No convincing evidence suggests that supplementation of vitamins
provides an advantage to individuals participating in prolonged
treks at high altitude, provided that energy intake is adequate.
However, antioxidants especially vitamin E and the energy releasing
B vitamins have received some attention.
Vitamins required to release energy from food include some
of the B vitamins; thiamine, riboflavin and niacin. Therefore,
if basal energy needs are increased the need for these vitamins
is increased. It is often assumed that the increased food intake
automatically supplies the increased levels of B vitamins required
for energy released. However, the theoretic increased requirements
for these nutrients at high altitude nor the assumed adequacy
of these B vitamins have been established.
From scientific journals to fashion magazines the words "free
radicals" and "antioxidants" (antioxidants quench
these free radicals) are commonly cited in health scares or
in improving your health. Factors that play a role in oxidative
stress (increased production of free radicals) are cigarette
smoking, alcohol and high altitude. High altitude exposure is
thought to be associated with an increase in oxidative stress
caused by increased ultra violet light, added stress of reduced
oxygen particle pressure, and increased metabolic rate. Vitamin
E is an antioxidant which is known to suppress oxidative damage.
In science there are tests which can be carried out to indicate
the level of oxidative attacks our DNA gets per day. Such tests
have been used to assess the damage caused by oxidative stress
during exercise. There are many studies suggesting that strenuous
physical activity cause DNA damage. In support of such findings
these studies have also shown that oxidative stress leads to
lowering of antioxidants in our bodies, indicating that more
antioxidants are being used to overcome the increased damage
caused by oxidative stress. However, if you are endurance trained
it is shown that you actually increase antioxidant enzyme activity.
In contrast, habitual inactivity reduces such protection and
as a result it appears that frequent physical activity is necessary
to maintain and promote our natural capacity to protect against
the damage of oxygen stress.
Most studies have reported no beneficial effect on performance
with vitamin E supplementation above what is already recommended
by the Food and Nutrition Board. However, vitamin E supplementation
at high altitude has shown positive effects in mountain climbers
working at 5000m, there were lower levels of oxidative damage
as well as a higher performance capacity. It was suggested that
this positive effect may be to do with the antioxidant properties
of vitamin E which may counteract the effect of increased lipid
peroxidation. However there are confounding factors in this
study and other studies have not conclusively proven that vitamin
E intake exceeding the recommended daily level would have any
beneficial effects on athletic performance.
Rich sources of vitamin E
- Vegetable oils are the richest source natural source e.g.
sunflower, olive oil
- Unprocessed cereal & nuts are also good sources
- Animal sources include meat
Foods rich in Antioxidant include:
- Fruit & Vegetables
- Tea- green and black
- Red wine
- Red grape juice (sorry, you can have the benefits without
Minerals (calcium, copper, iron, selenium, zinc)
Except iron, there is no data to support the
need for concern about other minerals at altitude.
At altitude the atmospheric pressure is lower and there is
less oxygen in each breath. In response to this the body adapts
by increasing the number of red blood cells from bone marrow,
so the capacity of the blood to carry oxygen increases. It is
for this reason that a variety elite endurance athlete's train
at altitude - it improves their aerobic capacity. Repeatedly
supported by the prevalence of some athletes illegal use of
blood doping to increase red blood cells.
However, the availability of iron is crucial for this oxygen
carrying as one function of iron is to deliver oxygen to cells
and facilitate the use of oxygen by cells. The importance of
adequate nutrition in the maintenance of this function at high
altitude is well documented. The general consensus is that iron
stores are of critical importance before prolonged exposure
to altitude greater than 2500m therefore attention to iron in
the diet before and during altitude exposure is important. It
has even been shown that athletes with low iron stores do not
benefit from training at moderate altitude.
If you think you have a low iron intake the best way to increase
your iron is through food (although if you have iron deficiency
or have frank anaemia, under medical advice a dose of iron through
supplements is normal). Iron at large doses is toxic as it is
stored in the body and supplements taken in large doses without
a medial reason can be seriously detrimental to your health.
Athletes often take a multivitamins with iron at the recommended
nutrient intake dose set by the Food and Nutrition Board, which
under normal circumstances is harmless.
Meats are an excellent source of iron which is well absorbed
(haem iron). In contrast, cereals, legumes, whole grain, deep
green leafy vegetables contain iron (non- haem) but are not
absorbed well. The best way to increase iron is to consume red
meat about 80g of lean beef three to four times a week. Poultry
and fish also contain haem iron but less than red meat. Meat,
poultry, fish and vitamin C enhance the absorption of plant
iron sources so it is a good idea to eat a mixed meal containing
both plant iron sources (non-heme) and animal (heme) food and
have a small amount of fresh orange juice with your meals.