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Probiotics

Dimulai oleh syx, Agustus 25, 2009, 07:10:59 AM

« sebelumnya - berikutnya »

0 Anggota dan 1 Pengunjung sedang melihat topik ini.

syx

Probiotics May Be Useful Against Colds, Flu-Like Symptoms in Children

August 12, 2009 — Probiotics may be useful as prophylaxis against cold and influenza-like symptoms in children, according to the results of a double-blind, placebo-controlled study reported in the August issue of Pediatrics.

"Selected strains of probiotics have been tested for human health benefits in a variety of disease conditions, but much less is known regarding prophylactic benefits in healthy populations," write Gregory J. Leyer, PhD, from Danisco in Madison, Wisconsin, and colleagues. "This study adds information supporting the use of the probiotics tested for prophylaxis against cold and influenza-like symptoms and compares the efficacy of 1-strain and 2-strain preparations."

The effects of probiotic intake on incidence and duration of cold and influenza-like symptoms during the winter season were evaluated in healthy children aged 3 to 5 years. Of 326 eligible children, 104 were randomly assigned to receive placebo, 110 to Lactobacillus acidophilus NCFM, and 112 to L acidophilus NCFM in combination with Bifidobacterium animalis subsp lactis Bi-07. Children were treated twice daily for 6 months.

Compared with the placebo group, the groups receiving single and combination probiotics fared significantly better in several outcomes. Fever incidence was 53.0% lower with single probiotics (P = .0085) and 72.7% lower with combination probiotics (P = .0009); coughing incidence, 41.4% (P = .027) and 62.1% (P = .005) lower; and rhinorrhea incidence, 28.2% (P = .68) and 58.8% (P =.03) lower, respectively.

Fever, coughing, and rhinorrhea duration were 32% lower with single strain vs placebo (P = .0023) and 48% lower with the strain combination (P < .001). Antibiotic use incidence was 68.4% lower for single strain vs placebo (P = .0002) and 84.2% lower for strain combination (P < .0001). Days absent from group child care were also 31.8% lower for single strain vs placebo (P =.002) and 27.7% lower for the strain combination (P < .001).

"Daily dietary probiotic supplementation for 6 months was a safe effective way to reduce fever, rhinorrhea, and cough incidence and duration and antibiotic prescription incidence, as well as the number of missed school days attributable to illness, for children 3 to 5 years of age," the study authors write. "No notable adverse events were attributed to study probiotic strains."

Limitations of this study include failure to evaluate mucosal colonization, underlying mechanisms, or the effect of probiotics in an acute response to signs of illness.

"Daily probiotic dietary supplementation during the winter months was a safe effective way to reduce episodes of fever, rhinorrhea, and cough, the cumulative duration of those symptoms, the incidence of antibiotic prescriptions, and the number of missed school days attributable to illness," the study authors conclude. "L acidophilus NCFM alone was effective. There was, however, a trend for a broader protective effect with the combination of L acidophilus NCFM and B lactis Bi-07."

Danisco USA sponsored this study, employs 2 of the study authors, and has contracted 3 other authors regarding this study.

Pediatrics. 2009;124:e172-e179.

syx

beberapa hal yang saya dapatkan dari seorang pakar probiotik:

istilah yoghurt sebenarnya dulu lebih banyak dipakai untuk produk yang dihasilkan dari fermentasi susu oleh Lactobacillus bulgaricus dan/atau L acidophilus. kedua bakteri tersebut banyak dijumpai di udara dan memiliki perkembangan yang cepat. karena itu keduanya mendominasi populasi dalam yoghurt dibandingkan dengan spesies bakteri yang lain.

pada perkembangannya sekarang banyak bakteri lain yang digunakan dan hasilnya bisa lebih baik dari segi manfaat dan rasa. karena bisa terjadi perbedaan bakteri makanya sekarang lebih banyak menggunakan nama fermented milk. perbedaan rasa bisa terjadi misalnya karena lactose tidak semata-mata difermentasi menjadi lactic acid yang berasa sangat asam, tapi bisa juga dipecah menjadi gula yang lebih pendek, yaitu galactose dan glucose yang tentu saja rasanya lebih manis.

bakteri yang disebut baik adalah Bifidobacterium lactis (BB) dan L rhamnosus (GG). yang disebut terakhir bahkan disebutkan bisa membantu penyembuhan tukak lambung akibat infeksi Helicobacter pylori.

probiotik sebaiknya tidak dikonsumsi saat perut kosong karena pH lambung yang sangat asam akan membunuh bakteri. agar bakteri bisa selamat sampai di usus maka sebaiknya probiotik dikonsumsi setelah makan. saat ada makanan pH usus bisa meningkat hingga pH 3-4 dan memungkinkan para bakteri selamat sampai tujuannya.

probiotik yang dikonsumsi secara oral bisa juga membantu menjaga keseimbangan normal flora vagina meskipun beda jalur. ini dimungkinkan karena posisi lubang vagina dan anus yang tidak terlalu jauh.


Notonektid

lho, bukannya yoghurt yg menjadi medium bagi bakteri itu ph nya asam juga?
atau bakteri itu tidak memiliki ketahanan khusus terhadap enzim HCl?

syx

yoghurt emang asam, tapi ga sampe pH rendah sekali sampe 1.2 seperti di lambung saat kosong. catatan: HCl bukan enzim.

syx

From U.S. Pharmacist
Probiotics and Microflora
Max Sherman, RPh

Introduction
Probiotic foods have recently become popular in the United States, although such products have been marketed for decades in Europe and Asia.[1] Probiotics are defined as living organisms that, when administered in sufficient numbers, are beneficial to the host. One probiotic food is Activia. It is a line of yogurt containing Lactobacillus, Streptococcus thermophilus, and Bifidobacterium animalis bacteria, and it is advertised to aid regularity. While new to the U.S., Activia has been sold in Europe since 1987.[1] Most probiotic products can be found in the dairy case of supermarkets or as dietary supplements. There are probiotic frozen yogurts and dairy-based drinks such as DanActive, a probiotic yogurt drink that contains Lactobacillus casei immunitas cultures. Its manufacturer (Dannon) indicates that the product is clinically proven to "help strengthen your body's defenses."[2] Products sold in the pharmacy include, among others, Culturelle (Lactobacillus GG), Florastor (Saccharomyces boulardii) and Lactinex (Lactobacillus acidophilus, Lactobacillus bulgaricus), which are indicated to reduce the chance of developing diarrhea due to antibiotics.[3] The FDA takes a neutral position on probiotics, policing food packages to ensure that companies do not try to equate probiotic products with disease-curing drugs.

The growth of probiotics comes as many scientists are now focused on the role of beneficial bacteria to aid digestion, boost natural defenses, and fight off bacteria that could cause health problems. Intestinal bacteria can benefit health by breaking down toxins, synthesizing vitamins, and defending against infection. They may also play a role in preventing such diseases as peptic ulcers, colorectal cancer, and inflammatory bowel disease.[4] This article will describe the genesis and evolution of our indigenous microbial community, the size and makeup of its inhabitants, its effects, its benefits, and new research.


syx

Genesis and Evolution

Most of us are aware that bacteria are a part of a healthy human ecosystem (i.e., an assembly of species and the organic and inorganic constituents characterizing a particular site). According to one author, the armies of bacteria that sneak into our bodies the moment we are born are the "primal illegal immigrants."[5] Most are industrious and friendly, minding their own business in tight-knit, long-lived communities, doing the grunt biochemical work we all rely on to stay alive.[5] The ecosystem forms at birth, but the human-microbe alliance begins months before. Midway through pregnancy, a hormonal shift directs the cells lining the vagina to begin stockpiling sugary glycogen, the favorite food of sausage-shaped bacteria called lactobacilli. By fermenting the sugar into lactic acid, these bacteria lower the pH of the vagina to levels that discourage the growth of potentially dangerous invaders.[6]

The infant mouth's first inoculation of bacteria includes a generous sampling of the lactobacilli present in the mother's birth canal. With the first gulp of breast milk, these lactobacilli are joined by millions of bifidobacteria, a related group of acid-producing microbes.[6] The source of these bacteria is the mother's nipples, where the bacteria appear during the eighth month of pregnancy. Bifidobacteria secrete acids and antibiotic chemicals that repel potentially dangerous organisms, including Staphylococcus aureus. Bifidobacteria and lactobacilli are soon joined by acid-tolerant Streptococcus salivarius bacteria, which appear on a baby's tongue during the first day of life. Bifidobacteria are anaerobic, pleomorphic rods that break down dietary carbohydrate and synthesize and excrete water-soluble vitamins.[7] Their name is derived from the observation that they often exist in a Y-shaped, or bifid, form.[8] These organisms predominate in the colons of breastfed babies, account for up to 95% of all culturable bacteria, and protect against infection.[9] Strangely, they do not occur in such high numbers in adults.[8] Several other streptococci, along with one or more kinds of Neisseria bacteria, settle in during the first week. The vast majority emanate from the mother's mouth, which is always within reach of a nursing baby's fingers.[10]

As the baby begins nursing or drinking formula, the bacterial population inside the mouth increases. These bacteria consume enough oxygen to create a zone where anaerobic bacteria can thrive. By the time the baby is 2 months old, a microscopic close-up of the gums will reveal clusters and chains of bacteria and fungi. Another wave of bacteria arrive when the first teeth appear. The first is Streptococcus sanguis, followed by Streptococcus mutans. By middle childhood, the diversity inside the mouth surpasses a hundred species, and their total number is greater than 10 billion.[6] Bacteria also settle in the nasal cavities, which are connected to the mouth via the upper respiratory tract. The bacteria eventually lodge in the intestinal tract. In the small intestine, incoming microbes engage the infant's dormant immune system. Pits on the surface of the Peyer's patches (aggregated lymphoid tissue in the ileum) capture passing bacteria, where they are ushered into the underlying lymph tissue. Interaction on the Peyer's patches triggers the production of an abundance of immunoglobulin A (IgA) antibodies. Instead of marking the bacteria for destruction, IgA clusters across the bacterial surface, preventing the bacteria from attaching to the intestinal wall. This action also leads to the proliferation of T and B cells that will marshal an attack against these same bacteria should they turn up in the blood or other forbidden areas.[6] The small intestine must provide a platform for nutrient absorption, but at the same time the epithelium and its associated immune cells must keep out pathogens that escape the inhospitable environment of the stomach. To satisfy these responsibilities, small intestinal epithelial cells divide at a rate of 13 to 16 cells every hour.[6] When the child reaches adulthood, his or her intestine becomes home to an almost inconceivable number of microorganisms. The size of the population—up to 100 trillion—far exceeds all other microbial communities associated with the body's surfaces and is more than 10 times greater than the total number of our somatic and germ cells combined.[11] (There is a significant variation in both the total number of bacteria and the composition of the bacterial flora in different body regions.[12]) Since humans depend on their microbial inhabitants (microbiome) for various essential services, a person should really be considered a superorganism, consisting of his or her own cells and those of all the commensal bacteria. Humans are not inherently endowed with a healthy immune or digestive system. Fortunately, the microbiome in our intestinal tract provides us with genetic and metabolic attributes we have not been required to evolve on our own, including the ability to harvest otherwise inaccessible nutrients and to modify host immune reactivity.[11]

Inhabitants

The adult human gastrointestinal (GI) tract contains all three domains of life—bacteria, archaea, and eukaryotes.[11] Archaea are a group of prokaryotic and single-celled microorganisms, and while similar to bacteria, have evolved differently. Archaea were originally described in extreme environments but have since been found in all habitats including the digestive tracts of animals such as ruminants, termites, and humans.[13] Eukaryotes are organisms whose cells contain a limiting membrane around the nuclear material (the nucleus). Bacteria living in the human gut achieve the highest cell densities recorded for any ecosystem.[14] The vast majority belong to two divisions, the Bacteroidetes (48%) and the Firmicutes (51%). Bacteroidetes include a number of Bacteroides genera, which have yet to be encountered in any environment other than animal GI tracts. Firmicutes include the genera Clostridium, Lactobacillus, Eubacterium, Ruminococcus, and several others. In the first comprehensive molecular survey of the gut microbiota (normal microflora), 395 bacterial and one archaeal phylotype (bacteria defined by their ribosomal RNA gene sequence) were identified.[14] Thus, the gut microbiota is a tremendously diverse bioreactor. Eight divisions with divergent lineages are represented. This diversity is desirable for ecosystem stability. There appears to be a strong host selection for specific bacteria whose behavior is beneficial to the host. Cooperative activity by bacteria is required to break down nutrients and provide the host with energy. Populations of bacteria are remarkably stable within the human gut, which implies that mechanisms exist to suppress undesirable bacteria and promote the abundance of those that are needed.[11]

Bacteroides thetaiotaomicron is the prominent and remarkable bacterial species in the distal intestinal tract of adult humans. It is a very successful anaerobic glycophile ("sugarloving" microbe) whose prodigious capacity for digesting otherwise indigestible dietary polysaccharides is reflected in its genome. It encodes 241 glycoside hydrolases and polysaccharide lyases. This means that the organism has the ability to break down xylan-, pectin- and arabinosecontaining polysaccharides that are common components of dietary fiber.[15] When dietary polysaccharides are scarce, B thetaiotaomicron turns to host mucus by deploying a different set of polysaccharide-binding proteins and glycoside hydrolases. Other Bacteroides species include B vulgatus, B distasonis, and B fragilis. All play a role in the digestive process.

syx

New Research

Microbiologists from Louis Pasteur (1822–1895) and Ilya Mechnikov (1845–1916) to present-day scientists have emphasized the importance of understanding the contributions of our microbiota to human health and disease. Mechnikov, who won the Nobel Prize for Physiology and Medicine in 1908, was one of the first researchers to study the flora of the human intestine.[16] He developed a theory that senility is due to poisoning of the body by the products of these bacteria. To prevent them from multiplying, he suggested a diet containing milk fermented by bacilli, which produce large quantities of lactic acid.[16]

Today, science is on the verge of understanding how the body maintains a state of equilibrium with its incredibly complex enteric microflora.[17] Appropriate immune recognition is also essential to host-bacteria symbiosis (i.e., the biological association of two individuals or populations of different species). It has recently been shown that the recognition of commensal bacteria by epithelial cells protects against intestinal injury.[17] Other research indicates that use of antibiotics reduces the capacity of intestinal microflora to metabolize phytochemicals into compounds that may protect against cancer.[18] However, antibiotic use also disrupts the intestinal microflora metabolism of estrogens, which results in lower levels that might decrease the risk of some hormonal cancers. Use of antibiotics may be associated with cancer risk through effects on immune function and inflammation, although little is known about these mechanisms.[19,20]

Intestinal bacteria release chemical signals recognized by specific receptors—called toll-like receptors (TLRs)—of the innate immune system. The interaction helps to maintain the architectural integrity of the intestinal surface and enhance the ability of the epithelial surface to withstand injury. A deficiency in any of the numerous signaling molecules can induce intestinal inflammation, which may be a precursor of inflammatory bowel disease. Research is now ongoing to understand various types of TLR activation to ascertain how this information can be used to treat irritable bowel syndrome, Crohn's disease, and other types of intestinal inflammatory conditions.[21]

A group of medical researchers in Ireland recently identified five probiotic bacteria than can prevent Salmonella infection in pigs and, if translatable to humans, could potentially reduce Salmonella-induced foodborne illnesses, which cause between 500 and 1,000 deaths every year in the U.S.[4] This same group is also investigating the human microbiome for antimicrobials against pathogens. They have isolated a compound called lacticin 3147 from the harmless bacterium Lactococcus lactis, which is used to make cheese. Recently, lacticin 3147 has demonstrated antimicrobial activity against a range of genetically distinct Clostridium difficile strains isolated from the human gut. This indicates that lacticin 3147 may offer a new treatment for C difficile–associated diarrhea, a serious condition that affects 3 million people per year in the U.S. and is a major problem in hospitals.[4]

There is evidence confirming the effects of Lactobacillus GG in preventing diarrhea and atopy in children.[22,23] These organisms are thought to occupy binding sites in the gut mucosa that prevent pathogenic bacteria from adhering. Lactobacilli also produce bacteriocins that act as local antibiotics. Diarrhea associated with antibiotics may result when the antibiotics disrupt the normal flora in the gut of a healthy person. Such disruptions cause dysfunction of the gut's ecosystem and allow pathogens to colonize the gut and gain access to the mucosa. A number of organisms have been studied as probiotics to prevent antibiotic- and C difficile–associated diarrhea (Table 1).[24] Whether probiotic supplements stop this process by reducing the disruption or by acting as substitutes for healthy flora is unclear.

Table 1. Strain-Specific Organisms Researched in the Prevention and Treatment of Antibiotic-Associated Diarrhea
Bifidobacterium
Lactobacillus GG (LGG) a
Lactobacillus casei
Lactobacillus plantarum299v
Enterococcus faecium (SF68)
Saccharomyces boulardii a
Saccharomyces cerevisiae
Bacillus clausii
Clostridium butyricum
Lactobacillus acidophilus

a S boulardii and LGG are the most promising.
Source: Reference [24].
Final Thoughts

Recent evidence has shown that microbes and their genes play important roles in the development of our immune systems, in the production of fatty acids that enhance healthy intestinal cell growth, in elaborating molecules that inhibit the growth and virulence of enteric bacterial pathogens, and in the detoxification of ingested substances that could otherwise lead to cancerous cell growth or alter our ability to metabolize medicines.[25,26]

Pharmacists will thus become more involved in counseling patients interested in taking probiotics. In Europe, probiotics are regarded as medicines and prescribed along with antibiotics.[27] In the U.S., pharmacists can advise patients to take such probiotic products as Culturelle, Florastor, or Lactinex while on antibiotics and for 3 to 7 days thereafter.[3] The same products can be taken to help prevent traveler's diarrhea. They should be taken a few days before the trip and continued through its duration. Instruct patients to separate any probiotic and antibiotic doses by 2 hours to prevent the antibiotic from destroying the probiotic organisms.[3] Immunocompromised patients should be advised not to use probiotics because of the potential for systemic infections. Other side effects can include GI upset (e.g., flatulence, discomfort).

syx

... semakin kuat bukti bahwa persalinan normal lebih menguntungkan dari segi mikrobiota dan kekebalan tubuh bayi.

syx

Probiotics May Lower Risk for Nosocomial Infections in Hospitalized Children

May 6, 2010 — Probiotics may lower the risk for nosocomial infections in hospitalized children, according to the results of a randomized, double-blind, placebo-controlled trial reported in the May issue of Pediatrics.

"The incidence of nosocomial infections, predominantly gastrointestinal and respiratory, in children in developed countries is high, ranging from 5% to 44%," write Iva Hojsak, MD, from the Referral Center for Pediatric Gastroenterology and Nutrition, Children's Hospital Zagreb in Zagreb, Croatia, and colleagues. "There is no effective strategy for preventing these infections. The objective of our study was to investigate the role of Lactobacillus GG (LGG) in preventing nosocomial gastrointestinal and respiratory tract infections at a pediatric hospital."

In this study, 742 children aged 1 to 18 years were randomly assigned to receive LGG (n = 376) or placebo (n = 366) during their hospitalization. LGG was given at a dose of 109 colony-forming units in 100 mL of a fermented milk product, and the placebo consisted of the same postpasteurized fermented milk product without LGG.

Compared with the placebo group, the LGG group had a significantly lower risk for nosocomial infections. For gastrointestinal tract infections, the relative risk (RR) was 0.40 (95% confidence interval [CI], 0.25 - 0.70; number needed to treat [NNT], 15 (95% CI, 9 - 34); for respiratory tract infections, the RR was 0.38 (95% CI, 0.18 - 0.85; NNT, 30; 95% CI, 16 - 159).

For vomiting episodes, the RR was 0.5 (95% CI, 0.3 - 0.9), and for diarrheal episodes, the RR was 0.24 (95% CI, 0.10 - 0.50). For gastrointestinal tract infections lasting more than 2 days, the RR was 0.40 (95% CI, 0.25 - 0.70), and for respiratory tract infections lasting more than 3 days, the RR was 0.4 (95% CI, 0.2 - 0.9).

Length of hospital stay did not differ between groups (P = .1).

"The results of our randomized, double-blind, placebo-controlled trial suggests that Lactobacillus GG administration decreases the risk for nosocomial gastrointestinal and respiratory tract infections in hospitalized children," the study authors write. "LGG administration can be recommended as a valid measure for decreasing the risk for nosocomial gastrointestinal and respiratory tract infections in pediatric facilities."

Limitations of this study include exclusion of infants because the study product contained 100 mL of fermented whole cow's milk. In addition, most of the nosocomial infections diagnosed during the study were of short duration and of unproven cause.

"In that respect and with the relatively high NNT of 15 for gastrointestinal infections and 30 for respiratory tract infections, it could be argued that LGG treatment for all hospitalized children may not be justified," the study authors conclude. "Identifying the appropriate groups of patients for whom the prevention of nosocomial infections is most warranted could be the right direction, particularly because it has been shown that an NNT below even 40 is significant if just 1 severe infection is prevented....We encourage future studies of children who are younger than 12 months."

Pediatrics. 2010;125:e1171-e1177.

syx

Probiotics May Help Babies With Constipation
By Genevra Pittman

NEW YORK (Reuters Health) Jul 02 - Some probiotics may help treat chronic constipation in babies, according to a new study.

Children with constipation have been shown to have different types of bacteria in their stool than healthy children, suggesting that taking probiotics might help ease their symptoms. But there had been no definitive evidence to recommend this, the authors say.

Led by Dr. Paola Coccorullo of the University of Naples "Federico II" in Italy, the authors followed 44 infants who had been referred for functional chronic constipation. Half were assigned to take a dose of Lactobacillus reuteri mixed with a few drops of oil once a day for eight weeks, while the others were fed an inactive placebo.

The researchers asked parents to keep track of how often their baby had a bowel movement and the consistency of the stool, in addition to babies' "inconsolable crying spells."

When it came to stool consistency and crying, it didn't matter whether a baby was taking L. reuteri or the placebo. Both groups had general improvements in their stool consistency but cried more later in the study than at its start.

Babies taking probiotics, however, had significantly more bowel movements than babies on the placebo after two, four, and eight weeks, suggesting an improvement in their constipation. At the beginning of the study, the probiotic babies had, on average, less than three bowel movements per week. By week eight, they had an average of almost five.

The probiotic treatment had no side effects, according to the report, which was published online June 14th in The Journal of Pediatrics.

Studies have shown that about 3% percent of babies suffer from constipation before their first birthday, and approximately a third of those continue to have symptoms for at least six months.

While not going so far as to recommend that parents of infants with constipation run to the pharmacy for probiotics, the authors conclude that "probiotics as a natural, safe, and well-tolerated treatment may provide a simple and attractive way" to treat chronic constipation in babies.

Current practices shouldn't change based on this study alone, said Dr. Marc Benninga, a pediatric gastroenterologist and nutritionist at Emma Children's Hospital in Amsterdam, who was not involved with the study. "I would never start with probiotics," he told Reuters Health. He would advise trying oral laxatives first.

Some doctors also recommend giving babies water or extra fiber to combat constipation.

Dr. Benninga said more studies of the effectiveness of L. reuteri are needed. Noos, an Italian company that sells the probiotic, provided it and the placebo, and contributed to the costs of publishing the paper in the journal.

[pranala luar disembunyikan, sila masuk atau daftar.]

J Pediatrics 2010.

syx

Clinical Evidence of Benefits of a Dietary Supplement Containing Probiotic and Carotenoids on Ultraviolet-induced Skin Damage

Deterioration of fibrillar structures of dermal tissue and clinical symptoms related to photoageing such as wrinkling, folding, shrivelling, patchy/mottled pigmentation, telangiectasia and sagging are the outcome of a long process and a progressive decline in skin function associated with cumulative UV-induced injury.[6]

As the alterations of dermal components and clinical signs require prolonged exposure over years to become apparent, it seemed more appropriate to focus our studies on early UV-induced alterations such as immune cell damage[36] and inflammatory responses as well as the development of pigmentation, the control of which is essential to prevent the appearance of sunspots and dyschromia. It also appeared interesting to study three types of exposure, i.e. 'extreme' (UV-SSR), 'moderate' (UV-DL) involving a far higher UVA content, and natural summer sunlight which corresponds to real conditions of sun exposure.

Sunburn related to UVR exposure can easily be quantified by noninvasive methods and represents one of the earliest effects of sun damage. The MED is defined by the COLIPA recommendations as the first perceptible unambiguous redness with clearly defined border,[37,38] and sun protection factor measurement is based on the determination of the MED. In the present study, DS intake resulted in a 19% increase in the UV dose required to produce erythema. This increase could be perceived as small regarding the sun protection factor provided by sunscreens, but the tested nutritional supplement exhibited this increase of MED without the absorbing or reflecting properties of sunscreens. Moreover, this result complies with previous papers reporting the effect of nutritional supplementation on skin erythema.[39,40] Lower skin erythema could result in less infiltration by neutrophils which release proteolytic enzymes such as elastase and metalloproteases that could play a role in skin photoageing.[41]

Investigating the effects of DS on the biological consequences induced by standard and cumulative exposure to UV-DL (i.e. nonextreme exposure conditions) reflects a more realistic situation for most human populations[14] compared with extreme UV-SSR. Moreover, it is impossible to study the effects of systemic photoprotection on the long-term effects of UVR exposure in humans. In this paper, we have addressed this question by studying early skin biomarkers biologically relevant for long-term damaging effects of UVR.

Among these damaging effects, sun exposure induces local and systemic immune suppression that might play a role in skin cancer in the long term.[42,43] This process is partly related to direct LC damage.[44,45] In a previous study, La1 intake was shown to accelerate the recovery of LC functionality after extreme UVR exposure.[32] Confirming previous results,[15] we observed that cumulative exposures to suberythemal doses of UV-DL resulted in a significant decrease in LC density. DS intake significantly prevented this decrease, suggesting a positive effect of DS in sustaining the cutaneous immune system following UVR exposure.

Photoageing refers to the effects of long-term UVR exposure and sun damage superimposed on intrinsically aged skin. Inflammation plays an important role in photoageing of human skin in vivo.[11] In CT1, we have shown that repeated exposure to suberythemal doses of UV-DL induces a significant increase in CD45+ cells. After supplementation, this increase was statistically lower, suggesting a beneficial effect of DS intake on UV-induced inflammation and probably on photoageing. These data are of importance with regard to a previous report[16] emphasizing a marked increase in inflammatory cells as a prominent dermal change induced by repeated suberythemal exposure to UVR.

Photoaged skin is characterized by pigmentary alterations such as lentigines and hyperpigmentation. Dermal dendrocytes share common features with macrophages,[46] and their density is increased in inflammatory dermatoses as well as in photoexposed areas.[47] They may be involved in photoageing[48] and hyperpigmented spots.[49] Controlling this cell population after UVR exposure might help to limit UV-induced hyperpigmentation. Repeated exposure to UV-DL had a tendency to increase numbers of type I dermal dendrocytes, and DS intake prevented this phenomenon.

Taken together, the effects of DS on early biomarkers of the UV signature suggest that nutritional supplementation with La1 associated with low doses of carotenoids may have beneficial effects on long-term UV-induced clinical features.

Another interesting point emerging from CT2 refers to the effect of DS intake on skin colour which is clearly more intense and more even in the DS group. Six weeks of DS intake induced a change in the colour of unexposed skin which is further mirrored in the colour change of tan developing after UV-SSR exposure. This result is probably not related to an effect on melanin synthesis but rather to a direct action of DS on skin colour, as we have shown a reduction of melanin content after DS intake, whereas the level of UV-DL-stimulated melanocytes in the exposed zone was similar before and after supplementation.

To our knowledge, there is no published study describing the effects of a nutritional supplement in real conditions of use (i.e. natural sunbathing during summer holidays). CT3 is thus representative of the most frequently encountered use of oral photoprotectants. In this study, both dermatologists and subjects reported the beneficial effects of DS intake on skin condition, skin colour, various types of sun intolerance and skin resistance to sun exposure.

Bioavailability of the nutritional supplement was not considered in this three-step study because serum and skin bioavailability of carotenoids is well documented[50,51] and La1 is speculated to be somehow able to modulate local or systemic cytokine levels that favour skin immune system homeostasis through interaction with the gut.

These three clinical trials demonstrate for the first time the effects of a DS combining probiotic La1 and nutritional doses of carotenoids in reducing early UV-induced skin damage as well as in modulating early skin biomarkers of UV effects. This latter result seems to suggest that DS intake may have a beneficial influence on the long-term effects of UVR exposure and more specifically on skin photoageing. This nutritional supplement thus represents a complementary strategy to sun avoidance and sunscreen use for a global approach to photoprotection.

syx

American Academy of Pediatrics Reviews Use of Probiotics, Prebiotics

December 2, 2010 — The currently known health benefits of probiotics and prebiotics, including those added to infant formula and other food products for children, are reviewed in an American Academy of Pediatrics (AAP) report published online November 29 in Pediatrics.

"Efforts to optimize the intestinal microbial milieu have increased the interest in adding probiotics and prebiotics to nutritional products. As with antibiotics, the use and efficacy of probiotics and prebiotics should be supported by evidenced-based medicine," write Frank R. Greer, MD, FAAP, and Dan W. Thomas, MD, FAAP, and the Committee on Nutrition; Section on Gastroenterology, Hepatology, and Nutrition. "The purpose of this clinical report is to review the medical uses of probiotics and prebiotics and to summarize what is currently known about their health benefits as dietary supplements added to food products marketed to children, including infant formula. The guidance in this report will help pediatric health care providers to make appropriate decisions regarding the usefulness and benefit of probiotics and prebiotics for their patients."

Probiotics are supplements or foods containing viable microorganisms capable of changing host microflora. Randomized clinical trials (RCTs) have shown probiotics to be modestly effective in treating acute viral gastroenteritis in healthy children. For otherwise healthy children and infants with diarrhea from acute viral gastroenteritis, giving probiotics early in the course may reduce the duration of diarrhea by 1 day.

Despite the lack of evidence for the efficacy of probiotics in treating antibiotic-associated diarrhea in otherwise healthy children, RCTs have shown that they are modestly effective for prevention.

Although more studies are needed, some evidence supports probiotic use to prevent necrotizing enterocolitis in very-low-birth-weight infants (birth weight between 1000 and 1500 g).

Before probiotics can be recommended for treatment of irritable bowel syndrome, Crohn's disease, colic, and constipation, or for prevention of common infections and allergy in children, additional studies are needed.

However, preliminary results were encouraging in RCTs in which probiotics were used to treat childhood Helicobacter pylori gastritis, irritable bowel syndrome, chronic ulcerative colitis, and infantile colic, or to prevent childhood atopy. Evidence to date has not shown a benefit of probiotics in treating or preventing human cancers or in treating pediatric Crohn's disease.

Routine use of probiotics or prebiotics added to infant formula and other foods intended for consumption by children is not supported by currently available evidence of clinical efficacy, but these formulas do not appear to harm healthy infants and children. However, probiotics should not be administered to children with chronic or serious diseases, including children who are immunocompromised, chronically debilitated, or who have indwelling medical devices.

Prebiotics are supplements or foods containing a nondigestible food ingredient that selectively promotes growth and/or activity of indigenous probiotic bacteria. Prebiotics found in human milk may help reduce common infections and atopic eczema in healthy infants, but more evidence is needed before adding prebiotics to infant formula can be recommended.

"Important questions remain in establishing the clinical applications for probiotics, including the optimal duration of probiotic administration as well as preferred microbial dose and species," the report authors conclude. "The long-term impact on the gut microflora in children is unknown. It also remains to be established whether there is significant biological benefit in the administration of probiotics during pregnancy and lactation, with direct comparison to potential biological benefit derived from probiotic-containing infant formulas."

Pediatrics. Published online November 29, 2010