Personal training: Vitamin D- your day in the sun
Today’s blog on health and fitness focuses on vitamin D, which is essential for healthy bones and therefore an important vitamin when it comes to personal training.
The benefits of vitamin D
Along with vitamins A, E and K, vitamin D is classed as a fat-soluble vitamin. Vitamin D in particular is associated with calcium; without vitamin D the body is unable to absorb calcium, which is essential for strong, healthy bones and teeth.
It is also a known antioxidant, believed to help prevent cancers and multiple sclerosis.
Food high in vitamin D
Vitamin D can be found in eggs, butter and liver. It can also be absorbed through the skin from natural sunlight.
Strength gain through vitamin D
Personal trainers and fitness instructors often work with clients following weight-training programmes, who will benefit from consuming sufficient vitamin D in order to build stronger bones. However, there is also believed to be a correlation between vitamin D and muscle strength.
The journal of the American College of Sports Medicine (ACSM) ran an article in 2012 entitled: “Vitamin D Is Associated with Greater Muscle Strength in Healthy Men and Women” by A Grimaldi, B Parker et al.
The article looked at a study carried out with 419 healthy men and women aged from 20 to 76 years old.
Exercise performance and muscle strength was tested for each of the subjects, who were split into a control group and groups who received differing amounts of a vitamin D serum.
The study supported a direct relation between vitamin D and muscle strength:
“Vitamin D was significantly associated with arm and leg muscle strength when controlling for age and gender. When controlling for other covariates… vitamin D remained directly related to both isometric and isokinetic arm strength but only to isometric leg strength.”
The study suggested that vitamin D was beneficial for increasing muscle strength in six out of seven arm strength measurements. The results for leg strength were more complex, with a positive association with vitamin D for four of six leg strength exercises when only taking the variables of age and gender into account, but a less significant result when other variations were taken into consideration.
Although the study saw benefits from vitamin D intake on muscle strength, it concluded that “there may be a differential effect of vitamin D on upper and lower body strength”, and acknowledged that further research is needed on the subject.
What advice should a personal trainer give about vitamin D?
A personal trainer working with clients looking to increase their vitamin D intake can recommend that they consume more eggs, butter and liver, as well as spending time in the sun, without overdoing it and while wearing the appropriate sun factor cream.
In addition, excessive alcohol intake should be avoided as this can affect the body’s ability to absorb vitamin D.
Being fat soluble, vitamin D ends up in the fat stores of our internal organs, and there is therefore a risk of overdosing on this vitamin on a long-term basis. A personal trainer may want to pass this advice on to any clients who take vitamin D supplements.