nmds311 sn07 lecture … · • combining different types of plant foods allows low levels of amino...

NMDS311Sports Nutrition

www.endeavour.edu.au

Session 7

Diets for Special Athletic

Populations

Part 1

Nutritional Medicine Department

© Endeavour College of Natural Health www.endeavour.edu.au 2

Sports Nutrition

Session 7

Diets for Special Athletic Populations

• Vegetarian diets

• Gluten free diets

• Diabetes and sports nutrition

Vegetarian

Diets


Types of Vegetarians

Type Comments Fruitarian Diet consists of raw or dried fruits, nuts, seeds,

honey and vegetable oilMacrobiotic Excludes all animal foods, dairy products and

eggs; uses only unprocessed, unrefined, "natural" and "organic" cereals, grains and condiments such as miso and seaweed

Vegan Excludes all animal foods, dairy products and eggs. In the purest sense, excludes all animal products including honey, gelatine, silk, wool, leather and animal derived food additives

(AIS Sports Nutrition, 2009)


Types of Vegetarians

Type Comments Lacto-vegetarian Excludes all animal foods and eggs.

Does however include milk and milk products

Lacto-ovo-vegetarian

Excludes all animal foods, however includes milk, milk products and eggs

"Quasi", "Pseudo", or Near-Vegetarian

Usually excludes red meat, however includes poultry, beef extracts and fats, fish, eggs and dairy products



Can it Improve Performance?

• Currently it is unclear as to whether a vegetarian diet will

improve athletic performance

• To date, studies have failed to examine the true benefit,

if any, of a vegetarian diet on exercise performance

• Studies have either controlled for the inherent

differences seen between vegetarian diets and non-

vegetarian diets, or have used populations that are not

representative of well-trained athletes




• Vegetarian diets tend to be higher in nutrient-rich

carbohydrates, antioxidants and phytochemicals which

are conducive to enhancing muscle re-fuelling and

maintaining health and well-being during periods of

strenuous training

• However, vegetarian diets are high in fibre and lower in

energy, protein, fat, vitamins B12, riboflavin, and vitamin

D, calcium, iron and zinc than omnivorous diets



Can it improve Performance?

• Female vegetarians have a higher frequency of

suboptimal micronutrient intakes, particularly iron, zinc,

calcium and energy than male vegetarians and

omnivores

• These characteristics often raise concern among

coaches and support staff as to whether a vegetarian

diet can fully support the nutritional requirements of

training and competition in athletes – this is where

dietetic expertise comes into play




• Vegetarian athletes, particularly children and

adolescents, those engaged in heavy endurance training

and those striving to increase muscle mass may have

difficulty meeting daily energy requirements

• These athletes should be advised accordingly.

Vegetarians have been found to consume, on average,

lower protein intakes than meat eaters, although most

protein intakes met population reference standards and

the slightly higher sport-specific guidelines for protein of

1.2–1.7g/kg BW/day




• While it was once thought that various plant proteins had

to be consumed in the same meal to provide all essential

amino acids, complementary meal planning is no longer

considered a requirement

• Misinformed or unplanned athletes following

a vegetarian diet may struggle to meet daily protein

intake goals and incorporate adequate protein at

strategic times throughout the day (i.e. during the post-

exercise period) to optimise the response from daily

training




• Furthermore, vegetarian athletes travelling for extended

periods that rely heavily on eating out may also be at risk

as many eating establishments do not typically

incorporate protein rich plant-based alternatives



Risk of Deficiencies in

Vegetarian Athletes

• Protein

• Iron

• Calcium

• B12

• Zinc(AIS Sports Nutrition, 2009)


Protein

• Vegetable or plant proteins may be limiting in one or

more essential amino acids (the building blocks of

protein), so food sources need to be combined in such a

way to ensure all amino acids are consumed

• This is a particular issue for athletes who avoid all animal

proteins such as milk and eggs (i.e. vegans)

• There is no requirement to include complementary

proteins at each meal as long as a variety of protein

sources are included throughout the day



Protein

• Combining different types of plant foods allows low levels of

amino acids in one food to be complemented by high levels

of amino acids in the other (i.e. legumes and grains, or

legumes and nuts/seeds)

• Furthermore, as plant proteins are less well digested than

animal proteins, vegetarian athletes are advised to

consume approximately 10% more protein than current

athlete protein recommendations

• This is of particular concern for vegetarians with relatively

low energy budgets



Iron

• Iron is arguably the nutrient most at risk in a vegetarian

diet

• Meat provides a source of haeme iron, which is

absorbed more effectively than the non-haeme iron from

grains and vegetables

• Iron status can be enhanced by consuming foods rich in

vitamin C and by avoiding iron inhibitors such as the

tannins in tea and, to a lesser extent, the caffeine in

coffee and cola drinks



Calcium

• Obtaining sufficient calcium can be a challenge for those

vegetarians not consuming dairy foods

• Poor calcium intake can increase the risk of low bone

density, thereby increasing the risk of fracture

• Calcium-fortified soymilks are an excellent alternative to

dairy products



Vitamin B12

• Vegan diets tend to lack vitamin B12, so supplemental

B12 from a fortified soymilk or dietary supplement is

recommended

• Vegetarian athletes should discuss with their sports

physician whether it is necessary for them to take a B12

supplement or infusion



Zinc

• Inadequate zinc intake may compromise immune function

and the healing of wounds

• Meat, chicken and fish are the major dietary sources of

zinc, and thus the vegetarian athlete needs to consume

alternatives such as whole grains, nuts and seeds, and

legumes

• Nutritional deficiencies of protein, iron, calcium, or vitamin

B12 may adversely affect performance by reducing energy

levels, delaying recovery and inhibiting muscle repair and

growth(AIS Sports Nutrition, 2009)

Gluten free

diets


Gluten Free Diets – Are They

Better for Non-Coeliac Athletes?

• ‘Gluten-free diets (GFD) are a clinical necessity for 5-

10% of the general population for health purposes

including coeliac disease, wheat allergy and non-coeliac

gluten sensitivity’

• ‘However, general population market reports indicate

that the adoption of a GFD has far exceeded the

requirement for clinical populations, with GFD uptake

exploding amongst non-coeliac athletic populations as

well’

(Lis D et al. 2015 )




• ‘Correspondingly, our recently published questionnaire-

based study, which investigated the frequency,

perceptions and beliefs surrounding GFD, found that in

942 non-coeliac athletes over 40% reported following a

GFD at least 50% of the time’.

• ‘Startlingly, this group of non-coeliac athletes mostly

relied on self-diagnosis of a gluten-related disorder and

subsequent self-treatment with a GFD’.

(Lis D et al. 2015)




• ‘General population gluten avoidance has become

prevalent due to a belief that a GFD is “healthier,” or

owing to self -diagnosed gluten-related gastrointestinal

(GI) disorders’

• ‘Non-coeliac athlete populations adopt a GFD in the

belief that it is not only healthier and augments weight

loss, but will also decrease GI distress and systemic

inflammation and improve psychological well-being and

athletic performance’

(Lis D et al. 2015)




• ‘Thirteen competitive endurance cyclists (8 males, 5

females) with no positive clinical screening for coeliac

disease or history of Irritable Bowel Syndrome were

allocated to a seven day gluten-containing diet (GCD) or

gluten free diet (GFD) separated by a 10-day washout in

a controlled randomized double-blind, cross-over study’

• ‘Cyclists ate a GFD alongside either gluten-containing or

gluten-free food bars (16g wheat gluten per day) while

habitual training and nutrition behaviors were controlled’

(Lis D. et al, 2015)




• ‘During each diet, cyclists completed the Daily Analysis

of Life Demand for Athletes (DALDA) and GI

questionnaires (post-exercise and daily)’

• ‘On day seven cyclist completed a submaximal steady-

state (SS) 45 minute ride at 70% peak power followed by

a 15 minute time-trial (TT)’

(Lis D et al. 2015)




• Blood samples were taken pre-exercise, post SS and

post TT to determine intestinal fatty acid binding protein

(IFABP) and inflammatory markers. Mixed effect logistic

regression was used to analyze data

• RESULTS: TT performance was not significantly

different (P = 0.37) between the GCD and GFD. GI

symptoms during exercise, daily, and DALDA responses

were similar for each diet. There were no significant

differences in IFABP or cytokine responses.





o CONCLUSION: A short-term GFD had no overall effect

on performance, GI symptoms, well-being, and a select

indicator of intestinal injury or inflammatory markers in

non-coeliac endurance athletes.


Diabetes and

Sports Nutrition


How does exercise affect diabetes

management

o Factors such as muscle contraction, increased blood

flow and increased body temperature cause the body to

more responsive or 'sensitive' to insulin during exercise.

o Therefore, in people who do not have diabetes, insulin

levels decrease during exercise.

o People with Type 1 diabetes usually need to adjust their

insulin dose to account for a reduced requirement for

insulin during exercise. Regular monitoring of blood

glucose levels and trial and error

(Burke & Deakin, 2015)



management

o Regular monitoring of blood glucose levels and trial and

error is needed to understand and manage each

individual's response to exercise (under the care of a

diabetes specialist).

o Intensity and duration of exercise

Pre-exercise insulin dose generally needs to be reduced

when exercise extends beyond 30 minutes. The level of

reduction varies for each individual but, in general, the

longer the period of exercise, the greater the reduction

required.




management

o Adjustments to insulin should be made with the guidance

of your diabetes specialist, especially in the early stages

of management.

o Degree of metabolic control before exercise

It is easier to manage and predict the body's response to

exercise when metabolic control is good. It is dangerous

to commence exercise when blood glucose levels are

high and ketones are present in the urine.




management

o Type and dose of insulin injected before exercise

It is common practice to use a mixture of short and long

lasting insulin to manage diabetes. It is necessary to

predict the peak period of insulin activity to avoid

excessive levels of insulin injection during exercise.

o Site of insulin injection

Insulin absorption is increased in exercising muscles.

The abdomen is usually the preferred site for insulin

injection prior to exercise.




management

o Timing of previous meal

Insulin requirements are influenced by the amount and

type of food consumed.



Eating Before Training and

Competition

o As for all athletes, a carbohydrate-based pre-exercise

meal 1-3 hours before exercise is recommended.

o It is important for people with Type 1 diabetes to ensure

blood glucose levels are at an appropriate level before

commencing exercise - ideally between 4-8 mmol/L.

o Exercising with high blood glucose levels disrupts normal

metabolic control and will elevate levels even further.



Eating Before Training and

Competition

o Apart from being dangerous, this will result in poor

performance. In general, exercise should be postponed if

blood glucose levels are above 10-14 mmol/L, especially

if ketones are present in the urine.

o Being attune to the symptoms of hypo- and

hyperglycaemia and regular monitoring is necessary in

these situations.



Eating During Training and

Competition o Research suggests 30-60 g of carbohydrate per hour will aid

performance.

o Usually it is not necessary to have extra insulin if you eat

during exercise.

o Choices such as sports drinks that provide fluid and

carbohydrate are a convenient option for most exercise

situations.

o Other options such as carbohydrate gels, fruit and sports bars

may also be tolerated.



Eating During Training and

Competition

o If additional carbohydrate is required during exercise, it

is better to consume small amounts frequently rather

than leave it until the last minute.

o TRY ANY NEW STRATEGIES DURING TRAINING

SESSIONS WHEN IT IS EASIER TO MONITOR THE

EFFECTS ON BLOOD GLUCOSE CONTROL



Eating After Training and

Competition

o The increased insulin sensitivity caused by exercise lasts

for several hours after exercise.

o Therefore the risk of hypoglycaemia persists for some

time.

o Delayed hypoglycaemia can occur 4-48 hours after

exercise.

o Preventing delayed hypoglycaemia involves making sure

you (Burke & Deakin, 2015)



Competition

o Preventing delayed hypoglycaemia involves making sure

you consume sufficient carbohydrate before, during and

after exercise.

o It may also be necessary to reduce the next insulin dose

after exercise. It is helpful to monitor your blood glucose

levels frequently after exercise.

o Inconveniently, delayed hypoglycaemia often occurs

during the night. If this occurs regularly, it can

exacerbate fatigue in athletes.




Competition

o Waking up feeling very tired and groggy in the morning

may indicate you have experienced a 'hypo' during the

night.

o This is a sign that you need to increase blood glucose

monitoring after similar exercise sessions in the future.

o Alcohol inhibits the release of glucose from the liver

therefore increases the risk of hypoglycaemia.

Consuming excessive alcohol also impairs the ability to

recognise the symptoms of hypoglycaemia.



Controlling Blood Glucose

Levels During Competition

o Excitement and nerves surrounding competition are

almost inevitable.

o A side effect of excitement is the release of hormones

such as adrenalin and cortisol. These hormones

stimulate the release of glucose from the liver and

reduce the effectiveness of insulin.



Controlling Blood Glucose

Levels During Competition

o This can cause fluctuating blood glucose levels. Ways to

avoid or cope with this include:

• Emulate your race/competition preparation in training

(including physical preparation and recovery, and nutrition

strategies)

• Try and practice some relaxation techniques (correct

breathing techniques, muscle relaxation techniques,

music, or talk to a sports psychologist)

• Write your routine down on paper before the event so you

don't forget your routine amongst all the excitement.



References

o AIS Sports Nutrition, last updated March 2009. © Australian Sports

Commission.

http://developingchampions.com.au/images/cms/content/Resource%

20Nutrition%20for%20Vegetarian%20Eating.pdf

o Burke, L & Deakin, V 2015, Clinical sports nutrition, 5th Ed, McGraw

Hill, Sydney.

o Lis, D, Stellingwerff, T, Kitic, C.M, Ahuja, K, Fell , J,. (2015) No

Effects of a Short-Term Gluten-free Diet on Performance in

Noncoeliac Athletes.Med Sci Sports Exerc. Dec; 47(12): 2563–2570.

doi: 10.1249/MSS.0000000000000699

http://developingchampions.com.au/images/cms/content/Resource Nutrition for Vegetarian Eating.pdf

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