In the chapter on food supplements, only products capable of improving athletic performance, either directly or indirectly, i.e. by improving the quality of recovery or body composition, were mentioned. On the other hand, all those products have been neglected which, although they do not act at these levels, can improve the general condition of health, which is an essential prerequisite for the regular continuation of training. It is precisely these supplements that will be discussed here, with a particular focus on the needs of athletes.

CALCIUM AND MAGNESIUM

Training load can sometimes cause significant fluctuations in blood levels of parathormone (PTH), which regulates bone mass. A calcium and magnesium supplement can prevent this from happening.

ANTIOXIDANTS

The deleterious effects that free radicals have on the body’s health, mainly due to their carcinogenic activity, has already been extensively discussed. Here we add that following the application of extensive metabolic load (i.e. the aerobic mechanism), a depletion of iron concentrations in the body may take place if there is considerable oxidative stress. Well, Aguilo (2004) showed that taking a mixture of antioxidants (namely vitamin E, β-carotene and vitamin C) can hinder this process, thus promoting greater iron retention in endurance athletes. In addition, antioxidants have a potential protective effect from pathogens on the digestive system, which may be weakened by the normal diversion of blood to the muscles that takes place during the application of the training load. According to Ashton (2003), taking 1g of vitamin C could minimise the passage of pathogens after exertion. In order to prevent oxidative stress, it is suggested to follow Aguilo’s example by mixing various substances. In fact, different substances act at different levels of the cell, complementing each other’s actions. In this case, vitamin E being fat-soluble, and cell membranes being made up of phospholipids, this micronutrient is able to cross them to exert its action from inside the cells; in contrast, vitamin C is water-soluble. It is known that vitamins E and C taken individually, even at very high doses, do not have an antioxidant effect of comparable magnitude to that of simultaneous supplementation, albeit in smaller doses, of the two nutrients.

THE BIOTICS

It has previously been illustrated how, following the application of a training load, the body tends to divert a significant part of the blood flow (up to 80%) to the muscles involved in exertion. Since a significant part of this diversion involves the digestive system, the latter can sometimes be damaged: in 91% of endurance athletes with an average of 13 hours of training per week, an alteration in the intestinal bacterial flora has been detected whereby the eubiota (good bacteria) are too few in comparison with the harmful bacteria. It is indeed common for these athletes to experience abdominal pain (although sometimes, for runners, it can also be caused by shaking of the bowels during activity). Now, in order to prevent this, it is possible to take supplements, called probiotics, containing eubiotics, or products based on indigestible organic substances that act as food for the good bacteria, but not the harmful ones. These are called prebiotics. In this regard, Berg (1999) points out that taking prebiotics and probiotics for 4 weeks improves the bacterial profile of the gut compromised by physical loading. Chos (1999) also points out an improvement in the previously compromised intestinal flora in swimmers of the French national team after daily intake of milk enzymes. A further effect of biotics, which goes beyond their influence on intestinal flora, concerns the level of production of interferon γ, a cell of the immune system whose synthesis is reduced following repeated strenuous training: taking probiotics (in particular lactobacillus acidophilus) can in fact raise its level of production.

ECHINACEA

Echinacea (Echinacea angustifolia) is a plant that grows mainly in dry, chalky places in grasslands or near sandbanks. It is able to stimulate the activity of the immune system, the effectiveness of which tends to be lower in committed athletes than in sedentary people and, even more so, than in individuals who take moderate exercise. Berg (1998) found a decrease in the incidence of airway infections as well as a reduction in the number of training days lost in athletes who took 8ml/day of liquid echinacea for 28 days. Echinacea products should be kept in mind by athletes who tend to fall ill frequently.

BEE POLLEN

Bee pollen is pollen from flowers that is collected by bees, transported to the hive and processed. Maughan (1982) notes that the use of bee pollen for a period of 6 weeks reduces the incidence of respiratory system infections and, consequently, the number of lost exercises. Bee pollen has no particular adverse effects, with the exception of allergic reactions in sensitive individuals.

PROPOLI

Like bee pollen, propolis is a by-product of beekeeping. It is composed of bee saliva, wax and resin. Imai (2005) and Young Soo (2004) noted an antioxidant effect of propolis, administered in their studies in amounts of 800mg/day to committed athletes. Speaking of adverse effects, like all beekeeping products it can have allergic effects in sensitive individuals. With the exception of this, propolis has no contraindications.

BCAAs

We have already seen how physical strain can negatively influence the activity of the immune system. One of the reasons why immune defences drop as a result of physical exertion is the depletion of the amino acid glutamine that normally takes place with training. Glutamine, in fact, is one of the constituents of immune cells such as lymphocytes and macrophages, whose numbers will only decrease as a result of the depletion of glutamine reserves available for their synthesis. Well, some studies (e.g. Bassit, 2000) show that taking BCAAs reduces the loss of glutamine stores more than glutamine supplementation itself does. For this reason, supplementation with branched-chain amino acids may reduce the incidence of infections and inflammatory diseases.

GLUTAMINE

As explained above, glutamine possesses a trophic action on the cells of the immune system, thus helping to reduce infection and inflammation. Relevant among the various studies is the one by Castell (2006), which highlights the efficacy of glutamine supplementation in preventing infections that are due to the suppression of the immune system by physical load. Unfortunately, not all studies confirm Castell. Furthermore, according to Bailey (2000), the intake of glutamine could prevent gastrointestinal disorders due to blood diversion during the application of extensive physical loading, but this function of glutamine is not confirmed by all studies.

CAFFEINE

Bishop (2006) shows that an intake of caffeine in the amount of 6mg/kg body weight one hour before exercise improves the retention rate of immunoglobulins (special cells of the immune system) during and after exercise. According to this author, this effect of caffeine is attributable to its stimulating effect on adrenalin.

FISH OIL

Among the various supplementation products with an anti-inflammatory effect, fish oil can also be included, as this product can moderate the secretion of cytokines and prostaglandins (certain molecules with a pro-inflammatory action).

FATTY ACIDS

Certain fatty acids such as those of the ω-3 group and ω-6 γ-linolenic acid appear to be effective in circumscribing mild joint inflammation (Zurier, 1996). According to Berbert (2005), their efficacy may be increased if olive oil is combined with them, while Tidow and Kebritchi (2001) find that they are enhanced in combination with vitamin E. It should be noted that, regardless of what they are combined with, fatty acids have a delayed action, so they are more effective as preventive than curative supplements. The dosages used in all studies were between 2 and 10g.

GLUCOSAMINE AND CHONDROITIN

Glucosamine is a molecule that is synthesised from a sugar and an amino acid (glutamine), while chondroitin is a high molecular weight polysaccharide. Both molecules are precursors of glycosaminoglycans, which serve as structural components of cartilage, tendons and ligaments. Although the human body is able to produce glucosamine endogenously, the demands sometimes exceed the synthetic capacity, so supplementation may be desirable. Research on glucosamine mostly concerns arthritic patients, but although a study by Leffler (1999) suggests it is also quite effective in the military, glucosamine products can only be recommended to athletes on an anecdotal basis. With regard to arthritic patients, glucosamine supplements can reduce joint pain (Reginster, 2001; Cohen 2003; Poolsup, 2005), as well as the degradation of inter-articular spaces (Reginster, 2001; Pavelka, 2002). Tant (2006) also found an improvement in back pain in patients suffering from it. Chondroitin shares the same mechanism of action with glucosamine and can be associated with it. The main study documenting its effectiveness is that of Mathieu (2002), but many others do not confirm this author’s findings. Furthermore, its application to athletics is even more controversial than that of glucosamine. Returning to glucosamine, it should be noted that this has a more preventive than curative action, since the benefits of supplementation can only be seen after several weeks, if not months. For this reason, and to this end, athletes could benefit from it to the extent that the physical load they undergo exposes them to the risk of experiencing the same problems as arthritis sufferers. Chondroitin should only be taken as a complement to glucosamine. On the subject of adverse effects, it should be remembered that, with some exceptions, glucosamine supplements are produced from the shells of crustaceans. Individuals who are allergic to them, therefore, may experience adverse reactions. Regarding the mode of administration, however, it is desirable to take glucosamine topically (Cohen, 2003), i.e. with creams applied topically. This is because, if taken orally, although absorption in the digestive system is around 90%, only 0.4% reaches the joint site. It is likely that the studies that failed to prove the efficacy of glucosamine were affected by this very issue. This recommendation is even more valid for chondroitin, which is less bioavailable than glucosamine when taken orally. There are several forms of glucosamine supplements on the market: glucosamine sulphate, glucosamine hydrochloride and N-acetyl-glucosamine. According to Hoffer (2001), many of the beneficial properties of glucosamine are justified by the sulphate, so the first of the three forms should be preferred. If you want to follow this author’s suggestion, when selecting the product to buy, make sure that the amount of sulphate in the product is 1/3 of the whole product, as it is in this proportion that it would best fulfil its function. Finally, regarding dosage, research on arthritis suggests that the optimal dose of glucosamine is 500mg 3 times a day, while for the aforementioned study by Mathieu, the recommended dose of chondroitin is 800mg/day as a single dose.

METHYL-SULPHONYL METHANE

Methyl-sulphonyl methane or MSM is a molecule that, although naturally present in living organisms, can be synthesised artificially. Its role in dietary supplementation is linked to an alleged anti-inflammatory and antioxidant action that is sometimes attributed to it in combination with glucosamine (Usha, 2004). In contrast to the latter, however, MSM appears to have more of a short-term than medium- to long-term action (Kim, 2006). Few studies have been conducted on this molecule, so neither its efficacy nor safety can be established with certainty. On the market, there are both products to be taken orally (soluble powder and tablets) and locally acting products in the form of spreadable creams. With regard to the former, while, as mentioned, the safety of MSM is in doubt, this is particularly true of supplements to be taken orally. On the other hand, with regard to topical creams, these appear to be poorly absorbable at skin level. Therefore, they may be completely ineffective.

GELATIN

Gelatin is a protein that can be synthesised from fibrous organic material and is often produced from the bones and skin of pigs. Gelatin exerts a protective action on joints by virtue of the high amount of the amino acids glycine, proline and hydroxyproline it contains, which act as precursors of collagen (a protein that forms tendons and ligaments). This effect has been found both in animal studies, in whose joints the amino acids in the gelatin intake were found, and in patients with severe arthritis (Moskowitz, 2000), as well as in athletes with knee pain, whose mobility of the painful joint was increased following gelatin supplementation (Pearson, 2000). It is a safe supplement, as there are no known adverse effects associated with its intake. With regard to dosage, the ideal amount to take is 10g per day, in one or more doses.

SILICON

Silicon is one of the chemical elements listed in the periodic table. Regular intake of silicon appears to play a role in improving performance in racehorses due to its ability to reduce the incidence of injuries (Wallace, 2006). It is hypothesised that in the athlete, topical application of silicon to joints before and after exertion may accelerate recovery, but there is insufficient evidence to support this theory. In the study on racehorses, silicon supplementation took place over a period of 8 weeks and led to an increase in plasma rates of this element in the subjects studied.

THE CREATINE

In addition to the effects already seen on athletic performance, creatine has the ability to protect the cell from degradation due to its antioxidant function. Furthermore, Greenwood (2003) notes a decrease in the incidence of injuries in athletes receiving creatine supplementation. Although the preventive effects of creatine take place at much lower dosages than those required for performance enhancement, this also requires alternating between a relatively short period in which a higher dosage is taken and a longer period in which the dose to be taken is reduced. In Greenwood’s study, subjects took 0.3g/kg body weight for the first 5 days and 0.03g/kg body weight for the next 115 days.