Categoría: Salud femenina

Efectos del mercurio en salud humana


A propósito de la situación suscitada con atún y mercurio en Colombia, con la firma van Camps, se comparten entradas en el sitio:

https://www.facebook.com/groups/161366980592425/search/?query=mercurio

vale la pena conocer lo que refiere la OMS sobre el mercurio y la salud humana, en

http://www.who.int/mediacentre/factsheets/fs361/es/

Anuncios

Fed-Up


Conocí este documental por un bloguero que describió su valiente lucha contra la ingesta de azúcar.

Este es el blog:

http://www.latercera.com/noticia/tendencias/2016/01/659-664289-9-en-guerra-contra-el-azucar.shtml

Versión en Youtube subtitulada en español

English version

Lo que constituye  el dulce de chocolate, en: http://despiertavivimosenunamentira.com/lo-que-hay-dentro-de-un-bote-de-nutella/

 

Limoneno: valor nutricional de cáscara de limón


Limoneno (limonene en inglés)

El limoneno es una sustancia natural que se extrae de los cítricos. Es la sustancia que da olor característicos a las naranjas y los limones. Pertenece al grupo de los terpenos.
El limoneno levógiro (-) se extrae de la cáscara de la naranja y le confiere su olor característico.
El limoneno dextrógiro (+) es un líquido aceitoso que puede extraerse fácilmente de la cáscara del limón y es el responsable de su olor.

Pues hay varios artículos en MedLine (PubMed)  http://www.ncbi.nlm.nih.gov/pubmed/ sobre diferentes efectos biológicos de limón y cítricos como naranja, especialmente en su cáscara, que es la que tiene mayor contenido de limoneno.

Los resúmenes a continuación son los que se obtienen con términos de búsqueda limonene and cancer and trial and humans 

  1. Life Sci. 2013 Jul 10;92(24-26):1151-6. doi: 10.1016/j.lfs.2013.04.013. Epub 2013 May 7. Oral administration of d-limonene controls inflammation in rat colitis and displays anti-inflammatory properties as diet supplementation in humans. d’Alessio PA(1), Ostan R, Bisson JF, Schulzke JD, Ursini MV, Béné MC.  Author information:  (1)Biopark Cancer Campus, University Paris Sud-11, 94807 Villejuif, France. endocell@wanadoo.fr  AIMS: To further explore the anti-inflammatory properties of d-Limonene. MAIN METHODS: A rat model was used to compare evolution of TNBS (2,5,6-trinitrobenzene sulfonic acid)-induced colitis after oral feeding with d-Limonene compared to ibuprofen. Peripheral levels of TNF-α (Tumor Necrosis Factor alpha) were assessed in all animals. Cell cultures of fibroblasts and enterocytes were used to test the effect of d-Limonene respectively on TNFα-induced NF-κB (nuclear factor-kappa B) translocation and epithelial resistance. Finally, plasmatic inflammatory markers were examined in an observational study of diet supplementation with d-Limonene-containing orange peel extract (OPE) in humans. KEY FINDINGS: Administered per os at a dose of 10mg/kg p.o., d-Limonene induced a significant reduction of intestinal inflammatory scores, comparable to that induced by ibuprofen. Moreover, d-Limonene-fed rats had significantly lowered serum concentrations of TNF-α compared to untreated TNBS-colitis rats. The anti-inflammatory effect of d-Limonene also involved inhibition of TNFα-induced NF-κB translocation in fibroblast cultures. The application of d-Limonene on colonic HT-29/B6 cell monolayers increased epithelial resistance. Finally, inflammatory markers, especially peripheral IL-6, markedly decreased upon OPE supplementation of elderly healthy subjects submitted or not to 56 days of dietary supplementation with OPE. SIGNIFICANCE: In conclusion, d-Limonene indeed demonstrates significant anti-inflammatory effects both in vivo and in vitro. Protective effects on the epithelial barrier and decreased cytokines are involved, suggesting a beneficial  role of d-Limonene as diet supplement in reducing inflammation.  Copyright © 2013 Elsevier Inc. All rights reserved.  PMID: 23665426  [PubMed – indexed for MEDLINE]
  2. Cancer Prev Res (Phila). 2013 Jun;6(6):577-84. doi: 10.1158/1940-6207.CAPR-12-0452. Epub 2013 Apr 3. Human breast tissue disposition and bioactivity of limonene in women with early-stage breast cancer.  Miller JA(1), Lang JE, Ley M, Nagle R, Hsu CH, Thompson PA, Cordova C, Waer A, Chow HH.  Author information:  (1)The University of Arizona Cancer Center, 1515 N Campbell Ave, Tucson, AZ 85724, USA. jam1@email.arizona.edu  Limonene is a bioactive food component found in citrus peel oil that has shown chemopreventive and chemotherapeutic activities in preclinical studies. We conducted an open-label pilot clinical study to determine the human breast tissue disposition of limonene and its associated bioactivity. We recruited 43 women with newly diagnosed operable breast cancer electing to undergo surgical excision to take 2 grams of limonene daily for two to six weeks before surgery. Blood and  breast tissue were collected to determine drug/metabolite concentrations and limonene-induced changes in systemic and tissue biomarkers of breast cancer risk  or carcinogenesis. Limonene was found to preferentially concentrate in the breast tissue, reaching high tissue concentration (mean = 41.3 μg/g tissue), whereas the major active circulating metabolite, perillic acid, did not concentrate in the breast tissue. Limonene intervention resulted in a 22% reduction in cyclin D1 expression (P = 0.002) in tumor tissue but minimal changes in tissue Ki67 and cleaved caspase-3 expression. No significant changes in serum leptin, adiponectin, TGF-β1, insulin-like growth factor binding protein-3 (IGFBP-3), and  interleukin-6 (IL-6) levels were observed following limonene intervention. There  was a small but statistically significant postintervention increase in insulin-like growth factor I (IGF-I) levels. We conclude that limonene distributed extensively to human breast tissue and reduced breast tumor cyclin D1 expression that may lead to cell-cycle arrest and reduced cell proliferation. Furthermore, placebo-controlled clinical trials and translational research are warranted to establish limonene’s role for breast cancer prevention or treatment.  PMCID: PMC3692564 PMID: 23554130  [PubMed – indexed for MEDLINE]
  3. Altern Med Rev. 2007 Sep;12(3):259-64. D-Limonene: safety and clinical applications.  Sun J(1).  Author information:  (1)Thorne Research, PO Box 25, Dover, ID 83825, USA. jidong@thorne.com  D-limonene is one of the most common terpenes in nature. It is a major constituent in several citrus oils (orange, lemon, mandarin, lime, and grapefruit). D-limonene is listed in the Code of Federal Regulations as generally recognized as safe (GRAS) for a flavoring agent and can be found in common food items such as fruit juices, soft drinks, baked goods, ice cream, and pudding. D-limonene is considered to have fairly low toxicity. It has been tested for carcinogenicity in mice and rats. Although initial results showed d-limonene increased the incidence of renal tubular tumors in male rats, female rats and mice in both genders showed no evidence of any tumor. Subsequent studies have determined how these tumors occur and established that d-limonene does not pose a mutagenic, carcinogenic, or nephrotoxic risk to humans. In humans, d-limonene has demonstrated low toxicity after single and repeated dosing for up to one year. Being a solvent of cholesterol, d-limonene has been used clinically to dissolve cholesterol-containing gallstones. Because of its gastric acid neutralizing effect and its support of normal peristalsis, it has also been used for relief of heartburn and gastroesophageal reflux (GERD). D-limonene has well-established chemopreventive activity against many types of cancer. Evidence from a phase I clinical trial demonstrated a partial response in a patient with breast cancer and stable disease for more than six months in three patients with colorectal cancer.  PMID: 18072821  [PubMed – indexed for MEDLINE]
  4. Drug Metab Pharmacokinet. 2004 Aug;19(4):245-63. Cancer prevention by natural compounds.  Tsuda H(1), Ohshima Y, Nomoto H, Fujita K, Matsuda E, Iigo M, Takasuka N, Moore MA.  Author information:  (1)Department of Molecular Toxicology, Nagoya City University Graduate School of  Medical Sciences, Japan. htsuda@med.nagoya-cu.ac.jp  Increasing attention is being paid to the possibility of applying cancer chemopreventive agents for individuals at high risk of neoplastic development. For this purpose by natural compounds have practical advantages with regard to availability, suitability for oral application, regulatory approval and mechanisms of action. Candidate substances such as phytochemicals present in foods and their derivatives have been identified by a combination of epidemiological and experimental studies. Plant constituents include vitamin derivatives, phenolic and flavonoid agents, organic sulfur compounds, isothiocyanates, curcumins, fatty acids and d-limonene. Examples of compounds from animals are unsaturated fatty acids and lactoferrin. Recent studies have indicated that mechanisms underlying chemopreventive potential may be combinations of anti-oxidant, anti-inflammatory, immune-enhancing, and anti-hormone effects, with modification of drug-metabolizing enzymes, influence on the cell cycle and cell differentiation, induction of apoptosis and suppression of proliferation and angiogenesis playing roles in the initiation and secondary modification stages of neoplastic development. Accordingly, natural agents are advantageous for application to humans because of their combined mild  mechanism. Here we review naturally occurring compounds useful for cancer chemoprevention based on in vivo studies with reference to their structures, sources and mechanisms of action.  PMID: 15499193  [PubMed – indexed for MEDLINE]
  5. Exp Biol Med (Maywood). 2004 Jul;229(7):567-85. Studies of the isoprenoid-mediated inhibition of mevalonate synthesis applied to  cancer chemotherapy and chemoprevention.  Mo H(1), Elson CE.  Author information:  (1)Department of Nutrition and Food Sciences, Texas Woman’s University, Denton, TX 76204, USA. hmo@mail.twu.edu  Pools of farnesyl diphosphate and other phosphorylated products of the mevalonate pathway are essential to the post-translational processing and physiological function of small G proteins, nuclear lamins, and growth factor receptors. Inhibitors of enzyme activities providing those pools, namely, 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase and mevalonic acid-pyrophosphate decarboxylase, and of activities requiring substrates from the pools, the prenyl protein transferases, have potential for development as novel chemotherapeutic agents. Their potentials as suggested by the clinical responses  recorded in Phase I and II investigations of inhibitors of HMG CoA reductase (the statins), of mevalonic acid-pyrophosphate decarboxylase (sodium phenylacetate and sodium phenylbutyrate), and of farnesyl protein transferase (R115777, SCH66336, BMS-214662, Tipifarnib, L-778,123, and, prematurely, perillyl alcohol) are dimmed by dose-limiting toxicities. These nondiscriminant growth-suppressive agents induce G1 arrest and initiate apoptosis and differentiation, effects attributed to modulation of cell signaling pathways either by modulating gene expression, suppressing the post-translational processing of signaling proteins and growth factor receptors, or altering diacylglycerol signaling. Diverse isoprenoids and the HMG CoA reductase inhibitor, lovastatin, modulate cell growth, induce cell cycle arrest, initiate apoptosis, and suppress cellular signaling activities. Perillyl alcohol, the isoprenoid of greatest clinical interest, initially was considered to inhibit farnesyl protein transferase; follow-up studies revealed that perillyl alcohol suppresses the synthesis of small G proteins and HMG CoA reductase. In sterologenic tissues, sterol feedback control, mediated by sterol regulatory element binding proteins (SREBPs) 1a and 2, exerts the primary regulation on HMG CoA reductase activity at the transcriptional level. Secondary  regulation, a nonsterol isoprenoid-mediated fine-tuning of reductase activity, occurs at the levels of reductase translation and degradation. HMG CoA reductase  activity in tumors is elevated and resistant to sterol feedback regulation, possibly as a consequence of aberrant SREBP activities. Nonetheless, tumor reductase remains sensitive to isoprenoid-mediated post-transcriptional downregulation. Farnesol, an acyclic sesquiterpene, and farnesyl homologs, gamma-tocotrienol and various farnesyl derivatives, inhibit reductase synthesis and accelerate reductase degradation. Cyclic monoterpenes, d-limonene, menthol and perillyl alcohol and beta-ionone, a carotenoid fragment, lower reductase mass; perillyl alcohol and d-limonene lower reductase mass by modulating translational efficiency. The elevated reductase expression and greater demand for nonsterol products to maintain growth amplify the susceptibility of tumor reductase to isoprenoids, therein rendering tumor cells more responsive than normal cells to isoprenoid-mediated growth suppression. Blends of lovastatin, a potent nondiscriminant inhibitor of HMG CoA reductase, and gamma-tocotrienol, a potent isoprenoid shown to post-transcription-ally attenuate reductase activity with specificity for tumors, synergistically affect the growth of human DU145 and LNCaP prostate carcinoma cells and pending extensive preclinical evaluation, potentially offer a novel chemotherapeutic strategy free of the dose-limiting toxicity associated with high-dose lovastatin and other nondiscriminant mevalonate pathway inhibitors.  PMID: 15229351  [PubMed – indexed for MEDLINE]
  6. Eur J Cancer. 2000 Jun;36(10):1292-7. The state-of-the-art in chemoprevention of skin cancer.  Stratton SP(1), Dorr RT, Alberts DS.  Author information:  (1)Arizona Cancer Center, College of Medicine, University of Arizona, Tucson, AZ  85724, USA. stratton@azcc.arizona.edu  The incidence of skin cancer (both melanoma and non-melanoma) continues to grow at an alarming rate. Our chemoprevention strategies include the development of novel agents evaluated by (1) preclinical mechanistic studies in models of ultraviolet (UV) radiation-induced skin carcinogenesis; (2) clinical studies of immunohistochemical surrogate endpoint biomarkers in high-risk patients; and (3)  randomised, placebo-controlled phase I, II and III clinical chemoprevention trials. Recent clinical results validate this development model. Molecular targets of chemopreventive strategies for melanoma and non-melanoma skin cancers  include the ras and activator protein-1 (AP-1) signal transduction pathways. A transgenic murine melanoma model has been developed for evaluating potential agents in vivo. Agents at various stages of study include the green tea catechin  epigallocatechin gallate (EGCG), the limonene derivative perillyl alcohol, the ornithine decarboxylase inhibitor alpha-difluoromethylornithine (DFMO), selenium, retinoids and salicylates. New chemopreventive agents that can be used to complement sunscreens may result in decreased incidence, morbidity and mortality  of skin cancer.  PMID: 10882869  [PubMed – indexed for MEDLINE]
  7. Cancer Chemother Pharmacol. 1998;42(2):111-7. Phase I and pharmacokinetic study of D-limonene in patients with advanced cancer. Cancer Research Campaign Phase I/II Clinical Trials Committee.  Vigushin DM(1), Poon GK, Boddy A, English J, Halbert GW, Pagonis C, Jarman M, Coombes RC.  Author information:  (1)Department of Medical Oncology, Charing Cross Hospital, London, UK. d.vigushin@cxwms.ac.uk  PURPOSE: D-Limonene is a natural monoterpene with pronounced chemotherapeutic activity and minimal toxicity in preclinical studies. A phase I clinical trial to assess toxicity, the maximum tolerated dose (MTD) and pharmacokinetics in patients with advanced cancer was followed by a limited phase II evaluation in breast cancer. METHODS: A group of 32 patients with refractory solid tumors completed 99 courses of D-limonene 0.5 to 12 g/m2 per day administered orally in 21-day cycles. Pharmacokinetics were analyzed by liquid chromatography-mass spectrometry. Ten additional breast cancer patients received 15 cycles of D-limonene at 8 g/m2 per  day. Intratumoral monoterpene levels were measured in two patients. RESULTS: The MTD was 8 g/m2 per day; nausea, vomiting and diarrhea were dose limiting. One partial response in a breast cancer patient on 8 g/m2 per day was maintained for 11 months; three patients with colorectal carcinoma had prolonged  stable disease. There were no responses in the phase II study. Peak plasma concentration (Cmax) for D-limonene ranged from 10.8+/-6.7 to 20.5+/-11.2 microM. Predominant circulating metabolites were perillic acid (Cmax 20.7+/-13.2 to 71+/-29.3 microM), dihydroperillic acid (Cmax 16.6+/-7.9 to 28.1+/-3.1 microM), limonene-1,2-diol (Cmax 10.1+/-8 to 20.7+/-8.6 microM), uroterpenol (Cmax 14.3+/-1.5 to 45.1+/-1.8 microM), and an isomer of perillic acid. Both isomers of perillic acid, and cis and trans isomers of dihydroperillic acid were in urine hydrolysates. Intratumoral levels of D-limonene and uroterpenol exceeded the corresponding plasma levels. Other metabolites were trace constituents in tissue. CONCLUSIONS: D-Limonene is well tolerated in cancer patients at doses which may have clinical activity. The favorable toxicity profile supports further clinical  evaluation.  PMID: 9654110  [PubMed – indexed for MEDLINE]
  8. Drug Metab Dispos. 1996 May;24(5):565-71. Identification and characterization of limonene metabolites in patients with advanced cancer by liquid chromatography/mass spectrometry.  Poon GK(1), Vigushin D, Griggs LJ, Rowlands MG, Coombes RC, Jarman M.  Author information:  (1)Cancer Research Campaign Centre for Cancer Therapeutics, Charing Cross Hospital.  Limonene is a farnesyl transferase inhibitor that has shown antitumor properties. The drug had been given orally to cancer patients. Plasma and urine samples collected from the patients were examined by reversed-phase HPLC-atmospheric pressure chemical ionization and electrospray ionization MS. The drug underwent rapid conversion to hydroxylated and carboxylated derivatives. Characterization and structural elucidation of the metabolites were achieved by LC/MS and NMR. Five major metabolites were detected in the plasma extracts, namely limonene-1,2-diol, limonene-8,9-diol, perillic acid, an isomer of perillic acid,  and dihydroperillic acid. Urinary metabolites comprised the glucuronides of the two isomers of perillic acid, dihydroperillic acid, limonene-8,9-diol, and a monohydroxylated limonene.  PMID: 8723738  [PubMed – indexed for MEDLINE]
  9. JAMA. 1996 May 1;275(17):1349-53. Chemoprevention of breast cancer.  O’Shaughnessy JA(1).  Author information:  (1)Medicine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.  PMID: 8614122  [PubMed – indexed for MEDLINE]
  10. J Cell Biochem Suppl. 1995;22:139-44. Prevention and therapy of mammary cancer by monoterpenes.  Gould MN(1).  Author information:  (1)Department of Human Oncology, University of Wisconsin-Madison 53792, USA.  Monoterpenes, found in a wide variety of plants, are a major component of plant essential oils. The unsubstituted monocyclic monoterpene limonene has been shown  to prevent carcinogen-induced mammary cancer at both the initiation and the promotion/progression stages. This terpene also causes the complete regression of the majority of advanced rat mammary cancer when added to the diet. Modification  of limonene by hydroxylation at various positions increases both its chemopreventive and therapeutic efficacy. For example, the naturally occurring hydroxylated limonene analog perillyl alcohol is 5-10 times more potent than limonene and has a similar therapeutic index. Several cellular, metabolic and molecular activities are associated with terpene exposure. These include induction of phase I and II hepatic detoxification enzymes, selective inhibition  of protein isoprenylation, inhibition of CoQ synthesis, and induction of the mannose 6-phosphate/IGFII receptor and TGF beta. Due to the therapeutic efficacy  of monoterpenes in experimental model systems, clinical evaluation of this class  of compounds has begun in advanced cancer patients. A Phase I trial of limonene is in progress in the UK. Efforts in the US will target perillyl alcohol for Phase I testing. Pre-IND toxicology is currently being completed. Phase I trails  are anticipated to begin in the Spring of 1995. We feel that the results of these therapeutic trials, if positive, will facilitate the development of current terpenes and more potent analogs for future chemoprevention trials.  PMID: 8538191  [PubMed – indexed for MEDLINE]
  11. Clin Nutr. 2015 Jul 15. pii: S0261-5614(15)00188-0. doi: 10.1016/j.clnu.2015.06.010. [Epub ahead of print]Impact of diet and nutraceutical supplementation on inflammation in elderly people. Results from the RISTOMED study, an open-label randomized control trial. Ostan R1, Béné MC2, Spazzafumo L3, Pinto A4, Donini LM4, Pryen F5, Charrouf Z6, Valentini L7, Lochs H8, Bourdel-Marchasson I9, Blanc-Bisson C9, Buccolini F10, Brigidi P11, Franceschi C12, d’Alessio PA13.
    BACKGROUND & AIMS:
    Eating habits may influence the life span and the quality of ageing process by modulating inflammation. The RISTOMED project was developed to provide a personalized and balanced diet, enriched with or without nutraceutical compounds, to decrease and prevent inflammageing, oxidative stress and gut microbiota alteration in healthy elderly people. This paper focused on the effect on inflammation and metabolism markers after 56 days of RISTOMED diet alone or supplementation with three nutraceutical compounds.
    METHODS:
    A cohort of 125 healthy elderly subjects was recruited and randomized into 4 arms (Arm A, RISTOMED diet; Arm B, RISTOMED diet plus VSL#3 probiotic blend; Arm C, RISTOMED diet plus AISA d-Limonene; Arm D, RISTOMED diet plus Argan oil). Inflammatory and metabolism parameters as well as the ratio between Clostridium cluster IV and Bifidobacteria (CL/B) were collected before and after 56 days of dietary intervention, and their evolution compared among the arms. Moreover, participants were subdivided according to their baseline inflammatory parameters (erythrocytes sedimentation rate (ESR), C-Reactive Protein, fibrinogen, Tumor Necrosis Factor-alfa (TNF-α), and Interleukin 6) in two clusters with low or medium-high level of inflammation. The evolution of the measured parameters was then examined separately in each cluster.
    RESULTS:
    Overall, RISTOMED diet alone or with each nutraceutical supplementation significantly decreased ESR. RISTOMED diet supplemented with d-Limonene resulted in a decrease in fibrinogen, glucose, insulin levels and HOMA-IR. The most beneficial effects were observed in subjects with a medium-high inflammatory status who received RISTOMED diet with AISA d-Limonene supplementation. Moreover, RISTOMED diet associated with VSL#3 probiotic blend induced a decrease in the CL/B ratio.
    CONCLUSIONS:
    Overall, this study emphasizes the beneficial anti-inflammageing effect of RISTOMED diet supplemented with nutraceuticals to control the inflammatory status of elderly individuals.
    KEYWORDS:
    Ageing; Diet; Inflammation; Nutraceutics; Probiotics; d-Limonene

Sigue leyendo

“Inflammaging” y envejecimiento


The association between the increase in life expectancy in humans and age related changes in the immune system promotes that individuals are exposed longer to endogenous and environment antigens which allows an activation of the innate immune system and the subsequent establishment of a low grade chronic inflammation state with an increased expression of proinflammatory cytokines (tumor necrosis factor alpha, interleukin 6, etc.). This inflammatory state referred as inflammaging.
Con el aumento en la expectativa de vida del ser humano, los individuos se encuentran expuestos por más tiempo a distintos antígenos que, junto con el envejecimiento del sistema inmunológico, favorecen el establecimiento de un estado inflamatorio crónico de bajo grado con aumento en la expresión de citocinas proinflamatorias (factor de necrosis tumoral alfa, interleucina 6, étc.). Este estado denominado inflammaging se caracteriza por un envejecimiento de origen inflamatorio.

INTERVENCIONES
 El ejercicio físico es hasta el momento una de las posibles intervenciones útiles para evitar los efectos de la inflamación en el origen de enfermedades asociadas al envejecimiento. El ejercicio promueve un estado de estrés regulado. Éste incrementa los niveles séricos de IL-6 lo cual conduce a un mayor consumo de tejido adiposo al favorecer la lipólisis para producir de forma eficiente energía durante la actividad física. Además, los incrementos en la IL-6 se relacionan con una reacción compensadora caracterizada por la producción de IL-10 y otras citocinas con funciones antagónicas al receptor de la IL-1 por lo que induce un equilibrio en la balanza de la inflamación.

Las asociaciones entre el riesgo para la Enfermedad de Alzheimer (AD) y la ingesta de Acido ascórbico (AA)  se han investigado en varios grandes estudios de población, tanto en los EE.UU. y también en una muestra grande de Europa. Uno de los primeros estudios parecía muy prometedor cuando los datos se informaron de la Healthy Aging Chicago Proyecto (CHAP) que muestra que ninguno de los mayores a 65 años, sobre los 633 participantes sin demencia que tomaron ácido ascórbico, desarrollaron AD en el período de seguimiento (promedio de 4 años ). Un patrón más complejo de los efectos se informó en el Estudio de Envejecimiento Honolulú-Asia que comprendía hombres de 71 años a 93 años. En los individuos cognoscitivamente intactos, la ingesta de ácido ascórbico se asoció con una mayor probabilidad para un mejor rendimiento de función cognitiva. La alta ingesta de ácido ascórbico y vitamina E se asociaron con una menor probabilidad de demencia vascular.(Referencia: Nutrients. 2014 Apr 24;6(4):1752-81.) Sigue leyendo

Internet y efectos en el cerebro


Introducción

Se hacen críticas a que el exceso de datos de google e internet genera más información y menos conocimiento. Las calculadoras digitales han hecho que ya no se hagan operaciones mentalmente o con lápiz y papel, consecuentemente muchas personas ya tienen dificultades con las tablas de multiplicar y muchas otras personas ya no se toman el trabajo de memorizar, dejando para sus memorias lo menos posible porque tienen la certeza de recuperar la información desde la “nube“.

univ rays

Sin duda, las nuevas tecnologías están cambiando los hábitos de la vida diaria, tanto a nivel laboral como familiar, lo que se ha descrito extensamente. La costumbre que dichas tecnologías han generado a los usuarios, las profunda sensación de necesidad y la dependencia de ellas para algunas actividades. generan un interrogante ¿Es esto bueno para el aprendizaje y para nuestra forma de pensar? (2)

Aunque algunos estudios constatan que en la actualidad hablamos más deprisa (en concreto, pronunciamos 160 palabras por minuto, quince más que en el año 2.000) y ahora escuchamos menos (1). Casualmente, los neurólogos están constatando algo que ya se venía sospechando: el cerebro gasta menos energía en observar el mundo exterior –las dimensiones y señales codificadas que le revelan lo que ocurre fuera son pocas y malas– que en elucubrar, experimentar e imaginar; de tal modo que si hablamos todo el tiempo, el cerebro ya no puede hacerlo. Esto que se constata en los escenarios de la neurociencia, confirma lo que el filósofo Epicteto había dicho hace varios siglos, en cuanto que “la naturaleza la ha dado al hombre una sola lengua pero dos oídos para que podamos oír el doble de lo que se habla.”

Homo zappiens

Y no sólo eso, sino que este ritmo acelerado se está trasladando al sexo, a la alimentación (y de ahí el surgimiento como reacción, del slow-food o comer sin prisa) y prácticamente a cualquier ámbito. Y hasta donde ha llegado esto, es que incluso los dibujos animados están bajo sospecha, como demuestra un estudio de la Universidad de Virginia (EE.UU.) que parece sugerir que el ritmo frenético que imprime el personaje de Bob Esponja generan un déficit de atención (otro trastorno emergente…) en los niños, hasta el punto de dispersar su atención en la escuela (2)

Desde el punto de vista cognoscitivo hay algunos datos de interés como que sólo utilizamos aproximadamente un 25% de nuestra capacidad de escuchar,  sólo usamos aproximadamente un décimo del potencial de memoria y en el término de 8 horas nos olvidamos de la mitad de lo que hemos oído, porque esa es la función usual de los llamados circuitos reverberantes cerebrales, descritos por el neuropsicólogo canadiense Donald Olding Hebb, que al dispararse en forma repetitiva, ayudan a ocasionar los trazos de memoria. Y La memoria de corto plazo, por ejemplo es la de aprenderse números telefónicos suele durar entre 10 y 15 segundos (3,7).

donad-hebb-2

El psicólogo canadiense Donald Olding Hebb Tomado de https://grupoespiritaisladelapalma.wordpress.com/tag/redes-hebbianas/

La alteración de las facultades cognoscitivas

Es bastante conocido el material de Nicholas Carr, un investigador que suele escribir sobre nuevas tecnologías en The New York Times, The Wall Street Journal y Financial Times; él sostiene que cada nueva tecnología obliga al cerebro a ajustarse a una nueva manera de procesar y almacenar la información. En este sentido, señala Carr, internet estaría fomentando el “picoteo” rápido y distraído de pequeños fragmentos de información de muchas fuentes a una velocidad inusitada, sin dejar espacio para la reflexión y el pensamiento crítico.

Y ese proceso reflexivo es algo que hace bastante falta, a la luz de las funciones mentales superiores prefrontales. La neuropsicología describe que las llamadas funciones ejecutivas hacen referencia a las capacidades para establecer nuevos patrones de conducta y reflexionar sobre ellos. Las funciones ejecutivas se requieren, principalmente, en situaciones novedosas o no familiares, en donde la persona no sabe exactamente qué es lo que tiene que hacer o cómo hacer algo. Dichas funciones están relacionadas con la búsqueda  de la conducta más adecuada cuando las conductas previamente establecidas no resultan útiles o apropiadas. De tal manera, las funciones frontales que están comprometidas porque no se deja tiempo para el pensamiento crítico, alteran un amplio rango de capacidades adaptativas como la creatividad o el pensamiento abstracto, la introspección y aquellos procesos que permiten al individuo analizar lo que quiere, como conseguirlo y como establecer el plan de actuación más adecuado.(4)

hairdo

Adicción a internet: nueva entidad?

Y aquí va de nuevo la adicción a Internet, (sigla en inglés IAD= Internet Adiction Disorder) como se acepta en la base PubMed de datos del NIH. Lo que se ha descrito de dicha adicción, es que ocurre en el grupo etáreo entre 20 – 30 años, y con frecuencia hay un retraso de más de una década desde el inicio hasta la aparición del problema.

La adicción a Internet se ha asociado con depresión y con indicadores de aislamiento social medido dimensionalmente . Y lo interesante es que ante este escenario de internet, hay comorbilidad psiquiátrica común, como trastornos del estado de ánimo, ansiedad, trastornos del control de impulsos y uso de sustancias alucinógenas. En este escenario hay involucrados factores psicológicos, neurobiológicos y culturales. Desde el punto de vista de la solución, aunque no existen tratamientos basados ​​en la evidencia para la adicción a internet, los enfoques cognitivo-conductuales podrían ser útiles. (5)

Impacto de adicción a Internet en el funcionalismo neuronal

Y desde  el punto de vista de evidencia de la neurociencia, ya hay informes que demuestran que existe una alteración significativa en el llamado conectoma funcional de los pacientes con trastorno de adicción a internet (sigla IAD en inglés) , en particular entre regiones situadas en los lóbulos frontal, occipital y parietal. Las conexiones afectadas son las de largo alcance y las conexiones inter- hemisféricas. Además, el análisis de correlación demuestra que las anomalías regionales observadas se correlacionan con la gravedad del IAD y las evaluaciones clínicas de comportamiento. Los resultados (6), publicados en la Librería Pública de ciencia-PLOS, en Septiembre de 2014,  son relativamente consistentes entre diversos atlas anatómica y funcionalmente definidos, que sugieren que la adicción a internet-IAD provoca interrupciones funcionales de la conectividad neuronal y ocasionan que tales interrupciones se pueden asociar a alteraciones del comportamiento o del estado del ánimo, arriba descritas.

conectividad

Referencias bibliográficas.

1. http://www.estimulacion-cognitiva.com/2012/03/07/%C2%BFcomo-influyen-las-nuevas-tecnologias-en-nuestra-estimulacion-cognitiva/

2. http://www.eduardpunset.es/8570/general/hablamos-en-exceso-y-no-escuchamos-lo-suficiente

http://en.wikibooks.org/wiki/Cognitive_Psychology_and_Cognitive_Neuroscience/Memory

4. http://ocw.um.es/cc.-sociales/neuropsicologia/material-de-clase-1/tema-8.-funciones-ejecutivas.pdf

5. Shaw M, Black DW. Internet addiction: definition, assessment, epidemiology and clinical management. CNS Drugs. 2008;22(5):353-65. http://www.ncbi.nlm.nih.gov/pubmed/18399706

6. Wee CY, Zhao Z, Yap PT, Wu G, Shi F, Price T, Du Y, Xu J, Zhou Y, Shen D. Disrupted brain functional network in internet addiction disorder: a resting-state functional magnetic resonance imaging study. PLoS One. 2014 Sep 16;9(9):e107306. doi: 10.1371/journal.pone.0107306. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4165900/pdf/pone.0107306.pdf

7. Información sobre la memoria: http://www.csi-csif.es/andalucia/modules/mod_ense/revista/pdf/Numero_15/ILDEFONSO_RAMIREZ_2.pdf

Video 

Hígado graso y síndrome metabólico


A propósito del llamado hígado graso no alcohólico: cada vez con mayor frecuencia se lo está considerando heraldo de malas noticias para el aparato cardiovascular, relacionado con el síndrome metabólico con el que suele ir de la mano.

En qué consiste el hígado graso

En qué consiste el hígado graso

El síndrome metabólico con su pluripatología se comporta -si se me permite la licencia mitológica-, como la Hidra de Lerna: muchas cabezas de una misma enfermedad.

Esta relación se está empezando a describir con cada vez mayor frecuencia, y hay que tenerla en cuenta en la medida que una de las formas de manejo es relativamente fácil: con probióticos, confirmado por meta-análisis (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3812493/pdf/WJG-19-6911.pdf )

Esta es la conclusión del artículo de Nan Hee Kim, Juri Park,  Seong Hwan Kim y colaboradores:

NAFLD was associated with early alterations of cardiovascular system, independent of established cardiovascular risk factors and MetS.
Acrónimo NAFLD: Non-alcoholic fatty liver disease. Enfermedad grasa hepática no alcohólica.

Referencia: http://heart.bmj.com/content/100/12/938.full.pdf+html

Otros recursos en la red:

Búsqueda en MedLine PubMed con términos de búsqueda: NAFLD and treatment and probiotics

http://www.ncbi.nlm.nih.gov/pubmed/?term=NAFLD+and+treatment+and+probiotics

Más sobre el hígado graso

http://www.gastroenterologosecuador.com/patologias/higado.htm

More information about HONcode


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http://nuevoenmedicina.blogspot.com/2014/01/

Este material sirve para ayudar a explicar determinadas condiciones al paciente, siempre y cuando se haga con la adecuada orientación por parte del médico tratante.

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