Digestive Health
Introduction
The digestive or intestinal tract runs from our mouth to our anus and is the organ which digests and absorbs the food and drink we ingest, and acts as a primary channel for the elimination of waste from the body. This includes waste and toxins generated by our body as well as that produced by the digestion of food.
How does the digestive process work?
The complex foods we eat (e.g. starches in pasta and potatoes) are acidified by the stomach and then broken down by enzymes produced by the pancreas into much simpler building blocks (glucose).
The importance of fibre
The components of foods that we cannot break down, like fibre, then pass into the large intestine. Once in the large intestine, the ‘soluble’ type of fibre is used for food by the billions of friendly bacteria that live there.
If there is insufficient fibre in our diet, then this whole process slows up as the person becomes constipated. In addition the more time it takes for food waste to move through the large intestine, the more water is extracted resulting in hard faeces. The digestive system is a hard working organ, processing approximately 50 tonnes of food in our lifetime.
The role of the intestine in the immune system
The primary function of the immune system is to defend our body to challenge from infections. The intestine is the largest immune organ of the body and this is due to the fact that the digestive tract is the main route through which many potentially harmful disease-causing organisms can gain access to the body.
Maintaining intestinal and digestive health
Because the digestive tract is essentially a conveyor belt for us to process food, if too much food is put onto the conveyor or the conveyor belt slows down, the result tends to be feelings of discomfort typified by constipation, bloating or fullness, and periodically, excessive wind. Sometimes these feelings of discomfort are accompanied by intermittent pain.
When these symptoms become more severe and are very frequent, they are often described as irritable bowel syndrome which is now believed to affect about 20% of the adult population at some time in their lives from the age of 20-45 years.
Outlined below are the nutrients which have a purported role in digestive health. They have been divided into those for which substantial scientific and clinical evidence of benefit exists, as well as those where some evidence of benefit exists but is not substantial. Finally, there are those nutrients where there is very little if any evidence of benefit.
Nutrients with substantial evidence of benefit:
- Probiotics
- Fibre
- Ginger
Nutrients with some evidence of benefit:
- Peppermint oil
- Aloe vera
Nutrients with Substantial Evidence of Benefit:
PROBIOTICS
Probiotics are cultures of living bacteria, which are considered to be the most beneficial of the hundreds of types which normally inhabit the intestine. The overall idea of using probiotics is that additional benefit will be obtained if larger numbers of these ‘very’ beneficial types are ingested on a daily basis so increasing their population level in the intestine.
Probiotics have been found to be effective in a number of different aspects of digestive health and related healthcare. Currently there is intense research interest in probiotics and it is likely that more evidence and a spectrum of health benefits will be uncovered. Currently, the major health benefit findings for probiotics are outlined below:
1) Numerous trials have confirmed that probiotics reduce the risk of diarrhoea and associated digestive tract problems which sometimes occur following the use of antibiotics.
2) Probiotics have been found to beneficially regulate the immune system, particularly in children. Indeed, the use of probiotics in newborn babies may actually reduce the risk of the child developing allergy. This work needs to be confirmed but the likelihood is that this effect will be substantiated in the next few years.
3) Probiotics have been found to be beneficial in people with intestinal symptoms such as bloating, and general discomfort. As a large percentage of the adult population experience these symptoms from time to time, probiotics may be of general benefit. Furthermore, probiotics have been found to be beneficial in people diagnosed with irritable bowel syndrome.
Most probiotics contain different species and sub species of Lactobacillus bacteria. An example is Lactobacillus Acidophilus. These organisms normally colonise the small intestine. The other type of bacterium commonly found in probiotics is Bifidobacteria e.g. Bifidobacterium Lactis. These are major colonisers of the large intestine. Therefore, products which contain both of these types have the potential to beneficially affect all parts of the intestine.
Evidence suggests that products which provide less than this amount would typically have little effect, and may take a long period of time to exert any noticeable benefits.
FIBRE
Fibre is a type of carbohydrate found in plant foods which we do not have the ability to digest in the same way as we digest protein, carbohydrate and fat. Fibre can be conveniently divided into two types: Insoluble and soluble fibre.
This type of fibre is the one most recognised and is typified by the course almost ‘husk’ like fibre as is found in wheat bran. It does not become particularly viscous when added to water, and passes through both the small and large intestine providing a noticeable laxative effect by adding bulk to the stool, and hence increasing frequency of bowel movement.
Soluble fibre
This type of fibre as the name suggests is reasonably soluble in water, sometimes producing viscous gel like substances. Also, although this fibre goes through our small intestine intact, the billions of friendly bacteria in our large intestine ‘ferment’ it to produce beneficial acids such as lactic and butyric acid, and also gas.
‘Prebiotics’ are actually types of soluble fibre
Because this type of fibre is used for growth by the friendly bacteria supplemented as probiotics they are now often termed ‘prebiotics’. As such, fibre will contribute to the maintenance of high populations of these friendly bacteria, and the benefits they provide
How much fibre do you need?
The average amount of fibre consumed per day in the UK is between 12-14g, whereas it is considered that the optimal amount is about double this quantity at 25-30g. For children above 2 years of age the formula of ‘age plus 5g/day’ is a good guideline for fibre intake e.g a 10 year old should have an intake of 10+5=15g/day.
Fibre products
Clearly, fibre intake can be increased by dietary means by simply eating greater amounts of fruit, vegetable, and wholegrain products. However, recently a number of soluble fibre products have been introduced into the market as soluble powders which are either tasteless or moderately sweet and which can be added to drinks etc. These products potentially offer a convenient way of increasing fibre intake.
GINGER
There is now significant evidence suggesting that ginger is effective at preventing or reducing the symptoms of nausea both in pregnancy and in post operative situations. This is particularly relevant during pregnancy as ginger is safe to take.
Similarly, ginger has been shown to be effective in reducing symptoms of travel/motion sickness. In one trial, with tourists on a whale watching safari, ginger was as effective as drug therapy in preventing seasickness.
To be effective, the dosage required needs to be the equivalent of 1000mg of dried ginger root powder.
PEPPERMINT OIL
Peppermint oil has for many generations been associated with digestive health, particularly the relief of indigestion and intestinal discomfort. In the early 1800’s the English Dictionary of Medical and Surgical Knowledge described peppermint oil as ‘an aromatic stimulant to allay nausea, and relieve spasmodic pain to stomach and bowels, expel flatus or cover the taste or the griping effects of other medicine’.
Recent research is now confirming the role of peppermint oil, particularly with regard to irritable bowel syndrome, where several trials have now found it provides significant relief to symptoms such as bloating and distension, intestinal discomfort and pain, and constipation, compared with taking a dummy tablet.
The amount of peppermint oil required is approximately 800mg divided into two doses taken just after food.
It is not essential but some people find it better if the tablets are enteric coated as this delays the release of the oil until it is past the stomach. If the tablets are of this type then take them one hour before meals.
Peppermint oil appears to work by producing a relaxing effect on the intestinal muscle.
ALOE VERA
Aloe vera is a succulent like plant which is grown in arid regions of southern USA, and which when mature has leaves which are about 2ft long. The thick green rind of the leaves is a source of aloin which is known to be a strong purgative, and which was used for relief of chronic constipation. This use is now less popular now as the aloin was prone to cause painful contractions. Similar, laxatives such as senna and cascara are now much more common.
The part of the aloe leaf now commonly used as a food supplement, is the watery, gelatinous content of the leaf often referred to as the gel. Aloe vera juice is made by directly from the aloe gel.
The popular use of aloe vera gel first occurred as a salve for burns, and wounds, where the use of the gel appears to produce an acceleration of the healing process. The mechanism of this reported effect is unclear, but may in part be due simply to the fact that the structure of the gel retaining a watery salve over the application area for an extended period. This is particularly in regard to burn treatment.
The Intestinal Effects of Aloe Vera Juice/Gel
A number of animal trials and at least one well conducted human trial have found that aloe vera is effective in reducing inflammatory conditions in the intestine including ulcerative colitis.
Trials suggest that if effects are to be observed they will probably be seen within about 6 weeks, and will require a minimum of 50ml of aloe vera juice per day.
