News and Articles on Health. Medical research topics.

Ultimately, data from confirmatory studies should either permit conversion to regular approval or lead to withdrawal of the indication in question. Hence, accelerated approval is provisional — a medium-term stopover en route to full approval or market withdrawal. There should be a clear end point and, after a reasonable period for confirmatory trials, the sponsor should provide evidence that meets the standard for regular approval. If such evidence emerges, the FDA must convert the drug’s status to regular approval. Otherwise, the FDA must rescind approval. Without a genuine option to withdraw accelerated approval in light of either inadequate or unfavorable confirmatory data, the FDA would have few tools to ensure that companies provide the new, rigorous data they promised to obtain.

Although such adverse decisions may be contested, the integrity of the accelerated approval process and the FDA’s reputation and authority as a public health agency require that it be willing to make and adhere to these difficult decisions. A central question in the bevacizumab dispute concerns whether the standard for conversion of accelerated to regular approval has been met. Genentech argues that progressionfree survival is an acceptable measure of direct clinical benefit in metastatic breast cancer and that confirmatory trials demonstrate that bevacizumab prolongs progression-free survival. Yet the progression-free– survival benefit in confirmatory trials, while statistically significant, was considerably smaller than that seen in E2100. In addition, safety concerns — both new and previously described — have arisen from the recent clinical trials. Genentech further claims that the FDA has switched approval standards for bevacizumab. The agency, however, has consistently maintained that progression-free survival is “not statistically validated as surrogate for survival in all settings” and is “not precisely measured.”4 Therefore, the FDA has full authority to respond to adverse safety and efficacy data by changing medication labeling. Genentech’s second claim, that the possibility of heterogeneity in the treatment effect should justify continued approval, suffers from an absence of data identifying which patient characteristics are associated with clinical benefit. As the FDA’s decision memorandum notes, the mere prospect of efficacy in subgroups of patients, without the ability to identify those subgroups in advance, is inadequate as a rationale for continued approval.

Genentech’s philosophical claim that “conflicting interpretations of data should be resolved in favor of retaining access and choice” represents a departure from federal statute and a bold challenge to the FDA’s mission. In a democratic republic, access and choice represent two among many values. The FDA must also protect scientific rigor, the integrity and legitimacy of federal regulations and guidance, and the public’s health. The agency’s reputation for using science to guide regulatory decisions in the public interest is its most critical institutional asset.

In February 2008, the U.S. Food and Drug Administration (FDA) granted accelerated approval to bevacizumab (Avastin) in combination with paclitaxel as first-line treatment for HER-2 negative metastatic breast cancer. Approval was based on the results of E2100, a cooperative-group randomized trial that showed a 5.5-month increase in progression-free survival associated with the addition of bevacizumab to paclitaxel therapy.
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Confirmatory studies by Genentech, the manufacturer, however, showed that bevacizumab’s benefits for progression-free survival may be appreciably smaller than those shown in E2100 and have demonstrated convincingly that the addition of bevacizumab to the chemotherapy agents they have tested offers no increase in overall survival among patients with metastatic breast cancer. As a result, the FDA proposed removing the metastatic breast cancer indication from bevacizumab’s label. Genentech filed an opposing petition to request an administrative hearing on the issue (available on the company’s Web site, www.gene.com), which is scheduled to begin June 28. Genentech has a legal right to appeal and request a hearing on scientific grounds, including the possibility that bevacizumab’s efficacy depends on the choice of chemotherapy partner or that progression-free survival is a direct rather than surrogate measure of clinical benefit in metastatic breast cancer. Given expert disagreement about how to interpret bevacizumab’s performance in the confirmatory trials, a hearing is appropriate to clarify the risks and benefits of the drug. In addition to its scientific claims, however, Genentech advanced four philosophical and political arguments to oppose the FDA’s proposed withdrawal of the indication: first, the move has no precedent; second, the possibility of benefit in subgroups of patients justifies continued approval; third, individual patients’ choice ought to be paramount; and fourth, the FDA’s move will obfuscate the drug-development picture and discourage innovation. In addition, Genentech, claiming that the members of the Oncologic Drugs Advisory Committee (ODAC) are biased and have inadequate expertise, specifically requested that its hearing be conducted before a different committee.
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The precedent for removing bevacizumab’s indication is implicit in the U.S. drug regulatory process. Requirements for thorough experimentation undergird that process and modern drug marketing. Phased clinical trials ensure that drugs’ safety and efficacy are established with a variety of data from research in humans. These trials also create a public good of vast proportions, since the data are used downstream in prescribing, formulary, and drug-development decisions by actors other than the FDA and the company. This system of experimentation, refined over the past 60 years, depends on the FDA’s regulatory authority.3 The key trigger inducing sponsors to conduct these studies reliably and rigorously is the FDA’s veto power over market entry for new drugs or for new indications for previously approved drugs. Begun in 1992 under Subpart H of the New Drug Regulations, accelerated approval has origins in the scientific and political battles over treatments for HIV– AIDS. The process permits the FDA to grant marketing authorization on the basis of so-called surrogate end points, such as progression-free survival, that are judged reasonably likely to predict clinical improvements in morbidity or mortality. The accelerated approval mechanism thus creates a contract between the FDA and a pharmaceutical company: in return for promises of further clinical studies, the company receives provisional approval and rapid market access. Accelerated approval requires the sponsor to “study the drug further, to verify and describe its clinical benefit,” doing so “with due diligence.”

Study Medication and Dosage
Infants were randomly assigned to receive either L. reuteri DSM 17938 [10(8) CFU] or placebo daily for 3 weeks. Parental questionnaires monitored daily crying time and adverse effects. Stool samples were collected for microbiologic analysis.

Key Findings
Those taking L. reuteri experienced a significant decrease in daily crying time. Stool microbiology revealed an increase in lactobacilli and decrease in Escherichia coli in the treatment group. L. reuteri was well tolerated and no adverse effects were noted.

Breastfeeding may serve as an equally powerful treatment, since it improves the microbial milieu of the gut.

Practice Implications
It is well known in the naturopathic field that probiotics address many gastrointestinal conditions effectively, even as a monotherapy. The same authors conducted a similar study in 2007, which found that a related probiotic strain, L. reuteri ATCC 77530, resulted in a decrease in colic symptoms in 95% of the treatment group vs. 7% in the control group.1 Critics of that study point out that it was unblinded, and controls were treated with simethicone.2 Therefore, blinding both groups in this study and removing interfering medications adds strength and significance. The mechanisms behind probiotics’ benefits are not fully understood. However, there are some clues in the literature: Savino and colleagues state that probiotics may improve gut motility and function and decrease visceral pain. Additionally, other research has shown that altered fecal microflora is found in infants with colic, and those children are found to have elevated levels of calprotectin in their stools. Interestingly calprotectin is a marker of intestinal inflammation and possibly increased intestinal permeability and can serve as a predictor of irritable bowel disease later in life. Breastfeeding may serve as an equally powerful treatment, since it improves the microbial milieu of the gut. This explains why a review of 79 articles shows babies who are breastfed have a decreased risk of irritable bowel disease development later in life. At this time, there is no general consensus on the most effective probiotic strains for the treatment of colic. Additional strains that have shown efficacy in colic include Bifidobacterium lactis and Streptococcus Thermophilus.10 It is quite likely that other strains also have benefit, warranting further research in this area.

The dietary supplement world is awaiting some critical guidance regarding new dietary ingredients from the FDA due to arrive by the end of June 2011. In anticipation of this guidance, chatter in the industry has increased, and this has even made the news. An article published in the Salt Lake Tribune on May 1, 2011 focused on this anticipated communication.

One of the provisions that Congress included in the Dietary Supplement Health and Education Act (DSHEA) addresses the safety of new dietary ingredients. This provision gives the FDA the right and responsibility to review new dietary ingredients for safety prior to their being marketed in dietary supplements. “New” is defined as any dietary supplement ingredient that was not marketed in the United States before October 15, 1994. It is the manufacturer’s responsibility to make this determination, and if new, submit a new dietary ingredient (NDI) application to document the safety of the new ingredient. If the FDA does not respond within 75 days after the application is submitted, the manufacturer can introduce the ingredient to the marketplace. It is important to note that a “successful” NDI submission does not mean that FDA has confirmed that the ingredient is safe for its intended use.
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Despite the growth in the number of natural products since 1994, Daniel Fabricant, the director of the FDA’s Division of Dietary Supplement Programs, reported that the FDA has received only 700 new dietary ingredient applications since 1994, out of an estimated 60,000 dietary ingredients in use. One of the reasons for this is that, in the absence of clear guidelines, the industry has been confused about what to submit. The FDA guidance expected by the end of June should clear up this confusion. And that is where the change is likely to start happening.

The requirements to prove safety may be quite onerous for smaller companies.

Depending on the requirements to demonstrate safety, hundreds to thousands of products may in be jeopardy of discontinued sales until their safety is proven. The requirements will also affect the introduction of new ingredients into the marketplace. This includes both advanced technology ingredients and botanical ingredients from other parts of the world (if not marketed for use prior to 1994). The requirements to prove safety may be quite onerous for smaller companies. A somewhat similar situation has recently taken place in the European Union. In the EU, the 7-year transition period set out in the 2004 Herbal Directive (2004/24/EC) has expired. This means that, as of May 1, 2011, only medicinal products that have been registered or authorized can remain on the shelves. A manufacturer who wishes to register a traditional herbal medicinal product must provide documentation showing that the product is safe for its intended uses. They must also provide evidence that the product has been used safely for at least 30 years, 15 of them in the EU. Although this legislation is different than the NDI requirement in the United States, the intent and approach is quite similar. Smaller herbal manufacturers in the EU are already voicing their concerns about their ability to comply with these requirements. This is, in part due to the scope of the documentation necessary to establish safety. Whether the clarified NDI requirements will present a similar challenge to smaller manufacturers in the United States remains to be seen.

Dietary supplement manufacturers are watchful of events in the EU as they await the NDI guidance. The implications to availability, and potentially cost, of affected dietary ingredients are yet to be determined. If a product is found to contain an NDI that does not have an application filed, that product is considered adulterated and will likely be removed from commerce. It’s possible that the FDA could require retailers and healthcare practitioners to pull thousands of products off the shelves as it determines the safety of these new dietary ingredients. This will also trigger remedial action on the part of the manufacturer. Despite the potential implications, most manufacturers are eager for NDI clarification. Ultimately, this guidance is what the industry has been asking for since 1994. Defining these requirements should help manufacturers submit what the FDA requires. This, in turn, will provide greater assurance of safety to dietary supplement users. Getting there may be somewhat painful, but the destination should be worth it.

Message From Emerson Ecologics: The Healthcare Practitioners’ Preferred Distributor of Professional Supplements
Emerson Ecologics is proud to be the leading provider of professional-grade nutritional supplements to the integrative healthcare community. Obtaining that recognition didn’t just happen overnight; it has been earned. For more than 30 years, Emerson has provided confidence and peace of mind to healthcare practitioners and their patients. We strive to maintain that trust and exceed the expectations of our customers every day.
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A broad offering of 20,000 products from more than 250 of the world’s top nutritional supplement manufacturers ensures we are the single source for all a professional’s needs. Placing one convenient order for multiple brands is one simple step to reducing your carbon footprint. Emerson’s real advantage, however, is in the service solutions we offer. By lessening the administrative burden for a practice or clinic, we enable an office to streamline its business practices and focus on what doctors do best—provide high-quality, personalized care to patients.

Since 1980, Emerson has not only worked to seamlessly and efficiently bring professional nutritional supplements to practitioners, we have also been fully committed to sharing the industry’s focus on safety and quality. We take this commitment very seriously and developed the Emerson Quality Programâ„ (EQP) to provide you a better vantage point into making informed decisions about the products you recommend.

As healthcare continues to evolve and patients seek a more proactive and balanced approach to their overall health, we will be here to fully support the healthcare community in providing care. Emerson Ecologics is committed to being the one-stop source for products you can trust, resources you need, and services you deserve.

Quality: The Confidence for Recommending the Best
Emerson Ecologics recognizes that high-quality manufacturing practices are central to the success of the dietary supplement industry. With ongoing concerns continually raised about contaminants, such as heavy metals, it is increasingly important for practitioners to be able to reliably secure information about the quality of supplements. A majority of manufacturers voluntarily apply for third-party quality certification to validate their manufacturing practices for product purity, identity, and potency; however, this information is not readily accessible to healthcare practitioners, and so the EQP was created.

The EQP is a one-of-a-kind, quality assurance program that showcases the quality practices of its participating manufacturers. Voluntary participants provide detailed data on FDA cGMP compliance, raw materials, and finished product testing, which is then scrutinized and verified by Emerson; manufacturers that meet or exceed Emerson’s quality standards are awarded the distinction of EQP Partner, EQP Silver Partner, or EQP Gold Partner. These partners understand quality as an integral part of their business and epitomize a commitment to quality manufacturing that goes above and beyond, representing some of the best quality practices in the industry.
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All this information is compiled into an easy-to-use online tool at emersonecologics.com/quality to provide practitioners and their patients what they need to make informed supplement decisions. Practitioners are able to access information to assist them in evaluating potency, bioavailability, and certainty of material identity and purity. The goal of the EQP is not only to recognize manufacturers that continue to raise our industry’s standards, but most importantly to give practitioners the information to confidently recommend and trust the source of supplements for their patients.

The article reported the overall average of the baseline and post treatment nitric oxide levels; the individual results of each of the 23 participants were not included.

Although pain and function were not measured, most participants reported an enhanced relaxation response after treatment.
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The cranial therapy was associated with changes in NO levels in exhaled breath. The level of NO increased from 13.3 +/- 2.09 (SD) to 15.0 +/- 2.95 (SD) ppb (P=0.001, based upon the paired t tests of the subjects). The median level of NO before the cranial therapy was 13.0 ppb (ranging from 8 to 17 ppb); after cranial therapy, it was 16.0 ppb (ranging from 6 to 18 ppb).

Although pain and function were not measured, most participants reported an enhanced relaxation response after treatment; the most relaxed participants were those with the highest post-treatment exhaled NO levels.

Practice Implications
This study is the first to explore the physiological effect of cranial therapy on NO production. These finding are significant, especially since we are increasingly learning of the important role that NO plays in various aspects of health. It is also a big step for the cranial community, because despite having a long, rich history and an immense archive of anecdotal evidence, cranial therapy lacks substantial clinical research studies. Currently an explanation of how cranial therapy can produce an increase in exhaled NO levels remains theoretical.

Traditionally, elevated exhaled NO levels have been closely associated with chronic pulmonary conditions such as asthma. This is why it was so vital to choose participants who were qualified as “healthy adults.” Since there were no asthmatic participants, and those with post-treatment elevated levels of NO reported an enhanced relaxation response, I would hypothesize that there is an intimate connection between naturally increasing the body’s ability to produce NO and being able to decrease the devastating effects that stress has on the body. The article also states that this therapy could be a key adjunct in the prevention of coronary artery disease (CAD) and diabetes—both of which damage epithelial lining of blood vessels (indicative of low NO production). When lowered NO levels allow damage to the blood vessels to occur, the endothelium is less able to produce the necessary amount of NO, thus facilitating further endothelial damage. This, over time, can manifest into serious pathological conditions. Given the noninvasive nature of the procedure, this cranial therapy could potentially be an incredible asset to those treating such conditions.

Since the 1990s, NO has been aggressively studied—its relationship to cardiovascular health only discovered in 1998—and it has been found that too little NO, as seen in CAD and diabetic cases, can have a damaging effect, but too much can also be detrimental. In the instance of an excess of NO, further research to examine whether this cranial maneuver may have a modulating effect on NO levels would be interesting, as colleagues in the cranial field have reported positive results with asthmatic patients.

Although this study is small and uncontrolled, which is not typically the type of study highlighted in this column, these findings are relevant to clinical practice. NO is, as we’ve seen, a critical component in maintaining health. In the clinical field, NO and its precursors are being utilized in a variety of ways, ranging from treatment of pulmonary vascular disease in pediatrics, to pain associated with angina, to erectile dysfunction. It’s also becoming a staple for preventative and anti-aging protocols.

We’ve long known that there are noninvasive, effective methods of increasing NO levels, whether through supplementing with arginine or even regular exercise, but until now there has not been a physical modality that has shown a possible systemic increase in NO. These findings also suggest that various healthcare providers and readers of this column may, in addition to their current prevention or treatment protocols, begin to incorporate this type of cranial therapy into their practice.

Main Outcome Measures
Various outcome data were collected, including length of hospitalization, need for postoperative analgesics, routine vital signs, and patient ratings of pain intensity and distress as well as anxiety and fatigue. Validated assessment metrics included the State-Trait anxiety Inventory Form Y-1, the Environmental Assessment Scale, and the Patient’s Room Satisfaction Questionnaire.

Key Findings
Post-study evaluation of data revealed that patients assigned to recovery rooms with foliage demonstrated significantly lower systolic blood pressure, perception of postoperative pain, anxiety, and fatigue than those in the control group. Validated surveys also revealed subjective increase in satisfaction with their assigned room, stating that the plants brightened the environment, reduced stress, and evoked more positive impressions of hospital employees engaged in their care.

Practice Implications
The true beauty of this study lies in its simplicity and elegance, reflective of nature itself. The investigators chose to evaluate postoperative pain after a common surgical procedure, and the intervention chosen was inexpensive, nontoxic, and required no randomized controlled trial or FDA approval prior to utilization.
Given the current clinical and fiscal need for alternatives to our conventional approach to pain management, this simple intervention holds promise as adjunctive analgesia for simple surgical procedures.
Given the current clinical and fiscal need for alternatives to our conventional approach to pain management, this simple intervention holds promise as adjunctive analgesia for simple surgical procedures.

This is not the first attempt to utilize the hospital environment as therapeutic modality. Architects and contractors across this country and abroad have been engaged in a revolutionary movement to redesign hospital buildings both inside and out, with more than 1,500 studies to date demonstrating that architectural design significantly influences rates of medical errors, clinical infections, accidental falls, and levels of stress in both patient and staff. As one example, researchers have documented that the simple addition of sunlight to a hospital room is associated with improvement in mood and affect, diminished mortality in cancer patients, reduced length of stay in patients with myocardial infarctions, and decreased analgesic use and costs after spinal surgery. The Center for Health Design, a non-profit based in California, has created the Pebble Project, a partnership of 44 hospitals to investigate the clinical and fiscal benefits of intelligent building design. Their data reveal lower noise levels, improved patient sleep, decreased staff turnover, reduced medication requirements, and declining drug errors. Given that the majority of our pharmaceutical medications have been extracted from living botanicals, it is poignant to consider that the original plant may prove a superior therapy in the long run. Future studies should be done to confirm this study’s findings and delineate what aspect of the live plant (eg, visual, olfactory, qi) might be responsible for improved outcomes.

“Both unadjusted tests and linear regression models indicated that CAM users had lower average expenditures than nonusers. (Unadjusted: $3,79β7 versus $4,153, P=.0001; β from linear regression -$367 for CAM users.) CAM users had higher outpatient expenditures that which were offset by lower inpatient and imaging expenditures. The largest difference was seen in the patients with the heaviest disease burdens among whom CAM users averaged $1,420 less than nonusers, P<0.0001, which more than offset slightly higher average expenditures of $158 among CAM users with lower disease burdens.”

Practice Implications
This paper is the latest in a series from this team to evaluate insurance claims databases resulting after a 1996 insurance inclusion mandate for CAM providers in Washington state. The change in regulation required that health insurance companies operating within the state to provide access to every state-qualified class of healthcare providers. Earlier papers from the group found that overall claims were little affected by coverage of CAM providers due to smaller claim size compared to conventional medical claims. Those studies also found that CAM users tended to have higher morbidity than non-users.

Cost studies are few in CAM research. Cost minimization, the approach of this paper, analyzes which of 2 approaches to care is associated with lower overall expenditures, assuming comparable health outcomes between the two approaches. “CAM users” were those who had made claims for visiting any of the following CAM providers: acupuncturists, chiropractors, massage therapists, and naturopathic physicians. Average claims costs in this analysis were about 9% lower over 1 year among CAM users than non-users, showing lower inpatient and ancillary costs (e.g., imaging, laboratory) but higher outpatient visit costs.

The cost outcomes, while favorable to CAM provider use, are associated with and not demonstrably caused by CAM provider visits reflected in the claims. The smaller costs among CAM users may be generated by other health and lifestyle factors associated with going to CAM practitioners (e.g., newly acquired patient activation in the face of a chronic problem, surrendering conventional medical interventions due to therapeutic failures).
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Though coverage of CAM providers was made available, coverage was generally not equal to coverage of conventional providers, being restricted among different insurance companies by limits to the number of CAM visits, to a specified network of a providers, or to an overall CAM costs cap.
Not all CAM care costs are included in the data set; for example, dietary supplements, which may be a necessary part of CAM treatment, are typically not covered even if provider visits are.
Not all CAM care costs are included in the data set; for example, dietary supplements, which may be a necessary part of CAM treatment, are typically not covered even if provider visits are. The analysis was done in three impactful conditions—back pain, fibromyalgia, and menopausal symptoms—which all have somewhat uncertain etiologies. They are also conditions that are often refractory to conventional treatment, so findings again may not be generalized to all conditions. These conditions fall into the emerging research area of medically unexplained physical syndromes (MUPS), in which the lowest hanging fruit for CAM research targets may be found.

To answer the question of causation requires prospective intervention studies; however, matching patients in the comparison groups of users versus non-users on the basis of their total medical claims in the year prior to initiating CAM claims makes this study suggestive of a generalizable finding in future economic analyses. Patients without a year of claims prior to initiating CAM claims were not included in analysis.

Different providers types were not distinguished in the analysis on the basis that there were too few claims for any 1 provider type for valid interpretation of the data by discipline (personal communication with first author). The study thus provides little guidance to consumers in choosing a provider, but more confidence that doing something alternative may be a good choice. Claims costs in only 1 year were evaluated; savings from CAM use may come with prevention, and thus subsequent savings could not be addressed. The study did not include Medicaid, Medicare, or state program–covered patients—populations that may be more susceptible to improvement under CAM care due to historical lack of access to it.

Despite its limitations, this creative use of existing data provides some evidence that costs of CAM providers are not redundant to conventional care and that CAM provider use may well be cost-saving. As more such data has become available with increasing inclusion and longevity of CAM providers in insurance coverage over the last decade, replication of this study in other regions and conditions is increasingly possible and should be performed.

GSH is one of the most extensively studied chemicals of the human body and its decline with aging and disease risk is well established. GSH is needed both for maintenance of normal metabolism and for defense against a range of disease and toxicity mechanisms. GSH is maintained by continuous processes of GSSG reduction and GSH transport, degradation, and synthesis. GSH concentrations are considerably higher in tissues than in most body fluids, but the fluid concentrations are important because they protect cell surfaces and support protective barrier defenses. Extensive research in model systems establishes that GSH is transported by cells and that added GSH protects against a range of chemical and infectious threats. Although most Americans consume an adequate supply of dietary precursors for GSH synthesis, there is a gap between the amount synthesized and the amount needed (ie, a decline in GSH is associated with disease risk). Based upon the loss of GSH from food during processing and the measured contents of reactive chemicals in food, this gap can be estimated to be 300 mg/day. However, higher values may be needed to compensate for adverse environmental conditions and disease, but the possible amounts can only be speculated.
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Because the American healthcare system is approaching crisis with the ballooning costs of late-stage disease treatment, cost-effective means are needed to preserve health. Available (but not FDA-approved) methods allow prospective assessment of GSH in individuals prior to disease onset, and health maintenance programs are beginning to adopt GSH analysis as part of quantitative health assessment (but not disease treatment). Simple strategies, including supply of GSH, GSH precursors, complementary antioxidants, and zinc, are available to improve GSH status in individuals with low or oxidized GSH. Such strategies could have considerable personal and societal health and economic impact.

Consequently, the scientific evidence supports the conclusion that the body can utilize exogenously supplied GSH. This characteristic is identical to some vitamins (eg, niacin), amino acids (eg, histidine), and amino sugars (eg, glucosamine), which are utilized from the diet even though they are synthesized within the body. For these, a nutritional deficiency can develop when the amount synthesized is insufficient to fulfill requirements. While GSH is not considered a required nutrient, the same principles apply (ie, a deficiency can develop when the amount of GSH synthesized is insufficient for detoxification needs).

GSH concentration and GSH/GSSG redox balance can be measured in human plasma, and this provides a means to identify individuals with poor GSH status. Plasma GSH levels decrease with age beginning at about 45 y, undergo a diurnal variation with lowest values at midday and are decreased and oxidized in association with disease risk and disease. However, despite the general utility of plasma measurements, deficiencies at barrier surfaces, such as the intestines, lung lining fluid, and immune cells associated with these surfaces, may not be apparent from plasma measurements. This leaves a dilemma in that at least some of the sites most likely to benefit from supplemental GSH are relatively inaccessible for measurement.

The Future: The Health Dividend of GSH

GSH supplementation can be implemented in individuals based upon their known risk factors, but validation that such strategies are effective in humans will require lengthy and costly controlled double-blind studies. In the meantime, validated methods are available to measure GSH and GSSG in body fluids but have not yet been approved by the Food and Drug Adminstration for clinical use. Availability of such measurements would provide means to evaluate health in individuals and to directly evaluate the efficacy of interventional strategies to normalize GSH and GSH redox balance in individuals with low values. Recent studies show that a related cysteine (Cys) redox balance for plasma cysteine and cystine is more directly related to extracellular oxidative processes and is associated with cardiovascular risk. Analyses of GSH redox and Cys redox have been performed in long-term interventional trials with free radical-scavenging antioxidants (vitamins C, E;) and also zinc in age-related macular degeneration. Results show that GSH redox balance and/or the Cys redox balance is preserved in association with protection against disease progression. Zinc has been found to activate mechanisms for GSH synthesis and also stimulate uptake of cystine. Consequently, combinations of GSH, GSH precursors (including preparations such as whey protein isolates), antioxidants, and inducers of transport and synthesis may provide complementary means to enhance GSH status.

GSH Support Strategies: How Can We Improve GSH Status?

GSH is synthesized from amino acid precursors, glutamate, cysteine and glycine. A considerable number of trials have used N-acetylcysteine (NAC) as a cysteine precursor, expecting it to provide a means to increase GSH synthesis. The logic for using NAC is complicated but generally assumes that cysteine is limiting for GSH synthesis. However, the American diet typically has an excess of sulfur amino acids. According to NHANES III, 99% of adult American males and females consume greater than the RDA, 50% consume more than twice the RDA and 1% of people consume more than 4 times the RDA for sulfur amino acids. Consequently, while NAC is likely to benefit individuals with insufficient sulfur amino acid intake, additional approaches are needed to address a functional need for GSH in most Americans. Supplementation with glutamate, cysteine, and glycine provides one alternative, and others include related sources of these amino acids (eg, whey), supplements to enhance synthesis (eg, silymarin), as well as the naturally occurring compound itself, GSH.

A common assumption is that dietary or supplemental GSH is not available for use by the human body because the intestines contain an enzyme (ie, γ-glutamyl transpeptidase; GGT) that degrades GSH. However, a substantial amount of scientific evidence shows that supplemental GSH is bioavailable. As indicated above, added GSH supports detoxification in body fluids such as the lining fluid of the lung and intestines, enhances macrophage function, and decreases influenza virus production. Thus, even for cells that do not absorb GSH, protection can be provided by supplemental GSH.
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Different research groups have also shown that GSH is transported across intestinal membranes, across the intestinal epithelium, into human intestinal cells, and from the intestinal lumen into the vascular circulation. Orally administered GSH increases GSH in mouse, rat, and human plasma, and the extent of increase is increased by a stress response. While studies are not universally consistent, and most organs do not take up GSH, experiments with isotopic tracers, inhibitors of GSH synthesis, inhibitors of GSH transport, and inhibitors of GSH degradation provide detailed evidence for GSH transport in intestines, lung, and kidneys. This subject has been recently reviewed by Lawrence Lash, and this should be consulted for additional details. Animal and human studies further show direct benefit of oral GSH in protection against age-related decline in immune function; enhancement of lymphocyte function; and protection against oxidative injury in newborn lung, influenza viral infection, chemically induced oral cancer, and uptake of peroxidized lipids and other toxic chemicals.