SPREAD

The majority of people eat a wide variety of food without experiencing any problem. However, a small percentage of people experience allergic reactions to certain foods or ingredients which may range from slight indisposition to serious allergic reactions.

Unfavourable reactions to food may be caused by an ALLERGY (body's reaction involving the immune system) or by an INTOLERANCE to food itself or one of its ingredients. One person out of three is intolerant to certain foods, however people who are really allergic are around 2% of the adult population. Among children, the figure is around 3-7%, however 80-90% of allergic children recover from allergies by the time they turn 3.

The family's medical history is one of the best tools to assess the likelihood  of suffering from food allergy. Children, whose mother or father are allergic, run a higher risk to be allergic to food if compared to children whose family members are not allergic. If both parents are allergic, risk is 4 to 6 times higher. Breast-feeding contributes to reducing the risk of allergies more than the use of humanized milk. A 4 to 6-month breast-feeding period seems to have protective effects.

SYMPTOMS AND CAUSES

Unfavourable reactions to food (one or more ingredients combined) is often mistaken for an allergic reaction. It could be a micro-biotic contamination of food instead, or a psychological reaction to certain foods or just an intolerance to one ingredient in that kind of food.

Foods that commonly cause unfavourable reactions include cow's milk, eggs, soy, cereals containing gluten, shellfish, fruits, peanuts.

Cooking and preparing food is usually enough for its allergenic power to be diminished, since ingredients causing the unfavourable reactions are totally or partially destroyed.

Food allergy is a serious food intolerance or intolerance to one or more ingredients which cause the reaction of the body's immune system.

The allergen (this is usually a protein causing “trouble” to certain people, but not to the majority of people) triggers off a series of chain reactions leading the immune system to produce anti-bodies (IgE) against the allergen that is identified as a “foreign” element in the body. Anti-bodies which are close to the area where the allergen is produce chemical elements, such as histamine, which cause those symptoms that can be easily observed: atopical dermatitis, intestinal irritability, asthma etc.

The atopical eczema is one of the symptoms that more often affect children and is caused by allergy to cow's milk. In the past, dermatologists and paediatricians denied that food allergy could play a pathogenetic role in the showing of the atopical eczema, they rather stated that emotional stress and itchiness were the causes, however the progress of immunology and studies carried out over the last decades explained those mechanisms on the basis of which food can cause allergic reactions and pointed out relations between the ingestion of certain foods and the appearance of eczema in a number of child carriers.
A few allergic reactions show immediately (in the most serious cases leading to anaphylactic shock a few minutes after the ingestion of the allergenic food or ingredient), other allergic reactions become apparent after a few hours or even days.

Food intolerance is related to the body's metabolism instead and not to the immune system.

A very simple case is intolerance to lactose (milk sugar), which is caused by the lack of an enzyme (lactase) which metabolises this enzyme, i.e. it separates lactose into glucose and galactose for them to be correctly digested.

Even today, intolerance to milk is not taken into serious consideration and, even though its consequences on to the body are indeed very serious, it ranks a far second after allergy.

This may be due to the fact that people suffering from milk intolerance passively experience this condition and “suffer” symptoms without going into details as for the causes of their indispositions since they think this is a “temporary” and unimportant indisposition. As a consequence, GPs are not encouraged to study the mechanisms behind the action of a certain food or ingredient or nutrient recognized as a foreign element by the body.

ALLERGY TO COW'S MILK

Difficulties lie in collecting definite and reliable epidemiological data on the incidence of allergy to cow's milk in the Italian population. At the statistical level 7-8% of children and 2% of breast-fed children are allergic to cow's milk. In the USA 20-50% of children suffering from intolerance or distress caused by cow's milk are also allergic to soy milk.
4% of babies – especially when a few family members already suffer from allergies - supposedly suffer from allergies caused by milk's proteins whose intensity decreases as the years go by.

The commonest symptoms are atopical dermatitis, vomiting and diarrhoea, asthma, even though medical symptoms change according to each patient. Reactions to protein in cow's milk do not last long and their incidence in adults and old people is very low.

The allergic power of cow's milk proteins can be reduced by heat treatment (UHT or sterilization) or enzymatic digestion. As for yoghurt and cheese, the proteins' structure does not undergo any change, so they can easily generate allergic reactions.

After confirming the allergic diagnosis, it is important to follow a balanced diet, especially during weaning and as babies grow. A diet without any cow's milk and its by-products must be integrated with essential nutrients such as iron, calcium, magnesium, vitamins A, D, B2 and B12, and fundamental fatty acids.

For the purpose of evaluating the allergic nature of substitutes for cow's milk (goat milk, sheep milk, soy milk etc.), a 1992 study that was carried out in the USA by the Medical School of the University of Southampton (UK), examined the bonding capacity of IgE thanks to in vitro tests by using both radioallergosorbent (RAST) procedures and methods for RAST inhibition.
This study showed that the ideal prophylaxis for patients suffering from allergies to cow's milk is breast milk, should breast milk not be available, it may be substituted by xenogenetic food, such as goat milk proteins, which may help reduce symptoms due to indispositions.

On the one hand, the use of vegetable drinks, such as soy- and rice-drinks, might be useful to solve the problems caused by allergies to milk; on the other hand, however, it might cause babies to grow less because of their content in substances (phytates ) that create bonds for essential micro-nutrients that are necessary for growth and hinder these substances' absorption on the part of the cells. What is also advisable is verifying that the soy used is not transgenic.

When breast-feeding is not possible and if children are allergic or intolerant to cow's milk, it is advisable to use milk produced by other mammal species (goat or donkey) – under medical supervision – before trying vegetable drinks (soy or rice drinks) that are very different from real milk as for taste and nutritional characteristics.

INTOLERANCE TO COW'S MILK

Food intolerance may often cause symptoms that are similar to allergies (these include nausea, diarrhoea, stomach cramps, etc.), however the body' reaction does not involve the immune system. This is the reason why allergic people must eliminate the allergen triggering the allergic reaction from their diets, whereas people suffering from intolerances are often able to tolerate small quantities of that food without suffering from any symptoms. Exceptions are people suffering from intolerances to gluten and sulphates.

The commonest cause of intolerance to cow's milk is sugar it contains – lactose - which is not broken down into its two simpler components, glucose and galactose, by intolerant people whose production of the lactase enzyme is very scarce or non-existent. Lactose is not digested and as such it gets to the intestines, there it is subject to fermentation by the bacterial micro-flora. This may be the cause for such symptoms as flatulence, aerophagia, meteorism, diarrhoea.

At the European level, approximately 5% of the white population and approximately 50-80% of people belonging to other ethnic groups, suffer from light intolerance to lactose, since production of lactase decreases with ageing and it is even smaller in those human races that traditionally drink very little milk (according to studies the ability to digest lactose may be due to a fairly recent DNA mutation occurred in populations who drank a lot of milk, for lack of other food).

However, a dose-dependent diet can also include a little milk for children, as well as adults or the elderly.

What is clear is that the tolerated quantity of lactose is extremely variable according to individuals.

The second reason why people are intolerant to milk – which is often very widespread, way more than medical diagnoses indicate – is fat, or rather, the difficulty for the body to digest long-chain fatty acids that can be found in cow's milk. Symptoms are often mistaken for intolerance to lactose, that is why reference is made to pseudo-intolerance to lactose. The diagnosis is not that easy since the demarcation line between the different causes of an identical symptomatology is very thin. Drinking cow's milk on the basis of definite doses is a simple but useful instrument to understand whether the triggering element is lactose or fatty acids.

If it is the case of pseudo-intolerance to lactose, a number of GPs suggest that their patients try goat milk since it is richer in short- and medium-chain fatty acids if compared to cow's milk, so that small-diameter fat globules can develop in the intestines and are more easily attacked by intestinal lipase and more quickly absorbed by cells. As a matter of fact, goat milk is commonly defined as highly digestible, a feature that has little in common with the high digestibility of cow's milk after lactose has been taken out.

THE COMMONEST DIAGNOSTIC INSTRUMENTS

-         Skin Tests (plasters on the skin containing the triggering factor. Low reliability and need to repeat the test);

-         Exclusion Diet (the factor that is likely to be the triggering element is excluded from people's diets for a while and then ordinary diet is restored. The use of this procedure is not advisable for babies and children, since milk is essential for weaning and growth);

-         RAST (radio-allergo-sorbent-test) blood samples of patients are brought into contact with possible allergens. If results are positive, anti-bodies are produced. This test shows whether a real allergy is present, but it does not provide indications as to its seriousness;

-         DBPCF (double-blind, placebo-controlled, food challenge test): possible allergens are given to patients according to the double-blind procedure, this means that neither patients nor doctors are aware whether this is a real allergen or a placebo;

-         Breath Test, it can be used for intolerance to lactose: it is a simple, not invasive test, it measures the quantity of hydrogen in the air breathed out by patients on an empty stomach and after drinking lactose (50g) diluted in water (300 ml) every 15 min. for the next 3 hours. The gas-chromatographic situation is then analysed and a diagnosis is made. The higher the hydrogen level, the greater the amount of lactose that was not metabolised by the body, but was fermented by anaerobic bacteria;

-         Lactose load test: blood test to analyse the increase in the levels of glucose after the breakdown of lactose into glucose and galactose;

-         Urine test: this test analyses the increase in the levels of galactose in urines after the breakdown of lactose into glucose and galactose.

THERAPY AND PREVENTION

If patients suffer from serious allergy, the exclusion diet that excludes the triggering element still remains the inevitable and most successful therapy.

Diets of allergic patients must then be strictly controlled by doctors in order to always guarantee a correct nutritional contribution, by substituting – if necessary – the allergen with other ingredients.

What is not advisable is treating allergy to cow's milk by using proteic hydrolyzed elements unless the latter are prepared using milk protein that have been highly hydrolyzed and reduced to tiny fragments (small peptides or amino-acids), so that these fragments are recognized by the body as "self", i.e. as body materials and not as foreign materials. Another simple and effective solution is boiling milk bought in supermarkets for a long time, even though it does result in the loss of essential micro-nutrients that are needed to develop important metabolic functions.

A good alternative are vegetable drinks, such as soy- or rice-drinks, however since they are 100% vegetable drinks, they cannot be compared to mammals' milk as for the quality of their nutritional components. Moreover, their taste is unpleasant and they require not only an integration of calcium, but of phosphorous in a 1:3 ratio in order to guarantee the correct development of the skeletal apparatus and bones of children and to prevent osteoporosis for adults. And the soy might be genetically modified.

If patients are affected by light allergy, milk from other mammals may be given to patients under medical supervision (e.g.: donkey or goat). Goat milk can be cautiously added to the diet (it must be diluted if given to small children), so as to test the tolerability of its proteins. These latter, even though they do belong to the same category as cow's milk proteins, are slightly different as for short sequences of amino-acids that give proteins a structure that does not trigger the reaction of the body's immune system. Important hypoallergenic proteins are those contained in UHT goat milk that is treated at high temperature for a few seconds.

Unfavourable allergic reactions to goat milk cannot be ruled out.

If patients are affected by intolerance to cow's milk - which is much more usual than allergy – and patients suffer from gastro-intestinal symptoms, goat or donkey milk is a valid alternative to cow's milk. Fat in goat milk is more easily digestible than fat in cow's milk since it is short-chain fat, that can be more easily attacked by digestive enzymes of the intestines.

This is the reason why, when patients suffer from pseudo-intolerance to lactose, GPs suggest to use goat or donkey milk, since the inclusion of this kind of milk, as well as its dairy by-products, e.g. cheese, in people's daily diet strengthens the hydroxyapatite deposits (this is a mineral composed by calcium and phosphorus) thus guaranteeing correct bone growth, and maintaining stable cholesterol levels (and favouring "good" cholesterol to the detriment of "bad" cholesterol), and contributes to prevent osteoporosis.

Goat milk (or donkey milk, when available on the market) is now drunk by many people who suffer from acute or chronic disorders due to colitis, gastritis, ulcers, or syndromes due to malabsorption. This kind of milk is requested by Paediatric Wards of important hospitals, it is used in post-op to restore the nutritional functions in those patients who undergo surgery to the gastrointestinal apparatus.

Patients suffering from asthma or pathologies connected to the respiratory apparatus (the causes of such a pathology must be looked for in damaged mucosae of the oro-rectal tract) do benefit from the regular consumption of goat products.