Levels of tryptophan and conduct

Levels of serotonin at central level are involved in several problematic impulsive behaviors. Modulation of brain concentrations of 5-HT is a suitable target to regulate behaviors and related pathological disorders. A balanced diet provides the precursors of the 5-HT needed for normal body functioning.

In preclinical studies change in 5-HT levels affect impulsivity initiation of response and sensitivity but not inhibited response to impulsivity. As a result is suggested the involvement of other biological processes in this component of the impulsivity.

5-HT levels can be altered in various ways, some of these are: pharmacological treatment, appropriate management of circadian rhythm, the formation of healthy lifestyle habits, moderate daytime exposure to light sources (especially blue light), consumption of foods rich in tryptophan, etc.

There is substantial evidence of preclinical and clinical studies where they emphasize the role of serotonin (5-HT) in the expression of impulsive behaviors.

Despite the strong evidence of the correlation of indicators for the synthesis of serotonin with impulsive behaviors, data from associative studies are considered a unusefulness for making causal inferences.

Unlike associative clinical experiments, the preclinical have the feature of review causal relationships of the 5-HT in the impulsiveness through the modulation of 5-HT system.

Researchers found reduced levels of 5-HT in association with a wide variety of alteration as impulsive behavior, alcohol and psychotropic substances abuse, suicidal thoughts, aggressive, violent behaviors and borderline personality disorder.

It is impossible to adopt preclinical methods in humans due to many constraints, for example the lack of verification of its effectiveness (dietary restriction), prominent unacceptable side effects (using paraclorofenilalanina) either on ethical grounds (manipulation of genes).

Modulation of 5-HT levels through modification of its precursor intake of amino acid tryptophan (Trp) is considered a suitable method.

Consumption of a Trp-free formulation includes the proper dose of amino acids with two principal related consequences: i) protein synthesis and incorporation of Trp increased with a substantially decrease on plasmatic levels of Trp, and ii) reduction in effective competition of Trp with other neutral amino acids (eg isoleucine, leucine, phenylalanine, tyrosine and valine) for transport to the CNS.

In opposition, a balanced formulation produces normal concentrations of circulating Trp and maintains physiological levels in the synthesis of 5-HT.

These food formulations are a safe and effective method to study the causal relationship between a decrease in the 5-HT and the conduct of impulsivity in humans.

Impulsivity is a complex multidimensional construct historically difficult to measure. It is characterized by the predisposition towards the rapid reaction without planning, in response to external stimuli without considering the negative consequences of these reactions to individual drive or towards others.

This construct includes at least three measurable components: 1) the presence of rapid responses prior to complete processing and evaluation of the stimulus (response initiation); (2) shortcomings in the inhibition of a response previously initiated (diminished response inhibition); (and 3) persistent elections aimed at retribution by insignificant rewards provided in shorter periods, despite the availability of better late fees (sensitivity to the result).

                                      Fig 1 Components of impulsivity.

There is evidence suitable for the assessment of these different aspects of impulsivity.

In the clinical study of Dougherty D. M. et al. 2010 the main objective is to determine the extent in which a acute decrease of Trp produces changes in impulsivity and if the decline of the amino acid has differential effects on the individual components of impulsivity.

The revised study found differences in impulsivity components in healthy participants attributed to the effect of an acute decrease of Trp and changes in brain 5-HT levels.

The experimental results suggest an important role to 5-HT in response to the mechanism underlying in the initiation of impulsivity and sensibility to reward. However, a minor contribution in mechanisms to manage the answer to inhibition.    

This latter may involve deficit at levels of adrenaline and dopamine, consistent with experimental data from other studies.

In conclusion, the trial demonstrates the selective production of differences in the impulse response of healthy subjects due to the sharp decrease of Trp. Associated with the ingestion of a diet free of the precursor of 5-HT and evaluated through the use of reliable laboratory tests of the components of impulsivity.

The practical aspect involves the prevention of behavioral problems, the consumption of a normal, varied and balanced diet rich in dairy food, tuna, turkey, chicken meat, cereals, fruits, vegetables, and healthy living habits.

Journal reference

Dougherty D. M., Richard D. M., James L. M. and Mathias C. W. (2010). Effects of Acute Tryptophan Depletion on Three Different Types of Behavioral Impulsivity.  International Journal of Tryptophan Research . 3, 99-111.

http://www.la-press.com.

Melotonin and memory

Some important characteristics of melatonin, changes in memory, inhibition of protein 2A phosphatases and its effect on tau, neurofilamentos and oxidative stress are reviewed in this document.

Melatonin (Mel) is a derivative of tryptophan, synthesized mainly in the pineal gland from the serotonin in the absence of light stimuli. It has maximum serum concentrations in the early morning, about four. They have designated it an important role in the regulation of various biological functions, circadian rhythms, sleep, mood, tumor growth and aging.  Is a powerful scavenger of free radicals and also has been shown the modulator effect direct activity of kinases and protein phosphatases.

                                                    Fig 1 Dark memory.

Inhibition of proteins phosphatases in PP-2A and PP-1 by calyculin A (Cl-A) produces in cellular tissues and in vivo synaptic loss and deterioration of retention in the spatial memory through tau hyperphosphorylation and neurofilaments (NFs). The synaptophysin is a synaptic vesicular protein with important properties in the regulation of the activity-dependent synaptic formation, their levels are lowered by the action of Cl-A.

The cytoeskeletal protein tau and the neurofilaments hyperphosphorylation, synaptic loss, and memory deficits are characteristic of Alzheimer's disease (Alz). hyperphosphorylation reduces the balance of the micrutubules and influences cell organization and stability. Currently there is no effective cure against its pathology and memory impairment.

Previous studies demonstrated efficient mitigation of damage similar to Alz induced by the Cl-A through the Mel, not only because of its antioxidant effect but also for the regulation of the system of phosphorylation. As a result, it is appropriate establish the scenario where the Mel has neuroprotective effects in vivo against pathological effects similar to the Alz and spatial memory impairment by Cl-A.  Therefore, protein phosphatases are considered a good therapeutic site for the treatment of the Alz.

Qing Tian et al. (2011) evaluated the effects of repeated pretreatment in vivo on laboratory animals via i.p., with Mel at low doses of 1 mg/kg and high of 10 mg/kg. They noted Mel protection in memory against the action of inhibitor Cl-A, the loss of synaptophysin in hippocampus and memory deficits retention prevention, as well as the improvement of the hyperphosphorylation of tau and neurofilaments. No significant difference in the two levels of dose exists. In addition, during the single administration to the established dose were absent evident consequences.

Mel partially reversed the effects of the Cl-A in phosphorylation of the catalytic unit of PP-2A in tyrosine 307, a crucial amino acid in negative regulation of activity of PP-2A, and decreased levels of malondialdehyde, an indicator of oxidative stress.

From preclinical studies and cellular systems, it is suggested the effectiveness of Mel as a therapeutic agent in the Alz and his unusual conduct via modulation of the activity of PP-2A and oxidative stress. In addition to reverse hyperphosphorylation of tau and NFs, loss of synapses and memory by Cl-A impairment.

Journal reference:

Qing Tian. (2011). Melatonin ameliorates Alzheimer-like pathological changes and spatial memory retention impairment induced by calyculin A. J Psychopharmacol August  vol. 25 no. 8 1118-1125.

http://jop.sagepub.com/content/early/2010/06/10/0269881110367723

CyberBullying

This document is reviewed a concept of CyberBullying (CBy), common forms of presentation among children and adolescents, as well as their characteristics and possibilities of prevention.

Aggression between people is a common event emerged with the beginning of humanity. Currently continuous and intensive development of information and communication technologies, followed by the rapid proliferation of personal computers and mobile phones, has improved almost all spheres of life, but has also created various possibilities of abuse. Therefore, the technology has been added to possible strategies deal with or harming someone.

Children and young people are definitely the most frequent internet users and are more open to accepting the opportunities offered by this technology. Therefore, they are more intense users of computers and cell phones, often without control of the content or the necessary surveillance of parents and teachers due to generational differences.

CBy is defined as any activity harmful intentional communication through the use of different technologies, such as internet or mobile phones. It involves the use of information or communication devices in support of repeated and deliberate hostile behavior by a group or individual with the intention of harming another.

It is possible to define several types of CBy: a) flaming, b) harassment, c) denigration, d) impersonate, e) outing, f) trickery, g) exclusion and h) cyber-stalking.

a) Flaming includes altered and brief exchanges between two or more individuals via any form of communication technology. It is referred to the angry confrontation messages often using vulgar and explicit language.

b) Repeated sending of cruel, offensive, rude or insulting messages is known as harassment.

c) Denigration is the process of making belittling remarks about a person and disseminating them electronically.  Includes sending or integrate cruel rumors about someone in the network to damage its reputation or his teammates.

d) Impersonation is the entry in someone personal account in order to send messages to represent as bad person, involve him in an issue or risk and damage his reputation or his friends. Requires advanced technology skills.

e) Outing is the public display, posting, issuing personal communications or images with sensitive issues, especially information or sexual content.

f) Trickery consists in inducing the disclosure of secret or painful information through gruesome ways, which is shared online.

g) Exclusion or ostracism consists of deliberate refusal of acceptance of friendship or participation in a social networking site.

h) Cyber-stalking is referred to the use of electronic means to "stalk" another person through repeated harassment and bullying nature communications.

Fig 1 Forms of cyberbullying

The cyber attack is a major problem of rapid growth at global level, however, the attention of this problem is insufficient.  The relevant legislation is outdated in many countries, without consider many of these forms of aggression.

Most children and teenagers use the internet on a daily basis and have a cell phone. They integrate the information technologies in everyday life.  In addition, the need for parents and teachers develop the skills required in the use of computers and electronic information systems.

Genre is a very important factor in the CBy.  The percentage of aggressors and victims is greater in male individuals.  These differences could not be explained by the level of use of telephones or the internet.

It is necessary create an inclusive and proactive system in response to CBy, which combine technological/software, legal, psychological, educational and social intervention measures. In addition to the involvement of children, adolescents, parents, teachers and members of the community, with the aim of tackling the problem of CBy and promote healthy communication styles in the virtual world.

Fig 2 Cyberbullying

Educate and instruct the children and adolescents on how to act or prevent a situation of CBy is of considerable importance.

In conclusion, the best way to handle the CBy is through the implementation of prevention and intervention programs aimed at all subjects with possible involvement in the problem.

 Journal reference

Branislava Popović-Ćitić, Sladjana Djurić, Vladimir Cvetković. (2011). The prevalence of cyberbullying among adolescents: A case study of middle schools in Serbia. School Psychology International August 2011 vol. 32 no. 4 412-424.

http://spi.sagepub.com/content/32/4/412

El desayuno y refrigerio en la función cognitiva y estrés

En este documento es revisada la asociación benéfica del consumo de alimentos durante el desayuno (DYU) en el desempeño cognitivo, estrés y la influencia del  refrigerio.

La frecuencia en el consumo de DYU está correlacionada con beneficios directos al estado de salud.  Es conveniente considerar como muestra el consumo de cereales, productos lácteos, frutas, pan y de preferencia los productos integrales con fibra natural o adicionada.  Algunas ventajas son el pertinente manejo del peso corporal, menor concentración de colesterol sanguíneo, riesgo reducido de padecer síndrome metabólico, mejor funcionamiento del sistema gastrointestinal, disminución de afecciones al tracto respiratorio superior y óptima función mental.

                                       Fig 1 Ventajas del desayuno 

El DYU regular está relacionado con la ingesta apropiada de vitaminas clave y micronutrientes. Al mantener el ayuno existe la probabilidad de perder la oportunidad de consumirlos en otros alimentos. En especial los DYUs a base de cereales preparados para empleo inmediato están adicionados con vitaminas y bajos niveles de grasa.  Contribuyen al consumo de cereales integrales (30%), lo cual disminuye el riesgo de diabetes y enfermedad cardíaca coronaria.   La leche es el alimento típico durante el DYU y contribuye de forma importante a cubrir las recomendaciones dietéticas de lácteos. El beber líquidos ricos en proteínas aumenta la velocidad en la cual son realizadas tareas relacionadas con memoria espacial y recuerdo de listado de palabras. De forma similar, en la contribución a los estándares diarios ocurre con el consumo de fruta pues incrementa temprano el total diario.

                                               Fig 2 Las frutas en el desayuno

Además, fue observada mayor eficiencia de memoria al consumir alimentos con velocidad de liberación lenta de glucosa al torrente sanguíneo. La comprobación del beneficio por un menor índice glicémico en los alimentos del DYU fue realizada en estudios clínicos y preclínicos.

El DYU tiene efectos benéficos en la cognición, con un soporte más importante en el mejoramiento de la memoria. En niños mejoró los resultados en pruebas de creatividad, resistencia física y habilidad matemática después de consumir un DYU con alto contenido energético, en comparación con uno de bajo.

La revisión de los hábitos en adultos, muestran al DYU regular como contribuyente de una mejor calidad de dieta, con más fibra, micronutrientes y menor cantidad de calorías.  En niños ha sido observada una mayor ingesta diaria de fibra, calcio, vitamina A, vitamina C, riboflavina, zinc y hierro.  En contraste con quienes no desayunan. 

Las personas en condiciones de ayuno presentan respuestas con tendencia a menores tiempos de reacción en evaluaciones de eficiencia fisiológica y mental. Aunque en algunos estudios, con diseños experimentales limitados, no fue posible observar resultados positivos.

                                        Fig 3 Problemas del ayuno

Los resultados de Smith AP, et al. 2011 confirman asociación de la frecuencia de consumo de desayuno (variado, aunque el 62% es cereal) con menor estrés, fallas cognitivas, daño y accidentes de trabajo. De forma contrastante,  el consumir durante el refrigerio papas fritas, chocolates o biscuits está asociado con mayor estrés, fallas cognitivas y accidentes fuera del trabajo.

Los efectos del refrigerio en el bienestar evidencian un mejor desempeño cognitivo en las personas acostumbradas a comer poco en varias ocasiones, en contraste a un menor número de comidas con mayor volumen.  Los refrigerios poco sanos están asociados con registros menores de bienestar. 

 En conclusión, es necesario desarrollar hábitos alimenticios adecuados para mejorar la calidad de vida a largo plazo, limitar fallas cognitivas, disminuir riesgo de accidentes y estrés. Además, la realización de estudios posteriores para establecer la posible causalidad y mecanismo de la asociación observada.

Bibliografía

Katherine Chaplin and Andrew P. Smith. (2011). Breakfast and Snacks: Associations with Cognitive Failures, Minor Injuries, Accidents and Stress.   Nutrients  3, 515-528; doi:10.3390/nu3050515

  

New adult neurons and cocaine

This document is discussed the concept of production of new neurons in adults and the effect of cocaine in memory and neurogenesis.

            A novel and attractive field of  research now focuses on the generation of new grown-up neurons. The mature mammalian brain has two major regions capable of continually producing new cells: the dentate gyrus (DG) of the hippocampus and the subventricular zone (SVZ) of the lateral ventricles.   Neural stem cells have been recognized as astrocytes in both regions. In the DG, newly formed cells differentiate into granule neurons, which are integrated into the granular layer. In the SVZ, neuroblasts move around a long distance via the rostral migratory stream (RMS) to the olfactory bulb (OB), where they differentiate into granular and periglomerular interneurons. In both cases, newly differentiate neurons are included in specific functional systems. 

The complete relevance of functional significance of grown-up neurogenesis is yet uncertain.  The careful ablation of the proliferative populations in neurogenic regions by irradiation or genetic management is established to produce severe cognitive deficits.

It is hypothesized that neurogenesis in the OB are concerned in the functions, the consolidation of olfactory memory and the distinction of odors.

However, the majority of research work has focused on adult neurogenesis in the DG. The function of DG is incorporated in the neocortical-hippocampus memory system, which is implicated in the establishment of temporal lobe dependent memories, such as episodic memories.  Some authors have proposed that DG function is related to the formation of working memory, complex spatial learning and associative context memories, and that new cells may play an important role in these processes.  The results suggest that the key to a deeper knowledge of mature neurogenesis function is better understanding of DG and OB functions. 

                                                            Fig 1 New adult neurons

Drugs of abuse, such as nicotine, ethanol and cocaine have also recently been considered as negative factors that influence grown-up neurogenesis, mainly in the hippocampus. Chronic or acute use of these drugs can provoke alterations in the proliferation rate, survival and differentiation of new cells in neurogenic regions. In addition, some hippocampus-dependent memories are affected by psychomotor drugs in humans and preclinical studies, and these memories are influenced by adult hippocampus neurogenesis.

Cocaine is one of the most widely consumed illegal drugs in developing countries and is associated with several health problems. This drug acts as an indirect agonist of several neurotransmitters, including dopamine (DA), norepinephrine (NE), and serotonin (5-HT). Chronic cocaine treatments produce toxicity and an increase in oxidative stress and pro-inflammatory mediators. 

Fig 2 Leaf of coca (Erytroxilon coca)

In the DG, some cognitive functions such as working and recognition memory are affected by cocaine treatments. The drug alters neurotransmission at structural and functional levels.

On the other hand, in the adult brain, the implication of new hippocampal neurons in some memory processes is firmly documented. The effects of drugs on the hippocampal neurogenesis seem to induce alterations on memory performance.

One report shows that adult neurogenesis is associated with drug-taking or drug-seeking behaviors. Also, that adult neurogenesis plays a function in addiction and relapse. The authors proposed that the suppression of new neurons may induce a hippocampal dishinbition, conduct to an enlarged activation of the neural circuit accountable for cocaine-taking.

However, repeated cocaine administration reduces the threshold of long term potentiation (LTP), required for the long term memory, and may induce stronger context-emotional memories.

Other types of memory without a high emotional association are not easy to link with adult neurogenesis. It has been described that working memory is damaged by high doses of cocaine.  The involvement of new cells to the generation of hippocampus LTP and the improvement in encoding of new information are possible mechanisms that assist working memory.

 As occurs with most recreational drugs, cocaine impairs the normal incorporation of new cells into the DG and OB. If we suppose that these systems are essential for the distinction of analogous events, a less efficient system would make it more complicated to forget memories associated with drugs and/or may be the cause of impairments of working memory.

Some results indicate that adult neurogenesis is essential in certain situations with increased memory demands or high emotional interference, such as context conditioning memories and consolidation of drug-seeking behaviors.

The modulation of adult neurogenesis by pharmacologic treatments or natural processes may contribute to an increase in the activity of the DG and positively influence anxiety behaviors.

The participation of the cocaine as a recreational product, in the deterioration of the work and long term memory is very likely. In addition, it is necessary to determine its precise effect on the production of new adult neurons.

Journal Reference

Vivian Capilla-Gonzalez and Vicente Hernandez-Rabaza (2011)

Review: Cocaine and MDMA Induce Cellular and Molecular Changes in Adult Neurogenic Systems: Functional Implications

Pharmaceuticals  4(6), 915-932; doi:10.3390/ph4060915

La transición nutricional (desbalance nutricional)

En este documento es revisado el impacto del estilo moderno de vida y algunos aspectos importantes relacionados. Se enfatiza en la diversificación de fuentes alimentarias, la elaboración y adopción de políticas adecuadas para combatir la epidemia de obesidad y mejorar la salud de las personas.

            La transición nutricional (TN) es definida como el cambio en los patrones dietéticos e ingesta de nutrientes cuando una población adopta estilos de vida modernos durante el desarrollo social y económico, urbanización y adopción de características culturales diferentes. Está asociada con el incremento documentado de enfermedades no transmisibles (NCDs). El efecto de la TN en los perfiles de enfermedad es exacerbado por el estilo de vida sedentario y estresante, consumo incrementado de alcohol y cigarrillos en las poblaciones urbanas.

            Han sido confirmados muchos cambios adversos en los patrones dietéticos cuando son comparadas las dietas en la nutrición de transición. Estos incluyen disminución en el consumo de alimentos básicos ricos en almidón y fibra dietética, incremento en el consumo de productos de origen animal ricos en grasas totales y ácidos grasos saturados, disminución en fuentes de proteínas vegetales tales como las legumbres, incremento en bocadillos energéticamente-densos, bebidas carbonatadas edulcoradas, disponibilidad comercial de bebidas alcohólicas, así como la adición de azúcar, grasas y aceites en los alimentos.

El cambio en los patrones dietéticos hacia alimentos con sabor más intenso en los bocadillos, alimentos rápidos y de conveniencia, pero también con más carne, traducido a un patrón de ingesta donde el esquema de macro-nutrientes (energía, grasa, carbohidratos totales, fibra dietética y proteína de origen animal) puede ser asociada con un riesgo incrementado de sobrepeso, obesidad y otras NCDs. Al mismo tiempo, el mejoramiento en la ingesta de micronutrientes no alcanza los valores mínimos recomendados. Es concebible que en muchos sujetos con sobrepeso u obesos, la ingesta sub-óptima de micro-nutrientes conduzca a una “doble carga” la coexistencia de sub- y sobre-nutrición en la misma persona. Un desbalance en los macro- y micro-nutrientes.

                                                       Figura 1 Transición nutricional

            Ante tal situación es necesario afrontar el problema mediante las políticas e intervenciones  adecuadas. Elaborar un plan para intervenciones nutricionales holísticas e integradas, alineadas con campañas de salud en el país. Todas las intervenciones deben basarse en las evidencias, dirigidas a los problemas de salud pública en el país. El problema de sub y sobre-nutrición debe ser abordado con dietas óptimas, balanceadas, adecuadas pero prudentes para la toda la población. Es importante involucrar a las comunidades en la planeación de la intervención nutricional. Estar incluidos todos desde el estado de planeación para asegurar su participación en la implementación de las políticas y/o intervención(es). Orientarse a la diversificación de dietas más en lugar de apoyarse en alimentos fortificados y suplementos dietéticos. Únicamente implemente las intervenciones a mayor escala a través de estudios de campo en los grupos de población apropiados. Utilice todos los recursos disponibles para implementar intervenciones con el objetivo de lograr hábitos de alimentación sanos.

            En conclusión, la TN puede ser orientada en una dirección más positiva si son utilizados los principios básicos sugeridos en la planeación de intervenciones holísticas y políticas integradas con el objetivo de lograr la nutrición óptima para la población total. Además, es fundamental desarrollar la suficiente capacidad humana para implementar las políticas en los programas de intervención apropiados.

Referencia bibliográfica

Hester H. Vorster, Annamarie Kruger, and Barrie M. Margetts (2011), The Nutrition Transition in Africa: Can It Be Steered into a More Positive Direction? Nutrients 3, 429-441; doi:10.3390/nu3040429

http://www.mdpi.com/2072-6643/3/4/429/

Resistance to Choroquine

The parasitic resistance to medications is a great interest topic due to the high morbidity and mortality associated. In this document a concept of parasitical resistance to Choroquine (CHL) is revised and some ideas of its mechanism, a possible focus is also presented to the solution of the problem by searching new anti-malarial agents through etnopharmacological methods.

Parasitic resistance is the capacity of survive to greater chemotherapeutic dose than normal. Emergence of strains of P. falciparum that are resistant to CHL has been observed since shortly after its introduction to therapeutics as antimalarial agent. During the past thirty years resistance to CHL has become widespread in all endemic areas where it is prevalent. Resistance appears to emanate from spontaneous chromosomal point mutations. Resistant mutants are able to survive in the presence of antimalarial agents. It is well recognized that erythrocytes harboring resistant strains of malaria are able to concentrate less CHL than sensitive strains. Indirect experimental evidence to resistance came from the finding that the CHL resistant phenotype is characterized by an increase in drug efflux rate compared to sensitive parasites. Resistant parasites pump CHL out 40-50 times faster than sensitive parasites.  When the cells become resistant to a wide variety of antimalarials and present cross-resistance, it is called multidrug resistance (MDR).Then the resistance or lower concentration to the drug may me caused partly by a decrease in the influx of the drug or an increase in the efflux. In resistant P. falciparum verapamil and other calcium channel blockers slows the efflux of CHL, but they do not have that effect in sensitive strains.

         Contrary to these findings there is reported that resistance to CHL could be multigenic and that there is a determinant of resistance that does not involve multidrug resistance.

Fig 1 Giemsa-stained thick blood films showing early trophozoites of P. falciparum (Courtesy JK Baird)

In malarial endemic places CHL and related quinoline derivatives are essentially useless. In addition, CHL resistant strains of P. vivax are now being reported in both Southeast Asia and South America. Where malaria has become resistant to CHL and other chemotherapeutic agent alternative drugs such as mephloquine, halofantrine, artemisin derivatives, and the combination of pyrimethamine and sulfadoxine (Fansidar) are used.  There is genetic diversity among wild strains of P. falciparum that infect humans in a given area. Thus there are differences in their sensitivity to CHL and other antimalarial agents.

There were an estimated 247 million malaria cases among 3.3 billion people at risk in 2006, causing nearly one million deaths, mostly children under five years of age. One hundred six countries were endemic for malaria in 2009, 45 within the WHO African region.

This worsening situation can be explained by resistance of P. falciparum to the current antimalarial drugs, lack of new therapeutic targets, unaffordability and poor quality of antimalarial drugs and their bad storage under tropical conditions. 

Then an urgent need for the development of new anti-malarial agents faces the scientific community. Traditional medical knowledge based on the use of natural products from plants is a promising basis for discovering new drugs. It is estimated that 80% of many developing countries population still use plant-based traditional medicines. These natural products and their derivatives represent almost half of the drugs approved since 1994 and more than 30% of the current anti-malarial market.

In this context, an ethnopharmacological survey of medical plants was carried out in Senegal and data were collected on some plants traditionally used for the treatment of malaria and fevers.

The plant extract and fractions revealed anti-plasmodial activity (IC50<5 microgr/mL) with no toxicity. Anti-plasmodial activity and toxicity of I. senegalensis are reported for the first time and showed promising results in malaria field research.

Journal Reference

Serigne O Sarr , Sylvie Perrotey , Ibrahima Fall , Said Ennahar , Minjie Zhao , Yerim M Diop , Ermanno Candolfi  and Eric Marchioni, 2011, Icacina senegalensis (Icacinaceae), traditionally used for the treatment of malaria, inhibits in vitro Plasmodium falciparum growth without host cell toxicity, Malaria Journal 2011, 10:85doi:10.1186/1475-2875-10-85

http://www.malariajournal.com/content/10/1/85

Risk of cancer and Table sugar

In this review is summarized some findings related to the consumption of sugars and cancer risk, and considers whether current intakes of sugar could be harmful to health. The table sugar and sweeteners are historically associate products with the beginnings of the human cultures.  The use of honey is documented in a recipe against cough that appears in a cuneiform script and goes back to V B.C. The composition of honey is fructose 41% and glucose 36% and was often used as sweetening.  The use of table sugar seems to have its origin in the India since ancient times.  Besides having psychological implications in behavior of who consume it, only at the present time has been related with health concerns.

         Many countries set quantitative targets for added sugars, justifying this by expressing alarm about the likely impact of sugar on weight control, dental health, diet quality, metabolic syndrome or cancer. Diet adequacy appeared to be achieved across sugar intakes of 6-20% energy. Studies on metabolic syndrome reported no adverse effects of sugar in the long-term, even at intakes of 40-50% energy.

                                                              Fig 1 Cuneiform recipe

Sugar-sweetened carbonated beverages, called soft drinks, and juices, which have a high glycemic load relative to other foods and beverages, have been hypothesized as pancreatic risk factors (PCR).  Mueller and others investigated whether higher consumption of soft drinks and juice increases the PCR in Chinese men and women. Regular consumption of soft drinks may play an independent role in the development of pancreatic cancer (1). Results in another study among men, greater intakes of total and specific sweets were associated with PCR. Sweets were not consistently related with increased PCR. In contrast low-calorie soft drinks were associated with increased risk among men only (4).

Prostate cancer PC is the most common male malignancy in the Western world. PC risk is related to age, race, and family history. Environmental factors, including dietary factors, have also related to PC, but this issue remains undefined. 

Some epidemiologic studies have reported a positive association between breast cancer risk (BCR) and high intake of sweets, which may be due to an insulin-related mechanism.

Also high-sucrose consumption is related with increased risk of human colon cancer (HCCR).

No association was found with intake of total proteins, total fat, monounsaturated fats, polyunsaturated fats, monosaccharides, and total carbohydrates. The findings provide evidence that a diet low in trans fat could reduce PC risk. Intake of sucrose and disaccharides was also related to risk of PC, mainly from cereals, cookies, chocolate, and milk (2). The evidence for colorectal cancer suggested an association with sugar, but this appeared have been confounded by energy intake and glycemic load (3).

                             Fig 2 Types of cancer risk for consumption of sugar

The existence of an association between consumption of a food grouping that included dessert foods, sweet beverages, and added sugar with BCR was confirmed. The association with desserts was stronger among pre-menopausal women than post-menopausal, although the interaction with menopause was not statistically significant. This study indicates that frequent consumption of sweets, particularly desserts, may be associated with an increased BCR.

Another Wang preclinical research indicated that high-sucrose diet (vs. cornstarch) promote intestinal epithelial cell proliferation and tumorigenesis as well as increase serum glucose and hepatic IGF-I mRNA levels in APC(Min) (5).

The results provide limited reinforce for the hypothesis that sweets or sugars increase cancer risk (PCR, PC, BCR, HCCR) because some are positives and others do not support that added sugar or sugar sweetened foods and beverages are associated with overall cancer risk (6). Further research is needed on the possible associations of carbohydrates with cancer risk (7).

Reference

1.  Mueller NT, Odegaard A, Anderson K, Yuan JM, Gross M, Koh WP, Pereira MA. (2010) Soft drink and juice consumption and risk of pancreatic cancer: the Singapore Chinese Health Study. Cancer Epidemiol Biomarkers Prev.  Feb;19(2):447-55.

2.   Hu J, La Vecchia C, Gibbons L, Negri E, Mery L. (2010) Nutrients and risk of prostate cancer. Nutr Cancer. 62(6):710-8.

3.    Ruxton CH, Gardner EJ, McNulty HM. (2010) Is sugar consumption detrimental to health? A review of the evidence 1995-2006. Crit Rev Food Sci Nutr. Jan;50(1):1-19.

4.         Chan JM, Wang F, Holly EA. 2009) Sweets, sweetened beverages, and risk of pancreatic cancer in a large population-based case-control study. Cancer Causes Control. Aug;20(6):835-46. Epub 2009 Mar 11.

 5.   Wang B, Bobe G, LaPres JJ, Bourquin LD.(2009) Dietary carbohydrate source alters gene expression profile of intestinal epithelium in mice. Nutr Cancer. 2009;61(1):146-55.

6.    Bao Y, Stolzenberg-Solomon R, Jiao L, Silverman DT, Subar AF, Park Y, Leitzmann MF, Hollenbeck A, Schatzkin A, Michaud DS.(2008) Added sugar and sugar-sweetened foods and beverages and the risk of pancreatic cancer in the National Institutes of Health-AARP Diet and Health Study. Am J Clin Nutr. 2008 Aug;88(2):431-40.

7. Key TJ, Spencer EA. (2007) Carbohydrates and cancer: an overview of the epidemiological evidence. Eur J Clin Nutr. 2007 Dec;61 Suppl 1:S112-21.