Last week I focused on how reactions to specific foods can precipitate the undesirable gut feelings collectively known as irritable bowel syndrome (IBS). While IBS is commonly triggered by food sensitivity, it can also be related to other internal issues. Another frequent underlying factor concerns the microbes in the gut. In health, the gastrointestinal tract is home to bugs that play an integral part in maintaining the proper workings of this organ. If the balance of these gastrointestinal organisms goes awry, however, digestive function can go belly up.
The internal ecosystem is made up of several pounds' worth of bacteria. Those within the gut, including the acidophilus and bifidus species, promote health in the lining of the digestive tract and protect the gut against disease-causing organisms. Some depletion of the gut's stocks of beneficial bacteria comes with age. However, the demise of these microbes can be enhanced by factors such as taking antibiotics. This depletion can compromise the gut's healthy functioning, and may also lead to problematic organisms emerging.
One organism that can assume an unhealthy degree of dominance, particularly as a result of antibiotic therapy, is yeast. This is a fermenting organism, and the gas it gives off can give rise to symptoms common in IBS such as bloating and/or wind. A glut of yeast can also be associated with fungal infections such as vaginal thrush and athlete's foot.
One key to getting better balance in the gut ecosystem is to avoid foods that encourage the growth of yeast and other organisms in the gut. This involves de-emphasising refined sugar, refined carbohydrates (such as pasta and white rice), and foods that are yeasty, mouldy or fermented such as wine, beer, mushrooms, Marmite, cheese and dried fruit. Ideally, the bulk of food intake should come from meat, fish, eggs, vegetables, beans, nuts and seeds.
Regularly eating 'live' natural yogurt (which has beneficial bacteria) may also help re-establish balance in the gut. Certain food components feed healthy bacteria. One such substance is the plant carbohydrate inulin, which is found in chicory. In addition to these dietary changes, I recommend healthy-gut bacterial supplements known as probiotics (found in good health food stores). Studies have found that this can bring significant relief in IBS symptoms within two or three months. For those who suffer from excessive fermentation in the gut, natural germ warfare can bring a breath of fresh air.
Dear John
I regularly drink three to four litres of water a day because I've been led to believe that it is healthy. But I have recently read reports that excessive water consumption can be damaging. Is this true?
LF
Many people find that drinking good quantities of water helps improve well-being, particularly mental and physical energy. Also, evidence links higher water intakes to a reduced risk of heart disease and some forms of cancer. Yet it is possible to get too much of a good thing. One potential consequence is low levels of sodium (hyponatraemia) which can cause swelling of the brain, coma and even death. This is rare, and is usually only seen in psychotic individuals (who can suffer from extreme over-drinking of water) or in those who drink excessively during endurance exercise.
The evidence does not suggest that drinking three to four litres of water a day is harmful, unless kidney function is compromised. You may find, however, that smaller intakes may be enough to ensure good hydration. My general advice would be to drink enough water to ensure that your urine is pale yellow throughout the day.
Nutrition news
Pregnancies normally last 40 weeks, though not all will go the distance. Premature birth is sometimes related to an early rupture of the amniotic sac which lines the womb, the medical term for which is premature rupture of membranes (Prom). One important component of the tissue that makes up the amniotic sac is a protein known as collagen, the making of which is to a degree dependent on the nutrient vitamin C.
In the past, research has shown that low body levels of vitamin C are associated with an increased risk of Prom. In a study published this month in the American Journal of Clinical Nutrition, researchers in Mexico treated women who were 20 weeks pregnant with 100mg of vitamin C or placebo (inactive medication) each day through the remainder of their pregnancies.
Compared to those taking placebo, women supplementing with vitamin C had about a quarter of the risk of suffering from Prom. This study suggests that supplementing with even relatively small doses of additional vitamin C taken during pregnancy may help to prevent premature birth as a result of Prom.
· If you have any issues you would like Dr Briffa to address in his column, please email him on john.briffa@observer.co.uk. Please note that Dr Briffa cannot enter into any correspondence. You can also visit www.drbriffa.com. Before following any recommendations in this column, you should consult your own medical adviser about any medical problems or special health conditions
