Last partial update: September 2019 - Please read disclaimer before proceeding
Organic foods, pesticides and food additives
Many people are concerned about the quality of the foods they are eating. Principal concerns center around additives that may be harmful, pesticides, food allergies, and reduced nutritional quality in present-day mass-produced foods. Most of these concerns are based on myths that have been propagated in the media. Such stories make good press and almost anything can be claimed by the selective use of evidence. Discussion of three common nutritional myths follows.
- Food additives are NOT responsible for most food allergies and other medical problems.Most food allergies are caused by proteins in food, not food additives. While many people may think they have a food allergy, true food allergies, where people have a positive skin test to the food and symptoms after consuming it, are relatively uncommon; it affects about 6% of children and 2% of adults. The main causes are eggs, peanuts, cow’s milk, fish, tree nuts, sesame, shell fish, wheat, and soy. In Australia, only food additives that have been thoroughly tested by the Food Standards Australia New Zealand (FSANZ), formerly known as the Australian and New Zealand Food Authority, and have been found to be safe for general consumption, are allowed to be used in foods. The FSANZ is a government body that no has commercial interest in the food industry. In allowing the use of an additive, FSANZ cannot guarantee that it will never cause adverse reactions. This is, however, an uncommon problem and only a few additives have been associated with problems. (Tartrazine and monosodium glutamate are examples of additives that have caused illness in some people.) If worried about a reaction to a particular food, see a GP or dietitian. All food ingredients, including additives, are listed as numbers (or according to function) on food packaging and a list of these numbers is available from the on the FSANZ web site: www.foodstandards.gov.au Despite popular belief, there is good evidence that food additives are not commonly responsible for behavioural problems, such as hyperactivity, in children. The best way to avoid food additives is to prepare meals from fresh food as most additives are used to preserve food.
- Foods DO NOT contain high levels of pesticides. While levels are not zero, they are very low and within accepted safety limits. Levels are regularly checked around the country by FSANZ.
- Organic foods are NOT significantly better than other produce Organic foods are those grown without pesticides and chemical fertilisers. Generally, organic products have few nutritional advantages over conventionally grown produce, although there is some evidence that their mineral content may be higher and they may be higher in plant nutrients (termed ‘phytonutrients’). It must be said that there is not a lot of reliable information about this subject. The main advantage of organically grown fruit and vegetables is that they protect our environment and that is an important consideration for all Australians. However, if the extra cost of organically grown produce is likely to reduce fruit and vegetable consumption, then conventionally grown produce is perhaps the best option. There is no evidence that the nutrient content of foods today, organic or not, is significantly different to that of times past.
Poor food handling techniques that cause contamination (see below) are a far greater health concern than the myths mentioned above. For more information on food additives etc., see the FSANZ web site www.foodstandards.gov.au or the Dietitians Association of Australia web site www.daa.asn.au
Preventing food-borne illness
The vast majority of food-borne illness in Australia is due to contamination from microorganisms, mostly bacteria (and the toxins they produce) and viruses. It is a common problem with about four to seven million cases occurring each year. Most cases are associated with restaurants and caterers.
Some foods are more likely to cause illness than others. They include:
- Cold processed meats (especially uncooked fermented meats)
- Cold cooked chicken
- Pate
- Salads prepared in advance for salad bars and packaged salads (These products are produced on farms and often contaminated by small numbers of organisms. In these small numbers the organisms are harmless. However, they can grow quickly on the cut surfaces of fruits and vegetables where they can feed off sugars and other nutrients inside the food. Thus, prepared salads should be eaten soon after preparation.
- Chilled seafoods, such as raw oysters, sashimi, sushi, smoked seafood, ready-to-eat peeled prawns. (Oysters are grown mostly in estuaries that are increasingly being exposed to human contact and preventing faecal contact is becoming increasingly difficult.)
- Soft cheeses
- Soft-serve icecream
- Unpasturised dairy products e.g. raw goats milk
- Delicatessen foods displayed so that cross contamination can occur between different products
Adopting good food handling procedures at home will reduce the risk. These include:
- Keeping hot foods hot (over 60 degreesC)
- Chicken and other poultry should be cooked so that the internal temperature reaches 75 degreesC. Determining this temperature requires a food thermometer.
- Cooked food that is not eaten and is to be stored in the fridge for later consumption should be placed in the refridgerator as soon as it stops steamming and has cooled somewhat. (It does not have to come down to room temperature.) The reason for this is that placing very hot food in the fridge will raise the temperature in the fridge and risk spoiling foods already there.)
- Keep cold foods cold
- Cooked food that is not eaten and is to be stored in the fridge for later consumption should be placed in the refridgerator as soon as it stops steamming. The refridgerator needs to be kept below 5 degreesC
- Foods can be kept indefinitely in the freezer (at below minus 18 dgrees C) but their taste will dteriorate after a few months.
- Avoiding contact between uncooked products (e.g. meats) and ready-to-eat foods
- Mould on food
- Mould can be cut of the edges of hard cheeses using a margin of a couple of cetimetres. Mouldy soft cheeses should be thrown away.
- Mouldy bread should aslsio be thrown away.
- Reheating Cooked rice. Cooked rice can be kept in the fridge for a maximum of three days. It should then be thrown out. Cooked rice stored in the freezer lasts for months. It is important that the unused cooked rice is placed in the fridge (or freezer) as soon as poosible after initially being cooked (after it stops steaming).
- Reheating cooked caseroles and pasta dishes. The same advice applies as for reheating cooked rice.
- Do not wash chicken before you cook it as this just distributes organisms around the kitchen where you are preparing food. Properly cooking chicken kills harmful organisms that might be on the chicken.
- Make sure food storage containers are clean and dry before you use them.
- Blackouts and refridgerator food storage
- Meat eggs and leftovers should be thrown out after four hours without power. Leftovers in the fridge should be eaten on the same day if power is lost for less than 4 hours.
- Food in the freezer is probably ok for up to about 48 hours.
People at high risk of serious illness from infections include young children, the elderly, immuno-compromised people and pregnant women. They need to seek medical attention sooner rather than later if they develop a significant bout of food poisoning.
Traveller's diarrhoea
Roughly 50% of travellers to developing countries will develop traveller's diarrhoea. It is most commonly caused by a vartiety of bacterial organisms, includinng Escherichia coli, Campylobacter jejuni, Salmonella species, and Shigella species. Protozoal infections (especially giardia) are common causes of persistent diarrhoea in treavellers. There is no long lasting immunity to these organisms so previously living in an an indemic area does not provide protection once the person has left.
Most cases settle quickly and hydration is the main issue. Sending a sample of feces for examination (and antibiotic treatment) should be considered when;
- the case is severe and hospitalisation is considered necessary
- there is blood in the bowel motion
- it persists onger than 14 days (Giardia is often the cause in this situation.)
Some travellers take antibiotic medication to use in case they get an infection but resistance is becoming an increasing problem. For example, increasing quinolone resistance has meant that drugs such as norfloxacin and ciprofloxapen are becoming less effective.
Enteric fever (typhoid and paratyphoid) - This illness is caused by two different types of salmonella bacteria. Typhoid vaccination is useful if going to endemic areas, especially if staying for a prolonged period. (The vaccination is only about 70% effective against typhoid and not effective at all against paratyphoid.
Hepatitis A - Hepatitis A is transmitted by faecal-oral route and while most cases are self-limiting, some people develop severe illness which can cause death. (THis is more likely in people over 50 years, where the death rate is 2% to 3%.) There is a vaccine against this condition. Half the cases that present in Australia are contracted overseas.
Food and water safety
Many infectious diseases are transmitted via contaminated food and water. While it is not always possible to adhere to the boil it, cook it, peel it or forget it rule, some simple precations are very helpful;
- Wash hands with soap and water frequently especially before eating. (If available, using alcohol-based hand rubs before eating and after using the toilet is very helpful.)
- Food
- Avoid high-risk foods such as uncooked salads
- Consume fresh foods that are served steaming hot
- Drinks
- Avoid ice in drinks
- Consume fresh foods that are served steaming hot
- Consume bottled water that is sealed
- Boil or trrat drinking water (with iodine or chlorine)
Food allergies
Many people have adverse reactions to foods but only a few of these are true allergic reactions (i.e. immune system mediated reactions). True food allergies usually occur within minutes to hours after ingestion (usually, but not always, within 24 hours). Food intolerance, which is not immune system mediated, is usually a delayed responses and is rarely severe. (Food intolerance is often due to chemicals naturally occurring foods, such as salicylate and glutamate, and sulphur-containing preservatives.)
Food allergies usually occur with the first exposure to the food, which is often before the age of two. Up to 4% of the population have an allergy to at least one food, with most of these being mild in extent. For example, symptomatic peanut allergy occurs in about 1% of children while severe anaphylsctic / life-threatening reactions only occur in about 10% of this group (i.e. about 0.1% of all children). It is important to note that significantly more people test positive for food allergy but have no symptoms. In the case of peanut allergy, about 3% of all children test positive for peanut allergy but, as stated above, only 1% have symptoms.
Common causes of food allergy
Food allergies are mostly caused by proteins in foods. Ninety per cent of food allergies that occur within a couple of hours of exposure involve one of the eight following foods; cows milk, hens egg, soy products, peanuts, tree nuts (and seeds), wheat (in bread cakes and biscuits), fish, shellfish ans some berry fruits (e.g. strawberries). Children often develop tolerance to cows milk, egg, soy and wheat by school age (i.e. they grow out of the allergy), whereas allergies to nuts and shellfish are more likely to be life-long.
Symptoms of food allergies
Symptoms include acute skin rashes such as hives (especially around the mouth), diarrhea, irritability, vomiting and wheezing, and are usually consistently related to exposure to the food. Poor weight gain is a longer-term symptom. Atopic dermatitis (eczema) and asthma may also be present.
Delayed-onset reactions (occurring within several hours to days after ingestion) do occur and are often difficult to diagnose. They usually do not give a positive skin prick test and elimination or challenge protocols are needed to make a diagnosis. Symptoms of delayed reactions include atopic dermatitis, infantile colic, gastro-oesophageal reflux, oesophagitis, diarrhoea and constipation.
Cow’s milk allergy occurs in about two per cent of infants, usually starting in the first few months of life. Most cases resolve by school age. Its onset should start within four weeks following the introduction of cow’s milk into the infant’s diet. Symptoms may occur soon after the ingestion of cow’s milk (e.g. rash or wheeze) or it may present with delayed onset symptoms. It normally responds to the replacement of cow’s milk with either soy-based formulas or hypoallergic formulas. Heating cow’s milk can also reduce symptoms by destroying most (but not all) of the proteins in the cow’s milk that are responsible for the allergic problem.
Peanut allergies seem to be increasingly common. It is important to actually document a suspected case by skin-prick testing as many foods contain peanut extracts e.g. chocolate and icecream.
Correct diagnosis (preferably by a specialist allergist) is important to avoid unnecessary dietary restrictions
In all food allergies, the best treatment is to correctly identify the food concerned and avoid its consumption. Because this involves the inconvenience of long-term dietary manipulation, it is important to make the diagnosis correctly. Many children are unnecessarily placed on inconvenient (and potentially harmful) restrictive diets; especially children with chronic eczema. Thus, a diagnosis of food allergy is best made by a specialist in allergies. (A GP will know one.)
Food avoidance and allergy prevention
Many parents adopt dietary manipulation (usually food avoidance) in the hope that it will prevent food allergies in their children, involving either the pregnant or breast feeding mother or the infant. While the evidence regarding food avoidance is not complete, the following comments can be made.
- Low-risk children: For families that are not at high risk of allergic conditions, there is no evidence that any dietary manipulation by mothers or infants provides any benefit with respect to avoiding allergic conditions in the infant. An allergic family is defined as one where the infant has too close relatives (either both parents or one parent and a sibling) with significant allergic problems, such as asthma or eczema. As only about 30% of the population has any history of allergy, the vast majority of infants are at low risk and dietary manipulation is NOT warranted in these families.
- High-risk children: In a few circumstances there is evidence that food avoidance may be helpful in preventing allergic disease in high-risk infants.
Food avoidance in infants at high risk of developing allergic disease
- Maternal restrictions in pregnancy in high-risk families
- Studies have not shown dietary restrictions during pregnancy to be effective and thus should probably not be recommended
- However, the American Academy of Pediatrics does recommend avoiding peanuts.
- Maternal restrictions while breast feeding in high-risk families
- Generally, studies have not dietary manipulation in lactating women to be of benefit in preventing childhood allergic disease, especially in children over the age of two years. (Eczema prevention may be a possible exception.)
- In children who already have allergic symptoms, reduction in exposure can be beneficial and restricting maternal intake while breastfeeding may be of benefit, depending on the individual situation.
- Delaying infant exposure to solids in high-risk families
- Breastfeeding should be the sole food consumed for the first four to six months. (Cow’s milk products and solids are best avoided during this time.) The most notable effect of this measure is a reduction in the incidence of eczema. There may also be a benefit in reducing wheezing / asthma, but this benefit is less certain.
- Exclusive breastfeeding beyond six months has not been shown to be of benefit.
- Infant formulas in high risk infants
- The preferred formula for women mothers who cannot or choose not to breastfeed is an extensively hydrolysed formula, which has been shown to have similar benefits to exclusive breastfeeding. (These are modified cow’s milk formulas and they should not be used in infants with established cow’s milk allergy as they still have small amounts cow’s milk protein present.)
- Soy formula is generally not recommended as a replacement where the mother cannot or chooses not to breastfeed.
- Introducing solids in high risk infants
- Research in this area is incomplete and thus it is difficult to make recommendations with any certainty. There is some evidence to suggest that delaying certain foods will reduce the severity or delay the onset of some food allergies developing to some extent. (They do not usually completely prevent the allergic condition from occurring.) The American Academy of Pediatrics suggests delaying introducing:
- Solid foods in general until after 6 months
- Whole cow’s milk products till after 12 months
- Eggs until after 2 years
- Peanuts, tree nuts, fish and shellfish until after 3 years.
- There is some evidence that delaying exposure to certain foods by avoiding them in early life actually increases the risk of allergy to these foods later in life. This makes giving advice difficult.
Consumer food information
Almost all packaged foods in Australia have a nutrition label. It shows the ingredients and the presence of common food allergens. It also provides information about the nutritional contents, including energy, fat, protein, saturated fat, sugars and sodium. This is expressed as the amount in a usual serving of the product and in 100g of the product.
By looking at the content of total fat, saturated fat, energy and sodium, people will be able to determine whether the food is detrimental or beneficial addition to their diet. Hopefully, where appropriate, many packaged foods will also provide the fibre content and the glycaemic index on their labels to aid in purchasing decisions. With regard to unlabeled foods, food nutritional guides, together with the comments on the fat and energy content of foods in this book, should enable an informed judgement regarding the food’s nutritional value.
An example of a typical nutritional label appears below and, as stated above, the nutrients, such as saturated fat, are shown as two different amounts. Different food items in the same group of foods will often have different serving sizes and the best way to compare nutritional values in similar items, such as butter and margarine, is to look at the quantity of the nutrient in 100g of the product.
The amount of in a typical serving is there to help people calculate how much of the ingredient they will consume when eating a typical serving. The quantity of product in a typical serving is also stated. It is important to recognize that the typical servings quoted are only a guide, as your portion size may vary significantly from this level. (Some manufacturers suggest unrealistic portion sizes to hopefully increase consumption of their product.) People need to weigh the portion on their plate to calculate its energy and fat contents accurately.
Example of an Australian food label
Nutritional information Servings per package: 3 Serving size: 150mg |
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Quantity per serving |
Quantity per 100g |
Energy Protein Fat - total Fat - saturated Carbohydrate - total Carbohydrate - sugars Sodium Calcium * percentage of recommended daily intake |
608kJ 4.2g 7.5g 4.5g 18.6g 18.6g 90mg 300mg (25%)* |
405kJ 2.8g 4.9g 3.0g 12.4g 12.4g 60mg 200mg |
Ingredients: Whole milk, concentrated skim milk, sugar, strawberries (9%), gelatine, culture, thickener (1442). |
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PRODUCT OF AUSTRALIA Queensland Yoghurt Makers, 32 Ginga Lane, South Brisbane, Qld. |
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Best before 1 APR 09 |
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Food shopping
There are now well over 15,000 different food items available at a large supermarket store and making choices while ‘strolling the isles’ can be very difficult.
Here is some advice.
- Plan ahead. Planning the week’s meals ahead allows people to go to the supermarket with a list of what they need and means unhealthy food choices can be eliminated before going to the store. It helps to have a range of main meals to choose most meals from, say at least 20, and then perhaps have one or two days a week where something different is tried.
- Try to avoid buying prepared foods when ever possible. Making sauces etc from scratch makes them tastier and is usually not too difficult.
- Do not be tempted by displays and advertising in the store. They are mostly unhealthy foods.
- Avoid buying unhealthy drinks. These include soft drinks and juices with added sugar. (All juices have some sugar and should be had in moderation.) Preferred drinks should be water and low-fat, calcium-enriched milk.
- Avoid buying problem ‘treat’ foods for the pantry. These include confectionary, cakes, biscuits, and most energy / fruit bars. This does not mean no treats. It just means that treats should be just that; something bought (or made at home) occasionally.
- When choosing between similar items, such as brands of tinned tomatoes or margarines, use the product information label to help in making the most nutritious choice. (See above.)
Caffeine
Caffeine is a commonly used drug!! About 450 billion cups of coffee are consumed in the world each year and coffee is the second most traded commodity in the world after oil. On average Australians consume about 2.3kg of caffeine per year.
Caffeine is a central nervous system (brain) stimulant drug that causes a mild increase in all the following; alertness, concentrating ability, mood, heart rate, metabolic rate and the passing of urine. It does not improve problem solving ability or intellect. Its effects occur about 15 to 45 minutes after consumption.
The commonest sources of caffeine are, in order of content per serving, strong espresso (up to 120mg), fresh coffee (80-90mg of caffeine), energy drinks such as ‘Red Bull and ‘Black Stallion’ (80mg to115mg), instant coffee (60-90 mg), strong tea (50-60 mg), 375ml cans of cola drink (30-50 mg), weak tea (20-30 mg) and chocolate products, including cocoa, hot chocolate and chocolate bars.
What is a safe level of caffeine intake? Caffeine is addictive and chronic intake at higher doses can cause palpitations, tremors, insomnia, flushing, agitation / hyeractivity, nausea, gastroesophageal reflux, and nervousness / anxiety. In order to help avoid these symptoms, it is wise to restrict caffeine intake to no more than 200-250mg per day; the equivalent of about 2-3 cups of coffee, 4 cups of tea or two energy drinks. Regular consumption of more than 350mg per day leads to dependence and ceasing use causes a short-term withdrawal syndrome characterized by irritability, headache, restlessness, fatigue, poor concentration and muscle stiffness. When cutting down on caffeine, doing it slowly will help minimize these symptoms.
Pregnant women should also keep to low intakes as high intakes have been associated with an increased incidence of miscarriage and stillbirths.
Coffees do vary somewhat in their caffeine content while all teas contain about 3 per cent caffeine. Decaffeinated coffee and tea contain only 0.3 per cent caffeine. New energy drinks also contain high levels of caffeine that is usually derived either from coffee or from guarana, a compound found in the seeds of a South American climbing plant ('Sapindacea'), which contains about twice the caffeine as coffee beans (seeds). Drinks containing guarana are not appropriate for children. Guarana is also used occasionally in some fruit juices available from ‘fruit juice bars’. The caffeine helps to entice people back for more. Guarana is more slowly absorbed than coffee and thus its caffeine effects have a slower onset but last longer.
Caffeine can increase blood pressure slightly for a couple of hours after it is consumed but there is no evidence that it causes a long term increase in blood pressure. People who have high blood pressure may be well advised to restrict coffee intake to one or two cups per day or use decaffeinated coffee.
Caffeine in energy drinks and cola drinks: A problem for children and adolescents. Caffeine causes anxiety like symptoms, such as palpitations, tremors and sleep disturbances, especially when taken to excess by adults or when taken by children. As both cola drinks and new energy drinks are high in caffeine and energy, children and adolescents should avoid them. The increasing use of such drinks in these age groups is a problem, especially as obesity, mild anxiety and attention deficit hyperactivity disorders are some of the most common medical problems of childhood. (Some cola drinks are unsweetened and these do not contribute to the obesity problem.) All cola drinks are also quite acidic and this causes erosion of tooth enamel.
Ready mixed drinks containing alcohol and caffeine
Recently caffeine has been mixed with alcohol in drinks targeted at teenagers. This is unfortunate as the stimulant effect of the caffeine masks the depressant effect of the alcohol (i.e. it stops alcohol making the person feel sleepy). Usually this alcohol depressant effect acts to reduce alcohol consumption and thus protects the individual from excess alcohol consumption. Thus, the addition of caffeine means the person consumes more alcohol (obviously the whole idea behind the product) and becomes more intoxicated, resulting in less coordination, less inhibition and an increased risk of alcohol poisoning.
The combination of the stimulant effect of the caffeine and the inhibition from the alcohol means that people are more likely to indulge in risky behaviour and males especially are more likely to involved in violence. Also, there is some evidence indicating that people who drink these products have been shown to be more likely to be involved in a motor vehicle accidents or be the victim of a sexual assault. Sleep disturbances are also more common, and dehydration is worse as both alcohol and cafeine are diuretics. This dehydration causes headaches, fatigue muscle cramps and a more severe hangover.
Two other compounds that are added to these drinks to help mask the intoxicating effects of alcohol are Taurine (an amino acid) and glucuronolactone. Both occur naturally in the body but the doses commonly used in these drinks are much greater than those normally found in the body. Time for a quote!!
‘The health and wellbeing of young people is a critical measure of a society for two reasons: in moral terms, how well a society cares for its weak and vulnerable is a measure of how civilised it is; in more pragmatic terms, a society that fails to cherish its young, fails. It’s as simple as that.’
Richard Eckersley, Australian scientist and author.
Thankfully in some countries the sale of these products is being reviewed / stopped. But not in Australia!!
Further information
Nutrition Australia
www.nutritionaustralia.org
A non-government, non-profit, community-based organisation that has offices in all states and territories. It aims to promote the health and well-being of all Australians.
Food Standards Australian & New Zealand (FSANZ)
www.foodstandards.gov.au
Provide current recommendations regarding food standards in Australia. Lots of good information.) Ph 02 - 6271 2222
OzFoodnet
http://www.ozfoodnet.gov.au
A health network designed to enhance the surveillance of food-borne diseases in Australia.
Further information on food allergies
FARE - Food allergy Research and Education
www.foodallergyalliance.org
Australasian Society of Clinical Immunology and Allergy
www.allergy.org.au