In a previous article earlier this year, I wrote about vitamin D, concentrating on its importance, and some of the science behind vitamin D supplementation.
In this article I’ll be concentrating more on the important factors that require consideration when selecting the particular vitamin D supplement that is most appropriate, in particular for athletes who may be subject to drug testing.
As a reminder, to summarise the most salient points from my previous article, vitamin D:
· Helps the body incorporate calcium into bones more effectively
· Helps regulate calcium and phosphate levels
· Stimulates bone and cell growth
· Reduces inflammation
· Helps regulate mental health
· Helps maintain the immune system
Additionally:
· Vitamin D3 (colecalciferol) is the preferred form over vitamin D2 (ergocalciferol)
· In winter months (October to March in the UK) it is almost impossible to get enough vitamin D from either sunlight or dietary intake (or both together!)
· Covering up in the sun (and using high SPF sunscreens) contributes to low vitamin D levels
And low vitamin D levels can contribute to:
· Osteoporosis
· Generally “feeling unwell”
· Musculo-skeletal pain
· Depression
· Compromised immunity
In the case of athletes, one of the most relevant factors to consider is that since the late 1980s and 90s, it has emerged that there are vitamin D receptors in skeletal muscle[i] meaning that for optimal muscle function, vitamin D levels should be “adequate” at the very minimum.
This is often classified as a blood level of 50 - 75 nanomols/litre (nmol/l), alternatively expressed as 20 – 30 nanograms/ml (ng/ml). However, it is not uncommon to find target levels of 100nmol/l (40ng/ml) or more[ii] in elite sport, and to achieve such levels in the UK in winter months, supplementation is the only pragmatic option.
Another important reason for vitamin D supplementation is to avoid compromised immunity as far as possible for athletes who train and compete in team/squad environments because infection can spread rapidly amongst these populations.
Factors affecting choice of supplement
From the perspective of an athlete, paramount when selecting a supplement is the risk of either deliberate, or inadvertent presence of a WADA prohibited substance that would lead to an Anti-Doping Rule Violation (ADRV), which in turn can be a career-ending catastrophe.
This is where due diligence is vital and should be undertaken by the athlete, or on behalf of the athlete to try to mitigate the risks. Setting aside the issue of deliberate inclusion of a prohibited substance, the risks of inadvertent cross-contamination are very real in the food supplement industry, primarily for two main reasons:
Firstly, the Good Manufacturing Practice (GMP) requirements for food supplements are nowhere near as stringent as they are for pharmaceuticals, and next, the fact that a high proportion of companies that market supplements are not themselves the product manufacturers – often the manufacturing is contracted out to manufacturers that also produce supplements for several different clients, not all of whom only market supplements that are designed to be free from WADA prohibited substances.
It therefore follows that unless such contract manufacturers have the strictest machinery cleaning procedures and/or clean air filtration between batches, the risk of trace contamination is always lurking. And the fact is that the laboratories that perform the drug tests on athletes’ samples have equipment that is super-sensitive in detecting microscopic levels of contamination that could result in a positive finding against the athlete.
Anecdotally, lab testing procedures are sensitive enough to detect a teaspoonful of a prohibited substance dissolved in an Olympic-sized swimming pool of water!
I mentioned that the GMP requirements for a licensed pharmaceutical in the pharmaceutical industry are far more stringent than in the food supplement industry, which should give a greater degree of confidence that using a licensed product has a low risk of harbouring prohibited substances.
However, it is worth looking at the case of Lizzy Banks, former professional cyclist, where the suggestion is that even licensed pharmaceuticals may not be immune from resulting in adverse findings. The other consideration is that if the vitamin D product is a licensed pharmaceutical, that takes it into the category of a prescription-only medicine (POM), in which case the regulatory requirements for POMs must be complied with.
As I mentioned in my previous article, if an athlete plans to take any supplement, they should make sure that the supplement has a Certificate of Analysis that demonstrates that the batch has been tested by a reputable independent lab (such as LGC in the UK) and are found to be free from WADA prohibited substances.
So how can an athlete be as sure as they can be if they are going to take a supplement? This is a (not exhaustive) list of questions that should be asked of any supplement manufacturer, which can go a long way to minimising the risks, primarily involving validation[iii] of the manufacturer/supplier:
· Source of original product manufacturer?
· Hygiene/cleanliness of manufacturing facility?
· Food Safety Certified?
· Number of organisations in supplier chain?
· Handling & storage, history known?
· Actual Product ingredients?
· Validation/laboratory testing of products?
· Counterfeit product?
· Validity of conformity documents?
· Reliability of stated product instruction / dosage?
· Reliability of sell-by-dates?
· Consistency of product quality?
· Product free from contamination?
· Product free from prohibited ingredients?
· Product genuine or falsified?
· Initial genuine product switched to inferior product?
· Product supplied from defunct manufacturer?
Purchasing vitamin D food supplements from suppliers that are not validated carries unacceptable risks to end users’ health and could result in serious consequences to buyers.
The advice is, to seek a UK Manufacturing Company that :
· Is well-established
· Is validated with traceable evidence, including microbiological and product conformity assays
· Has track record of zero recalls
· Welcomes customer audits and/or visits
Again, as mentioned in my previous article, Synergy Biologics’ Pro D3 Sport supplements are manufactured here in the UK in their own production facility, featuring state-of-the-art clean rooms etc, and are made to higher standards, including independent assays, than are required in the food supplement industry. Furthermore, Pro D3 Sport is free from gluten, gelatin, peanut and soya, and are Halal and Kosher, so will suit most dietary requirements. Synergy Biologics can confidently answer positively to all of the above considerations, as well as providing LGC certificates of analysis for tested batches.
What is the best way of taking vitamin D?
The dosage of vitamin D should be determined by a team/organisation doctor or nutritionist who is able to gauge the appropriate strength and frequency of vitamin D required for each athlete, also taking into consideration the best frequency that ensures compliance. Some may prefer a daily dose of either a capsule, tablet or liquid, and for others, a once weekly higher strength capsule may be an easier-to-remember option that can be more economical in the longer term.
Hopefully, taking all of the above into consideration, those of us who might be classified as athlete support personnel, can provide advice as to safe vitamin D sourcing and supplementation having done the required due diligence to help minimise the risks and maximise the benefits to our athletes.
[i] Identification of 1, 25-dihydroxyvitamin D3 receptors and activities in muscle. RU Simpson, GA Thomas, AJ Arnold, Journal of biological chemistry, 1985
[ii] Athletic Performance and Vitamin D JOHN J. CANNELL1, BRUCE W. HOLLIS2, MARC B. SORENSON3, TIMOTHY N. TAFT4, and JOHN J. B. ANDERSON5 PDFnbsp;(www.omega3galil.com)
[iii] Validation factors courtesy of AIM Management Services
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