Manuel Mangani of Sedqa is right to raise awareness of some connection between excessive alcohol consumption and particular cancers (Talking Point, November 16) but he exaggerates that danger.

Perhaps he’s unaware that Lloyds life insurance actuaries found teetotallers live less than moderate alcohol drinkers. Medical research put this down to alcohol’s lowering of blood coagulability, lowering risk of fatal blood clots.

Taken in excess, alcohol is a poison to many body tissues. But its role in cancer promotion should not be exaggerated. Cancer is a complicated disease of stem cells whose DNA information has been altered by hereditary and lifestyle factors which accelerate ageing. Heavy smoking, too much food (particularly the wrong type), too much alcohol and lack of exercise all accelerate ageing changes.

Alcohol (spirits rather than wine) does have a strong secondary role (primary is smoking) in mouth, throat and food-pipe (oesophagus) cancer but ‘newer’ type mouth and throat cancers are thought to be related to oral sexual activity and ‘newer’ type oesophageal cancers seem to be related to increasing incidence of gastric acid reflux (related to obesity) and the powerful pharmaceutical drugs used to treat it.

Common cancers, such as breast, bowel and prostate, are strongly related to diet type, obesity and lack of exercise. Obesity raises blood oestrogen and insulin levels, increasing cancer risk. Diabetics, and pre-diabetics, have high blood insulin for many years and they have a higher cancer risk. A diet rich in starchy carbohydrates raises blood insulin. Alcohol has only a minor role in these cancers.

Plant protein (as found in lentils and legumes) lowers cancer risk but too much animal protein (in animal milk products and all meats) raises it. No disease prevention strategy should be broadcast before the scientific work on the disease-promoting properties of animal protein, conducted by T.C. Campbell, is studied (The China Study, 2006). Scandinavian studies further confirm that processed meats (hams, bacon, salami) are particularly related to bowel cancer. Industrial and agricultural toxins (including chemicals in plastic water bottles) are often blamed for cancer but the danger they pose still appears much smaller than that of too much animal protein consumption.