vitamin – so-called because the
most efficient source is the sun as
it is synthesised when chemicals
in the skin react to ultraviolet rays
- can speed up your recovery from
sessions and enhance your overall
exercise performance.
Adults need at least 400
international units - or 10
micrograms - of the vitamin every
day (children under the age of four
need 7 to 8.5mcg).
Dr Graeme Close, a researcher
in sports nutrition and exercise
metabolism at Liverpool John
Moores University, found that “even
using conservative guidelines” up to
70% of the recreational and serious
athletes he tested had worryingly
low vitamin D levels.
In tests on a group of footballers
who were given either a vitamin D
supplement or a placebo Close
found that, after eight weeks of
training, the nutrient group showed
significant improvements in 10m
sprint times and vertical jumps –
compared to no change among
their placebo counterparts. It is
found in fortified cereals and
dairy products, oily fish, cod
liver oil, milk and eggs,
but the best source is
sunlight and you may a
supplement.Iron
Try: Blueiron (£14.99;
blueiron.co.uk) which
contains vitamin C-rich
blueberries that help
iron absorption and
Healthspan Elite Iron Complex
(£10.99; healthspan.co.uk),
a non-constipating formula
which also contains immune-
boosting copper.
Men of all ages and aged 50 to 64
years need 8.7mg iron a day; for
women aged 19 to 50 years it is
14.8mg a day. To find out if you are
low, you need a blood test from
your GP which will determine if your
haemoglobin levels are below thenormal range of 130-170g
per litre (g/l) for men and
120-150g/l for women.
Low levels can have
a huge impact on
performance and
some marathon
runners are prone
to “foot-strike
haemolysis” where
red blood cells are
damaged by the feet
repeatedly hitting the
ground over many
miles of training which
reduces haemoglobin levels. Of the
two types of dietary iron, the haem
iron in meat, fish and poultry is
better absorbed, but pulses, tofu,
sardines, prunes, leafy green veg
and salmon all contain iron.
Add beetroot leaves to salads as
they contain more iron per serving
than spinach. Gut-friendly probiotics
can also help. In a 2015 study
published in the British Journal
of Nutrition, a team of Swedish
scientists reported that the “intake
of probiotics can increase iron
absorption by approximately 50%.Bicarbonate of soda
Try: Sodium bicarbonate
capsules (£9.99; pas-
nutrition.co.uk)
So called ‘soda-doping’ – drinking
a bicarb solution before training
as a means to enhancing
performance – is popular among
athletes. Why? Because of its
alkalinity, bicarbonate of soda isthought to act as a buffer against
performance-limiting by-products
that lead to soreness and fatigue.
And there’s reams of evidence it
might work.
One study conducted at the
University of Hull and published
in the Journal of Strength
and Conditioning showed that
swimmers who took a drink
containing bicarb recorded a 4%
improvement in performance
compared to those who took a
placebo of salted water.
“It’s a useful ergogenic aid
for some people,” says Damien
Gleadall-Siddall, a researcher in
sport and exercise nutrition and
biochemistry who carried out the
trial. Paul Andsell, a researcher
at the University of Northumbria’s
school of sport, exercise and
rehabilitation, says it helps to
prevent a build-up of negative
metabolites, such as hydrogen ions,
which cause the pH of a muscle
to drop and become more acidic,
during intense training.
“If these negative metabolites
build up, it means the muscle cells
can’t contract as forcefully,” he says.
A dose of 0.2-0.4 grammes per kg
of body weight should be consumed
60-90 minutes before a training. For
an 80kg male, that means 16-32
grammes of sodium bicarbonate
as a supplement or added to water.n Peta Bee has a degree in
sports science and an MSc
in nutritionVitamin D: as many
as 70% of athletes
don’t get enoughBicarbonate of soda: a buffer
against muscle sorenessPERFORMANCE NUTRITION