They are a class of nutritional substances to which little attention has been paid, but now research is beginning to indicate that nucleotides, which are found in only a few foods, may be much more important than previously realised, especially in relation to irritable bowel and gut health. Alex Gazzola looks at whether boosting your intake could be useful, both in IBS and other GI conditions and intolerances.

You may not have heard of nucleotides, but they are key components of every cell in your body, being involved in protein synthesis, tissue repair and regeneration, and the formation of the backbone of your DNA. They have been called the ‘building blocks of life’. But are you getting enough of them? One of the key areas of need for nucleotides is in the lining of the gut, which is constantly being worn down by digestive processes, enzymes and gastric acids, as well as by the rough surfaces of the foods we eat, and potentially by bacteria and yeasts too. Other factors such as medicines (antibiotics, drugs, painkillers) and excess alcohol can also contribute to this erosion of the lining, which ultimately affects the gut’s ability to digest and absorb food. Nucleotides are needed to repair the gut and keep the intestine healthy – and they are even more important when the integrity of the gut is diminished to start with, as is often the case in people with digestive illness.

Nucleotide rich food
But the problem is that foods rich in nucleotides feature rarely on our menus these days. Meat products from organs which degenerate rapidly – such as tripe and liver – are particularly rich sources, as are kidney and lung, but these have slipped off British plates. Ham is another decent meat source; mackerel a respectable fish source. Modest vegetarian sources include yeast extract, mushrooms, watercress and seed sprouts (like alfalfa) – though it would be difficult to eat a large enough quantity of these foods to get a good intake of nucleotides. With a widespread tendency to cut down on meat consumption, it could be that our overall intake is on a worrying downward slope. Could this be the cause of so much digestive illness?
Dietitian Nigel Denby thinks it may well be. ‘In IBS, the lining of the villi in the gut may already be under stress, and if this is the case the
absorption of all nutrients, including nucleotides, will be compromised. If the patient’s diet is low in nucleotides to start with it adds up to a triple whammy for gut health. A gut under stress is unable to absorb the nutrients it needs to repair itself – it’s a vicious circle.’

Studies and research
In the last decade, it has been suggested that a proportion of people with IBS may be experiencing localised allergic reactions to food proteins in the gut. Probably the best known study in this area was conducted by Whorwell and colleagues at Manchester University (published in Gut in 2004).

It took patients with IBS placed on food elimination diets based on levels of raised IgG antibodies to individual foods, and compared them with patients with IBS placed on sham or randomised diets. Those on diets eliminating high-IgG foods experienced modestly fewer symptoms, and the researchers concluded that the area was worthy of further research.

A few more recent studies have come to similar conclusions: that food antigens may be involved in IBS. A review by Kalliomäki at the University of Turku, Finland, suggested that food antigens can trigger mast cells to release mediators that regulate the motility of the GI tract, possibly resulting in increased wave-like movements or spasms of the gut, and the associated discomfort in IBS.

Food hypersensitivity
Nucleotides attract interest in the area of food hypersensitivities because it is the gut and the immune system that depend most on a ready supply of them to meet the rapid ‘turnover’ of cells typical of both these parts of our systems. Indeed, earlier studies (over the last five years) into the benefits of nucleotides have supported their beneficial qualities in this area.

For instance, it has been found that the incidence and duration of childhood diarrhoea is reduced when supplemental nucleotides are given, and that nucleotides modulate the expression of inflammatory cytokines in the intestine. They also help repair immune cells in animals, and studies in pigs show that nucleotide supplements help the height of intestinal villi and crypt depth – which are key factors in an
increased surface area of the gut for effective digestion and
absorption.

In infants, nucleotides have been found to boost the production of immunoglobulins and increase the tolerance towards food antigens, and hence nucleotides are added to formula milk (breast milk is rich in them). Nucleotides are also required by ‘good’ (probiotic) bacteria in the gut.

IntestAid trial
It is the strong relation between nucleotides and immune and gastrointestinal health that was the motivation behind a small 2006 study published in Nutrition Journal looking at the direct effect of supplementing IBS sufferers’ diets with nucleotides in the form of the neutroceutical product IntestAid IB. The study found that, when compared with IBS sufferers given a placebo (dummy) pill, those taking the nucleotide supplement showed a ‘consistent improvement in most of the symptoms of irritable bowel syndrome’. The improvement over placebo was in the range of 4–6% for most symptoms.

The researchers, led by IBS expert Professor Christine Clancey at East London University, said: ‘A feeling of urgency to have a bowel movement and abdominal pain showed the most improvement… and since abdominal pain is the symptom most likely to prompt people to seek medical help, this is an important finding. A feeling of incomplete evacuation after a bowel movement also improved following treatment.’

Also improved were diarrhoea, flatulence and bloating. The researchers acknowledged, though, that improvements were modest, possibly due to the strong placebo effect for which IBS studies are renowned for, and the great variability of symptoms between volunteers. Symptoms of constipation actually worsened overall.
The researchers concluded: ‘Further studies need to replicate and extend these results, and clarify the mechanism by which improvements occur.’

The value of diet
Despite the failure with regards to constipation, Nigel Denby says ‘From a practitioner’s point of view, constipation is not difficult to fix through lifestyle changes. But the issues which surround urgency, diarrhoea and abdominal pain can be more tricky. It is the patients with these symptoms who tend to be the ones who self-medicate or self-prescribe exclusion diets, without really knowing why they’re doing it, or how to do it in the first place, potentially putting themselves at risk nutritionally. Their problem could just be poor gut integrity – and if we can improve that, it could solve a lot of problems.’
Denby is concerned that many with IBS act independently of professional advice and blame wheat or dairy products in their diets. Those in great discomfort are often quite understandably looking for a quick solution, and are keen on the idea of an exclusion diet – often as a result of media reports of health improvements following wheat and dairy exclusion among celebrities. While sensitivities in genuine cases of coeliac disease, lactose intolerance and IgE allergy are undeniable, sometimes intolerances are inappropriately self-diagnosed.

‘The actual solution could be quite different,’ says Denby. ‘It could involve adding foods, not taking them away. In trying to keep health messages simple we have failed to demonstrate to the public that red meats and offal products can sit perfectly well in a healthy diet, provided you adjust cooking methods to moderate saturated fat intake.’

Other gut conditions
Nucleotides may also have a role to play in other GI conditions. If they can improve gut integrity and digestive processes, some food intolerances could theoretically be eased, and anecdotal reports of patients with Crohn’s and ulcerative colitis who have supplemented with nucleotides have been encouraging. There may be relevance too for patients newly diagnosed with coeliac disease in helping speed up the regeneration and recovery of the gut damaged by a gluten-containing diet. Denby says further studies will be needed in all these areas. Watch this space.

Links
www.intestaid.co.uk
www.probiohealthcare.com
www.nigeldenby.co.uk
www.nucleotides4health.org

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