Natural supplements (1): popular off-the-shelf potions that claim to enhance athletic performance

As the popularity of nutritional supplements continues its apparently limitless rise, athletes of all standards are particularly susceptible to manufacturers’ claims that promise them that ‘little bit extra’ – in the legal non-doping sense. The range of supplements on offer is huge, including all types of sports drinks, nutritional bars, vitamins, herbs, protein supplements, ergogenic acids and so on.

The driving ambition to improve one’s performance makes athletes a very vulnerable group, who need good guidance from the sports professionals caring for them.

While most big manufacturers of supplements do have standards, this rapidly expanding, profitable and largely unregulated sector also attracts cowboy operators who do not guarantee quality and may mix their nutritional products with other substances; as we know from a succession of ‘doping scandal’ headlines, the consequences for an unwitting young athlete can be devastating.

It can only be a matter of time before a sports support professional is sued by an athlete for having recommended a supplement to which they’ve had a reaction – or even worse, tested positive in a doping test.

So therapists and coaches need to be up to date on the latest fads, the evidence behind them and any reports of adverse effects. As mentioned, there are well publicised cases involving top-level athletes testing positive for banned substances after apparently taking natural remedies and drink supplements. A quick search through the medical literature will reveal other cases of people who have suffered debilitating and often long-term health problems after taking natural supplements^(1-4).

If you are going to recommend nutritional supplements, take a careful medical history from your athlete and stick to reputable suppliers. Cutting corners on price could be a false economy with very serious consequences.

Here, in the first of a two-part series, we examine a few of the more exotic and popular recent additions to the alternative medicine chest – and at least one older but unceasingly controversial supplement.

Colostrum

What is it?

The first milk produced by female mammals after giving birth, usually in the first 72 hours. Contains proteins, immunoglobulins, vitamins and minerals. Held to be the best kick-start possible for a newborn’s developing immune system. The commercially available forms of colostrum are generally bovine or goat in origin and are taken as tablets.

How does it work?

We do not know. Some work has been done on how colostrum boosts plasma insulin-like growth factor (IGF-1), an important cellular substance. IGF-1 promotes the passage of nutrients across the cell membrane and increasing its presence may stimulate early repair and recovery. However, this is still very much an unproven theory⁽⁸⁾.

Is there any evidence for its use?

Surprisingly, yes! Some small well conducted studies show improvements in athletes’ running and cycling speeds after two months and improved recovery after endurance events^(5-7).

Any adverse side effects?

None are reported in the medical literature. But be aware that the commercially available tablets, commonly known as ‘Transfer Factor’, will be bovine or goat colostrum, so athletes with a dairy intolerance should avoid these formulations. Other formats may come from proteins extracted from human white blood cells, but the difficulty of the processing makes this product prohibitively expensive. While concerns have been raised about the risk of blood-borne diseases from these products (eg, HIV, Hepatitis B and C, and CMV), there have been no reports of infections in the literature.

Is it worth recommending?

Hard to say. Studies have shown that it does not improve performance in female rowers; others have shown an improvement in hockey players^(5,7).

Note, also, that these scientific studies use far larger doses of colostrum than the recommended dose of the commercially available forms. If an athlete follows the manufacturer’s instructions, this supplement will cost them approx £30 a month, but if you were to dose at the levels used in the studies, the cost would be almost 10 times more! The financial pain may not be worth the possible performance gain.

Bee pollen

What is it?

Plant pollen that bees carry back to the hive, thought to consist of carbohydrates (in particular, a sugar compound with antioxidant properties), plant fat and protein, phenols, flavanoids, fungi and (in its original form) bacteria, hair, mites and faeces.

How does it work?

We do not know. Research suggests the flavanoid component may have a part to play. Claims that it has ergogenic properties are not substantiated.

Is there any evidence for its use?

No. In 1972 Finnish marathon runners claimed that it had enhanced their performance, but subsequent trials failed to substantiate this. Claims that it improves oxygen carrying in the blood were not upheld in a study of swimmers and a further study of runners showed no difference in performance between the bee pollen group and the placebo^(9,10).

Any adverse side effects?

Yes. Considering the high incidence of allergies to plant pollens, it is hardly surprising that ingesting bee pollen can cause the same side effects. Acute anaphylaxis, nausea, diarrhoea and abdominal pain have all been reported⁽¹¹⁾.

Is it worth recommending?

Given the lack of evidence in support, it would be hard to justify recommending bee pollen to any athlete.

Ginseng

What is it?

Ginseng comes from the root of the Panax ginseng plant. There are two main forms: white ginseng (from dried, peeled root) and red ginseng (from steamed unpeeled root). It has been used in Chinese medicine for thousands of years, and the first recorded case of its benefits refer to the superior performance of a runner. For the western world, it sprang controversially to prominence during the Seoul summer Olympics in 1988.

How does it work?

We do not know. The active ingredients in ginseng are saponins. Exactly what they do remains unclear, although some studies suggest they affect the hypothalamus-pituitaryadrenal axis and the immune system. Other studies indicate that Panax ginseng enhances the immune system (phagocytosis, natural killer cell activity and the production of interferon). How this affects athletes’ performance is not known.

Is there any evidence for its use?

Early studies did suggest that ginseng improved the efficiency with which muscles utilised oxygen. However, more recent studies from cyclists did not seem to show performance gains⁽¹²⁾. It is hard to judge many of the studies because the forms and doses of ginseng used vary widely.

Any adverse side effects?

Yes, lots. Nausea, vomiting and diarrhoea are often reported but also more serious reactions, for example, hypotension and hypertension. Ginseng interacts with warfarin and some psychiatric medications, producing acute manic episodes. It has a marked effect on blood glucose levels and may induce hypoglycaemia in diabetic athletes. You may need to remind your diabetic athlete to monitor blood sugars and even to reduce their insulin dose.

Is it worth recommending?

The jury is still out. With 5,000 years of history behind it, one feels there must be something there, but there is still much work to be done to establish whether ginseng has a positive effect on athletic performance. It does have other proven health benefits, however, which may be of value to an athlete.

Creatine

What is it?

Creatine monohydrate is marketed as the natural muscle builder for athletes and is being consumed in vast quantities, it comes in gels, tablets, powder and capsule formats. It is supposed to help speed up the transfer of energy from cells to muscles and thus improve performance. Creatine is a natural derivative of an amino acid that is synthesised in the liver, kidneys and pancreas. A 70kg human has approx 120g of creatine naturally occurring in their muscles, with a daily turnover of 2g, which is replaced from diet and within the body. If an athlete increases their dietary intake of creatine, the body reduces its production. Any excess ingested is excreted via the kidneys.

How does it work?

Muscles derive their energy from a series of reactions that convert ATP (adenosine triphosphate) to ADP (adenosine diphosphate). Phosphocreatine helps replenish the ATP stores. This is particularly important for sprint and power-sports athletes.

Is there any evidence for its use?

Numerous studies have shown that creatine supplementation does help improve performance in short-burst activities, with running, cycling and swimming all showing improvements. However, endurance athletes showed no benefits and in some cases decreased performance, possibly because of the associated weight gain.

Any adverse side effects?

Lots. Weight gain is reported, believed to be not the widely marketed effect of muscle bulking, but predominantly water gain. There are reports of muscle cramps, diarrhoea dehydration, compartment syndrome and heat intolerance. US FDA reports also cite cardiac arrhythmias, deep vein thrombosis, myopathies and death.

As with any supplement, the quality of the product is always questionable, with some life-threatening complications being reported from contaminated supplies.

Should you recommend it?

The evidence unquestionably supports its efficacy in enhancing short, sharp bursts of sporting activity. However, no guidance is available on dosing, length of treatment, safe protocols or withdrawal regimes. We do not know what happens when creatine is combined with other ergogenic products. There are still many unanswered questions and for the average athlete, the cost versus performance benefit is probably not worth it.

References

1. Dimitrakakis C, Gosselink L, Gaki V, Bredakis N, Keramopoulos A. Phytoestrogen supplementation: a case report of male breast cancer. Eur J Cancer Prev. 2004 Dec; 13(6): 481-4.
2. Fraunfelder FW. Ocular side effects from herbal medicines and nutritional supplements. Am J Ophthalmol. 2004 Oct;138(4): 639-47.
3. Kabalak AA, Soyal OB, Urfalioglu A, Saracoglu F, Gogus N. Menometrorrhagia and tachyarrhythmia after using oral and topical ginseng. J Women’s Health. 2004 Sep;13(7): 830-3.
4. Wooltorton E. Several Chinese herbal products may contain toxic aristolochic acid. CMAJ. 2004 Aug 31; 171(5): 449.
5. Hofman Z, Smeets R, Verlaan G, Lugt R, Verstappen PA. The effect of bovine colostrum supplementation on exercise performance in elite field hockey players. Int J Sport Nutr Exerc Metab. 2002 Dec; 12(4): 461-9.
6. Coombes JS, Conacher M, Austen SK, Marshall PA. Dose effects of oral bovine colostrum on physical work capacity in cyclists. Med Sci Sports Exerc. 2002 Jul;34(7):1184-8
7. Brinkworth GD, Buckley JD, Bourdon PC, Gulbin JP, David A, Oral bovine colostrum supplementation enhances buffer capacity but not rowing performance in elite female rowers. Int J Sport Nutr Exerc Metab. 2002 Sep;12(3):349-65.
8. Buckley JD, Brinkworth GD, Abbott MJ Effect of bovine colostrum on anaerobic exercise performance and plasma insulin-like growth factor I. J Sports Sci. 2003 Jul;21(7):577-88.
9. Steben RE, Boudreaux P. The effects of pollen and protein extracts on selected blood factors and performance of athletes. Journal of Sports Medicine and Physical Fitness vol 18, pp221-226, 1978
10. Mahan LK. Nutrition and the allergic athlete. J Allergy Clin Immunol. 1984 May;73(5 Pt 2):728-34.
11. Pieroni RE, et al. Miracle bee pollen: don't let your patients get stung, J Medical Assoc Alabama 1982;51(12):11-13
12. Eschbach LF, Webster MJ, Boyd JC, McArthur PD, Evetovich TK, The effect of siberian ginseng (Eleutherococcus senticosus) on substrate utilization and performance. Int J Sport Nutr Exerc Metab. 2000 Dec;10(4):444-51.