The effects of low and high glycaemic carbohydrates on endurance performance

The concept of glycaemic index (GI) was originally introduced to classify carbohydrate-rich foods, usually having an energy content of >80 % from carbohydrates, according to the differences in effects on post-meal glycaemia. The GI, which is a nutritional property of a carbohydrate-rich food, is defined as the incremental area under the blood glucose response curve following a 50 g glycaemic carbohydrate portion of a test food expressed as a percent of the response to the same amount of carbohydrates from a standard reference product taken by the same subject (FAO/WHO, 1998).

Carbohydrate-rich foods can be classified according to their GI values (glucose as the standard): high GI >70 (white bread, most white rices, corn flakes, extruded breakfast cereals, glucose); normal GI 55-70 (whole wheat products, basmati rice, sweet potato, sucrose); low GI 40-55 (most fruits and vegetables, legumes/pulses, whole grains, nuts, fructose) and very low <40.

On the other hand, is not easy to outline glycaemic index of foods rich in carbohydrates because many other factors in the diet (e.g. amount and type of dietary fibre, amount of dietary fat, energy density, physical properties, mode of preparation) are involved.

EFSA (European Food Safety Authority) expressed its negative opinion on the substantiation of health claims related to carbohydrates that induce low/reduced glycaemic responses and carbohydrates with a low glycaemic index. The claims effect was related to carbohydrates with a low glycaemic index (GI) and Impact on blood glucose / Glycaemic control / Glycaemic response or to maintain healthy cholesterol levels. The main cause of rejection of these claims was that the food constituents, carbohydrates that induce a low/reduced glycaemic response and carbohydrates with a low glycaemic index (e.g. <55), which are the subject of the health claims are not sufficiently characterised. On the other hand, there are also positive opinions concerning natural and artificial sugar replacers such as xylitol, sorbitol, mannitol, maltitol, lactitol, isomalt and sucralose for which EFSA approved the claims related to consumption of these substances and reduction of post-prandial glycaemic responses, furthermore the same opinions have been given for slowly digestible starch in starch-containing foods, beta-glucans from oats and barley and others.

Concerning this topic a recent human trial study has highlighted effects relevant to sportsmen. The study involved 10 well trained cyclists to investigate the effects of high and low glycaemic index (GI) 24 h recovery meals on the physiological responses and subsequent athletic performance, following a glycogen depleting protocol.

On day 1, subjects performed a glycogen depleting protocol after which they then consumed either high or low GI recovery diets over the next 24 h, which provided 8 g.kg BWˉ¹ of carbohydrate. On day 2, the subjects returned to the laboratory, 2-3 h postprandial, to perform a 40 km time trial (TT) on the Velotron cyclePro© ergometer. The results showed no significant differences between the two groups of subjects with respect to both physiological parameters (carbohydrate, fat oxidation and blood glucose concentration) and related to endurance performance.

The study suggests that type of carbohydrate intake (low GI or high GI carbohydrate) does not affect performance. This calls into question some long-standing formulation principles, and requires further research. The available evidence strongly supports carbohydrate intake in the context of sports; the final word on the use of low GI carbohydrates over high GI carbohydrates had not been said, and high GI carbohydrates still have a place.

Jacopo Angelucci – Sport nutrition Team

Leucine plays a key-role in protein synthesis during moderate steady state exercises

Leucine is one of the essential amino acids (EAA) and belongs to the group of BCAAs (branched chained amino acids), the only ones (together with Isoleucine and Valine) that are not degraded in the liver. BCAAs are found mainly in the skeletal muscle and offer an important contribution to the muscle building. Studies suggest that leucine offers the greatest contribution to the energy production at muscular level, slowing the degradation of the tissue by stimulating muscle protein synthesis. In fact, through the insulin-pathway signaling, leucine seems able to trigger muscle anabolic process.

Nevertheless, EFSA‘s Panel on Dietetic Products, Nutrition and Allergies (NDA) published a scientific opinion regarding BCAAs, providing a negative opinion related to the proposed claims, such as ‘Growth or maintenance of muscle mass’, ‘Faster recovery from muscle fatigue after exercise’ and ‘Reduction in perceived exertion during exercise’, noting that there was no proof of benefit over that of all aminoacids as protein building blocks. Some countries, however, are still allowing claims to be made on leucine and BCAAs.

A recent study was performed in the US to evaluate how supplementation with essential amino acids containing two different amounts of leucine can influence post-exercise muscle protein synthesis. Eight adults drank two amino acid based beverage containing respectively 1.87 g and 3.5 g of leucine during their physical exercises. Muscle protein synthesis was determined by using two stable carbon and hydrogen isotopes as marker. Results showed that muscle protein synthesis was 33 % greater (P < 0.05, then statistically significant) after drinking the leucine-enriched beverage, than after consumption of non-enriched one. This trial suggests that ‘increasing the concentration of leucine in an EAA supplement consumed during steady state exercise elicits a greater MPS response during recovery’. It should be noted however that EFSA has indicated that the markers used are not adequate, as positive effects on muscle mass should be proved via actual measurements of mass, not through markers of degradation or synthesis.

The study supports higher ratios of leucine in BCAA supplements, or increasing the leucine content of supplements and other foods for sportsmen.

Given EFSA’s negative opinion, claims on the effect of BCAAs on muscle protein synthesis (which EFSA said is not a benfit per se) rest on shaky ground. It’s just possible, and only for now, to claim BCAAs effects allowed at national level (e.g. for Italy: ‘trophism and muscle recovery’); this must be checked country by country.

Armando Antonelli – Sport Nutrition Team

Hylobates’ consultants get ready to work with EFSA’s application desk

Hylo’s consulting team is preparing to work closely with the newly created EFSA’s application desk on applications submitted on behalf of clients.   According to EFSA, the mission of the newly created application desk is to act as a front office and support desk for applicants.   The application desk should handle requests of applicants, Member States, stakeholders and other interested parties and register and conduct an initial administrative compliance check on application dossiers, among other duties.  The application desk is part of the new EFSA’s REPRO Directorate whose aim is to provide independent scientific advice related to risk assessment of substances, products and processes intended to be used in the food chain and, substantiation of claims made on foods.

“EFSA is a pillar of food safety and the rule-based food information system in the EU. Working closely with the Authority has always been a priority for Hylobates” according to Luca Bucchini, Hylobates’managing director “Being based in Italy, we are close to the Authority; we scrutinize, seek to understand all its actions. The setting up of the desk is a step in the right direction, in line with the most efficient food administrations in the EU. We believe it will help us aid applicants in a more effective way, rewarding rapidly good applications”.

Hylobates Consulting

PlantLIBRA, Prof. Silano wishes success to the PlantLIBRA Brasov meeting

Prof. Silano, chairman of EFSA’s Scientific Committee and of PlantLIBRA’s Scientifi Advisory Board, has asked us to share a message with PlantLIBRA partners (he will not be able to attend the meeting):

I would be very grateful if you could express to all our colleagues participating in the PlantLIBRA meeting in Brasov, my sincere regrets for not being able to participate. I hoped to help develop the project in a concrete way and help avoid some pitfalls to the project. In any case, my wish is that everything goes well, considering that this project is unique in its nature and also represents a significant success for those who have put forward the proposal. Furthermore, the results of this project will not fail to provide long-waited responses with substantial benefits for consumers of food supplements with botanicals.

[translated from Italian]

The PlantLIBRA Management Team

Low glycaemic “properties” claims: EFSA brings new hope

Low glycemic “properties” are an industry’s favorite when it comes to sports nutrition, particularly for bars. Though such claims are rather carelessly used in some EU countries, with little official scrutiny, there was concern that claims such as those would not be allowed under Reg. 1924/2006 or would fall outside its scope and hence in a limbo of regulatory uncertainty.

Although the recent batch of EFSA opinions on health claims resulted in several sadly negative opinions, sugar replacers such as xylitol, sorbitol, mannitol, maltitol, lactitol, isomalt, erythritol, D-tagatose, isomaltulose, sucralose and polydextrose came out as clear winners. EFSA’s NDA panel declared that “a cause and effect relationship has been established between the consumption of foods/drinks containing xylitol, sorbitol, mannitol, maltitol, lactitol, isomalt, erythritol, D-tagatose, isomaltulose, sucralose or polydextrose instead of sugar and reduction in post-prandial blood glucose responses (without disproportionally increasing post-prandial insulinaemic responses) as compared to sugar-containing foods/drinks“.

The Panel was apparently convinced that the Regulation’s restrictions on comparative claims as well as art. 3 (“...the use of nutrition and health claims shall not….give rise to doubt about the safety and/or the nutritional adequacy of other foods“, with sugar possibly the loser in this case) did not present a problem, although this may come back at the enforcement level in Member States.

In practice, while the immediate implications of this EFSA opinion vary in different Member States, there is a clear possibility of making “low glycemic” claims on food supplements (e.g., protein with sucralose) and bars with polyols (news which will make many happy).

However, the conditions set by the Panel deserve a careful analysis before using the claims.

– Sports Nutrition Team –

NB: Stevia, which, at the moment, is not allowed anyway, is not in the list.

EFSA: caffeine for sports ok, but not for weight loss

The 8 of April 2011 EFSA’s NDA Panel has published the outcome of the evaluations of a fourth series of ‘general function’ health claims proposed for use on food products.

Only few opinions are positive for sports nutrition. Among these 442 health claims, the most relevant are related to caffeine; in particular  health claims such as ‘Increased alertness’ , ‘ increased attention’, ‘increase in endurance performance’, ‘increase in endurance capacity’, ‘reduction in the rated perceived exertion/effort during exercise’ are now accepted for caffeine. Other positive outcomes are related to resistant maltodextrins ( ‘Changes in bowel function’), Choline (‘ Contribution to normal lipid metabolism ‘) and olive poliphenols  ( ‘Hydroxytyrosol protects LDL particles from oxidative damage’).

Instead most EFSA opinions are negative. It should be noted that all the health claims on ‘reduction of body weight’ related to caffeine and green tea have been rejected. Other negative outcomes are related to several aminoacids such as  L-Arginine, Lysine, Tryptophan and aminoacidic derivatives such as Taurine and Carnosine, particularly interesting are the rejected health claims concerning  ‘management of body mass’  and “improvement of endothelium-dependent vasodilation’ (Arginine),  ‘Contribution to normal protein synthesis’ (Lysine), ‘Maintenance of normal muscle function’ (Taurin). Also Quercetin, Lutein, Alpha Linoleic Acid (ALA), FOS and PUFAs DHA/EPA (Omega 3) received general negative opinions from the Panel.

“The positive opinion on caffeine is important specifically for the benefits which EFSA has recognized within the domain of the Nutrition and Health Claims Regulation, and the standard that it sets.” commented Luca Bucchini, managing director of Hylobates “Though EFSA’s opinions are important when thinking to new products, they should not be the only driving force. EFSA’s processs is welcome when compared to the less than transparent situation in several EU countries; at the same time, it should be noted that EFSA’s approach has been less than consistent between micronutrients and other substances. It is time for the sports nutrition industry to think carefully about the future.”

– Armand and Jacopo, Sport Nutrition Team –

EFSA: la caffeina per lo sport funziona, altre sostanze no

In data odierna il gruppo di esperti dell’EFSA ha pubblicato i risultati della valutazione di 442 claim sulla salute proposti per l’uso nei prodotti alimentari.

Solo poche opinioni possono essere considerate positive nel campo della nutrizione sportiva,  in particolare sono stati accettati claim relativi al consumo di caffeina e aumento dello stato di allerta/attenzione, diminuzione della percezione dello sforzo durante l’esercizio fisico ed aumento della capacità in esercizi fisici di resistenza. Gli esperti dell’EFSA hanno dato inoltre parere positivo per il claim relativo alle maltodestrine resistenti affermando che c’è una relazione di causa effetto tra il consumo di questi carboidrati e il miglioramento della funzionalità intestinale. Altri esiti positivi sono riscontrabili per claim relativi alla Colina (‘contribuisce al normale metabolismo lipidico’) e ai polifenoli dell’ulivo (‘Idrossitirosolo protegge le LDL dal danno ossidativo’).

Gran parte dei claim valutati sono stati respinti, tra cui i principali relativi al consumo di caffeina e tè verde che riguardano ‘mantenimento e controllo del peso corporeo’ non potranno più essere utilizzati per prodotti ed integratori alimentari, a meno che il processo a livello comunitario abbia un esito diverso e solo quando i pareri diventeranno legge, con lo specifico regolamento di attuazione. Nessun parere positivo per quel che riguarda i claim  sugli aminoacidi come arginina, lisina, triptofano e derivati aminoacidici quali taurina, carnosina: infatti i principali claim sulla massa muscolare, attività di tipo tonico e vasodilatazione sono stati bocciati.Numerosi altri claim sono stati valutati e bocciati, in particolare molti relativi a Quercetina, Luteina, Acido Alfa Linoleico (ALA), FOS e i PUPA DHA/EPA (Omega 3) generalmente per carenza di dati sufficienti.

“Non bisogna dimenticare che EFSA ha ampiamente riconosciuto i benefici di vitamina e minerali che sono i tipici principi degli integratori alimentari, anche per lo sport (come per vitamina C e sistema immunitario dello sportivo)” ha commentato Luca Bucchini, direttore gestionale di Hylobates “Per le altre sostanze ha usato uno standard di prova molto diverso e a volte discutibile, anche se riteniamo un processo trasparente e scientificamente qualificato come quello di EFSA sia importante e necessario. Il riconoscimento per la caffeina è importante ed univoco; sarà importante bilanciare l’effetto positivo dei pareri EFSA con la necessità di portare sul mercato prodotti equilibrati, indirizzando attentamente la ricerca. Su un piano più squisitamente tecnico è importante, che con l’opinione sulla caffeina, EFSA ha confermato la possibilità di claim sulla salute nel quadro del Regolamento 1924/2006 riferiti ad attività sportive”.

Le indicazioni fornite dal Ministero della Salute sul proprio sito, fino all’entrata in vigore di un regolamento applicativo (atteso per metà 2012), restano permesse.

– Armando e Jacopo, Sport Nutrition Team –

Aggiornato alle ore 18:03 dell’8/4 con riferimento al Ministero Salute

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