Over the past century, nutritional knowledge has increased relatively steadily and both fitness enthusiasts and competitive athletes have been able to take advantage of this new information. The purpose of this article is to discuss nutritional supplements i.e. special nutrients and dietary supplements that are used to supplement or replace so-called normal nutrition. It should be noted that people usually employ the terms nutritional supplements, special nutrients and dietary supplements interchangeably although they often refer to the same thing. The information in this article is based on research findings published in scientific articles.
Nutritional supplements which most likely powerfully increase muscle mass and / or body strength
This group includes high-quality protein and carbohydrate products. The following describes in more detail the role of the most important proteins in increasing muscle mass along with physical exercise.
Proteins and carbohydrates are recommended to be consumed before, during and after exercise as they speed up recovery and have a better impact on the acceleration of the protein synthesis when taken simultaneously. Protein intake, along with strength exercising, appears to increase muscle growth although the indication of increased power is not as strong as the indication of muscle growth. However, since there is a positive and recognized relationship between strength and muscle mass, we can assume these indications are quite strong.
The most commonly used nutritional supplements are milk whey, casein and soy. Of these, whey and casein seem to be the most recommendable options for athletes. Whey is a fraction of milk including a variety of proteins that are rapidly absorbed and increase protein synthesis and tend to not decrease protein degradation. Based on this present knowledge, whey is the best single source of protein when taken immediately after exercise.
Casein, the other fraction of milk protein, has a slow and steady effect, reducing protein degradation more than whey. However, it doesn’t increase protein synthesis as much as whey. That is why it is thought that casein is a better source of protein than whey after training if there is a lot of time before the next meal. However, in practice the differences are probably small.
Physical activity, especially hard physical exercise, increases the need for protein. Thus, the protein needs and intake recommendations for active exercise enthusiasts are higher than the average ones.
The protein intake recommendations for children and adolescents are, according to some sources , up to 2 – 4 g / kg of body weight / day, especially if the child or adolescent undertakes in physically challenging junior sport. For 18 to 65 year-old adults who don’t do any specific exercises, the recommendation is 0.83 g / kg of body weight / day. Based on studies, strength training athlete recommendations are 1.5 – 2.0 g / kg of body weight / day. Recommendations for endurance athletes are somewhat lower.
Nevertheless, it should be noted that research data on extreme sports that require challenging physical training is scarce. With elderly people, the skeletal muscle loss (sarcopenia) is associated with aging. To slow skeletal muscle loss or even increase muscle strength, it is recommended for elderly people to undertake strength training and 1.6 grams of protein / kg of body weight / day. The normal protein dosage recommendation for adults, 0.83 grams / kg of body weight / day, is insufficient for them.
Potentially effective muscle mass expanders are the branched-chain amino acids (leucine, isoleucine and valine), creatine with amino acid structure and colostrum products. The study evidence for the aforementioned is however partly contradictory. Colostrum product effectiveness depends specifically on how much protein and insulin-like growth factor 1 i.e. IGF-1 it contains [1, 3, 4].
Nutritional supplements most likely to have powerful impact on boosting energy production
The three principal means of energy production are the use of creatine phosphate, anaerobic glycolysis and aerobic energy production of the muscles. The nutritional supplements boosting aforementioned energy production are creatine, eating of alkaline nutrition for acidity buffering, carbohydrate products and caffeine.
The use of creatine increases muscle creatine and creatine phosphate content, which results in enhanced energy production in short-term high-intensity performances. The use of creatine along with strength training is found to lead to greater maximum strength, better endurance and increased lean body mass and larger cross-sectional surface area of muscles.
Creatine has also been shown beneficial for performing exercises demanding repetitive bursts of short-duration. Further research on long-term effects of using creatine is needed. Its effects must be examined in detail for women and older people too because the majority of studies have been carried out on young men.
Eating of alkaline nutrition (usually sodium bicarbonate or sodium citrate 0.3 g / kg of body weight for about three hours before exercise) can be used to improve performing short exercises requiring maximal resistance properties in high speed and which produce large quantities of lactate and muscle acidity content increases strongly. Eating of alkaline nutrition can be used against acidity that causes fatigue in the muscles. Eating of alkaline nutrition may, however, cause gastrointestinal problems. In practical situations it has been found that powder taken in capsules causes fewer gastrointestinal problems than the powder mixed with liquid.
Carbohydrate preparations are well known to be used both in competitive sports and other physical exercises. The major need for carbohydrate preparations is in endurance performances but also in other physical exercises, such as strength training. The needed quantities are obviously larger when taken along with resistance performances and training.
Depending on the sport type and person the energy consumption for endurance sport enthusiasts is 2500 to 10 000 calories per day. Most of the energy is produced from fats in low intensity exercising but the importance of carbohydrates as an energy source increases when the performance intensity increases. Thus, the most of the energy for almost all durability sports is produced from glycogen reserves of muscle and blood glucose. Only a small amount (a few percent) of energy is normally produced from proteins during exercise.
The recommended intake of carbohydrates in durability sports is at least 55 to 65 percent of the total daily energy. Eating carbohydrates (8 to 12 grams of carbohydrate / kg of body weight /duration, for between 1 to 4 days) is useful for performances that last more than 90 minutes.
Caffeine appears to improve performance capacity in long-term sporting performances that require aerobic energy metabolism due to enhanced fat metabolism. Performance-enhancing effects of caffeine may be based at least partly on its ability to modify and reduce the sensation of pain during a long-lasting sport performance.
The research results on the effect of caffeine on anaerobic performance are still partly contradictory but there is evidence for the positive effect of caffeine on the power of six-second sprint performance (7 percent improvement with caffeine) . Caffeine has adverse effects that appear more frequently when the caffeine dose increases. Caffeine research planning and interpretation of results is hampered by the fact that there is still little information regarding caffeine action mechanisms since caffeine has a strong tendency of tissue invasion.
Potentially effective energy production boosters can also be beta-alanine or carnosine (for acid buffering), various types of energy and stimulant drinks (for endurance performance) and glycerol (for endurance performance). The study indications regarding the efficacy of the aforementioned are partly contradictory. [4, 7]
Professor in Exercise Physiology
Department of Biology of Physical Activity, University of Jyväskylä