L-Carnitina este o substanta a carei functie principala este de a facilita transportul si metabolismul acizilor grasi in celula, unde sint oxidati si transformati in energie. In afara imbunatatirii performantelor atletice si a starii de sanatate a aparatului cardiovascular, L-Carnitina este utila in cazul persoanelor supraponderale sau obeze, care doresc sa slabeasca. Studiile au demonstrat ca administrarea a 2g de L-Carnitina pe zi, impreuna cu un program de exercitii si regim alimentar, au produs o scadere semnificativa a greutatii corporale.
Surplusul de L-carnitina este eliminat de organism prin urina, cazurile de supradozaj fiind foarte greu de atins.
Alimente care contin L- Carnitina:
Carnea de vită gatita (120 grame): 56-162 mg
Lapte integral (1 cană): 8 mg
Peste – cod (120 grame): 4-7 mg
Piept de pui gatit – (120 grame): 3-5 mg
Inghetata (½ ceaşcă: 3 mg
Branza, cheddar (60 grame): 2 mg
Paine integrala (2 felii): 0,2 mg
Sparanghel fiert (½ ceasca): 00,1 mg
Carente si sintetizarea in organism a L-Carnitinei:
Pentru sintetizarea L-carnitinei de organismul uman avem nevoie de amoniacizii: lisina si metionina si de vitaminele: C, B6, Fe2 si niacin. Oboseala asociata lipsei de vitamina C este automatic legata de implicarea acesteia in producerea de L-carnitina. Lipsa aminoacizilor si vitaminelor avand o implicare directa asupra producerii de L-carnitina a corpului nostru. Detalii mai jos:
"Carnitine deficiency
Nutrition -related carnitine deficiency was not found in healthy people without metabolic disorders until now , suggesting that most people enough to L -carnitine ( 1) synthesize . Even strict vegetarians ( vegans ) do not show signs of carnitine deficiency, although most of carnitine comes from animal sources (8).
Premature babies , infants and toddlers with low storage of L- carnitine, are at risk of carnitine deficiency due to their rapid growth. One study reported that infants who were fed carnitine -free soy- based , normally grew and showed no evidence of a clinically significant carnitine deficiency. However, some biochemical values differed with respect to lipid metabolism significantly from infants who have the same food supplemented with L -carnitine (14 ) were given . Soy -based infant formula is therefore supplemented with the amount of L-carnitine, which is found in human breast milk (15).
Secondary carnitine deficiency
Secondary carnitine deficiency can have either genetic or acquired causes. Hereditary causes are genetic defects in amino acid metabolism (eg propionic aciduria ) and lipid metabolism (eg acyl -CoA dehydrogenase deficiency in medium chain fatty acids ) . These inherited disorders can lead to an accumulation of organic acids, which are then renally excreted from the body by means of acylcarnitine esters.Increased losses of carnitine in the urine may lead to a systemic depletion of carnitine levels (1). This can also occur in disorders of renal reabsorption (20). Therefore, any malfunction of the kidney, resulting in a higher loss of carnitine in the urine.
An example of an acquired exclusively carnitine deficiency , however, relates to the use of chronic pivalate conjugated antibiotics. Pivalate is a branched chain fatty acid which is metabolized to an acyl -CoA ester, which is esterified to acyl carnitine and is excreted in the urine as pivaloyl -carnitine. Losses of carnitine in this way can be 10 -fold greater than the sum of the daily carnitine uptake and biosynthesis , leading to systemic carnitine deficiency (16).Furthermore , patients with kidney disease who are undergoing hemodialysis have an increased risk for secondary carnitine deficiency, carnitine as hemodialysis removed from the blood (21). Regardless of the etiology is a secondary carnitine deficiency clinically characterized by low plasma concentrations of free carnitine (less than 20 micromol / L) as well as an increased ratio of free carnitine , acylcarnitine to (greater than 0.4 ) (19 , 22). A secondary deficiency is more common than the rare primary carnitine deficiency .Nutrient interactions
The endogenous biosynthesis of L- carnitine is catalyzed by the concerted action of five different enzymes. This process requires two essential amino acids (lysine and methionine ), iron ( Fe 2 ), vitamin C, vitamin B 6 , and niacin in the form of nicotinamide adenine dinucleotide (NAD ) ( 3). One of the first symptoms of vitamin C deficiency is exhausted , which is believed to be associated with decreased synthesis of L -carnitine (23).
Influence on the physical performanceInterest in the potential of L- carnitine supplementation to improve athletic performance is related to the important role of the substance together in energy metabolism . A number of small , uncontrolled studies have already shown that either acute ( administration of L- carnitine one hour prior to the sport) or with short-term ( regular administration over two to three weeks) L- carnitine supplementation in 2 to 4 g / day associated an increased maximum oxygen uptake and the decrease in plasma lactate levels is ( 82-85 ) .Most studies so far show no effect of supplementation with L- carnitine on physical performance (86). The possible information that may have been drawn from this research , however, is limited both by the small number of participants and short duration of the addition and by the lack of suitable control groups.Several studies have shown that supplementation with carnitine plasma carnitine levels increased (87-91 ) , but have failed to prove that the carnitine levels increase in skeletal muscle , where more than 95 % of the total carnitine in the body is present ( 92).
The available data do not yet clearly on an athletic performance enhancement in healthy people out ."sursa: wikipedia
studii:
- u.a. Axel G. Feller and Daniel Rudman: Role of carnitine in human nutrition. In: The Journal of nutrition, Volume 118, Issue 5, 541 – 547, Januar 1988 ↩
- z.B. bei Malaguarnera M et al.: L-Carnitine supplementation reduces oxidized LDL cholesterol in patients with diabetes; Am J Clin Nutr. 2008 Dec 3 ↩
- M. Malagurnera et al.: L-Carnitine treatment reduces severity of physical and mental fatigue and inreases cognitive functions: a randomized an controlled clinical trial; American Journal of Clinical Nutrition; Vol. 86, No. 6, 1738-1744 Dec. 2007 ↩
- Serati AR, Motamedi MR, Emami S, Varedi P, Movahed MR. L-carnitine treatment in patients with mild diastolic heart failure is associated with improvement in diastolic function and symptoms. Cardiology. 2010;116(3):178-82 ↩
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