The aspects of candidiasis discussed so far – the infection of specific parts of the body – is not in doubt. What is more contentious is the claim that Candida overgrowth in the gut can affect other parts of the body, where there is no actual infection. The belief that Candida can affect distant parts of the body -including the brain – is not based on hard scientific evidence. But some doctors report that such ‘distant’ symptoms clear up, along with the diarrhoea and bloating, when candidiasis in the gut is successfully treated. The type of symptoms commonly reported are fatigue, poor concentration, irritability, headaches, migraine, aching joints and muscles, hypoglycaemia (low blood sugar), irregular heartbeat, sinusitis, urticaria, psoriasis, eczema and other skin conditions. It has also been suggested that candidiasis can cause asthma, although only very rarely.
How might symptoms like these be produced? One possibility is that the yeast is releasing toxins and other products that travel around the body in the blood. Some toxins have been identified, and one makes the blood vessels more leaky, which might account for the production of urticaria. But the main effect of the Candida toxins is to depress the immune system – while this may well be important in perpetuating the Candida infection, it would not account for the symptoms described above.
Rather than toxins, it may be the yeast’s waste product, acetaldehyde, that is causing problems. This is a small chemical molecule that the yeast produces when it ferments sugar – in the same way that brewer’s yeast produces alcohol. If enough acetaldehyde passed into the blood, it might alter the oxygen-carrying ability of the blood, and this could affect the amount of oxygen reaching the brain. At present, there is no evidence for this, however.
For toxins or acetaldehyde to produce multiple symptoms, quite large amounts would have to be produced. Whether the yeast could ever be as abundant as this is open to question. An alternative explanation is that the person becomes sensitized to chemicals produced by the Candida yeast, and therefore reacts to quite small amounts of them. Some patients with candidiasis give a positive skin-prick test to Candida antigens, showing that they have indeed developed an allergic reaction to them. This is unusual, however. Other patients give a negative skin-prick test but respond positively to an intradermal test, which is more ‘sensitive’ because it uses more antigen and places it in a deeper layer of the skin. Whether this actually demonstrates anything is debatable – we all have antibodies to Candida because we are exposed to it from birth, and a positive response to an intradermal test is seen in some healthy individuals. Even if there is an immune reaction to Candida antigens in a majority of patients, this would not explain all the symptoms attributed to candidiasis.
*243\180\8*