What is a food allergy?
An allergy is an exaggerated immune system response to something the body believes is foreign. This results in an overproduction of a particular type of immunoglobulin (such as IgE, IgG or IgA) when the person encounters the allergen.
With food allergies it may begin as soon as a person touches (hands, lips etc) the food, resulting in swelling. These types of extreme reactions may cause a shock reaction in the body known as anaphylaxis, where the blood vessels become leaky causing swelling that may block the airways, as well as cause a dangerous drop in blood pressure. This complex and extreme reaction can affect all the major organs in the body and can be fatal. In Australia, these types of allergies are on the increase. The incidence of peanut allergies alone have doubled in the past 9 years.
While anaphylaxis is dramatic and obvious, most reactions we see to the food occur once it has been eaten. These are usually classified as “food intolerance” and in some cases are caused by a lack of enzymes (enzymes are made in the liver and break down the food as part of digestion). Symptoms may include mouth ulcers, digestive pain, bloating, change in bowel habits, eczema, asthma, wheezing, migraines, hives, hayfever, recurrent ear, nose or throat infections or even behavioural changes. Intolerance symptoms may come on within minutes of eating the suspect food or be delayed and take up to 24 hours to become noticeable.
Coeliac “disease” is classified as an intolerance to gluten (the protein found in wheat and other members of the grass family). Contact with gluten causes the absorptive surfaces of the gut (villi) to deflate, causing malabsorption and ultimately nutrient deficiencies, immune problems and other chronic health problems.
While lactose (a reaction to milk sugar) intolerance has been considered to be common for a long time, the diagnosis of an intolerance to fructose (a natural sugar in some fruits and vegetables) is becoming more frequent.
Can you grow out of a food allergy?
In traditional naturopathy we tend to view this issue differently than in conventional medicine. If a child has an “atopic allergy” such as eczema or asthma what we tend to find it that they are allergic for life but the way that allergy is expressed by the body may change. For example, as a baby they may begin with purely digestive symptoms – when they have the food (even via breast milk) they may vomit, have colic, cry or have changes to their bowel. If they continue to be exposed to the allergen, this gut symptoms may be less prominent but the child develops eczema or frequent ear infections. As they get older asthma may develop or frequent colds and sore throats. The symptoms may shift but the body continues to react in some way.
While conventional medicine does not expect a person to “grown out of” coeliac/gluten intolerance or anaphylactic reactions to food, strangely many doctors still perpetuate the myth that children grow out of other food intolerances and allergies as they get older.
There has been some interesting new research desensitsing children with a peanut allergy using peanut flour. It would be helpful to follow the children over the next 5 years once they are “desensitised” to see any other allergic symptoms or chronic health problems emerge.
What are the most common allergenic foods?
This may vary from country to country depending on the diet. In the Western world, the “big eight” are allergies to dairy, wheat, eggs, shellfish/seafood, peanuts, tree nuts, soy and corn.
In Japan, buckwheat allergies are common, while corn is more common in North America.
Common intolerances to foods include – milk sugar, milk protein, fructose, salicylates, sulphur, sucrose and citric acid.
How do you get a food allergy or intolerance?
In most cases of allergy you are born with it but specific allergic predispositions or a lack of specific enzymes to break down some components of food, but it may also be acquired from over use of a food or as a result of an infection in the digestive system, when the gut lining is weakened (sometimes referred to as “leaky gut” and larger molecules of food may cross into the blood stream and cause an antibody-antigen reaction.
How do you diagnose a food allergy or intolerance?
There is no irrefutable, reliable form of testing for all food allergies or intolerances. Because an allergic reaction causes an over production of IgE it should be easy to pinpoint but it is not as easy as it seems. There needs to be recent exposure to the allergen to get an accurate result. Further more our diets are more complex now and we can be exposed to hundreds of different types of foods and food additives, each one needs to individually tested. An intolerance is even more challenging to scientifically detect.
Skin prick/IgE/rast tests for foods are commonly used in conventional medicine. This is the done by pricking the skin with a needle or probe and dropping serum containing the allergen into the exposed skin. In naturopathy this form of testing is considered to be notoriously inaccurate for food allergies and intolerances, yielding both false positive and negative reactions.
Elisa/IgG blood tests for food sensitivities are carried out by some labs in Australia but are not covered by Medicare. Apart from this (and ALCAT below) type of testing being not accepted by conventional medicine the biggest potential issues are the lack of labs doing this test in Australia to compare results for accuracy and also the relatively small number of foods that are tested. Most use less than 100 common foods, which are Northern European in source. For example common Australian fish like flathead and flake are not tested.
The Antigen leukocyte cellular antibody test (ALCAT), measures platelet aggregation and changes in white blood cells after mixing whole blood with extracts of foods and chemicals. This is equally as controversial and more expensive than the IgG test but anecdotally the responses are promising and can test a wider range of foods and additives. However I have experienced some major issues with one Melbourne lab and at the current time am not referring clients for this test.
The above two tests can be useful when a person is reacting to a common food that most people tolerate (ie: not one of the “big eight”. For example I have had clients test positive to chicken, lemons and rice.
Traditional forms of diagnosis in naturopathy include an elimination diet, ie: removing suspect foods and reintroducing them one by one to see if a reaction is provoked (sometimes called “fast and challenge) or doing a pulse test. To do an elimination diet, you need to be totally in control of your food and usually cook everything from scratch. This is time consuming and inconvenient but a cheap way to build a list of food suspects. Remember it is not always a single allergen or intolerance that is the problem, often people have multiple food issues.
The Pulse Test – this is purely anecdotal but is an interesting experiment.
1. Take and record your pulse for a full minute before you get out of bed each morning. (Normal resting pulse in adults is between 60 and 80 beats a minute.)
2. Take your pulse again right before you eat any one food that you suspect is an allergen or you'd like to rule out.
3. Take your pulse immediately after eating the food.
4. Don't eat any other foods. Take your pulse again at 30 minutes and at 60 minutes after eating the food in question. Keep a record of the foods you test.
If your pulse is raised by 10-15 (or greater) more beats a minute at any of the three tests the food is considered to by suspect. Retest the next time you eat the food to see if you get the same results.
Living with a food allergy or intolerance
We don’t know why the incidence of childhood food allergies are increasing but we do know that it has doubled in the past nine years in Australia. Most worrying is the rise in serious allergic reactions.
On the last show I covered the five stages of grief and mentioned being challenged to take a suspect food out of your diet can often cause denial, bargaining, anger and even depression. If you are having trouble identifying the foods or implementing a diverse, low allergy diet see an experienced naturopath for help.
Further resources
Building healthy bones: the dairy/calcium myth.
Asthma: including low allergy diets.
Hayfever.
The soy controversy: are soy foods dangerous for boys?
Coeliac “disease": gluten and wheat-free diets.
Study comparing peanut allergies in Jewish children in the UK and Israel: children introduced to peanuts earlier in life had a lower rate of allergy.
Showing posts with label dairy. Show all posts
Showing posts with label dairy. Show all posts
Monday, March 02, 2009
Monday, October 08, 2007
Helping children build healthy bones
The CSIRO has recently released a Wellbeing Plan For Healthy Kids with the aim that every primary school aged child will bring home information and a fridge magnet to teach their family how to eat and live well. While this is a wonderful initiative – looking at creating lifelong healthy habits like drinking lots of water, eating breakfast every day, upping the vegetable intake and being more active – the advice on creating strong bones tells a very limited and heavily biased story. Today’s Health Trip looks at the bigger picture about creating a lifetime of healthy bones.
Evidence shows that calcium alone does not create healthy bones
While calcium is the major building block in bone formation, it is totally useless without Vitamin D. This vitamin basically promotes calcium absorption (from the blood) and regulates bone formation and loss. Focusing all our education about bone health on dietary calcium is immaterial is we can’t actually use it.
Vitamin D can be made by the body under the right conditions. It begins in the skin when exposed to UV. Some fatty fish (eg: sardines, tuna, mackeral, eel), egg yolks (though some commercial farming practices can alter this) and cod liver oil also give us Vitamin D. In such a sun drenched land like Australia you may be surprised to learn that a significant number of Aussies are deficient in Vitamin D. Though smog and dark skin can be a factor, the greatest reason for this is the successful education campaign around skin cancer prevention. While we are deligently covering up, slathering on the sun block and avoiding overt sun exposure we are decreasing our chance of developing a deadly melanoma but unfortunately becoming D-deficient and osteoporotic as a side effect. The link above gives some good recommendations on sun exposure for different cities in Australia and New Zealand as well as a good guide to supplementation for all ages.
A report in the EMJA published last year described vitamin D deficiency in Australian children as now being “a significant paediatric health issue”. Another recent study (looking at the higher incidence of Vitamin D deficiency in children with Type 1 diabetes) found that Vitamin D levels in blood samples of Queensland children and adolescents were lower overall than those found in the subjects of the Swedish study.
But don't forget, all the Vitamin D and calcium in the world won’t stop bone loss without adequate weight bearing exercise. Kids who become couch potatoes can’t grow healthy bones.
Other important nutrients for healthy bones
Aside from the Vitamin D issues, there is no debate around the need for adequate calcium intake for many aspects of good health. The debate centres around how much calcium we actually need, the most effective dietary sources and how other foods and substances impact on our calcium bioavailability. Here are some of the major players that are often overlooked in all the ‘official’ hype about calcium:
Sodium: The more salt in your diet the more calcium we pee out. While it is one thing to not have the salt shaker on the table at meal times don’t underestimate the amount of sodium added to processed foods (even some healthy looking breakfast cereals, let alone chips) and restaurant as well as takeaway foods. Raising children to not have a salt craving palate is a great addition to their healthy bone plan.
Phosphorous: This is another mineral essential to the calcium regulation and healthy bone story. Like sodium, this is a case of too much (and rarely, too little) upsetting the calcium applecart. Excess phosphorous gets into the diet from soft drinks, phosphate additives and in diets high in dairy, poultry and meat. We need equal amounts of phosphorous to calcium in our diet in order to use the calcium. The average diet has 2-4 x more phosphorous than calcium!
Magnesium: We need 1/2 as much magnesium to calcium, for the calcium to be used in our body for building strong bones. There are 2 major issues that contribute to magnesium deficiency becoming increasingly common. Firstly the best sources of magnesium tend to come from whole foods like unrefined grains and nuts. But most people eat refined plant foods such as flour and white rice which promotes magnesium deficiency. The other problem is excess calcium. While a cup of whole milk may contain 115 mg of calcium the magnesium content is around 10-15 mg. [Source: Tricky, R. "Women, Hormones and the Menstrual Cycle"]. The average calcium:magnesium ratio in dairy foods ranges from 8:1-12:1 versus the bio availability requirement of 2:1.
Vitamin K: This little talked about vitamin, rich in green, leafy vegetables is another important co-factor in the regulation of calcium in the body. Most Australian children do not get the recommended amount of fruit and vegetables in their diet, so we are likely to learn more about Vitamin K if this trend continues.
Protein: The more protein you eat, especially from animal sources such as meat, poultry and dairy, the more calcium you loose through your urine. For every gram of protein you eat, you loose 1 milligram of calcium. Most official dietary plans do not take this into account. While vegetarian, especially vegan, diets are criticized for an overall lower intake of calcium, it doesn’t take into account that a low animal protein diet causes less calcium loss. New evidence is emerging to show that a balanced vegan requires lower RDI of calcium
Phytates and oxylates: Plant foods however, can reduce calcium utilization. High fibre such as straight bran can reduce calcium absorption. If you had a bowl of 100% wheat bran, you would only be able to absorb half the amount of calcium from other foods eaten at that meal. However, it is rare for someone to eat just bran. Likewise oxylates in some foods such as spinach and beans can reduce calcium absorption. Soaking beans and cooking in fresh water reduces the oxylate content.
Caffeine and smoking (which may include passive smoking) also disrupt the healthy bone story but we would hope kids are exposed to neither of these. Never give your children or teens cola or energy drinks, as the combination of phosphorous and caffeine is a surefire recipe for osteoporosis.
Calcium
While calcium is considered an important building block for healthy bones, the literature repeatedly demonstrates that calcium alone does not build stronger bones in children. Nor does having your RDI of calcium in the form of dairy prevent bone fractures in adults.
Dairy foods are repeatedly promoted as the “best” sources of calcium. Other than supplements, it is true that gram for gram (perhaps with the exception of unhulled sesame seeds and kelp) dairy products contain more calcium than any other food. However, whether these are the best foods to grow healthy bones is debatable considering the issues of phosphorous, magnesium and protein, as discussed above.
Another factor to consider is dairy intolerances and allergies, either to lactose (which is even higher in low fat dairy foods) or the dairy protein. Some indications that your baby or child is negatively reacting to dairy products may include: skin rashes, digestive upsets (like wind, colic, diarhhoea or constipation), mood changes and atopic allergies (such as asthma, eczema or hayfever). Naturopathically we tend to find children who have recurrent ear, nose and throat issues potentially have a higher rate of dairy intolerance.
If your child does have an inflammatory bowel condition, whether caused by a food allergy or common conditions such as Crohns disease, very little of their food sources of calcium may be utilized when loose bowels are involved.
The official rate of dairy allergies in Australia is 1:50 children, however this only includes children who have had immunological testing (not every child with a food allergy is referred for testing) and doesn't include dairy intolerance, meaning the actual occurrence of children not tolerating all or some dairy foods is much higher. Certain ethnicity's, such as children with an Asian background, have a very high risk of dairy allergy and I would advise them to avoid dairy completely. Interesting to note is that approximately 1:4 children with a dairy allergy will also be allergic to soy foods.
How much calcium do we need?
According to the Victorian government the RDI’s for children and teens are as follows:
Babies – 0 to 6 months (breastfed) recommended dietary intake (RDI) 300mg
Babies – 0 to 6 months (formula-fed) RDI 500mg
Babies – 7 to 12 months RDI 550mg
Children – 1 to 3 years RDI 700mg
Children – 4 to 7 years RDI 800mg
Children – 8 to 11 years (girls) RDI 900mg, (boys) RDI 800mg
Children and teenagers – 12 to 15 years (girls) RDI 1000mg, (boys) RDI 1200mg
Teenagers – 16 to 18 years (girls) RDI 800mg, (boys) RDI 1000mg.
The UK Vegan Society has some good resources on non-animal sources of calcium.
Keep in mind these figures assume that there are adequate amounts of co-nutrients and no other factors interfering with the bio availability. Compulsory reading for anyone interested in the whole debate is this excellent article from the Harvard School of Public Health “Calcium and Milk: What’s Best For Your Bones”. Their conclusions are drawn from long term studies (minimum 12 years) of over 100,000 men and women, which makes them the most credible source currently available on the subject. While they question conventional assumptions as to the the amount of calcium required (they suspect it is actually lower than the official recommendations) on the issue of dairy for strong bones they conclude:
What else can stop a child growing healthy bones?
As if the average Aussie diet, lack of UV and not doing adequate amounts of weight bearing exercise wasn’t enough to complicate the healthy bone picture, the use of steroids (such as cortisone used in asthma and eczema) and the increase rate of eating disorders from a young age also has a detrimental impact on the development of healthy bones.
So you can see, healthy bones is not all about having 3 cups of milk a day after all.
* (My emphasis). Along with the concerns that the Harvard studies mentioned around dairy intake and an increase in ovarian and prostate cancers, other studies show a link between drinking milk and developing Type 1 diabetes and the issue of Low fat dairy foods and infertility
Evidence shows that calcium alone does not create healthy bones
While calcium is the major building block in bone formation, it is totally useless without Vitamin D. This vitamin basically promotes calcium absorption (from the blood) and regulates bone formation and loss. Focusing all our education about bone health on dietary calcium is immaterial is we can’t actually use it.
Vitamin D can be made by the body under the right conditions. It begins in the skin when exposed to UV. Some fatty fish (eg: sardines, tuna, mackeral, eel), egg yolks (though some commercial farming practices can alter this) and cod liver oil also give us Vitamin D. In such a sun drenched land like Australia you may be surprised to learn that a significant number of Aussies are deficient in Vitamin D. Though smog and dark skin can be a factor, the greatest reason for this is the successful education campaign around skin cancer prevention. While we are deligently covering up, slathering on the sun block and avoiding overt sun exposure we are decreasing our chance of developing a deadly melanoma but unfortunately becoming D-deficient and osteoporotic as a side effect. The link above gives some good recommendations on sun exposure for different cities in Australia and New Zealand as well as a good guide to supplementation for all ages.
A report in the EMJA published last year described vitamin D deficiency in Australian children as now being “a significant paediatric health issue”. Another recent study (looking at the higher incidence of Vitamin D deficiency in children with Type 1 diabetes) found that Vitamin D levels in blood samples of Queensland children and adolescents were lower overall than those found in the subjects of the Swedish study.
But don't forget, all the Vitamin D and calcium in the world won’t stop bone loss without adequate weight bearing exercise. Kids who become couch potatoes can’t grow healthy bones.
Other important nutrients for healthy bones
Aside from the Vitamin D issues, there is no debate around the need for adequate calcium intake for many aspects of good health. The debate centres around how much calcium we actually need, the most effective dietary sources and how other foods and substances impact on our calcium bioavailability. Here are some of the major players that are often overlooked in all the ‘official’ hype about calcium:
Sodium: The more salt in your diet the more calcium we pee out. While it is one thing to not have the salt shaker on the table at meal times don’t underestimate the amount of sodium added to processed foods (even some healthy looking breakfast cereals, let alone chips) and restaurant as well as takeaway foods. Raising children to not have a salt craving palate is a great addition to their healthy bone plan.
Phosphorous: This is another mineral essential to the calcium regulation and healthy bone story. Like sodium, this is a case of too much (and rarely, too little) upsetting the calcium applecart. Excess phosphorous gets into the diet from soft drinks, phosphate additives and in diets high in dairy, poultry and meat. We need equal amounts of phosphorous to calcium in our diet in order to use the calcium. The average diet has 2-4 x more phosphorous than calcium!
Magnesium: We need 1/2 as much magnesium to calcium, for the calcium to be used in our body for building strong bones. There are 2 major issues that contribute to magnesium deficiency becoming increasingly common. Firstly the best sources of magnesium tend to come from whole foods like unrefined grains and nuts. But most people eat refined plant foods such as flour and white rice which promotes magnesium deficiency. The other problem is excess calcium. While a cup of whole milk may contain 115 mg of calcium the magnesium content is around 10-15 mg. [Source: Tricky, R. "Women, Hormones and the Menstrual Cycle"]. The average calcium:magnesium ratio in dairy foods ranges from 8:1-12:1 versus the bio availability requirement of 2:1.
Vitamin K: This little talked about vitamin, rich in green, leafy vegetables is another important co-factor in the regulation of calcium in the body. Most Australian children do not get the recommended amount of fruit and vegetables in their diet, so we are likely to learn more about Vitamin K if this trend continues.
Protein: The more protein you eat, especially from animal sources such as meat, poultry and dairy, the more calcium you loose through your urine. For every gram of protein you eat, you loose 1 milligram of calcium. Most official dietary plans do not take this into account. While vegetarian, especially vegan, diets are criticized for an overall lower intake of calcium, it doesn’t take into account that a low animal protein diet causes less calcium loss. New evidence is emerging to show that a balanced vegan requires lower RDI of calcium
Phytates and oxylates: Plant foods however, can reduce calcium utilization. High fibre such as straight bran can reduce calcium absorption. If you had a bowl of 100% wheat bran, you would only be able to absorb half the amount of calcium from other foods eaten at that meal. However, it is rare for someone to eat just bran. Likewise oxylates in some foods such as spinach and beans can reduce calcium absorption. Soaking beans and cooking in fresh water reduces the oxylate content.
Caffeine and smoking (which may include passive smoking) also disrupt the healthy bone story but we would hope kids are exposed to neither of these. Never give your children or teens cola or energy drinks, as the combination of phosphorous and caffeine is a surefire recipe for osteoporosis.
Calcium
While calcium is considered an important building block for healthy bones, the literature repeatedly demonstrates that calcium alone does not build stronger bones in children. Nor does having your RDI of calcium in the form of dairy prevent bone fractures in adults.
Dairy foods are repeatedly promoted as the “best” sources of calcium. Other than supplements, it is true that gram for gram (perhaps with the exception of unhulled sesame seeds and kelp) dairy products contain more calcium than any other food. However, whether these are the best foods to grow healthy bones is debatable considering the issues of phosphorous, magnesium and protein, as discussed above.
Another factor to consider is dairy intolerances and allergies, either to lactose (which is even higher in low fat dairy foods) or the dairy protein. Some indications that your baby or child is negatively reacting to dairy products may include: skin rashes, digestive upsets (like wind, colic, diarhhoea or constipation), mood changes and atopic allergies (such as asthma, eczema or hayfever). Naturopathically we tend to find children who have recurrent ear, nose and throat issues potentially have a higher rate of dairy intolerance.
If your child does have an inflammatory bowel condition, whether caused by a food allergy or common conditions such as Crohns disease, very little of their food sources of calcium may be utilized when loose bowels are involved.
The official rate of dairy allergies in Australia is 1:50 children, however this only includes children who have had immunological testing (not every child with a food allergy is referred for testing) and doesn't include dairy intolerance, meaning the actual occurrence of children not tolerating all or some dairy foods is much higher. Certain ethnicity's, such as children with an Asian background, have a very high risk of dairy allergy and I would advise them to avoid dairy completely. Interesting to note is that approximately 1:4 children with a dairy allergy will also be allergic to soy foods.
How much calcium do we need?
According to the Victorian government the RDI’s for children and teens are as follows:
Babies – 0 to 6 months (breastfed) recommended dietary intake (RDI) 300mg
Babies – 0 to 6 months (formula-fed) RDI 500mg
Babies – 7 to 12 months RDI 550mg
Children – 1 to 3 years RDI 700mg
Children – 4 to 7 years RDI 800mg
Children – 8 to 11 years (girls) RDI 900mg, (boys) RDI 800mg
Children and teenagers – 12 to 15 years (girls) RDI 1000mg, (boys) RDI 1200mg
Teenagers – 16 to 18 years (girls) RDI 800mg, (boys) RDI 1000mg.
The UK Vegan Society has some good resources on non-animal sources of calcium.
Keep in mind these figures assume that there are adequate amounts of co-nutrients and no other factors interfering with the bio availability. Compulsory reading for anyone interested in the whole debate is this excellent article from the Harvard School of Public Health “Calcium and Milk: What’s Best For Your Bones”. Their conclusions are drawn from long term studies (minimum 12 years) of over 100,000 men and women, which makes them the most credible source currently available on the subject. While they question conventional assumptions as to the the amount of calcium required (they suspect it is actually lower than the official recommendations) on the issue of dairy for strong bones they conclude:
Currently, there's no good evidence that consuming more than one serving of milk per day in addition to a reasonable diet (which typically provides about 300 milligrams of calcium per day from nondairy sources) will reduce fracture risk. Because of unresolved concerns about the risk of ovarian and prostate cancer, it may be prudent to avoid higher intakes of dairy products.*
What else can stop a child growing healthy bones?
As if the average Aussie diet, lack of UV and not doing adequate amounts of weight bearing exercise wasn’t enough to complicate the healthy bone picture, the use of steroids (such as cortisone used in asthma and eczema) and the increase rate of eating disorders from a young age also has a detrimental impact on the development of healthy bones.
So you can see, healthy bones is not all about having 3 cups of milk a day after all.
* (My emphasis). Along with the concerns that the Harvard studies mentioned around dairy intake and an increase in ovarian and prostate cancers, other studies show a link between drinking milk and developing Type 1 diabetes and the issue of Low fat dairy foods and infertility
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