Fuente: Medscape, Becky McCall, 17-05-2020
En la última semana se han publicado varios informes especulando si la vitamina D reduce la gravedad de la infección por COVID-19.
Fuente: Medscape, Becky McCall, 17-05-2020
En la última semana se han publicado varios informes especulando si la vitamina D reduce la gravedad de la infección por COVID-19.
October 23, 2015Australia is the skin cancer capital of the world, and clinicians worldwide often look to the sunny continent for guidance on prevention and treatment in their locales.
However, the conclusion of an Australian chemoprevention study of nonmelanoma skin cancer — that nicotinamide is associated with a lower rate of new nonmelanoma skin cancers — has been met with caution by some experts.
Findings from the ONTRAC (Oral Nicotinamide to Reduce Actinic Cancer) trial were published in the October 22 issue of the New England Journal of Medicine.
In the phase 3 trial, nicotinamide — an over-the-counter form of vitamin B₃ — taken twice daily at a dose of 500 mg for 12 months, was compared with placebo.
All 386 study patients had had at least two nonmelanoma skin cancers in the previous 5 years, so were at high risk for more basal cell and squamous cell carcinomas. All were Australian residents.
At 12 months, the rate of new nonmelanoma skin cancers was 23% lower in the nicotinamide group than in the placebo group (P = .02).
The median number of new skin cancers developed during the year-long study was lower in the nicotinamide group than in the placebo group (2.4 vs 1.8).
Go ahead and use nicotinamide in high-risk patients, the ONTRAC team concludes.
Nicotinamide «presents a new opportunity for the chemoprevention of nonmelanoma skin cancers that is readily translatable into clinical practice,» write the investigators, led by Andrew Chen, MBBS, from the Royal Prince Alfred Hospital at the University of Sydney in Australia.
A similar statement was made when the data were first presented in May at the American Society of Clinical Oncology (ASCO) Annual Meeting.
«It is safe and…inexpensive, and this one is ready to go into the clinic,» senior investigator Diona Damian, MBBS, PhD, from the Dermatology University of Sydney, said at that time.
Some outsiders have hesitations.
«The level of evidence is not high enough,» said Aleksandar Sekulic, MD, PhD, from the Mayo Clinic Arizona in Scottsdale. «This is just the first study, and it was a small number of patients for a prevention study.»
For those reasons, the data are «not sufficient» for broader populations, such as, for example, Germans or Arizonians, whose genetic make-up might be very different than Australians, Dr Sekulic told Medscape Medical News this week.
It is sufficient for Australians.
At the ASCO meeting, a European echoed some of these comments. There was a relatively small number of study patients, and the Australian high-risk population might not be representative of skin cancer populations elsewhere, particularly in less sunny climates, said John Lear, MD, from Manchester University in the United Kingdom.
Nonetheless, Dr Lear said that this is «very exciting and promising research to prevent skin cancer using a simple therapy which could easily be translated into clinical practice quickly, with a large clinically meaningful reduction in skin cancers and actinic keratoses.»
At the time, he told Medscape Medical News that it was «surprising» to see a treatment effect in «such a short period,» given that skin cancers «develop many years after the ultraviolet exposure that caused them.»
Dr Sekulic agrees. «It’s a somewhat short time to see this preventive effect.»
Nicotinamide is not in use routinely at the Mayo Clinic, he said, unless it is being ingested as part of a patient’s multivitamin. Nonetheless, he believes «many people» in the United States will read about the study and start using the supplement.
Another American was a bit more enthusiastic.
«I have not used nicotinamide in our practice, but would consider discussing it for high-risk patients with our dermatologists in our multidisciplinary cutaneous tumor board,» said Jeffrey Farma, MD, from the Fox Chase Cancer Center in Philadelphia.
Still, Dr Farma said he wonders about «ongoing unanswered questions,» like length of use (beyond the 12 months assessed in the study) and possible changes over time in adverse events, which were comparable to placebo in the study.
When the Drug Stopped, the Effect Stopped
The study population reflects a typical skin cancer clinic population, the investigators note. The average age was 66 years, two-thirds of the patients were men, and many patients had ongoing concomitant disease, such as heart disease, arthritis, hypertension, and chronic lung disease.
The reduction in nonmelanoma skin cancer in the study patients was not limited to one cancer subtype. New diagnoses of basal cell carcinoma were reduced by 20% (P = .12), squamous cell carcinoma by 30% (P = .05), and actinic keratoses (a precursor to squamous cell disease) by 13% (P = .001).
Notably, the benefit stopped when the daily supplement stopped.
That is, the effect of nicotinamide on nonmelanoma skin cancers was not maintained after it was discontinued. A 6-month follow-up, the relative difference between the nicotinamide and placebo groups was –17% (P = .33). The benefits were not modified by age, baseline actinic keratosis count, sex, smoking status, nonsteroidal anti-inflammatory drug use, or statin use.
Patients in both groups used sun screen regularly during the study period, at about the same rate. Only half the patients had used sunscreen in the week before baseline — a fact that reinforces the results. «Hence, potential exists for oral chemopreventive agents to become an effective component in the prevention of skin cancers,» Dr Chen and his colleagues note.
Nonmelanoma skin cancer is the most common cancer in the world, and four times more common than any other cancer in Australia, they report.
Just how nicotinamide works has not been established. It is possible that nicotinamide acts by «boosting cellular energy and enhancing DNA repair,» and that the vitamin «reduces the level of immunosuppression induced by UV radiation,» the investigators write.
The study received funding from Australia’s National Health and Medical Research Council. Two study coauthors report consulting agreements with several pharmaceutical companies.
N Engl J Med. 2015;373:1618-1626. Abstract
September 22, 2015
NATIONAL HARBOR, MD — Patients with fibromyalgia show deficiencies in red blood cell (RBC) magnesium and insulin-like growth factor 1 (IGF-1), a small study shows, suggesting potential clues to underpinnings of the condition and avenues for treatment.
In a condition that is challenging to treat and complicated by the subjectivity of pain, identifying such deficiencies can represent important, objective measures of abnormalities with definable treatment goals, lead author Thomas J. Romano, MD, PhD, a pain specialist based in Martins Ferry, Ohio, told Medscape Medical News.
«Fibromyalgia is a disorder that is notoriously devoid of objective markers,» he said.
«In identifying a comorbidity that can be objectively verified, you can let patients know that one of the reasons they could be having problems is because of these abnormal levels. Restoring those levels to where they should be, we have found, can truly turn people’s lives around — they have more stamina and more energy,» Dr Romano said.
Their research was presented here at the American Academy of Pain Management (AAPM) 2015 Annual Meeting.
Having reported on low RBC magnesium levels among his patients with fibromyalgia back in the 1990s, Dr Romano noted some previous studies also linking low IGF-1 to the condition and sought to further investigate whether the two comorbidities were often related.
He enrolled 60 patients with confirmed fibromyalgia: 10 men with a mean age of 49.5 years and 50 women with a mean age of 42.8 years.
In tests evaluating IGF-1, the patients as a group had a mean IGF-1 level of 59.33 ng/dL, which is lower than the mean of 235 ng/dL that would be expected according to calculations of patients’ ages. IGF-1 levels are age dependent.
Measures of RBC magnesium levels were also taken on the same day, and results as a group showed a mean magnesium level of 4.49 mg/dL, lower than the mean level in a control group of 12 osteoarthritic patients and the laboratory standard of 5.5 mg/dL.
«The findings suggest that if you determine that fibromyalgia patients have low magnesium levels, you might want to check IGF-1,» Dr Romano said.
He noted that in referring such patients to an endocrinologist, the results have been consistent.
«When I suspect a patient’s IGF-1 levels are low, I send them to an endocrinologist for confirmation and they will do the intravenous GHRH [growth hormone–releasing hormone]-arginine stimulation test,» he explained.
«The typical response is a peak and then the level comes down, but in the vast majority of fibromyalgia patients it’s just a flat reading, with no response.»
Treatment with growth hormone to restore normal levels typically starts with low dose, 0.2 mg, of subcutaneous injections daily for several months, with increased titration if levels are not restored within several months, Dr Romano said.
Although the study is small, Dr Romano urged clinicians to consider such factors when struggling with fibromyalgia management.
«The take-home message is to keep looking,» he said. «Fibromyalgia patients tend to have numerous comorbidities and they may be related.»
Studies that have also linked IGF-1 levels to fibromyalgia include a randomized, double-blind, placebo-controlled study published in 1997 in the American Journal of Medicine, which showed significant overall improvements in fibromyalgia symptom scores after IGF-1–deficient women were treated with daily growth hormone injections.
The «Future» of Chronic Pain
Pain specialist Forest Tennant, MD, PhD, from the Veract Intractable Pain Clinic in West Covina, California, who has also explored the role of hormones in chronic pain and presented a talk on the topic at the meeting, noted that, aside from the few earlier studies, the role of growth hormone in fibromyalgia has not been extensively explored.
«When it comes to pain, we’re not entirely certain what growth hormone does, but that it affects mainly hard tissue such as bone cartilage,» he told Medscape Medical News.
«But we’ve been extensively studying human chorionic gonadotropin and that looks like it works more importantly in the nervous system and really seems to be becoming an essential compound.»
«I’m glad they’re studying this, however, because [hormone involvement] is the future of chronic pain, there’s no question about it.»
Dr Romano has disclosed no relevant financial relationships. Dr Tennant receives speaker’s bureau fees from Ethos Labs, Regenesis Biomedical, and INSYS Therapeutics.
American Academy of Pain Management (AAPM) 2015 Annual Meeting. Presented September 19, 2015.
Una ingesta excesiva de vitamina D podría alterar negativamente a la salud en la adolescencia – correofarmacéutico.com
Varios estudios observacionales también han apuntado vínculos entre las deficiencias de la vitamina D y un gran peso asociado a complicaciones médicas, incluyendo enfermedades cardiovasculares y resistencia a la insulina. Otros estudios previos demostraron una relación entre la vitamina D en sangre y la mejora en la función vascular. Como resultado, padres, cuidadores y proveedores de salud a menudo suministran altas dosis de suplementación, tanto en niños como adolescentes, en un intento de disminuir o revertir alguna de las complicaciones asociadas a la obesidad.
«Me ha sorprendido que no hemos encontrado más beneficios de salud», dijo Kumar. «no estamos diciendo que los suplementos con vitamina D sean malos a dosis razonables, y sabemos que la mayoría de los obesos adolescentes tienen deficiencia en vitamina D. Solo estamos diciendo que no está comprobada su utilidad para mejorar la salud en adolescentes».
Este es el primer estudio en el que Kumar informa del aumento de colesterol y triglicéridos durante la suplementación con vitamina D, un hallazgo, dice, que podría ser atribuido al menor número de niños que participaron en el estudio y a un periodo relativamente corto de tiempo.
La investigadora decidió estudiar la vitamina D en adolescentes con sobrepeso porque esta población tiene un riesgo elevado de enfermedad crónica, y por la creciente popularidad de los compuestos homeopáticos o tratamientos complementarios para la obesidad. Apuntó que la hipervitaminosis de vitamina D provoca poco apetito, náuseas, vómitos y complicaciones renales.
Una forma de vitamina B3 regularía el metabolismo del hígado – DiarioMedico.com
Redacción | firstname.lastname@example.org
| 07/08/2015 17:00
Una forma de vitamina B3 regularía el metabolismo del hígado – DiarioMedico.com
El hígado juega un papel central en todos los procesos metabólicos, incluyendo la descomposición de las grasas para producir energía. Debido a que un número de diferentes proteínas están involucradas en los efectos metabólicos de NAD +, el equipo de investigación planteó la hipótesis de que podría haber una vía de vitamina B3, aún no identificada, que regulara directamente el metabolismo del hígado.
Para probar esta hipótesis, llevaron a cabo una serie de experimentos que evaluaron estas proteínas. Los resultados revelaron que la nicotinamida N-metiltransferasa (NNMT), una enzima que ayuda al cuerpo a excretar el exceso de vitamina B3, también juega un papel metabólico prominente.
En experimentos posteriores, observaron que NNMT correlacionó positivamente con Sirt1 en un perfil metabólico saludable de ratones, y también que los seres humanos con bajo nivel de colesterol y triglicéridos bajos exhiben altos niveles de NNMT y Sirt1 en sus hígados.
Pissios sentenció que «hemos identificado una nueva vía de vitamina B3 que regula el metabolismo del hígado y nos ofrece la oportunidad de buscar el desarrollo de nuevos tratamientos para enfermedades metabólicas».
August 04, 2015Postmenopausal women who took vitamin D supplements to a level of 30 ng/mL increased calcium absorption, but that did not translate into benefits in bone density, muscle function, muscle mass, or falls in a single-center, randomized, double-blind, placebo-controlled trial. Low doses of vitamin D supplementation gave outcomes equivalent to placebo.
Karen E. Hansen, MD, from the Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, and colleagues published their findings online August 3 in JAMA Internal Medicine.
«It is possible that treatment beyond 1 year would result in better outcomes, but these data provide no support for use of higher-dose cholecalciferol replacement therapy or indeed any dose of cholecalciferol compared with placebo,» Deborah Grady, MD, MPH, from the Department of Epidemiology at the University of California, San Francisco, writes in an accompanying editorial.
The low-dose regimen consisted of 800 IU vitamin D per day, and the high-dose regimen was 50,000 IU twice monthly. Women in the high-dose group received extra doses as needed to keep their serum 25-hydroxyvitamin D levels above 30 ng/mL, the level currently recommended by some researchers. (The Institute of Medicine recommends 20 ng/mL.)
The investigators enrolled 230 postmenopausal women with 25-hydroxyvitamin D levels ranging from 14 to 27 ng/mL and counseled them to consume between 600 and 1400 mg calcium per day, an amount typical of postmenopausal American women. The study excluded women older than 75 years because age is associated with intestinal resistance to vitamin D. The researchers also excluded women with certain intestinal disorders, diabetes, or fractures or who had taken bone-active medications. The researchers stratified participants by parathyroid hormone level and calcium intake and gave the women sunscreen to use in summer months.
After 1 year, calcium absorption, the primary outcome, increased by 1% in women who received the higher dose, but decreased by 2% in those who received the low dose and 1.3% in those who received placebo.
There was no difference among the three groups in bone mineral density (adjusted P = .12), timed up-and-go and sit-to-stand tests, muscle mass, number of falls, health assessment questionnaire score, or fractures.
The investigators note that few participants were black, and the results are not generalizable to men, young adults, or women older than 75 years.
«We found no data to support experts’ recommendations to maintain serum 25(OH)D levels of 30 ng/mL or higher in postmenopausal women,» the authors conclude.
One author reported working as a local principal investigator for a Takeda clinical trial. The other authors and Dr Grady have disclosed no relevant financial relationships.
JAMA Intern Med. Published online August 3, 2015. Article abstract, Editorial extract
July 17, 2015COPENHAGEN, DENMARK — Although findings that a healthy diet is good for the heart aren’t really a surprise anymore, new research suggests that this may be because of the increase in vitamin-C levels that come from a high intake of fruit and vegetables.
Evaluation of almost 100,000 individuals from the Copenhagen General Population Study (CGPS) and Copenhagen City Heart Study showed that those who ate the most fruit and vegetables had a 13% lower risk of CVD and a 20% lower risk of all-cause mortality compared with the subgroup that ate these foods only rarely.
Additional analysis showed that genetically high levels of plasma vitamin-C concentrations were also linked to reduced risks, although «the 95% CI overlapped 1.0, which made certain statistical inferences difficult,» write the researchers, led by Dr Camilla J Kobylecki (Copenhagen University Hospital, Denmark).
Still, «our data cannot exclude» that benefits from these healthy foods could, at least in part, be driven by high vitamin-C concentrations, they add.
The findings were published in the June 2015 issue of the American Journal of Clinical Nutrition.
Vitamin C and the Heart
The investigators examined data for 87,030 participants in the CGPS and 10,173 participants in the Copenhagen City Heart Study, all of whom were white and had DNA samples available for assessment.
For this measure, the Mendelian randomization approach was chosen for use because it’s «based on the assumption that the inheritance of a genetic variant from parents to offspring is independent of the environment; thus, genetic variants that either alter or are markers of alterations in plasma vitamin-C concentrations provide an ideal system to assess . . . lifelong high vitamin-C concentrations,» write the researchers, adding that they genotyped for solute carrier family 23 member 1 (SLC23A1) rs33972313.
Vitamin-C levels were also measured in blood samples from 3512 of the CGPS study members.
In addition, 83,256 of the CGPS participants were split into the following four subgroups based on how often they ate fruit or vegetables: almost never (n=6369, 71% men), less than once a day (n=17,576, 59% men), once a day (n=28,517, 45% men), or at least twice a day (n=30,794, 31% men).
The subgroup with the highest intake of these foods had a significantly lower risk for ischemic heart disease vs the group with the lowest intake (adjusted hazard ratio [HR] 0.87, 95% CI 0.78–0.97, P=0.01), as well as an even lower risk for all-cause mortality (HR 0.80, 95% CI 0.73–0.88, P <0.001). Similar results were found regarding just fruit or just vegetable intake.
«We showed stepwise-higher plasma vitamin-C concentrations with higher fruit intake,» report the investigators.
For «genetically determined 25% higher» vitamin-C levels, the odds ratio (OR) for ischemic heart disease was 0.90 (95% CI 0.75–1.08) and for all-cause mortality was 0.88 (95% CI 0.72–1.08).
The researchers note that because these foods are high in vitamins and minerals, antioxidants, and micronutrients, «it is plausible that one or a combination . . . might confer cardiovascular protection through an effect on vascular function, a reduction of blood pressure, lower plasma concentrations of LDL cholesterol, or a reduction in oxidative stress.
«The latter effect could be mediated through vitamin C, which is abundantly present in fruit and vegetables and considered a powerful antioxidant,» they add.
The study was funded by the Michaelsen Foundation, the Danish Council for Independent Research, and the Chief Physician Johan Boserup and Lise Boserup Foundation. The authors report no relevant financial relationships.
La vitamina B12 potenciaría la expansión de la bacteria ‘P. acnes’ en la piel – correofarmacéutico.com
May 13, 2015An inexpensive vitamin B₃ product, widely available over the counter, has been shown to reduce significantly the risk of developing further skin cancers in patients who have already been diagnosed with nonmelanoma skin cancer. The product is nicotinamide, taken orally 500 mg twice daily.
«This is the first clear evidence that we can reduce skin cancers using a simple vitamin, together with sensible skin protection,» commented senior study author Diona Damian, MBBS, PhD, professor of dermatology at the Dermatology University of Sydney in Australia.
«It is safe and…inexpensive, and this one is ready to go into the clinic,» she said.
Nonmelanoma skin cancer is the most common cancer worldwide, she said.
In Australia, it is four times more common than any other cancer, and it affects more than half the population during their lifetime.
The finding, from the Australian ONTRAC (Oral Nicotinamide to Reduce Actinic Cancer) study, was presented during a press briefing held in advance of the American Society of Clinical Oncology (ASCO) 2015 Annual Meeting.
The results released today show that patients who took nicotinamide 500 mg twice daily for 1 year showed a 23% reduction in new diagnoses of nonmelanoma skin cancer, compared with those who took placebo (P = .02). Specifically, new diagnoses of basal cell carcinoma were reduced by 20%, squamous cell carcinoma by 30%, and actinic keratoses by 13%.
During the year-long study, the patients in the placebo group developed a median of 2.5 new skin cancers, whereas those in the nicotinamide group had a median of 1.77 new cancers.
We have a remarkably simple and inexpensive way to help people avoid repeat diagnosis of some of the most common skin cancers.
«With this study, we have a remarkably simple and inexpensive way to help people avoid repeat diagnosis of some of the most common skin cancers,» commented ASCO President Peter Yu, MD, who is director of cancer research at the Palo Alto Medical Foundation in Mountain View and Sunnyvale, California. During the press briefing, he described this research as a «major advance» in prevention.
In the United States, about 5 million people each year are diagnosed with nonmelanoma skin cancer.
High-Risk Skin Cancer Patients
The study was conducted at two tertiary treatment centers in Sydney from 2011 to 2014. It involved 386 patients who had at least two nonmelanoma skin cancers in the last 5 years (median was eight skin cancers, but one patient had 52 lesions), and hence were considered to be at high risk. The study population reflects the sort of patients typically seen in a skin cancer clinic, the researchers note; the average age was 66 years (range, 30 to 90), and two-thirds of the patients were men. Many patients also had ongoing concomitant disease, such as heart disease, arthritis, hypertension, and chronic lung disease.
Patients were randomly allocated to receive either the vitamin or placebo, and underwent regular dermatologist review every 3 months. Discontinuation rates were similar for the two groups, and there were no clinically relevant differences in adverse events rates between the two groups, the researchers report. «Nicotinamide was very well tolerated,» Dr Damian said, and there were no interactions with other medications that the patients were taking.
The benefit from nicotinamide started to be seen at 3 months, but the benefit wore off quickly when patient stopped taking the vitamin, Dr Damian noted. In the 6 months after the year-long trial, when patients had stopped treatment but were still being monitored, the rate of new skin cancers was similar in the two groups, she said. «You have to keep taking the tablet in order for it to be effective,» she added.
Nicotinamide «presents a new chemopreventive opportunity against nonmelanoma skin cancer that is readily translatable into clinical practice,» the researchers conclude.
They speculate that nicotinamide offered protection against the development of subsequent skin cancer by working in two ways: enhancing the repair of DNA in skin cells damaged by sunlight, and preventing immune suppression in the skin by ultraviolet light.
Approached for comment, John Lear, MD, from Manchester University and from the Dermatology Department at Salford Royal Hospital in the United Kingdom, agreed that this is «very exciting and promising research to prevent skin cancer using a simple therapy which could easily be translated into clinical practice quickly with a large clinically meaningful reduction in skin cancers and actinic keratoses.»
However, Dr Lear pointed out that the study was conducted in a relatively small number of patients, and the Australian high-risk population may not be representative of skin cancer populations elsewhere, particularly in less sunny climates. In addition, he told Medscape Medical News that «it is surprising to see such a reduction in basal cell carcinoma numbers given such a short period of treatment, given that they often develop many years after the ultraviolet exposure that caused them.»
Not for General Population
During the press briefing, Dr Damian emphasized that this research shows the benefits of nicotinamide in patients who already have skin cancer. When asked about the general population, who may be worried about sun-damaged skin, she emphasized that the data are not there. It may be that nicotinamide would also reduce their risk of developing skin cancer, «but we don’t know that,» added press moderator Gregory Masters, MD.
Dr Damian also emphasized the importance of sun protection measures.
The study received funding from Australia’s National Health and Medical Research Council. Dr Damian has disclosed no relevant financial relationships. Two study coauthors report consulting agreements with several pharmaceutical companies. Dr Yu reports stock and other ownership interests with ContraFect, Citrix Systems, EMC Corp., Google, IBM, Oracle, FireEye, and Apple; and receiving research funding from Berg Pharmaceuticals.
American Society of Clinical Oncology (ASCO) 2015 Annual Meeting: Abstract 9000. To be presented May 30, 2015.
Los niveles bajos de vitamina D en menores elevarían el riesgo de enfermedad cardiovascular – correofarmacéutico.com
«Los niveles de vitamina D sérica observados en este colectivo son similares a los encontrados en otros escolares españoles y de otros países. Esto confirma que la deficiencia en vitamina D es un problema prevalente en niños y adolescentes», han subrayado los autores.
La vitamina D se adquiere a través de los alimentos como, por ejemplo, el pescado azul, la yema de huevo o los productos lácteos. Por ello, los investigadores achacan «gran parte» de las carencias de vitamina D presentadas por los menores a una dieta inadecuada.
Pero también, esta vitamina se adquiere de la propia síntesis que realiza el organismo con la luz solar aunque, tal y como ha advertido la investigadora de la Facultad de Farmacia de la UCM y autora principal de la investigación, Ana María López-Sobaler, la latitud de España «no es la óptima» y en los meses de invierno la inclinación de la Tierra «no es la más favorable» para la síntesis de la vitamina D. «Incluso en los meses de verano, los valores siguen siendo insuficientes», ha concluido.