There’s a connection between allergies and poor intestinal flora

This column is written by Stig Bengmark – Professor Emeritus, scientist, lecturer and writer. Read more of Stig Bengmark’s columns here.

Numerous epidemiological studies show that people living close to nature have certain health advantages. Among others, reduced death from chronic diseases such as Alzheimer’s, cardiovascular disease, diabetes and cancer, and in addition, significantly fewer psychiatric problems and far fewer allergies. A lot of positive psychological, physiological and endocrinological effects have been reported, something which is attributed to more exercise, more social contacts and also, among other things access to sunlight (Rook GA Proc Natl Acad Sci USA. 2013;110:18360-18367).

Allergies are both local and general inflammations

Allergies are reactions that occur when one or more of the body’s tissues/cells are exposed to threats from substances that do not normally belong in the body. When our bodies are exposed to such substances, a defensive reaction is triggered which we humans handle in different ways and which have different effects, depending on how prepared or sensitive we are. Basically, an allergy is both an increased local and general inflammation, which in its classic description has four more or less pronounced ingredients: redness, swelling, heat development and impaired tissue function. The reaction can occur in all the tissues of the body but is most often seen on the skin, in the lungs and in the gastrointestinal tract.

The gastrointestinal tract is particularly exposed, as it’s supplied daily with billions of different substances, many of which have the properties to trigger allergies (these substances are called allergens), as well as with unpleasant microorganisms with the ability to cause inflammation and infection. The combination of allergens and disease-causing bacteria is also particularly effective as well as undesirable.

Antibiotic treatments put protective mechanisms out of action

It’s important that the body learns to recognise harmless substances and doesn’t trigger any inflammation when it’s not needed. Studies in animals show that normal defence mechanisms are largely put out of action in those which are treated with antibiotics or exposed to other chemicals, as well as in those who don’t take care of their intestinal flora and have an intestinal flora that’s significantly depleted both in number and function (Stefka AT et al Commensal bacteria protect against food allergen sensitisation. Proc Natl Acad Sci USA. 2014;111:13145-13150). For example, it’s has been shown that mice that have been exposed to antibiotics during the neonatal period develop peanut allergies, for example, much later in life.

Excessive hygiene has created today’s explosion of allergies and chronic diseases

A properly-functioning gut flora is therefore a prerequisite for proper protection against a variety of allergies. If the person is not given the opportunity to develop a good gut flora and a good immune system, they become easy prey for allergies and, later in life, also chronic diseases. In 1989, Strachan pointed out (Strachan DP (1989) Hay fever, hygiene, and household size. BMJ 299 (6710): 1259–1260) that the efforts that society makes to protect newborns and young people against infectious microorganisms, for example, in fact greatly reduce the immune system’s ability to develop and function to its full potential in protecting us from diseases, infections, allergies and chronic diseases. Strachan’s remarks, which have been given the name ‘the hygiene hypothesis’, are now broadly accepted in research circles.

There are a lot of things that interfere with the optimal development and function of the immune system

We now know that exposure of the foetus and the newborn to microorganisms and the opportunity to develop a wide-ranging, stable and well-functioning collection of protective bacteria (microbiota), play a major role in the individual’s future health. Anything that interferes with this process such as excessive hygiene, vaccination, incorrect nutrition, artificial infant formula, medicines (especially antibiotics and especially during the foetal, neonatal and early childhood periods) is of paramount importance for future health (Blaser M (2011) Antibiotic overuse: Stop the killing of beneficial bacteria. Nature 476(7361):393–394).

Unfortunately, the incidence of severe and often life-threatening allergic reactions (often called anaphylactic shock) is increasing at an alarming rate (Cao S et al. The role of commensal bacteria in the regulation of sensitization to food allergens. FEBS Lett. 2014;588:4258-4266). Even more ‘everyday’ allergies are increasing rapidly, and today 8% of children and 2% of all adults in the western world suffer from some form of visible allergy. One reason among many is that we now eat industrially produced western food that contains an insanely small amount of plant fibre. We, and especially our children, get almost none at all of the ‘tough’ fibres that are our intestinal bacteria’s favourite food and without which they can not exist, function, or protect us from disease.

The nutrients that the bacteria produce from fibre protect us

In recent years, attention has been given to the significant allergy- and disease-inhibiting effects of certain substances that the intestinal flora produces locally on the surface of the intestinal mucosa membranes and especially in the first half of the large intestine. It’s something called short-chain fatty acids – a kind of health mystery, you could say. Short fatty acids are often referred to by the English abbreviation, SCFA (short chain fatty acids) and consist mainly of acetic acid, propionic acid and butyric acid – all known to nourish the intestinal wall mucosa and thereby counteract the dangerous permeability of the intestinal wall (leaky gut) which always occurs in the absence of short-chain fatty acids/poorly functioning intestinal flora. In addition, a number of other very positive short- and long-term health effects of short-chain fatty acids have been observed, not just on the intestinal wall but on the immune system as a whole.

About three times as much acetic acid is produced compared to propionic acid and butyric acid, and the excess is converted into nutrients in the liver.  However, there is often a shortage of short fatty acids and especially butyric acid (which is considered to be the most important of all for the function of the intestinal wall) and therefore the intestine is especially miserly with the butyric acid it creates – it’s all used, with only a few percent being lost in the stool.

Lack of ‘tough’ fibre handicaps the intestinal flora – maybe forever?

Short fatty acids are really short – they have only 1-6 carbon atoms and are formed by so-called microbial fermentation in the large intestine from ‘tough’ fibres such as polysaccharides, oligosaccharides but also from various proteins and peptides – perhaps an emergency solution when not enough fibre is available? The most important fibres for the production of short-chain fatty acids are cellulose, beta-glucans, guar gum, fructans, resistant starch, galactomannans, xylans and pectins – fibres that most people do not consume in anywhere near sufficient quantities.

Unfortunately, most of us, through our modern lifestyles and general intake of processed foods, have lost important parts of our intestinal flora, which has meant that we have difficulty in metabolising/breaking down ‘tough’ fibres. Unfortunately, this in turn means that many of us, perhaps most, have to limit our intake of such fibre, as otherwise we’ll develop problems – simply no longer having any bacteria left that have the ability to break down such ‘tough’ fibres. In fact, the breakdown of these should begin as early as in the upper part of the small intestine, there should be bacteria there that can begin the breakdown of plant fibre. But since they’re now often missing, these fibres remain unfermented and instead cause problems: stomach rumbling, alternating diarrhoea and constipation, etc. Unfortunately, this forces a lot of people to abstain/strongly limit their intake of our true super-fibre – something which I’ve discussed in this and this column.

If you can’t cope with the A-team, you’ll have to settle for the B-team

It’s estimated that more than half the people in North America, Australia, and Europe suffer from various types of gut problems. The most common is what’s known as irritable bowel syndrome – IBS. Unfortunately, these people have to abstain from or at least severely limit their intake of ‘tough’ fibre (now called Fodmap-rich foods) and mostly focus their intake on ‘gentler’ fibre.

The Fodmap-rich foods (which contain a lot of ‘tough’ fibre) which you’re then recommended to limit include apples, apricots, blackberries, dried fruit in general, figs, mangoes, nectarines, papaya, peaches, pears, plums, watermelon, cauliflower, artichokes, mushrooms and peas.

Fodmap-low foods (containing a small amount of tough fibre) that you can eat freely from a fibre perspective include bananas, blueberries, cantaloupe, cranberries, grapes, kiwi, lemon, lime, tangerines, oranges, passion fruit, pineapple, raspberries, rhubarb, strawberries, tangerines, as well as the vegetables alfalfa, bamboo shoots, bell peppers, carrots, cucumbers, aubergines, green beans, kale, lettuce, parsnips, pumpkin, potatoes, radishes, seaweed, spinach, squash, tomatoes, turnips, courgettes, quinoa (however, most of these are rich in fruit sugar).

The foundation of allergies begins in the foetal stage and in early childhood

The picture summarises how scientists view the connection between lifestyle and the development of allergies at different times in life, and especially in early life: the foetal stage, the neonatal period and early childhood (Kim BJ et al. Environmental Changes, Microbiota, and Allergic Diseases. Allergy Asthma Immunol Res. 2014;6:389-400). Factors that contribute to increased allergies are the mother’s lifestyle before and during pregnancy as well as during the breastfeeding period, whether the birth takes place via caesarean section, consumption of western processed food, exposure to endotoxins (dust in the air and inappropriate food), tobacco, pollution and environmental toxins, climate change and much more – i.e. much the same factors that have been shown to contribute to chronic diseases later in life.

Probiotics reduce the risk of allergies

So far, probiotics have mostly been tested against allergies on animals. Among other things, a strong inhibitory effect on the development of asthma has been observed with the administration of lactobacilli to mice (Yu J et al Allergy Asthma Immunol Res. 2010,2,199-205). In recent years, albeit too cautiously, probiotics have also been tested on humans. The results have so far varied greatly – some bacteria have proven effective and others have not. The doses have varied too much and the size of the groups treated has often been too small, and so far no extra fibre has been given at the same time. In fact, as it stands right now, there is no evidence to recommend probiotics for various manifestations of allergies at this stage – at least not to alleviate or cure allergies, but rather to prevent the onset of allergies.

In my previous column on ADHD, I spoke about the pioneering work of the Finnish researchers Erika Isolauri & Seppo Salminen. As far back as 15 years ago, pregnant women who came from families severely affected by allergies, were treated with probiotics during the last months of pregnancy, and their newborn babies for another six months – a treatment that actually turned out to halve the incidence of allergies (Kalliomäki M et al Lancet 2003 ; 361 (9372): 1869-1871). The really big news, however, was that this treatment completely prevented the onset of ADHD later in life.

There’s no doubt that access to large amounts of short-chain fatty acids is essential for optimal gut health. We also know that allergic children have lower levels of propionic acid, acetic acid and butyric acid in their gut compared to non-allergic children (Böttcher MF et al Clin Exp Allergy 2000; 30,1591). The task is obviously to try by all means to increase the level of these important short fatty acids in the intestine – and hopefully a bacterial composition rich in important health-promoting fibre can contribute to this.

Synbiotics give hope

Children with allergic skin lesions (atopic dermatitis) are at high risk of also getting asthma. For preventive purposes, such children (average age 17 months) were administered a synbiotic combination consisting of a small dose of a bifidobacteria and a small dose of a mixture of galacto- and fructo-oligosaccharides (0.8 g / 100 ml) during a 12-week study. The treated children developed significantly fewer allergies – after one year, 14% in the treated group had signs of asthma compared to 34% in the control group, and 6% in the treated group had begun taking asthma medication compared to 26% in the control group. Five children in the control group had developed a visible allergy to cats, something which was not seen in the synbiotic-treated group (van der Aa LB et al.  Allergy. 2011;66:170-177). This small and partially deficient study gives hope that synbiotic treatment can be significantly more effective than just probiotics alone. And especially if it’s not limited to just a few weeks but is given permanently and contains a larger amount of bacteria and fibre.

For almost 15 years, I’ve been conducting research into a specific synbiotic with four beneficial bacteria (lb plantarum, Lb paracasei, Pediococcus pentsaceus and Leuconosdoc mesenteroides) and a large dose of four important and well-known fibres (beta-glycan, inulin, pectin and resistant starch). A total of 10 grams of fibre – almost equivalent to one third of the recommended daily requirement of fibre and also enough for the daily requirement of ‘tough’ fibres.

Unfortunately, so far I have not had time to try the treatment with Synbiotics on allergies. It seems to me it should be given the highest priority.

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