Functional foods and food supplements for athletes: from myths to benefit claims substantiation through the study of selected biomarkers

Abstract

The development of the sports food market and industrial involvement have led to numerous nutritional studies to define the type of nutrients that are most suited to support energy metabolism, fluid balance and muscle function. The key question in many of these studies was: ‘Does the product lead to a significant product/consumer benefit that can be used as a claim on the package?’ New methods and techniques have been developed, partly with sponsorship of the food industry, with the goal of measuring the effects of specific nutrients and supplements on athletic performance and metabolism. In line with this development, a wide variety of supplements and sports foods/drinks labelled with various performance or health benefit statements have been launched on the sports nutrition market. Although a variety of products have been tested clinically, there are also many products on the market with benefit claims that cannot be supported by sound nutritional and sports physiological science. The current short review highlights some of the methods and biomarkers that are used to substantiate product/consumer benefit claims for foods and drinks that are marketed as functional foods for athletes.

Comparative effects of selected non-caffeinated rehydration sports drinks on short-term performance following moderate dehydration

“…The generally higher gastric emptying rate of glucose polymer solutions than that of free glucose solutions [28] may result in increased intestinal absorption and nutrient supply to the active muscles [10]. Solutions containing glucose polymers possess a higher energy density than simple sugar containing beverages with similar osmolality [29] and also show the ability to maximize glycogen re-synthesis in the muscles [10].…”

“…The generally higher gastric emptying rate of glucose polymer solutions than that of free glucose solutions [28] may result in increased intestinal absorption and nutrient supply to the active muscles [10]. Solutions containing glucose polymers possess a higher energy density than simple sugar containing beverages with similar osmolality [29] and also show the ability to maximize glycogen re-synthesis in the muscles [10]. Glucose polymers undergo degradation to glucose by salivary and pancreatic amylases and mucosal glucoamylase in the upper gastrointestinal tract, resulting in a more prolonged absorption, utilization and oxidation than that obtained with simple sugars [30,31].…”

“…Glucose polymers undergo degradation to glucose by salivary and pancreatic amylases and mucosal glucoamylase in the upper gastrointestinal tract, resulting in a more prolonged absorption, utilization and oxidation than that obtained with simple sugars [30,31]. The rate of oxidation of maltodextrin is higher than that of fructose [10,32]. Their combination, however, may facilitate sustained conversion/oxidation in the body and produce higher oxidation than that obtained with single carbohydrates [33], delaying the onset of fatigue, sparing endogenous carbohydrate reserves, and thus enhancing endurance.…”

<b>How does the dietary cottonseed hull affect the carcass characteristics and meat quality of young bulls finished in a high-concentrate diet?

“…CH21 presented with smaller cottonseed hulls, while there was an increased proportion of the soybean hull pellets. According to Brouns, Van Nieuwenhoven, Jeukendrup, and Lichtenbelt (2002), the isoflavonoids that are present in soybean products may reduce the free radical contents and have antioxidant properties in human health. King, Mano, and Head (1998) observed that lower isoflavonoids values in the milk of cows that were fed silage did not elicit a biological response in humans.…”

Effects of an isotonic beverage on autonomic regulation during and after exercise

“…Fluid replacement using isotonic solution may attenuate or prevent many metabolic, cardiovascular, thermoregulatory and performance perturbations [4,5]. Moreover, according to Brouns et al, [6] and Coyle [7], sports drinks without caffeine can help to maintain physiological homeostasis.…”