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Zah─ârul, adev─ârul amar

Sugar: the bitter truth[1] (Zah─ârul, adev─ârul amar) este prezentarea doctorului Robert H. Lustig. Este profesor de pediatrie clinic─â la Universitatea din California, San Francisco (UCSF)[2].

El explic─â cum boli ce odat─â erau v─âzute numai ├«n adul┼úi (ca diabetul tip 2) acum se g─âsesc frecvent la copii. Copiii supraponderali tind s─â devin─â adul┼úi supraponderali, fapt care ├«i expune la risc de hipertensiune arterial─â ┼či boli cardiovasculare[3].

Profesorul Lustig arat─â cum obezitatea[4] la copii, sindromul metabolic[5], sau diabetul tip 2 [6], sunt cauzate de dietele vestice deoarece procesarea m├ónc─ârii s-a modificat ├«n ultimii 30 de ani: cu adaosul de zah─âr unei mari variet─â┼úi de m├ónc─âruri ce nu con┼úineau zah─âr[7], ┼či cu eliminarea fibrelor (exemplu: sucurile cu zah─âr[8] sunt concentrate); devin m├ónc─âruri de ÔÇŁdependen┼ú─â[9]ÔÇŁ ┼či cum zah─ârul produce senza┼úia de ├«nfometare ├«n creier (efectele zah─ârului asupra insulinei - hiperinsulinemie).

  

Lustig explic─â cum hormonul insulin─â ac┼úioneaz─â asupra creierului ┼či ├«ncurajeaz─â consumul de m├óncare prin 2 mecanisme separate:

  • Blocheaz─â semnalele de la gr─âsimea corporal─â la creier prin suprimarea eficien┼úei hormonului leptin─â rezult├ónd un consum m─ârit ┼či activitate fizic─â sc─âzut─â Ôćĺ activitatea fizic─â sc─âzut─â nu este cauza obezit─â┼úii, este rezultatul consumului m─ârit de fructoza, vezi ┼či zah─ârul este otrav─â.
  • Insulina promoveaz─â semnalul ce caut─â recompensa m├óncatului, transportat de dopamin─â ÔÇô ceea ce face ca persoanele s─â ├«┼či m─âreasc─â consumul de m├óncare ca s─â mareasc─â pl─âcerea.

Insulina pe termen scurt cre┼čte expresia ┼či activitatea transportorului de dopamin─â[10] ┼či scoate dopamina din sinapse, astfel expunerea acut─â la insulin─â atenueaz─â recompensa m├ónc─ârii (hiperinsulinemie ÔÇô foame constant─â). Obezitatea poate fi cauzat─â ┼či de de rezisten┼úa la leptin─â[11].

Fructoza

Sursa de fructoza este zah─ârul (sucroza ÔÇô dizaharid compus din glucoza ┼či fructoza), sirop de porumb (HCFS, sirop de fructoza) fructe ┼či miere. Sursele de fructoz─â difer─â de la ┼úar─â la ┼úar─â. ├Än ┼ú─âri unde produc┼úia de sirop de porumb/sirop de fructoza este mare acesta este ├«n cantitate mare ├«n alimente. Dac─â ├«n America aceasta reprezint─â 50% din ├«ndulcitori[12], ├«n Japonia ajunge la 25%; ├«n restul ┼ú─ârilor zah─ârul (sucroza) este ├«ndulcitorul principal[13].

Studiile pe oameni au ar─âtat c─â ┼či 50 g de fructoz─â intravenos poate provoca deple┼úia de ATP (Adenozin trifosfat) ├«n ficat[14] [15]. Alte studii sugereaz─â c─â fructoza, (nu glucoza) cauzeaz─â sindromul metabolic[16] [17].

Fructoza poate provoca rezisten┼úa insulinic─â (diabet tip 2) ├«ntr-o s─âpt─âm├ón─â la 250g fructoza ├«n diet─â /zi [18]. Fructoza cre┼čte trigliceridele serice la b─ârba┼úi[19] [20] dar ┼či la femei[21].

  

Cine c├ó┼čtig─â:

 

Concluzie:

  • Controversa oficial─â exist─â de peste 40 de ani c─â excesul de zah─âr sau fructoz─â este nociv[22] dar ignorat din motive economice ┼či a teoriilor gre┼čite, azi considerat legitim prin cre┼čterea dramatic─â a consumului de sucuri, dulciuri ┼či alimente cu zah─âr ad─âugat, cre┼čterea obezit─â┼úii, diabetului ┼či sindromului metabolic la nivel global[23].
  • Cre┼čterea obezit─â┼úii la nivel global devine normalitate ÔÇô mai ales la copii ┼či adolescen┼úi [24] [25] [26] [27] [28] [29] [30] (ce consum─â frecvent sucuri, cornuri ┼či dulciuri) Ôćĺ cauza fiind ├«nlocuirea gr─âsimii cu zah─âr [31] [32].
  • ├Äntreaga cultur─â ce se promoveazăÄ de căÄtre presa corporatist─â, filme, vedete ┼či reclame, este artificial─â ┼či ├«ncurajeaz─â societatea de consum prin distrugerea tradi┼úiei ┼či valorilor = ├«ndoctrinare. Astfel contribuie la agravarea s─ân─ât─â┼úii ┼či destabilizarea economiei tuturor ┼ú─ârilor prin sc─âderea locurilor de munc─â (ex: depende┼úa de ├«mprumuturi).
  • Cultura Americii se bazeaz─â pe zah─âr, dulciuri (ex.: bomboane de haloween, bomboane de Cr─âciun, ciocolat─â de St. Valentine, ciocolat─â de Pa┼čte (easter bunny), tort la ziua de na┼čtere), sosuri dulci ├«n m├óncare ┼či restul inutilit─â┼úilor. Consumul mediu curent de fructoz─â la americani este de 70 -100 grame de fructoz─â pe zi fa┼úăÄ de 15 ÔÇô 40 g/zi de fructoz─â [33] media de la ├«nceputul secolului 19.
 
 
Referinţe:

1. Sugar: The Bitter Truth UCSF Osher Mini Medical School for the Public http://www.uctv.tv/search-details.aspx?showID=16717

2. The Real Truth About Sugar: Dr. Robers Lustig's "Sugar: The Bitter Truth" http://chc.ucsf.edu/coast/faculty_lustig.htm

3. International Journal of Obesity 34, 18-28 (January 2010) | doi:10.1038/ijo.2009.61 http://www.nature.com/ijo/journal/v34/n1/full/ijo200961a.html

11. Flier JS (1998) What's in a name? In search of leptin's physiologic role. J Clin Endocrinol Metab 83: 1407ÔÇô1413 http://jcem.endojournals.org/content/83/5/1407

12. Haley S, Reed J, Biing-Hwan L, CookA (2005) Sweetener consumption inthe United States: distribution bydemographic and product characteristics. In: Economic Research Service(ed) Situation and outlook report:sugar and sweetener. US Departmentof Agriculture

13. World and U.S. corn sweetenersÔÇö1990/1991 world corn sweetenerproduction, consumption, prices. In:Economic Research Service (ed) Situation and Outlook Report: Sugar and Sweetener. US Department of Agriculture

14. Bode JC, Zelder O, Rumpelt HJ, Wit-tkamp U (1973) Depletion of liveradenosine phosphates and metaboliceffects of intravenous infusion of fructose or sorbitol in man and in the rat. Eur J Clin Invest 3:436ÔÇô441

15. Nair S, V PC, Arnold C, Diehl AM(2003) Hepatic ATP reserve and effi-ciency of replenishing: comparisonbetween obese and nonobese normalindividuals

16. Elliott SS, Keim NL, Stern JS, Teff K, Havel PJ (2002) Fructose, weight gain, and the insulin resistance syndrome. Am J Clin Nutr 76:911ÔÇô922

17. Gaby AR (2005) Adverse effects of dietary fructose. Altern Med Rev 10:294ÔÇô306

18. Beck-Nielsen H, Pedersen O, Linds- kov HO (1980) Impaired cellular insulin binding and insulin sensitivity induced by high-fructose feeding in normal subjects. Am J Clin Nutr 33:273ÔÇô278 http://www.ajcn.org/content/33/2/273.abstract

19. Bantle JP, Raatz SK, Thomas W, Georgopoulos A (2000) Effects of dietary fructose on plasma lipids in healthy subjects. Am J Clin Nutr 72:1128ÔÇô1134

20. Reiser S, Powell AS, Scholfield DJ, Panda P, Ellwood KC, Canary JJ (1989) Blood lipids, lipoproteins, apoproteins, and uric acid in men fed diets containing fructose or high- amylose cornstarch. Am J Clin Nutr 49:832ÔÇô839 http://www.ajcn.org/content/49/5/832.abstract?ijkey=5b2f5d97663f397132adbbae76579ec26de6a21c&;;keytype2=tf_ipsecsha

21. Teff KL, Elliott SS, Tschop M, Kieffer TJ, Rader D, Heiman M, Townsend RR, Keim NL, DÔÇÖAlessio D, Havel PJ (2004) Dietary fructose reduces cir- culating insulin and leptin, attenuates postprandial suppression of ghrelin, and increases triglycerides in women. J Clin Endocrinol Metab 89:2963ÔÇô2972

22. Pure, white and deadly: The problem of sugar, Yudkin Md. 1972 http://www.amazon.com/Pure-white-deadly-problem-sugar/dp/0706700406

23. Tappy L, Lê KA. Metabolic effects of fructose and the worldwide increase in obesity. Physiol Rev. 2010 http://www.ncbi.nlm.nih.gov/pubmed/20086073

24. Ogden CL et al. (2002) Prevalence and trends in overweight among US children and adolescents, 1999ÔÇô2000. JAMA 288:

25. Obesity in children and young people: a crisis in public health. http://www.ncbi.nlm.nih.gov/pubmed/15096099?dopt=Abstract

26. Wang Y,Lobstein T. Worldwide trends in childhood overweight and obesity. Int J Pediatr Obes 2006;1:11ÔÇô25.

27. Secular Trends in Prevalence of Overweight and Obesity from 2006 to 2009 in Urban Asian Indian Adolescents Aged 14-17 Years >ncbi

29. Secular trends in adiposity in Norwegian 9-year-olds from 1999-2000 to 2005 http://www.ncbi.nlm.nih.gov/pubmed/19828037?dopt=Abstract

30. Intake of sugar-sweetened beverages and weight gain: a systematic review. http://www.ncbi.nlm.nih.gov/pubmed/16895873

31. Sugar Nation: The Hidden Truth Behind America's Deadliest Habit http://www.amazon.com/Sugar-Nation-Hidden-Americas-Deadliest/dp/1401323448/ref=sr_1_3?s=books

32. Suicide by Sugar: A Startling Look at Our #1 National Addiction http://www.amazon.com/Suicide-Sugar-Startling-National-Addiction/dp/0757003060/ref=sr_1_4?s=books

33. Yudkin J (1967) Evolutionary and historical changes in dietary carbohydrates. Am J Clin Nutr 20:108ÔÇô115