Almost 70 per cent of the immune system is found in the gut. The gut also has a nervous system – the enteric nervous system – which is every bit as complex as the central nervous system (the brain and spine) and appears to have as much of an influence on mental and emotional health. So keeping your gut healthy is important.
To do this requires a balance between the good and bad bacteria native to the human gut. In a healthy gut, the ‘good’ usually outnumber the bad; and when they flourish they also help to ferment organic acids into glucose, lower blood cholesterol, synthesise vitamins, break down the enzymes, proteins and fibres in food and boost the immune system.
There is plenty of evidence to show that eating plain live yoghurt – which contains beneficial live organisms known as probiotics – is a healthful habit that can improve immune system function. The evidence for quasi-pharmaceutical products such as Actimel – marketed as ‘functional foods’ – is less clear.
A recent study at Reading University found that half the probiotic drinks, yoghurts and supplements tested did not meet six basic criteria for good quality products: namely that they should be safe for human consumption; alive and able to survive gastric juices in order to reach the gut in sufficient numbers to have an effect; have clinically proven health benefits demonstrated by scientific trials; have their contents clearly defined; be clearly labelled; and be ‘shelf-stable’ – guaranteed to deliver benefits up until expiry date.
Some, including Danone’s Actimel, were deemed ‘satisfactory’ – that is, they contain live organisms that survive to reach the gut. Even so, little is known about the long-term benefits or otherwise of sucking down these sugary drinks every day in the name of health.
One reason is that probiotic drinks are relatively new; 12 years ago the market didn’t exist. Today in the UK, what is known as the ‘active health drinks’ market – which encompasses probiotic and cholesterol-lowering drinks – is now worth £227 million, and has grown by an amazing 65 per cent in the past year. More than 830 million bottles were sold in the past 12 months, equivalent to 14 bottles per member of the UK population.
Of these, more than one million bottles of Danone Actimel are purchased every day. Sales of Actimel account for 49 per cent of all probiotic drinks purchased in the UK, twice as much as any other brand.
Pots of goodness?
Lax food-labelling laws mean that manufacturers are not obliged to say which ‘friendly bacteria’ they have used or how many organisms you will receive per serving. To be healthful, a probiotic should contain 10 million – preferably 10 billion – live viable organisms. While Actimel does state which strain it contains – Danone’s own patented L. casei imunitass® – no claim is made here for the number of organisms present.
Indeed, the label is more advertising than information, encouraging parents to pop a bottle of Actimel in their children’s lunch box to ‘protect’ them and help to ‘support their natural defences’.
While short-term studies have shown that supplements of L. casei strains can help to prevent diarrhoea in children in the developing world, and may – at least in mice – give a temporary boost to immunity, there are no studies on this (or any other probiotic drink) to show what happens over the longer term.
Whatever benefit might be derived from Actimel’s probiotic content is likely to be offset by the fact that it is also high in sugar. Each 100g pot contains 13g of liquid sugar. To put this in perspective, a recent report by the World Health Organization claims that, for adults, daily consumption of free, or added, sugars should be no more than 12 teaspoons (48g) a day. Nutritionists say this should be lower, around 10 teaspoons (40g). On this basis, one pot of Actimel would give you one-quarter to one-third of the maximum amount of free sugar you should have each day.
While it’s clear that probiotic drinks like this don’t carry the range of carcinogens, neurotoxins and reproductive toxins that usually feature in the products in this column (unless they are sweetened with artificial sweeteners), neither is there any evidence that they will do any genuine good, especially for those on an already healthy diet.
Feeding the gut
Lack of variety in our diets means lack of variety in our gut bacteria. All the so-called ‘good’ bacteria in the gut need to be ‘fed’ each day so that organisms that die off or are excreted are replaced regularly. To do this we ideally need to include around 40g (about 1½oz) of various hard-to-digest carbohydrates, often referred to as ‘prebiotics’, in our diet each day. Without their preferred food supply, numbers of beneficial gut bacteria can decline rapidly, with a knock-on effect on immunity and other bodily functions.
Prebiotics are found in most unprocessed fruits, vegetables and wholegrains – banana, artichokes, chicory and wheat grains are particularly good sources. The more you include these in your diet, the more you will encourage the healthy diversity of beneficial bacteria that is natural to your gut and the less likely you are to need a special probiotic supplement that supplies you with an over-abundance of one strain of bacteria.
YOGHURT, SKIMMED MILK: Basic ingredients. Both these are pasteurised, which destroys nutrients and changes the structure of the milk proteins (especially casein) into ones your body wasn’t designed to digest. It virtually eliminates the good bacteria naturally present in milk and yoghurt.
LIQUID SUGAR: Sweetener. The label doesn’t say if it is a high-fructose syrup or high-glucose syrup. The former is devastating for health, elevating cholesterol, making weight regulation more difficult, altering magnesium balance, increasing insulin resistance and promoting high blood pressure.
DEXTROSE: Sweetener. Also called glucose. A simple sugar that causes an instant spike in blood glucose, leading to excessive insulin production, a drop in blood glucose, feelings of fatigue and depression. Dextrose is wheat-derived – a factor if you have a wheat intolerance.
MODIFIED TAPIOCA STARCH: Thickener, stabiliser. This all-purpose thickener, derived from cassava root or yucca plants, is as at home in yoghurt drinks as in adhesives, explosives, paper manufacture and textile finishings. It is not a substance found in nature, adds no nutritional value and as yet there is no information on its effects on health.
L. CASEI IMUNITASS®: Probiotic organism. Studies show that this can help to combat diarrhoea in children, and disease causing bacteria such as E. coli (in mice). In people, unpublished studies show a small boost in immune function.
FLAVOURINGS: Adds taste. Flavourings are perfumes. They will be derived from petrochemicals and contain the same neurotoxins, carcinogens and allergens found in all perfumes.
This article first appeared in the Ecologist April 2007