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In general, there is concern by the medical world about the efficacy and safety of most herbal-extract supplements, or even natural forms, be it for medicinal purposes, weight control or as ergogenic aids. Adverse effects are common, and since most herbal supplements come combined with other herbs or chemicals for which no scientific data is available, using them might be an unnecessary risk; the weight loss products are perhaps the ones most associated with adverse side-effects. Moreover, many herbal supplements contain banned substances, so it is best to seek the advice of a sport physician before using them.
is a climbing plant, native to the Amazon basin, that contains about twice as much caffeine as coffee beans, so its extract is often used as a stimulant in much the same way. However, although Guarana has had some positive results when combined with other extracts and substances, there has been little or no positive results when tested in isolation.
is a blue-green algae. It is a simple aquatic plant that includes many vitamins and minerals and is particularly rich in protein and iron. It is perhaps one of the more common so-called superfoods (a non-scientific term often used to describe food that contains high levels of nutrients) in supplementation form; natural examples are blueberries, broccoli, spinach and tomatoes. The term is often used misleadingly as a marketing tool, even though the health claims made for superfoods are rarely supported by dietitians and nutritional scientists.
(image by Willpower Studios)
Many sports people claim that it improves sporting performance, recovery time and stamina, and some recent studies have shown some positive results in this regard. A small study in 2006 suggested that spirulina intake reduced skeletal muscle damage that perhaps lead to a better time to exhaustion. More recently, a study in 2010 showed several benefits, including a significant increase in exercise performance and fat oxidation, and in 2012 a trial of 41 runners showed a lowering of fat in the blood after meals. However, there are too few studies to make any claims with confidence.
Although spirulina contains all eight indispensible amino acids, the US National Library of Medicine views it as no better a source than milk or meat, even though it is about 30 times more expensive. Moreover, many suppliers of spirulina advocate its high vitamin B12 content, but this is misleading as it is in a form that is biologically dormant in humans. In trials, common doses seem to be 1-10 g day with no apparent side effects, and most commercial recommended doses are well within this range. It seems that spirulina is safe to try, though not recommended for those lactating or with child, and that it may have some benefits. However, owing to its cost and lack of supportive evidence to date, it is not advocated in this article.
is a chemical compound extracted from the bark of an African tree called Yohimbe. It is prescribed as a stimulant or aphrodisiac by conventional doctors and herbalists alike, and for these purposes it has been reviewed positively. Further claimed benefits include improvements in stamina, performance, fat burning in general and even losing fat in particular places, but most of these are not supported by scientific evidence. However, one 2009 study concluded that yohimbine might be useful for promoting fat loss in élite athletes, but all other claimed benefits are purely anecdotal. There are several reported side-effects of over-the-counter yohimbine, such as gastrointestinal upset, increased blood pressure, headaches and agitation.
Other herbal extracts
such as those from the gingko biloba leaves (a unique species of tree), St John’s wort (a plant species that grows worldwide), ginseng (a plant native to N America and Asia) and kava kava (a narcotic sedative drink in Polynesia made from crushed roots of a type of pepper plant) have all been tested for various medical conditions, but none have any strong evidence to support supplementation for fat metabolism, weight management, strength, muscle mass, performance or any other benefits expected from a sport supplement for healthy athletes. No matter, kava kava may reduce the symptoms of anxiety, which might indirectly help an athlete who is very nervous before an event.
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