NEW FOCUS ON ASPARTAME-SAFETY ISSUE RESURRECTED

Amongst all the synthetic sweeteners Aspartame has been able to capture substantial market till recently because of its inherent properties to satisfy consumers regarding its efficacy in simulating taste of natural sugar and its relatively low cost. Its major competitor Sucralose, though sweeter by three times, costs 10 times more making the industry opt for the former. However use of Aspartame, permitted in all foods in countries like the US, is self-limiting because it is stable only at a pH of about 4.3 and its major is restricted to soft drinks with pH range between 3 and 5. It is also unstable under alkaline conditions and at high temperatures making it an unsuitable candidate for use by the bakery industry. At a pH of 7 the half life of Aspartame is hardly a few days while at pH 4.3 it can be as high as 300 days.

Though Aspartame was discovered as early as 1965, its widespread use became common from 1996 onwards with the USFDA clearing it for use in all food products. This makes sense because it cannot be used in many products because of pH conditions and temperature of processing. Still it is believed that over 6000 products contain Aspartame singly or in admixture with Saccharine or Acesulfame in about 90 countries in the world. Relatively high ADI of 50 mg per kg body weight for adults make it suitable for many products and generally an average consumer takes less than 10% of the ADI through products containing this synthetic sweetener. As such there ought not to be any safety scare while using Aspartame by the food processing industry.

One of the serious apprehensions while using Aspartame as a sweetener is its break down products that may accumulate in products standing on the retail shelf for long or others which have undergone severe processing conditions. The artifacts in such products include Phenylalanine and Methanol. While Phenylalanine may pose heath risks for consumers with the genetic disorder Phenylketonuria, Methanol is a toxic substance considered highly harmful beyond a certain concentration. Of course suitable label declaration can forewarn consumers suffering from Phenylketonuria regarding the potential harmful effect it can have on them but presence of Methanol evokes fears about its likely impact on health. What is not realized in this debate is that concentration of Methanol that can cause injury has to be much higher than what is generated in products containing Aspartame. Added to this human blood, urine, saliva and exhaled air do contain methanol and many fruits have methanol as a natural constituent.

A recent controversy regarding the safety of consuming a particular diet drink from a beverage major containing Aspartame has brought back the memories of earlier skirmishes between pro and anti Aspartame lobbies during nineteen eighties and nineties. Though it has some political and economic implications, EU is not taking any chance and has undertaken urgent review of the safety of Aspartame in the light of some new studies linking its consumption to premature births and cancer. The European Food Safety Authority (EFSA) and the UK's Food Standards Agency (FSA), have categorically ruled out any link between Aspartame and any health disorder.

The focus has been on the likely toxic effect of Methanol, a nerve toxin, generated in the products on human health as formic acid and formaldehyde are formed when Methanol is metabolized in the body and these metabolites are also strong nerve toxins. According to a most recent medical review "weight of the existing scientific evidence indicates that Aspartame is safe at current levels of consumption as a non-nutritive sweetener". Of course there could be many non-believers in such assertions because of the enormous economic stake the Aspartame manufacturing industry has in safe guarding its interests. One can only hope that the review being undertaken by EU which can be expected to bring out a balanced conclusion, will settle this issue once for all.

V.H.POTTY
http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com

ASPARTAME SAFETY-A CONTROVERSY REVISITED

Whether one likes it or not artificial sweeteners are here to stay as an ingredient in many consumer food products because there are millions of people who have restrictions regarding intake of natural sugars either for medical reasons or for weight control. The question of selection of a particular non calorie sweetener is difficult because each one available to day has one or the other drawback as none is considered absolutely satisfactory. Consumer is further confounded by claims and counter claims by different brands regarding the virtue of their products. Amongst the sweeteners which have been established as acceptable with adequate safety credentials, Aspartame was predominantly in use till the year 2004 and more recently Sucralose and Stevia glycosides are in the lime light because of their perceived superiority and cost considerations.

Aspartame, discovered by G D Searle and Company in 1965 had a turbulent history before becoming universally accepted as a sugar substitute till recently. It is the methyl ester of aspartic acid/phenyl alanine dipeptide and got its first approval in 1975 and to day it is considered safe in more than 90 countries. It is 200 times sweeter than sucrose and both Sucralose and Stevia score over it in terms of intensity of sweetness. Under continuous attack from critics on safety issues, it was subjected to hundreds of safety studies and most recently it was declared safe again in 2007. Besides the stability of Aspartame under high temperature or under acidic and alkaline media is not considered adequate for application in many foods though there are more than 6000 consumer food products in the market containing this sweetener. After the expiry of its patent protection in 1994, there are more producers of Aspartame, most prominent being the Ajinomoto Company which enjoys a market share of 40% out of a total world production of 15000 tons.

The controversy regarding the safety refuses to die down and no matter how much scientific evidence is generated there will always be skeptics who do not want to believe the claims, probably out of too much concerns for their own health. How ever keeping the controversy alive can be harmful to the product as is evidenced by some sustained legal and other obstructions against Aspartame. This has of course added to general concerns over artificial sweeteners and fed growing interest in natural ingredients, including Stevia, which comes from a plant native to South America. Stevia has been used in food and drink products sold in markets in Asia and South America for decades but industry recognition of the ingredient has grown since the FDA cleared its use in the US in 2008. The food and drinks sector is awaiting full EU clearance, although France has given its approval under a rule that allows a member state to give a temporary, two-year green light to an ingredient.

Stevia has to go a long way to catch up or replace Aspartame though giants like Cargill have joined the Stevia club to corner significant share of global sweetener sales. It is estimated that out of a world business of $ 350 million in artificial sweeteners, Aspartame has a share of 27% while Stevia sales were just $79m, or 6% of the market. If Stevia and Sucralose become more attractive choices, Aspartame market is bound to slide go down progressively, especially because of the on-going controversies vis-à-vis its safety. Given the choice, the safety of the sweeteners being not an issue, users may increasingly prefer Stevia and Sucralose as their sweetener intensity is much higher than Aspartame while the unit cost is almost same. With large mega players like Cargill entering Stevia business the sugar substitute business is bound to heat up in the coming years and if competition can bring down the prices, consumer will be the happiest lot! Natural sugar, be it from Sugarcane or Sugar beets may see its role increasingly being marginalized because of the plethora of health disorders attributed to its consumption.

V.H.POTTY

http://vhpotty.blogspot.com/
http://foodtechupdates.blogspot.com

NANOTECHNOLOGY-FOOD SAFETY ISSUES

Reproduced below is a contribution from Dr Ramesh V Bhat, an internationally eminent food safety expert which dwells upon the safety issues that confront the food industry because of the application of emerging nanotechnology processes and products. He is Hyderabad based and can be contacted through this blog.

V H Potty
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Maintaining a safe and nutritious food supply is an essential pre-requisite to achieve food security, nutrition and safeguard the general health of the population. Though food is the most regulated commodity in the world, rapid advances in food technology in the globalized era are posing newer challenges to food safety.

Nanosciences and nanotechnologies are new approaches to research and development that concern the study of phenomena and manipulation of materials at atomic, molecular and macromolecular scales, where properties differ significantly from those at a larger scale. Applications for the use of nanotechnology in food products, dietary supplements and their packaging offer tremendous potential. The potential health and environmental risks of nanoscale materials need to be assessed before they are introduced into food. At present there is insufficient data publicly available to reach meaningful conclusions on the potential toxicity of food or color additives incorporating nanomaterials. Nanoparticles may be handled differently in the body than their previously approved, macro counterparts. Information on the bioaccumulation and potential toxic effects of inhalation and/or ingestion of free engineered nanoparticles and their long-term implications for public health is needed. Nanoscale materials may also present new challenges in relation to exposure assessment, including measurement of nanoparticles in the body and in complex food matrices.

Nano-sized particles were found to traverse through heart, lung, transported along nerves, pass through blood brain, blood retinal and blood placental barriers etc. opening the area of nano-toxicology. Potential toxicity could include, generation of reactive oxygen species with concurrent inflammatory response, mitochondrial perturbation producing inner membrane damage, Uptake by reticuloendothelial cells in various organs producing asymptomatic enlargement and potential dysfunction, Protein denaturation and degradation, Uptake in neuronal tissue and DNA damage.

In the past, approval systems for food additives have not generally taken into consideration the particle size of the additive. For nanoparticles, this is obviously an important aspect Future food regulations may therefore need to be more specific in relation to such issues. In 2007, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) affirmed that neither the specifications nor the ADIs for food additives that have been evaluated in other forms are intended to apply to nanoparticulate materials. Recently WHO had provided more information on the safety of Nanoparticles in food.

The European Food Safety Authority (EFSA) has issued a draft opinion that there are broad uncertainties over the safe use of nanotechnology for foodstuffs, and more research is recommended. According to it only a limited number of oral toxicity studies using Engineered Nano Materials (ENM) have been published. Potential intracellular targets of ENM toxicity are e.g. plasma membranes, mitochondria and nucleus. The general mechanisms of injury have been shown to include e.g. lipid peroxidation, ion channel blockage, pore formation, physical disruption, oxidative stress; protein aggregation and DNA damage There are preliminary indications of association of GI disorders with absorption of ENM. There are reports of increased uptake of ENM during GI inflammation, findings of particles in colon tissue in subjects suffering from ulcerative colitis and speculations that ENM exposure might be associated with Crohn’s disease.

Several studies report oral toxicity of 20-60 nm selenium nanoparticles (Se-NP) in rats. With single gavage dosing, sodium-selenite ions were more toxic than the Se-NP . This was confirmed when the Se-NP were administered in feed to rats (2-5 mg/kg; appearance in the feed not defined) for 13 weeks. Single gavage administration to mice of copper nanoparticles (Cu-NP) with average size 23.5 nm was compared to microparticle (MP)-Cu (17 μm) and Cu ions .The doses were high (up to 1,080 mg/kg bw), which caused agglomeration of particles, with intestinal obstruction.. Dose-dependent pathology occurred in kidney, liver, spleen and blood (but not lung, heart, brain, testes or ovaries) in animals exposed to nanoparticles (but not in those exposed to microparticles). After single gavage administration of high doses (5 g/kg bw) of zinc as nanoparticles (58 nm) and MP (1.08 μm) to mice there was GI inflammation in both groups, in spite of attempts to avoid particle agglomeration The toxicity patterns were not consistent: in some aspects, the nanoparticles were more toxic (anemia, kidneys, heart) than the MP, which seemed to be more hepatotoxic. In a later single-dose oral toxicity study of ZnO (1-5 g/kg bw) in mice, two sizes of ENM (20 and 120 nm) were compared to conventional macroscale material. The sizes of the ENM were checked in the gavage, and were found to average 44.8 and 187.5 nm, respectively. Again, the toxicity pattern was complex: the 120 nm ENM were most toxic in stomach, liver, heart, spleen, kidneys and blood, while the 20 nm ENM were similar to the toxicity of the macroscale material (except in pancreas, where they were the most toxic). However, no dose-dependency was observed.

Titanium dioxide (TiO2) nanoparticles (25, 80 and 155 nm) administered as single high-dose 682 gavage (5 g/kg bw) to mice resulted in frequent oesophagus rupture. Titanium dioxide (TiO2) nanoparticles (25, 80 and 155 nm) administered as single high-dose gavage (5 g/kg bw) to mice resulted in frequent oesophagus rupture. The 80 nm particles accumulated predominantly in the liver, the 25 and 155 nm ones accumulated primarily in spleen. Kidney, liver and heart damage was observed with all sizes, with 80 and 155 nm particles producing the most pronounced effects, while blood effects (e.g. increased serum lactate dehydrogenase and alpha-hydroxybutyrate dehydrogenase levels) were most pronounced for the 25 nm particles.

The presence of ENM in food might affect normal food components or contaminants. Lectins used for coatings of nano encapsulates can be cytotoxic or induce inflammatory responses carbon nanotubes with similar characteristics to asbestos, in terms of fibre length, rigidity and persistence, were shown to induce "asbestos-like" granulomatous inflammation after intraperitoneal administration in a mouse model which indicates that the morphology of the ENM affects toxicity. Numerous in vitro studies have shown that some ENM induce oxidative stress at high concentrations. There are some data to indicate possible genotoxic and inflammatory responses in vitro.

A recent intraperitoneal study indicates that fibrous shape of some ENM might be important in determining toxicity. A common finding in the in vitro assays, independent of the ENM studied, seems to be the generation of reactive oxygen species A major consequence of oxidative stress is damage to nucleic acid bases, membrane lipids and proteins. Immune and inflammatory effects can be triggered by oxidative stress and/or production of pro-inflammatory cytokines in the lungs, liver, heart and brain Effects of inhaled ENM on the cardiovascular system include heart rate changes, pro-thrombosis and acute myocardial infarction.

It is prudent to conclude, after taking into account the above observations of the EFSA that more food safety studies and risk analysis carried out before accepting use of nanotechnology for food and beverage.

Dr Ramesh V Bhat