in this article. It is quite easy to state that sports
nutrition supplements are necessary to jump higher, run faster, and get
bigger muscles. The outpouring of non-scientific information seems
to support the use of nutritional supplements. The uncertainty of
research suggests that exercise physiologists should be more cautious.
Of course, this is the problem. Ironically, among the best of us,
there are beliefs so embedded in our education and/or professional experiences
that cannot be put aside. These beliefs have created a void between
some exercise physiologists who believe in sports nutritional supplements
and those who do not. In many ways, it is really no different from
those who have their views about what limits maximum oxygen consumption
and those who disagree based on their views. No one has "expert"
right to any particular topic or subject matter among educated professionals.
And, since there is an attendant ethical consideration that has not been
adequately addressed among exercise nutritionists, it is not just logical
that questions are raised but required of every professional who understands
open and honesty inquiry..
Does this mean there are no benefits from
nutritional supplements? No, of course not. My point is that
the subject is not a “finished product”. There are too many questions
left unanswered and too few professionals who seem willing to ask the questions.
There are too many individuals supporting sports nutritional aids with
scant scientific support and, in many cases, with no support at all.
One only has to recall the recent events in the California lawsuit against
Cytodyne to know the aggressive nature of the supplement industry [2].
Does this mean that all supplement companies are equally questionable?
No, but it does suggest that athletes (and professionals) should not automatically
conform to the dietary supplement culture. After all, it is not the
exercise physiologists’ job to agree with the business initiatives (or
the bottom line) of different fitness and/or supplement businesses.
Similarly, it is not the exercise physiologists’ responsibility to argue
that athletes should use sports nutrition supplements to meet a special
dietary need or to provoke an improvement in performance. What really
is important is the athlete’s training regimen. It seems as though
some exercise physiologists don’t understand this point. This is
not to say that we will all agree to get rid of sports nutrition supplements.
But just maybe, as Lowenthal and Karni put it in their chapter on nutritional
needs of athletes in Total Nutrition by Herbert Subak-Sharpe [3],
"we will teach the precise nature and determinants of excellence in athletics."
For example, several of the unsettling statements for exercise physiologists
who support the use of sports nutrition supplements must be the following:
“…once the basic nutrient needs
have been met by a well-balanced diet, the only special requirement for
most athletes is a greater intake of calories to meet the body’s increased
energy needs.” [3, p. 403].
“…athletes and individuals involved in
training programs often eat four to five times the amount they need in
the hope that extra protein will enhance their athletic abilities or build
bigger muscles. It will not.” [3, p. 406]
“A little extra protein is also required
to supply the amino-acid building blocks for new lean tissue, but if additional
calories come from a variety of foods, abundant protein also will be present.”
[3, p. 415]
“A high-protein diet or protein supplements
offer no advantages and are not recommended.” [3, p. 415]
“…vitamin supplementation is not necessary
or advantageous in well-nourished athletes.” [3, p. 407]
“…should not take supplements as insurance
against iron deficiency.” [3, p 408]
“…there is no agreement as to how or to
what degree body levels of [trace minerals such as zinc, copper, and chromium]
affect exercise performance, and supplements are not recommended.” [3,
p. 409]
“Sports beverages spiked with vitamins
are definitely better left on the supermarket shelf. No significant
amount of vitamins are lost during exercise and taking extra vitamins will
not improve performance.” [3, p. 412]
“Coaches, trainers, and parents must be
constantly on the lookout for athletes who ‘believe’ that the key to big
muscles lie in unbalanced diets, nutritional supplements, and drugs and
the like rather than in weight training in conjunction with a proper diet.”
[3, p. 417]
Similarly, Murray [1] states that:
“Advertising claims for the benefits
of minerals [to enhance the athlete’s performance] such as boron, chromium,
molybdenum, selenium and zinc have not been borne out by scientific research.”
[1, p. 529]
“There is little…scientific evidence to
indicate that ingesting protein supplements will…promote anticatabolic
activity, pack on solid, rock-hard mass, and increase lean muscle mass
and promote fat loss.” [1, p 529]
“Dibencozide, yohimbe, phosphatidylserine,
and vanadyl sulphate are among the ingredients that can be found in current
products promoted as having growth-enhancing properities…there is an absence
of scientific research confirming such effects.” [1, pp. 529-530]
Athletes, coaches, sports nutritionists, and
others who target the ergogenic properities of sports nutrition supplements
as having a “positive” effect on sports performance appear to overlook
the “alleged” effect. This is obvious in the sales of supplements.
But, what is missed in the literature are the hedge words used in
explaining the relationship between the sports nutritional supplements
and the alleged increases in sport performance. For example, consider
the following statements:
“Supplementation with…arginine,
ornithine, and lysine… [has been used to increase serum levels of human
growth hormone, hGH], …[which] may lead to increases in muscle mass
and strength.” [4, p. 357]
“Although its metabolic role in humans
is uncertain, HMB supplementation is proposed to help exercisers
maximize muscle gains during resistance training….” [4, p. 358]
“Current research is equivocal as to whether
or not phosphate loading may improve physiological functions important
to endurance performance.” [4, p 360]
“L-Carnitine may affect various
physiological functions important to exercise….” [4, p. 360]
“Theoretically, choline supplementation
will enhance acetylcholine synthesis and prevent acetylcholine depletion
and subsequent fatigue in endurance events.” [4, p. 362]
“Theoretically, increased levels of 2,3-DPG
may facilitate the release of oxygen from the red blood cells to
the muscle and enhance aerobic endurance exercise.” [4, p. 362]
“Investigators theorize that a combination
of glycerol-water supplementation may be a more effective hyperhydration
technique than water hyperhydration alone.” [4, p. 363]
Williams and Leutholtz [4] have done an excellent
job in presenting a “balanced” perspective of the assumed benefits of nutritional
supplements. In fact, this is a basic theme throughout the book,
Nutrition in Sport. As an example, Kiens and Helge [5] wrote
that: “It is well known from the classic literature that increasing the
dietary fat relative to carbohydrates results in increased fat and decreased
carbohydrate utilization during submaximal exercise….[therefore] it has
been hypothesized that increasing the availability of fatty acids for oxidation
might increase the oxidation of fat and spare carbohydrate and furthermore
increase performance.” What is interesting is that despite the notion
of elevating plasma FFA concentration, no clear effects on endurance performance
have been demonstrated. This finding could be explained by obvious
factors such as the research design, the training status of the athletes,
or the mixture of a fat-rich diet before and/or during a given training
period. What is important is that the authors have not written the
chapter to convince the reader of yet another nutritional manipulation.
Point blank: they conclude that “…there are no scientific data to support
the notion…that dietary fat can improve endurance performance.” [5, p.
200]
Lemon [5] concluded a somewhat similar
point of view with regard to the effects of exercise on protein metabolism.
As an example, the author wrote “…despite the fact that regular participation
in an exercise programme (either strength or endurance) will apparently
increase protein requirements, special protein supplements (which are considerably
more expensive than food protein per kilogram of protein mass are rarely
necessary.” In short, there really isn’t much scientific data to
support the popular notion that associates performance with high protein
diets or the supplementation of individual amino acids. Why the scientific
information is misunderstood by so many athletes and sports-related individuals
is open for discussion? Athletes and their coaches ought to
seek ways of improving performance through better training and psychological
preparedness. They should also try to get beyond the “win at all
costs” mentality. In actuality, there is no reason for sports to
be viewed that differently from life. Here, I’m suggesting that if
adults were pushed, encouraged, or believed that they have the right to
“win [at work] at all costs”, there would be obvious problems throughout
our varied work communities.
There are concerns, especially as they
relate to substances (such as buffering agents) that may improve performance,
but may be in conflict with doping rules for athletics. One such
substance is sodium citrate, although not confirmed by any means.
It may enhance high-intensity performance between 1 and 10 minutes [6].
There are possible side effects, however. In fact, it is obvious
that the Nutrition In Sport, edited by Ronald J. Maughan, is an
excellent example of experts coming together with well-written and balanced
chapters about sport nutrition. The only short coming in the entire
book is the lack of a chapter on the ethical considerations of using sports
nutrition supplements. Otherwise, it is (as I said) excellent.
The authors are to be commended for their balanced perspective.
References
1. Murray, R. (2000). Sports Nutrition
Products. In Nutrition In Sport. Edited by Ronald J. Maughan.
Malden, MA: Blackwell Science, Inc.
2. Lega News Watch, (2003). Ephedra: Cytodyne
to Pay $12.5 Million in 'Xenadrine' Case. News Source: The Associated Press.
Published Date: May 30, 2003. http://www.legalnewswatch.com/news_208.html
3. Lowenthal, D.T. and Karni, Y. (1995).
The Nutritional Needs of Athletes. In Total Nutrition:
The Only Guide You’ll Ever Need. D.T. Lowenthal and Y. Karni (Editors).
New York, NY: St. Martin’s Press.
4. Williams, M.H. and Leutholtz, B.C.
( 2000). Nutritional Ergogenic Aids. In Nutrition In Sport.
Edited by Ronald J. Maughan. Malden, MA: Blackwell Science, Inc.
5. Kiens, B. and Helge, J.W. (2000). Adaptations
to a High Fat Diet. In Nutrition In Sport. Edited
by Ronald J. Maughan. Malden, MA: Blackwell Science, Inc.
6. McNaughton, L.R. (2000). Bicarbonate
and Citrate. In Nutrition In Sport. Edited by Ronald
J. Maughan. Malden, MA: Blackwell Science, Inc.
