Nutraceutical: Food as Medicine

By Olubunmi Tayo-Fasuan
Lemon-TreeNutraceutical is a broad term used in describing a food or food component that provides health and medical benefits in addition to the basic nutritional value found in the food. It is a new focus in preventive medicine due to its therapeutic and prophylactic properties.

The benefits derived from nutraceuticals are:

  • prevention of chronic diseases;
  • delay in aging process;
  • increase in life expectancy;
  • improvement of health;
  • boosting of self confidence and mood.

Nutraceutic chemicals are found in plant as phytochemicals, in food as antioxidants and in microorganisms as probiotics. Nutraceuticals can be categorized into different types:

  • Dietary Supplements – isolated or purified food component sold in medicinal forms e.g.  capsule, tablet, powders, liquid or extracts;
  • Functional foods – foods that have been fortified or enriched to restore the original nutrient content before processing  back to it e.g. addition of vitamin D to milk.

Hippocrates, the father of Western medicine advocated the healing effects of food when he said “let thy food be thy medicine and thy medicine be thy food”.  Therefore, eating food with nutraceutical properties is an optimum goal of anyone who wants to be healthy. Examples of food components with nutraceutical properties are:

  • Lycopene, a natural red pigment synthesized by plant and microorganisms. It is found in red fruits and vegetables particularly tomato.
  • Beta Carotene is found in carrots, broccoli and other green-leafed vegetables.
  • Lutein is found in Peas and green vegetables, particularly Spinach.
  • Soy Isoflavones found in Soybeans and Soybeans products such as Soymilk and Soysauce
  • Tea polyphenols found in Camellia sinensis, an evergreen shrub native to South-East Asia
  • Flavonoids found in Citrus and tea.

The list cannot be exhausted here. But arguably, preference for consumption of nutraceuticals can do us more good than synthetic foods and drugs. But the future of curative and preventive medicine can definitely be in nutraceutical foods.

Microorganisms in Respiratory Tract Infections

lungsRespiratory tract infections (RTIs) are infections which affect the organs involved in the exchange of gases in the body, and they range from mild to fatal infections. They can be broadly divided into two: the upper respiratory tract infections (URTIs) and lower respiratory tract infections (LRTIs).

URTIs are usually common and self-limiting, involving organs like the pharynges, nasopharynges, paranasal sinuses and tonsils. However, some microbes can cause LRTIs independently or through dissemination from URTIs, affecting organs like the lungs, bronchioles and alveoli.

RTIs are caused by a variety of microorganisms including bacteria, viruses and fungi. Bacterial URTIs are usually acute infections which can resolve with little or no treatment. They include Strep Throat caused by Streptococcus pyogenes and Diphtheria caused by Corynebacterium diphtheriae. Strep throat often proceeds to tonsillitis and pharyngitis if treatment is not given fast enough.

LRTIs caused by bacteria are usually serious and chronic, especially when treatment is also delayed. Examples are Tuberculosis caused by Mycobacterium tuberculosis and Pertusis (whooping cough) caused by Bordetella pertusis. The well-known pneumonia can be caused by three different bacteria: Steptococcus pneumoniae, Klebsiella pneumoniae and Mycoplasma pneumoniae.

Fungal RTIs are less frequent, but are usually chronic in nature due to the filamentous nature of fungi. The most common fungal RTIs are Coccodiomycosis (valley fever) caused by Coccodiodes immiitis and Histoplasmosis (Splunker’s disease) caused by Histoplasma capsulatum. Both infections are common in patients with AIDS or other immunodeficiency states.

Viruses are perhaps the most common causative agents of RTIs, given that 70-80% of most RTIs are viral in origin, with bacterial RTIs as secondary, superimposed infections, which also cause complications. Most viruses can cause infections which present the same symptoms or pathologies.

For instance, the common cold, otherwise called acute viral nasopharyngitis, is a mild URTI of the nose and throat caused chiefly by rhinoviruses and other viruses like coronaviruses, echoviruses, paramyxoviruses and coxsackieviruses. Sore-throat, another URTI otherwise called pharyngitis, is the inflammation of the pharynx, and it is usually caused by over 45 antigenic types of adenoviruses.

Viral LRTIs, like their bacterial counterparts, are more serious and life-threatening. As noted in viral URTIs, different viruses can produces the same infection and diseases. Examples include Bronchiolitis caused by respiratory syncytial virus (RSV), influenza virus, parainfluenza viruses and coronaviruses to mention some.

Other diseases include viral pneumonia, which like bacterial pneumonia is an inflammatory diseases caused when fluids fill the alveoli. Viruses which commonly cause pneumonia include influenza virus, RSV, adenoviruses and metapneumovirus. Others include herpes simplex viruses (HSV), varicella-zooster virus (VZV) and cytomegalovirus (CMV).

Severe acute respiratory virus (SARS) is caused by a coronavirus now known as SARS coronavirus. It is a serious form of pneumonia resulting in acute respiratory distress and sometimes death. Also, there is Respiratory syncytial virus infection common in infants and young children caused, as the name implies, by RSV.

While the various infections and diseases mentioned above are caused by different microorganisms and result in varying pathologies, most if not all, are transmitted basically the same way: through contact with respiratory droplets from either infected individuals or inanimate objects. In another words, it is contracted through nasal discharge from infected people.

During the infection cycle of these microbes, especially viruses, cells of the respiratory system are destroyed, including the immune cells, paving way for secondary infection from bacterial or fungi. Also, viral infection of the upper respiratory tract are usually localized, that is, they don’t spread toward the lower tract; although, super-infection by bacteria may occur, leading to dissemination.

LRTIs are more serious and severe due to their interference with the exchange of gases in the lungs as a result of inflammation (bronchiolitis) and influx of fluid into the lungs (pneumonia). Generally, dominant symptoms of URTIs and LRTIs are due to the inflammatory response of the body defense system. These symptoms include runny nose, nasal congestion, coughing, headache, fatigue, breathing difficulty, fever, dizziness and even coma and death.

The modes of transmission of both URTIs and LRTIs are basically the same, hence the methods of prevention are also the same: avoiding contact with nasal discharges from infected persons and regular washing of hands. Treatments are however different from one disease to another because of the nature of microorganisms involved.

Antibiotics/antibacterial drugs are used in treating infections caused by bacteria, while antivirals drugs are used in treating those caused by viruses. The use of antibiotics is ineffective against virus-induced infections, though they can be used to treat bacterial secondary or super-imposed infections.

Use of antibiotics should also be cautioned against in treating RTIs as they can lead to death of the normal microbiota of the body and/or emergence of virulent, antibiotics-resistant bacteria which can cause secondary bacterial infection.

More comprehensive articles would be written later where incisive and intensive discussion would be given on individual respiratory tract infections and diseases together with their causative agents, pathogenesis, symptoms, epidemiology, prevention, control and treatment.

Immunopathology: How our immune system can turn against us.

immuneOur immune system is designed to primarily protect us, and over thousands of years of evolution, they have developed to be a dynamic and adaptive system capable of containing any infection or/and its agent(s).  However, they can become real nuisance or deadly concern whenever they overdo their work due to overzealousness or failure of the control mechanisms. So much has these occurrences become an issue that a branch of medicine has emerged to study and proffer solutions to them under clinical pathology. These defects are called immune disorder.

The immune system can be subdivided into cell-mediated immunity and antibody-mediated immunity. Of course, as the names imply, the former consists of vast arrays of immune cells like the phagocytes (macrophages and neutrophils), T-lymphocytes and B-lymphocytes, while the latter chiefly involves the antibodies or the immunoglobulins.

Also, we have the innate – general or non-specific – immunity and adaptive – specific – immunity. Innate immunity refers to inherent or in-born defences against infection, they are like the first line of defence against coming infection and their mode of defence is usually general in nature. Examples include the skin, the stomach acidity, the mucociliary escalator of the respiratory system and the flushing action of urine and tears. In fact, I’ve read somewhere that the normal microflora of the body can even be considered as an innate defence.

Other highly ‘specialized’ but non-specific, local defences employed during the early stages of infection include the cytokines, complements, acute phase proteins e.g. C-reactive proteins (CRP), Natural Killer (NK) cells and the phagocytic cells. Cytokines include interferons (IFNs), interleukins (ILs), Tumour Necrosis Factors (TNFs).

The adaptive immunity is quite the opposite: they are highly specific against a wide range of microorganisms and they have immunological ‘memory’, that is, they can remember the offender (infectious agent) that causes the last crime (infection). They consist mainly of the T-lymphocytes or T cells and the B-lymphocytes or B cells. The T cells mediate the cell-mediated immunity, while the B cells mediate the antibody-mediated immunity or popularly called humoural immunity.

These vast arrays of immune components all help in protecting the body against external and internal antigens like viruses, bacteria and tumour cells. However, trouble comes when they are too over-enthusiastic in carrying out there functions. In fact, some diseases are caused largely by the immune system in response to ‘superficial’ infections which would have resolved on their own without much ado.

Notable diseases associated with this state of immunological disorders are tuberculosis and hypersensitivity reactions. In tuberculosis, the engulfment of the causative agent Mycobacterium tuberculosis by macrophages and degrading it basically ought to control the infection. However, the microbe is smarter than allowing that to happen, secreting substances like sulpholipids in its cell envelope which inhibit the phagosome-lysosomal fusion, thus allowing intracellular survival of the organism. Even if fusion occurs, the waxy nature of the cell envelope of the microbe reduces the killing effect.

What’s more, the microorganism starts multiplying within the macrophage.

But the immune system, especially the macrophages, are having none of that, mobilising themselves in large numbers in order to contain the infected macrophage(s). This leads to the formation of granulomas, a collection of macrophages, which prevents dissemination of the mycobacterium to other cells.

Most of the time, this situation induces the bacterium to go dormant within the granuloma, leading to a form of latent infection and development of abnormal cell death called necrosis. This may eventually lead to the release of the organism to cause infection again propelling further action from the immune system and causing extended damages.

 

Hypersensitivity reactions, which include the common allergic reactions like asthma, are other cases of the system turning against its owner. There are presently four types of hypersensitivity reactions: including Type I (Immediate) reaction, mediated by immunoglobulin E and mast cells; Type II reaction, mediated by antibodies; Type III reaction, mediated by immune complexes and; Type IV reaction, mediated by T lymphocytes.

All these reactions are mediated by different components of the immune system and they follow three basically steps: (i) the first exposure to the antigen sensitizes lymphocytes (ii) subsequent exposures elicit a damaging reaction and (iii) the response is specific to a particular antigen.  For instance, in type II reaction, antibodies are produced against self-antigen or foreign antigens which can cross-react with self component of tissues.

In this case, the antibodies may cause opsonization, leading to antibody-dependent cellular cytotoxicity (ADCC); activate the complement system, another devastating immunological response if uncontrolled; recruit neutrophils and macrophages to cause further damage; or hinder the functions of normal cellular receptors.

These autoimmune reactions lead to diseases like systemic lupus erythematosus, rheumatoid arthritis, autoimmune haemolytic anaemia, insulin-dependent and –independent diabetes mellitus. The development of autoimmune conditions is due to the failure of tolerance toward the self components of the body by reactive immune components. Environmental and hormonal factors may also contribute to this, as well as infections which may modify self antigens and make them liable to attacks from the immune system.

Curing and preventing autoimmune responses is a not a staright-forward thing; it entails taking different paths to eventually reach the stage at which the reactions would be reduced or stopped. However, all efforts are always directed toward altering the function of the T cells, especially the T helper lymphocytes, whose main function is to ‘license’ other immune components to carry out their functions. This can be achieve by inhibiting their proliferation (using cyclosporine); inhibiting their functions (using corticosteroids); or simply killing the cells (using cyclophosphamide).

Mosquitoes: The Tiny Couriers of Infectious, Diseases-Causing Agents

By Tayo Fasuan
mosquitosMosquitoes are mainly known in Nigeria to be associated with malaria. The miniature, winged insect is the vector or carrier for Plasmodium, the causative parasite of malaria fever. This is also the reality in most tropical and subtropical regions of the world where malaria is either pandemic or epidemic. At the recently concluded World Malaria Day observed on 25th of April at the University College Hospital, Ibadan, the deadliness of malaria was again brought to fore, and various speakers at the occasion laid emphasis on how to eliminate the disease and put an end to its reign of death, especially in children and pregnant women. Feelers out there were like if mosquitoes could be overcome, then it’s bye to malaria.

However, the obvious truth in the country is that most people don’t know that mosquitoes transmit more than the malaria parasite. Initially, countries which are malaria-free are known to be occasionally and periodically ravaged by other mosquito-borne disease-causing agents.However, researches have shown that even in malaria-infested areas like Africa, the incidences of other mosquito-borne disease are on the rise. Now with mosquitoes having found other disease-causing agents to transmit, we have to deal with diseases caused by agents like viruses, as if the scourge of malaria is not enough.

I once had this ridiculous notion that mosquitoes are calculatedly avoiding transmitting Plasmodium due to the incessant activities of humans to eradicate them because of malaria. So, they switched sides, preferentially transmitting other causative agents of diseases like viruses. Of course, I know that theory was ludicrous when I made; the only thing a mosquito is after, especially the female one who is always doing the biting (males don’t suck blood!), is to take a meal of blood from warm-blooded animals and use the warmness and proteins as materials for egg production.

You have to give thumbs up for these tiny creature anyway, because they don’t actually need the blood taken to feed themselves (mosquitoes feed mainly on glucose gotten from nectars and plant juices), but to take care of their eggs. And some of these females die trying while the males wouldn’t take the risk!

I was recently with a colleague of mine who is trying to isolate some viruses from mosquitoes (over 1000!), and she was trying to sort them out into various species and types (genus). When observing her working, I couldn’t help but wonder how life would be fun if all mosquitoes suddenly disappear. I know that is impossible, and I know my colleagues presently carrying out researches on mosquitoes would not even tolerate that idea. Besides, according to Professor O.G. Ademowo, a researcher on malaria at the Institute of Advanced Medical Research and Training, College of Medicine, University of Ibadan, that is not about to happen at all, especially when even most developed countries have failed in doing just that. They are just too many and the factors supporting their growth and proliferation are just too numerous.

There are different types/species of mosquitoes under various genera (about 41) around the world. In Nigeria and Africa, the major ones include Culex, Aedes and Anopheles. Between these three large groups, there exists different species common to different parts of the world. Female Anopheles mosquitoes are the ones associated with the spread of malaria. Aedes and Culex are notorious for transmitting some group of viruses called arboviruses (arthropod-borne viruses). These viruses are generally transmitted by arthropods such as mosquitoes, mites, ticks, sand-flies and other haematophagous (blood-sucking) insects which can feed indiscriminately on animals.

Mosquito-transmitted arboviruses are many and they include the following: flaviviruses such as Yellow Fever Virus, Dengue Virus, West Nile Virus and Usutu Virus; alphaviruses such as Chikigunya Virus, Sindbis Virus, Semliki Forrest Virus and the Equine Encephalities Virus; and bunyaviruses such as Rift Valley Fever Virus, Crimean-Congo Haemorrhagic Fever Virus, Hantaan Virus and Dugbe Virus.

All viruses mentioned above are notably present in Africa, with some having long been isolated in Nigeria, while some are recently been discovered. They will be discussed individually in series in subsequent weeks, together with other viruses which have not been found to be in Africa, but whose circulation might be enhance by various factors including environmental and economical factors.

Conclusively, while some groups of mosquitoes are strictly associated with some specific infectious agents, researches have shown that other mosquitoes can be employed in the quest to disseminate the diseases. Though there hasn’t been any report indicating this change of vectors in Anopheles and malaria, there are already numerous publications indicating that arboviruses are capable of employing Anopheles, Culex or Aedes as vehicles in propagating their gospel of infections.

Stay tuned and stay healthy.

The Protective Characteristics of Breast Milk

Culled by Ade Oluwasanmi
breast feedingMammalian species produce breast milk which is suited to the specific nutritional needs of their youngsters. The chemical nature of various milks has been well studied in the last two hundred years. Recent immunologic studies have revealed some fascinating information which shows that breast milk boosts the host defenses of the neonate.

Up to the turn of this century, infants were exclusively breast fed, since it was considered not only the best but the safest food for them. Despite the universal practice of breast feeding, very little information is available about the advantages of breast feeding in the medical writings of the eighteenth and nineteenth centuries, except the mention of high mortality associated with “dry nursing” of infants. In fact, much effort was wasted by the medical practitioners of the day in establishing criteria for the selection of wet nurses on the basis of their hair color and temperament.

Artificial feeding of infants was looked upon with horror because of the attendant mortality, as high as 85-99% in foundling homes of Paris and Dublin in the late eighteenth century. Similar trends in mortality in artificially fed infants persisted throughout the nineteenth century in the, overcrowded cities of the U.S. and Europe, leading Holt (c. 1855-1924) to remark:

“In my practice, it is exceedingly rare to find a healthy child who has been reared in a tenement house and who has been artificially fed from birth.”

Much of this mortality, associated with cow’s milk, of course, resulted from bacterial contamination, a problem which was resolved only after pasteurization was instituted-and Chicago was the first city in the world to require it, in 1908. However, not all the reduction in morbidity and mortality in neonates can be attributed to improved sanitation, health care, and affluence. Careful analysis of several old studies from Europe and U.S., and some recent ones from developing countries, comparing mortality and morbidity of bottle fed and breast fed infants, showed significant protection from respiratory and intestinal infections in breast fed infants. Indeed, this information has considerable significance for the developing world.

As mentioned earlier, work by Ehrlich and Moro provided some information about the contribution of breast milk to the neonatal immune response. Recent improvements in immunology coupled with advances in technology, have seen a remarkable understanding of the functional qualities of breast milk.

The infant at birth has only one type of immunoglobulin, IgG, acquired transplacentally. Analysis of breast milk proteins shows that they contain a high level of IgA and some IgM and IgG-immunoglobulins which do not cross the placenta. There is little correlation between serum and milk antibodies in several other areas. Quantitative differences exist between the antibody titres to the same antigens at the two sites. Qualitatively, different classes of antibodies appear in the breast milk and serum following challenge with the same pathogen, e.g. antibody to poliovirus in the serum resides in the IgG class primarily, whereas in the colostrum it is in the IgA class. The third difference is within the IgA class itself. In breast milk 80% IgA is of the dimeric secretory type and only 20% resembles the monomeric serum IgA.

The immunoglobulin characteristics of breast milk, therefore, resemble those of the mucosal sites in the intestinal and respiratory tract. High titres of antibody are present in the colostrum which drops sharply over the next few days. There is no information to suggest that milk immunoglobulins are absorbed in sufficient quantities to contribute to the serum immunoglobulins of the newborn. However, secretory IgA can bind microorganisms and prevent their penetration of the intestinal mucosa. IgA can also lyse certain enteric bacteria in the presence of complement and lysozyme. In addition to the specific antibodies, breast milk also contains nonspecific humoral factors such as lysozyme, lactoferrin and lactoperoxidase.

Colostrum and breast milk contain I-2×106 leukocytes/ml. Macrophages make up 90% of these white cells; they form the primary line of defense against many pathogens. The other 10% of colostral cells are small lymphocytes with about equal proportions of B and T cells. The function of these lymphocytes is not precisely known, though an interesting relationship has been observed between the colostral B cells and antibodies, and the mucosal immune system. Recent work has demonstrated the existence of an immunologic broncho-mammary and entero-mammary axis, as evidenced by the following observations. First, a majority of B cells in colostrum differentiate into IgA secreting plasma cells just like the B cells at mucosal sites. Secondly, most of the antibodies secreted by breast milk are directed against enteric and respiratory pathogens. Indeed, experimental studies show that highest titres of antibodies develop in the breast milk following immunization by the oral and intratracheal routes rather than by the parenteral route.

According to Mabel Charles-Davies, a professor of Neonate Immunology at the University of Ibadan, breast milk also contains, in addition to the antibodies mentioned above, essential nutrients which are needed for the growth of the baby, and the development of its immune system. This statement was corroborated by John Anetor, a professor of Chemical Pathology and an expert in the field of nutrient-based immunity at the same University. According to Anetor, since the baby is usually being exclusively breast-fed for the first few months of delivery, the development of its immune system is fully dependent on the availability of nutrients from its mother’s breast milk.

It is evident then, that in the course of evolution each mammal has developed special characteristics in the milk which fulfill not only the nutritional needs but also provide other biologic advantages for its nursing newborn.

Additional information by Tayo Fasuan

Food-borne Microorganisms: The Basis and the Basics

By Susan Ogah      July 9, 2012

spoilt orangesMicroorganisms are everywhere. They can be found in the air, soil, water, on animals, and even on humans. Some are beneficial, such as those used to make fermented dairy, bread and wine. Some cause food spoilage. And, a small number are pathogenic (or harmful) and so can cause disease, such as foodborne illness.

The types of microorganisms can contaminate food and cause foodborne illnesses include bacteria, viruses, and parasites. Another group of microorganisms that one also needs to be concerned about are fungi, which are yeast and molds. When harmful microorganisms get into food and it is eaten, foodborne illness could result. The most common symptoms of foodborne illness are: diarrhea, vomiting, fever, sore throat with fever, and jaundice.

Foodborne illness can be grouped into two categories namely; food infection and food intoxication. Food Infection occurs when food contaminated with harmful microorganisms is ingested, while food Intoxication is as a result of eating food contaminated with the toxins (poisons) produced by some types of bacteria or mold; eating food contaminated with other biological or chemical toxins. Yet, there are some microorganisms which cause toxin-mediated infection that occurs when the microorganisms in the contaminated food proliferate in the body after ingestion and then release toxins.

Bacteria, as with most microorganisms, are not visible to the naked eye. Therefore, you cannot look at a food to determine if bacteria are there. Pathogenic bacteria cause foodborne illness and can grow in potentially hazardous food. Potentially hazardous foods are moist, have low acidity, and contain protein. Some examples of these foods are meat, milk, cooked vegetables, cooked rice, baked potatoes, poultry, and seafood.

Unlike animals and plants that are made up of many cells, bacteria are single-celled microorganisms. They come in varieties of shapes and are impossible to see without a microscope. Only when bacteria are in the form of a vegetative cell are they able to grow in food. However, some types are able to change into a different form, called a spore. When bacteria are in the form of a spore, they cannot grow in food. One major concern with spores is that proper cooking does not destroy them. Cooking will heat shock the spore so that it can turn back into a vegetative cell. If potentially hazardous food is cooked and then allowed to sit at room temperature, the heat shocked spores become vegetative cells; the vegetative cells then grow, and if their number is large enough, they could cause foodborne illness.

Therefore, it is very important that potentially hazardous foods be maintained at proper temperatures after cooking. If they are not at proper temperatures, they must be thrown out after four hours. Cooking or reheating potentially hazardous food that has been temperature abused will not always make it safe to eat.

As stated earlier, some bacteria form toxins and unfortunately, not all toxins are destroyed by proper cooking. Therefore, if potentially hazardous food is kept in the temperature danger zone for more than four hours, toxins might be produced. Common foodborne bacteria that cause produce toxin and cause food intoxication include Bacillus cereus, Clostridium botulinum, Clostridium perfringens, Shigella, Staphylococcus aureus. Those implicated in causing food infection areCampylobacter, Listeria monocytogenes, Salmonella, Vibrio, Yersinia.

Viruses are the smallest of the microorganisms that can also cause foodborne illness. One cannot also look at a food to determine if viruses are present. They are different from bacteria in that they do not grow in food and simply use food as a vehicle to get from one person to another. Therefore, viruses can contaminate any food. Water, salads, shellfish, iced drinks, and other ready-to-eat foods are sources of viral foodborne illnesses. Examples of viruses that cause foodborne illnesses are Hepatitis A, Norovirus and Rotavirus.

Like bacteria and viruses, most parasites cannot be seen. Like viruses, parasites also do not grow in food. There are two ways that parasites are commonly transmitted to humans through food: (i) Some parasites present in human feaces may contaminate drinking water or foods handled by infected persons, or vegetables and fruits grown on soils fertilized with infected feaces; (ii) Parasites naturally present in many animals, such as pigs, cats, rodents, and fish, may be transmitted if their meats are not cooked to proper endpoint temperature. Examples of parasites that can cause foodborne illness are: Cryptosporidium parvum, Cyclospora cayetanensis, Giardia duodenalis, Toxoplasma gondii.

Molds usually spoil foods, while some produce toxins which can cause illness. Molds can grow in a wide range of foods, but unlike bacteria, mold can grow in foods which have high acidity and low moisture content. Freezing does not destroy molds, they need air to grow and most produce spores. These spores can be transported by air, water, or insects. Spores produced by molds, when dry, float through the air and find suitable conditions where they can start growing again.

While most molds like warm temperatures, they can grow at refrigerator temperatures – 41oF (5oC) or colder. They can also tolerate salt and sugar, so they can grow in opened jars of jams, jelly and on cured, salted/salty meats, such as ham and bacon. Molds form roots and branches which are like very thin threads. The roots may be difficult to see when the mold is growing on food and may also be very deep in the food. Therefore, if mold are seen on a food, the whole of it must be discarded and not just the moldy portion, as most people commonly practiced.

Some molds cause allergic reactions and respiratory problems, and a few molds, in the right conditions, produce mycotoxins (myco – fungi) which can make a person sick. Mycotoxins are produced by certain molds found primarily in grain and nut crops, but are also known to be on fruit juice, apples, and other produce. However, not all molds are harmful. Some are used in industrial and food fermentation.

Yeasts are another group of fungi commonly found on plants, grains, fruits, and other foods containing sugar. They are present in the soil, in the air, on the skin, in the intestines of animals and in some insects. They are transferred from place to place by people, equipment, or food and air currents. Yeasts mainly cause food spoilage and do not really cause foodborne illness.

Prevention of foodborne illness can be achieved by the following ways:

  •     Buy all food from an approved and safe source.
  •     Use portable water for food preparation and cleaning
  •     Practice good personal hygiene
  •     Cooking foods to proper endpoint temperatures is the most common way to eliminate     parasites from food.
  •     Frequently and properly washing of hands.
  •    Store foods properly and only use cleaned and sanitized utensils and surfaces to store,     prepare, and serve food.
  • Keep food out of the temperature danger zone – Cook foods to proper temperatures and hold potentially hazardous foods at 41oF (5oC) or colder or 135oF (57oC) or hotter.
Fluoride in Toothpaste and Mouthwash: Does it really work?

By Ade Oluwasanmi

toothpasteIn most countries of the world, almost all toothpastes produced contain fluorides, especially tin (II) or stannous fluoride, which has been touted to help in strengthening the teeth. But like all seemingly good things, does it actually work? If yes, how does it work? If no, why is it being included in oral treatment? In a world where almost all sugary things taste like toothpaste, could this be a sweet cover-up? Or is this writer just being mischievous?

First, let us study the microbial population of the oral cavity, especially those affecting the teeth. The mouth offers an ideal ecological niche for a wide range of microorganisms due to the fact that it is perhaps the organ or cavity which interacts most with the outside environment after the skin. The activities which expose the mouth to these diverse microbial communities include:

  • eating different kinds of food and drinking water from different sources;
  • possessing uncouth behaviour of yawning without covering the mouth or perpetual habit of opening the mouth most time;
  • having a culture which permits kissing during greeting or more often than not having various sexual activities which involves kissing different partners

The list is endless because most of the time our oral cavity is working, either for speech making or chewing or… just opening it. Infancy is another issue because babies put most of the things they encounter in their mouths in order to determine its edibility or just its acceptability.

Due to all these activities, the mouth is second only to the skin in daily encountering of external microbes. However, just like any other ecological niche, some microorganisms, which are mainly bacteria, are more dominant than the others. The prominent ones include the streptococci especially Streptococcus mutans and S.sanguinis, lactobacilli, staphylococci, corynebacteria, and anaerobic bacteroides. Most of these organisms, called cariogenic microorganisms because of their roles in dental carries, are however been kept under control by the immune system.

Health conditions caused by these organisms are dental plaque, dental caries and periodontal infections. It should also be noted that most oral infections originate from the teeth or the gums. Dental plaque is a biofilm which forms naturally on the teeth by colonising bacteria due to the presence of food particles remaining on the teeth. These food particles act as substrates for these bacteria, which can be up to 1000 species at a time These plaques, though soft and can be removed easily using the fingernail, can however become a hardened and difficult biofilm called dental calculus.

Dental plaques can eventually proceed to dental carries and periodontal problems. Streptococcus mutans and Lactobacilli are the bacteria chiefly responsible for dental caries which is also called tooth decay, and they do this by producing “organic acids at the levels that induce demineralization of tooth structure…” Acids produced are as a result of fermentation of simple sugars (sucrose, glucose and fructose) deposited on the teeth.

In most countries of the world, almost all toothpastes produced contain fluorides, especially tin (II) or stannous fluoride, which has been touted to help in strengthening the teeth. But like all seemingly good things, does it actually work? If yes, how does it work? If no, why is it being included in oral treatment? In a world where almost all sugary things taste like toothpaste, could this be a sweet cover-up? Or is this writer just being mischievous?

First, let us study the microbial population of the oral cavity, especially those affecting the teeth. The mouth offers an ideal ecological niche for a wide range of microorganisms due to the fact that it is perhaps the organ or cavity which interacts most with the outside environment after the skin. The activities which expose the mouth to these diverse microbial communities include:

  • eating different kinds of food and drinking water from different sources;
  • possessing uncouth behaviour of yawning without covering the mouth or perpetual habit of      opening the mouth most time;
  • having a culture which permits kissing during greeting or more often than not having various  sexual activities which involves kissing different partners

The list is endless because most of the time our oral cavity is working, either for speech making or chewing or… just opening it. Infancy is another issue because babies put most of the things they encounter in their mouths in order to determine its edibility or just its acceptability.

Due to all these activities, the mouth is second only to the skin in daily encountering of external microbes. However, just like any other ecological niche, some microorganisms, which are mainly bacteria, are more dominant than the others. The prominent ones include the streptococci especially Streptococcus mutans and S.sanguinis, lactobacilli, staphylococci, corynebacteria, and anaerobic bacteroides. Most of these organisms, called cariogenic microorganisms because of their roles in dental carries, are however been kept under control by the immune system.

Health conditions caused by these organisms are dental plaque, dental caries and periodontal infections. It should also be noted that most oral infections originate from the teeth or the gums. Dental plaque is a biofilm which forms naturally on the teeth by colonising bacteria due to the presence of food particles remaining on the teeth. These food particles act as substrates for these bacteria, which can be up to 1000 species at a time These plaques, though soft and can be removed easily using the fingernail, can however become a hardened and difficult biofilm called dental calculus.

Dental plaques can eventually proceed to dental carries and periodontal problems. Streptococcus mutans and Lactobacilli are the bacteria chiefly responsible for dental caries which is also called tooth decay, and they do this by producing “organic acids at the levels that induce demineralization of tooth structure…” Acids produced are as a result of fermentation of simple sugars (sucrose, glucose and fructose) deposited on the teeth.

Periodontal (around the tooth) infections are infections affecting the gums and the structures supporting the teeth. When the bacteria causing dental carries spread downward toward the gum and the connective tissues, the immune system responded resulting in inflammation. Among the resulting infections are gingivitis and periodontitis, which as the names imply, are as a result of the inflammatory actions of the immune system.

So, how do fluoridated toothpastes, mouthwashes and varnishes prevent all these ‘toothy issues’? And what are the implications?

According to a study carried out in 2008 by A. Deepti and his colleagues of Meenakshi Ammal Dental College and Hospital in India, the actions of fluoride in dental carries prevention include:

  • altering the physiochemical properties of the teeth by making it more resistant to acid     dissolution due to the formation of fluoroapatite or fluorohydroxyapatite;
  • increasing the post-eruptive maturation of the teeth while also enhancing remineralization and inhibiting demineralization;
  • inhibiting bacterial enzymes like enolases, phosphatases, pyrophosphatases and proton- extruding ATPases.

It has also been reported by William E. Clapper that sodium fluoride affect the metabolism of oral lactobacilli by reducing their ability to produce lactic acid, inhibiting the dehydrogenase enzymes of lactobacilli and permanently reducing the ability of an actively acidogenic strain of lactobacilli to produce acid from glucose.

Additional evidence of fluoride effectiveness has also been given by Barboza-Silva et al (2005), where the inhibitory effects of fluoride on three urease-positive bacteria commonly found in the mouth were examined. In the study, it was found that “ureolysis by cells in suspensions or mono-organism biofilms of Staphylococcus epidermidisStreptococcus salivarius or Actinomyces naeslundii was inhibited by fluoride at plaque levels of 0.1–0.5 mm in a pH-dependent manner.”

Nevertheless, the experimental result actually means that fluoride inhibitory effect could also be inhibited by the acidity or alkalinity of the immediate environment!

According to their findings “direct fluoride inhibition of urease enzyme is enhanced by acidification” and microorganisms like Staphylococcus epidermidis with high ureolytic capacity, would lessen any tendency to lower the cytoplasmic pH value. This simply translates to the fact that fluoride does not have effect on all cariogenic microorganisms, though it should be noted that most of these organisms actually cause carries by producing acids, hence providing an optimum condition for fluoride to work.

Supporting reports which dent fluoride seemingly ‘invincibility’ was also provided by Tanomaru, J.M.G. et al.(2008), where it was reported that the interactions with other constituents of mouthwashes and at different concentrations may actually lessen its antimicrobial effects on the microbial community of the oral cavity.

A more direct attack on the antimicrobial ability of fluoride came two years ago in the 2010 review by Carole Clinch, of the dental research conferences in 1990 and 2001 where it was concluded that fluoride does not produce clinically relevant changes in the number or concentration of bacteria species found in dental plaque. According to her, fluoride may have subtle anti-microbial effects in vitro, but the in vivo evidence using fluoride concentrations commonly used in toothpastes (500–1500 ppm), with subsequent mouth-rinsing with water, fails to demonstrate any clinically significant antagonistic effect on the bacteria involved in dental carries.

“In fact, no available research has shown that F at 1 ppm in water significantly alters plaque metabolism or plaque growth (bactericidal effects)”, she reported. The reasons for this, according to the reviewer, might be due to the fact that either the oral bacterial community have developed antimicrobial resistance to the substance (as in antibiotic-like) or it has not been actually working as promoted by the agencies and organization producing fluoride-containing toothpastes and mouthwashes.

At the conclusion of her review, she asked lots of salient questions among which the most important one to me is: …Do the benefits of high concentration topical fluoride in dental products outweigh the risks of acute and chronic toxicity? This is a question for a vast majority of us whose unshakable faith in fluoridated toothpastes and mouthwashes have somehow blinded us to the fact that fluoride has been, and will always be, a chemical; like any chemical, no matter how good, it might be toxic, and hence its intake, like a Greek gift, should be regulated

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