Intravenous nutrition risks becoming the norm for athletes, despite no evidence it works
Intravenous (IV) nutrition, once considered a "last resort" treatment , threatens to become the norm for competitive athletes, despite no scientific evidence that it works or is safe, experts warn in an editorial published online in the British Journal of Sports Medicine .
Use of intravenous nutrition products in sports
The authors regularly interact with professional team sport players in European and American leagues and their multidisciplinary support teams, and we are aware that players regularly receive intravenous nutrition (IVN) products. Furthermore, this is often evident in blood biomarker profiles where specific nutrients are beyond the upper limit of clinical laboratory measurement. The precise prevalence of IVN use is not known, however, anecdotally, some players receive IVN on a weekly basis as part of a pre- or post-game routine.
So-called "drip bars" and concierge IVN services are easily accessible, although they apparently lack proper regulation. These offer a menu of IVNs containing nutrients such as B vitamins, amino acids, glutathione, vitamin C and electrolytes, which claim to improve health and performance, restore hydration, speed recovery, etc. Additionally, players may request parenteral administration of nutrients such as iron and vitamin B12 from the team physician when not otherwise indicated.
IVNs administered by sports physicians are typically reserved for clinical presentations such as anemia, significant impairments with accompanying symptoms, or in race medicine (e.g., severe dehydration/collapse caused by an ultramarathon in the desert). While these are clearly different from the self-directed IVN use described above, there is crossover regarding potential risks and benefits.
Guidance for players and practitioners in the peer-reviewed Sports Medicine/Sports Science literature outlining the evidence base and risks associated with IVNs is largely absent. IVNs are not mentioned in recent nutrition consensus statements, and this is consistent with the principle of reducing needle use in sport and a "food first" approach taught in sports nutrition courses across the world. world.
The use of needles by athletes in the Olympic Games has been banned for all recent Games, except for appropriate medical use, and where a Therapeutic Use Exemption (TUE) is obtained. Similarly, the World Anti-Doping Agency prohibits intravenous infusions of more than 100 ml (every 12 hours) unless a TUE is obtained; However, these controls are not reflected in all sports leagues.
Is there any evidence of benefit for athletes beyond placebo?
IVN products are often used as a means to address tiredness, fatigue, or recovery, but the evidence is sparse and does not support their use . We know of only two studies that evaluated vitamin injections in otherwise healthy participants; none of which produced an effect for the injection group. Tin May et al observed no effect of 1 mg injections of cyanocobalamin (synthetic B12) or placebo (3/week) for 6 weeks in a double-blind manner, in various physical performance tests, nor any difference compared to placebo.
A cross-sectional study of elite Polish track and field athletes reported that 34% (n=82) received vitamin B12 injections over a 6-year period. While a beneficial effect of vitamin B12 on red blood cell parameters was observed, there was no additional benefit when the athlete’s vitamin B12 concentration was above 700 pg/mL. Additionally, where a vitamin B12 deficiency exists, one study found no additional benefit of an injection over oral supplementation.
Risks
It is well known that the gut-liver axis actively protects humans from infections, from the acidity of bile to the intricate immune pathways in the epithelial mucosa, and the dynamic role of the gut microbiota in providing protection against toxicity (e.g. e.g., heavy metals). Overlooking these mechanisms seems foolhardy unless there is significant clinical justification and no studies have addressed the long-term impact.
However, through biomarker profiling, we have observed vitamin B6 and cobalamin (vitamin B12) often beyond the laboratory measurement range, in a subset of professional players. These observations may be a direct result of intravenous therapies, although inadvertent intake through fortified foods and energy drinks may also be the cause.
While the long-term effects of high cobalamin are unknown, the long-term effects of vitamin B6 are classically associated with peripheral neuropathy . Athletes who regularly receive parenteral iron are at risk of liver disease and, in fact, elevated body stores (hepatic iron concentration) have been observed in road cyclists.
Since the long-term effects of supratherapeutic doses of B vitamins and other nutrients in athletes are unknown, it does not appear to be worth the risk, especially given the lack of evidence-based benefits. There are also direct risks related to venous access, including infections and thromboembolic complications. More than this is the risk to the sport’s reputation if it becomes normalized for athletes to regularly engage in self-directed IVN use with a worrying shift from what "works" (by scientific standards), to what is unproven . Additionally, some athletes risk committing an anti-doping violation by engaging in self-directed IVN use.
Figures on the prevalence of IV nutrition should be collected in conjunction with governing bodies and players’ associations of professional leagues that provide guidance on the potential risks of IV nutrition use, the authors say.
“The messages of ’food first’ and ’no needles’ must be amplified among all athletes and multidisciplinary support teams to prevent what was once a ’last resort’ treatment from becoming normal without scientific evidence of benefit," they warn. .
