Summary Lecture 3:
Common nutrition deficiencies- Are you at risk?
Calcium is a major dietary mineral in the body, and is imperative for good bone health and
healthy teeth. In addition, the skeleton protects our vital organs. Stress fractures in the bones
are a high risk for athletes and can result from a number of dietary factors, including eating
disorders, inadequate calcium intake, high alcohol, salt and animal protein intake. There are
other non-nutritional risk factors, which include a lack of weight bearing activity or strength
resistance training and poor muscle flexibility and strength. How much should you consume?
Infants, children and adolescents require a higher intake of dietary calcium to assist the
developing and growing of bones. A higher intake is also required for women above the age of
Dairy is one of the best sources of dietary calcium. A serve of dairy is equivalent to a cup
(250ml) of milk, 200g yoghurt or 40g Cheese and is approximately 330mg calcium. It is
suggested the upper limit of calcium consumption per day is equivalent to 2500mg
(~ 7 ½ serves). Strategies to increase your calcium intake:
Many people find it difficult to consume adequate calcium on a regular basis. The fol owing are
some strategies to improve your calcium intake:
1. Add dairy to cooking, eg low fat evaporated milk to pasta and soup 2. Add nuts or low-fat cheese chunks to salads or vegetables 3. Use yoghurt in place of cream in desserts for a great low-fat alternative 4. Consume non-dairy sources: eg green leafy vegetables, nuts, canned fish with bones,
5. Crush the bones in canned fish 6. Choose low-fat dairy sources to assist weight control 7. If you are someone who does not consume adequate calcium, try using fortified
calcium products, such as Anlene™ Milk or fortified soy milk
8. Remember white cheese such as fetta, ricotta, brie have a lower content of calcium
Iron is essential for healthy red blood cel production and is a key component in the
transportation of oxygen in the blood and muscles. Iron is also involved in the release of
energy from cel s and required for healthy immune function.
Athletes have increased iron requirements as a result of a higher blood cel mass, and
increased losses from sweat, gut damage and mechanical trauma (eg From the pounding on
pavement during running). A lack of iron can cause decreased aerobic and endurance capacity
(Haas and Brownlie, 2001), and disturbances in brain and muscle metabolism, immunity and
temperature (Bothwel , 1995).
The human include body is unable to manufacture iron, and therefore it must be total y supplied
in the diet. There are two types of dietary iron, Haem and Non-Haem. Haem iron is more easily
absorbed in the body and is found in animal products. The best available sources are found in
red meats (liver, lamb, kangaroo and beef). Non-haem sources are found in plant foods and
breakfast cereals, legumes, nuts, green leafy vegetables and dried fruit.
A nutritional deficiency in iron is more likely to occur in vegetarians/vegans, those who
consume little or no red meat, or breakfast cereals, avoid packaged or fortified foods, have very
high carbohydrate intakes or are constantly on a fad diet (Burke, 2006). Strategies to Increase your iron intake:
The fol owing are some strategies to increase iron intake:
1. Consume plenty of iron-rich plant foods on a daily basis
a. Including fortified cereals and bread; and green leafy vegetables b. Lean red meat (liver, lamb, kangaroo, lamb or beef) at least 3-4 times/week
2. Add foods high in vitamin c (fruit, juice, capsicum, broccoli, cabbage, cauliflower) to
3. Avoid drinking tea or coffee with food high in non-haem iron 4. If vegetarian or vegan, consume iron-rich plant foods at most meals, AND combine
5. Avoid consuming non-haem iron sources with inhibitors such as wheat germ or bran. (Deakin & Pel y, 2006, p302)
Calcium and Iron Supplements
As with al supplements, calcium and iron supplements must be taken with caution. Iron
overload can occur if consumed in quantities greater than needed by the body. It is a serious
medical condition known as haemacromatosis. Over consumption of calcium or iron may also
impair absorption of other nutrients. Supplements should only be consumed when directed by
your Sports Dietitian or Physician.
For further information and fact sheets on Iron and Calcium see
Cramps and stiches-
What causes them to occur and how can you prevent them?
See Cramps and Stiches fact sheets: http://www.ais.org.au/nutrition/HotTopics.asp
Caffeine and Sports Supplements-
What you really need to know before you pop that pill or drink that potion?
Caffeine is arguably the world’s most widely accepted and consumed ‘drug’. It is neither an
essential nutrient nor necessary for health maintenance, and is a natural y occurring stimulant
found in the leaves, nuts and seeds of a number of plants. Major dietary sources include
coffee, tea, chocolate and soft drinks. It is also found in appetite stimulants, analgesics, and
cold and sinus preparations.
Caffeine has a direct effect on many of the body’s systems, including the central nervous
, where it appears to reduce a person’s perception of effort (Cole et al, 1996); Cardiac
, increasing the heart rate and blood pressure; respiratory system
, increasing the
breathing rate and relaxing lung’s smooth muscle; and diuresis
(the body’s process of
eliminating fluid), although research suggests the previously thought effect of dehydration is
overstated, especial y in habitual users; and neuromuscular function
, where an alteration of
neurotransmitter function occurs. Neurotransmitters are the ‘languages’ of the nervous system,
the means by which each neuron communicates with others to process and send messages to
the rest of the body. For example, caffeine blocks Adenosine (a neurotransmitter) that plays a
role in sleep and suppressing arousal, hence the feeling of increased alertness after ingestion.
(Graham et al, 1994, Tarnopolsky, 1994 and Graham, 1997)
In addition to the above, caffeine also increases the core body temperature, and can have
adverse affects such as tachycardia, insomnia, irritability and increased anxiety. Caffeine
withdrawal can result in irritability, fatigue, drowsiness, and decreased alertness and activity
levels (Rogers and Dinges, 2005).
The mechanism underpinning performance benefits of caffeine ingestion remain unclear,
although a number of theories are suggested. These include:
1. The effect of the increase in fat utilisation, and therefore the sparing of glycogen,
however the results are inconsistent, and therefore unlikely to explain the increase in performance.
2. Change in perception of effort as a result of the effect on the central nervous system. 3. May be related to the blockage of adenosine 4. Breakdown products from caffeine, paraxanthine and theophyl ine may also have
Summary on Caffeine Supplementation:
There is sound evidence for caffeine supplementation when used correctly in the
right dose, at the right time, and in the right situation
Not recommended for novice competitors or people under the age of 18. The effects of supplementation vary between individuals. Some may be non-
responders; others may have negative side effects, which may impair performance and health.
Recent research shows a ~3% improvement in endurance power for athletes (Cox
et al, 2002) This equates to a 3.6min improvement in a 2hr race.
Caffeine may also be useful as a training aid to al ow better and more consistent
Peaks at ~1hr post ingestion and lasts for up to 3-7hrs, however the timing of
ingestion is crucial, and is likely to be different for each individual athlete and the type and duration of the race.
1-3mg/kg Body weight is probably enough, but more research is needed (Cox et
There is little evidence of a dose-response relationship. That is, performance does
not increase with increased quantities of caffeine
Choose caffeine (eg No Doz), not coffee. Coffee as a source of caffeine is not
optimal as the content varies and is unpredictable. The presence of other compounds in coffee may also negate the effect of caffeine (Graham et al, 1998). Cola may be a suitable option for a change in taste and texture and provision of caffeine
Female/male difference is trivial, but unclear Regular consumption of caffeine may diminish the physiological responses to
caffeine and a tolerance can develop within 3 days. It is therefore recommended to withdraw for at least 2 days or maybe more for greater effect.
It is recommended to consult your Sports Dietitian and coach prior to consuming
For more information of caffeine see www.ais.org.au/nutrition
Sports Supplements- Getting the edge of performance
Nutritional supplements when used appropriately can provide a significant
improvement in health and or performance
Be conscious of marketing ploys such as scientific theories and anecdotal testimonials.
Scientific Theories usual y predict
the outcome of a supplement, using the ‘idea that ‘supercharging’ a system by adding additional amounts of certain compounds or nutrients, metabolic processes wil proceed faster or for a longer time span, thereby enhancing sports performance’. Often lengthy descriptions of the metabolic pathways are provided, however it is important to remember that a theory is not
proof the action proposed wil actual y
occur! (Clinical Sports Nutrition, 2006).
Weigh up the pros and cons when considering a supplement
: 1) Assistance in meeting nutritional goals, 2) Direct effect on performance and/or
3) A placebo effect (a psychological boost from the belief
you are consuming
something that wil improve your performance) Cons:
1) High expense, 2) Contamination of a nutrient or metabolite that may cause
an inadvertent doping outcome, 3) Risk of an adverse outcome on your health, short or
long term, 4) Re-direction of time and resources from real performance enhancing
factors, such as proper equipment, hard training and a wel balanced diet.
(Clinical Sports Nutrition, 2006)
Seek professional advice prior to taking supplements
AIS sports Supplement program
AIS Nutrition Department designed the sports supplement program to assist AIS athletes and
coaches in meeting their specific needs, and to assist in determining the safety and efficacy of
particular supplements. This program is open for public viewing on the website, and also
provides fact sheets on many current supplements and ergogenic (performance enhancing)
aids available in the marketplace. Before you consider a taking a supplement, it is highly
recommended you visit the website, www.ais.org.au/nutrition
Remember, when considering supplements, it is easy to get caught up in the marketing hype,
and it is important to assess whether the supplement is really effective, or whether it is
you, the athlete
. As an example, Beedie and co-workers (2006) conducted a study where
they informed subjects they were investigating effects on performance with different levels of
caffeine (0, 4.5, 9mg/kgBW). They in fact gave al participants a placebo Results showed a
dose-response relationship was evident. That is, the more caffeine participants thought
received, the better their performance. Al subjects reported caffeine related symptoms,
increases in mean power, similar to the magnitude of other studies that actual y
The moral of the story? Supplements can be effective when consumed in the right context, at
the right time and at the right dose, but they wil not replace al the factors required to perform
wel , including the right equipment, hard work and a good diet.
For ful overview see AIS Sports Nutrition Fact sheet:
Supplements in Sport- Why are they so tempting? Available at
Accredited Practising Dietitian
Accredited Sports Dietitian
AVIVA PLC Estate, GB-KY6 2SD Glenrothes; Tel: +44-1592 ASSOCIATION OF INDEPENDENT RESEARCH & TECHNOLOGY ORGANISATIONS Adr: GB-KT22 7YG Leatherhead; Tel: ++44/01372/www.ardmel-group.co.uk; A: 1980; Eff: 175; Dev:GBP and Euro; Cap: 40.002000 (GBP); Act: [email protected]; Eff: 5; Dev: £; TO: 132000; Act:and testing equipment; Decid: R. Fernando (DirectorInternational
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