Creatine: What is it? Is it harmful? And should we supplement our diets with it?

Hayley Dickinson, Hudson Institute and Stacey Ellery, Hudson Institute

Named after the Greek word kreas, meaning flesh, creatine is an amino acid derivative found in all cells in the body, but is stored primarily in muscle. It plays an important role in tissues where energy levels quickly rise and fall, such as muscle.

Creatine acts as a short sharp burst of recharge for our cells. Creatine also moves energy around the cell, from where it is generated to where it is needed.

As the name suggests, creatine is naturally found in flesh and is acquired through a diet rich in fish, meat and other animal products such as dairy. As creatine is important for all cells to function, our body also makes its own.

A diet containing animal products can account for 50% of daily creatine requirements, with the other 50% being made by the body.

Those on an animal-free diet will naturally have a higher burden placed on the body to meet its entire creatine requirement. However, under normal circumstances, a healthy person can maintain adequate creatine levels even if they choose to follow a vegetarian or vegan diet.

Why do people take creatine supplements?

Natural and supplemental creatine have the same effect in the body – the concentration of creatine in a supplement is just much higher. This is why athletes often use creatine supplements to help them train and increase muscle performance.

The standard dosing regime for an athlete is an initial dose of 0.3g for each kilogram of body weight per day (so if you're 60kg you would take 60 x 0.3 = 18g of creatine every day) for a week. Then an ongoing dose would be 0.075g per kg per day (or 4.5g per day for the same 60kg person). When your body reaches the threshold of creatine it can absorb, the excess will come out in urine.

Creatine is also important for brain function, as your brain uses a lot of energy. Some choose to take creatine to help boost alertness, and numerous studies are underway to assess whether creatine supplements might be useful for neurodegenerative diseases such as Parkinson's and mild depression.

There isn't enough information about the use of creatine supplementation in children, adolescents and pregnant women, so current guidelines recommend that they don't take it. Those with pre-existing kidney conditions should also seek professional advice before taking supplements including creatine.

While the supplements are safe for the general public, there is no need to supplement a normal balanced diet with creatine products.

Therapeutic uses of creatine

Dietary creatine supplements have been trialled as a treatment for a range of conditions where muscle fibres break down. A successful application of creatine in this area is the treatment of Duchenne Muscular Dystrophy.

While still in the trial phase, long-term creatine supplementation (over four months) appears to improve muscle strength and mass without adverse side-effects.

Creatine is also considered as an additional therapy to help ease the progression of neurodegenerative diseases such as Parkinson's and Huntington's disease. Although the results of these studies have been relatively unconvincing.

And while it is marketed as a supplement for the young and buff, creatine is also being trialled to help the elderly maintain their muscle and bone mass to help reduce the burden of falls.

A link between creatine and fetal growth was established back in 1913. During pregnancy, the rapidly increasing nutrient demands of the growing baby pose a considerable energy challenge for the mother.

Our recent studies show creatine synthesis, excretion, transport and storage are all changed by pregnancy. In a study of 270 women, our team found that pregnant woman who had less creatine in their urine gave birth to significantly smaller babies.

These results raise the possibility that improvements in maternal diet, ensuring inclusion of foods containing creatine (meat and fish), could protect a baby from poor growth.

The next step is to study maternal diet and maternal creatine concentrations throughout pregnancy. The findings may inform development of new dietary guidelines, including a minimum recommended creatine intake during pregnancy.

Is creatine harmful?

At times, creatine is confused with its breakdown product creatinine. The body maintains a tight ratio of creatine to creatinine, so the more creatine in your system the more likely you are to excrete excess creatinine in your urine.

Increased creatinine in the urine is commonly taken as a sign that our kidneys aren't properly filtering blood. This had led to published case studies that link creatine use to kidney dysfunction.

While case studies have been published that point to potential harms or side effects, scientific studies testing these cases have concluded that creatine is safe.

In some cases creatine causes water retention. This could mean it has the potential to alter kidney function, but most studies have found this not to be the case. Some studies found that the supplement caused weight gain, probably due to this increase in water.

The opinion of most experts is that creatine does not cause the type of nephrotic syndrome (kidney disease) that sadly claimed the life of rugby league star Jonah Lomu, as some thought.

Should pregnant women take creatine supplements?

The evidence to support the use of creatine to enhance muscle performance is pretty clear. Throughout the countless studies of creatine supplementation in the sports arena, and in clinical studies, creatine has a good safety record.

But there is no human safety data of creatine supplementation during pregnancy. While our work found mothers with higher levels of creatine in their urine are less likely to have a small baby, these data are based on women's regular diets, without creatine supplementation.

So, at this time there is no evidence to suggest creatine supplements are necessary for pregnant women. Simply eating a balanced diet, containing meat and fish, will ensure women receive adequate creatine for themselves and their babies.

Hayley Dickinson, Research Group Head, Embryology and Placental Biology, Hudson Institute and Stacey Ellery, , Hudson Institute

This article was originally published on The Conversation. Read the original article.