Poisoning occurs when substances harmful to the normal functioning of the body are swallowed, inhaled, absorbed into the skin or injected. Signs that poisoning has occurred include abdominal pain, nausea, vomiting, drowsiness, burning pains from the mouth to the stomach, difficulty in breathing, congestion in the chest, headaches, ringing in the ears, blurred vision and sudden collapse. If possible the type of substance which has been ingested should be determined before giving first aid. Vomiting should not be induced if corrosive or petroleum based substances have been swallowed, nor in cases where the source of poisoning is unknown.
Food poisoning or gastroenteritis is usually caused by bacteria which inflame the lining of the stomach and intestines. The bacteria salmonella and staphylococcus are among the most common culprits and their growth is encouraged by reheating or half cooking food. It is important to practise good personal hygiene, especially washing hands, when handling food and to keep utensils and food preparation areas clean. Frozen food should be defrosted properly before cooking and not refrozen after it has thawed out. Previously reheated food should be cooked at a high temperature. Hot, cooked food should not be left in a cooling oven or other warm place. Bacterial growth develops. Food poisoning also occurs with contaminated seafood.
Symptoms of food poisoning are vomiting, diarrhoea and abdominal cramping, sometimes accompanied by sweating and fever. Diarrhoea and vomiting can lead to fluid loss, so dehydration may follow.
To treat food poisoning, fluid should be replaced by drinking small amounts of water, flat lemonade or diluted fruit juice frequently. Often the stomach will not tolerate solid foods. Taking garlic capsules can help fight infection. Peppermint tea is helpful in cases of nausea.
Poisoning can also occur as a result of absorption of various toxic metals in the environment. Lead, cadmium, mercury and aluminium are widely used by industry and our environment is now permanently polluted by them. These metals cannot be biodegraded into the environment. Lead poisoning can be caused when sanding off old lead based paint during renovations. The bioflavonoid, quercitrin, contained in the juice of citrus fruits, is a good chelating agent for lead, and gradually removes it from the body.
Cadmium is found in tobacco and cigarette paper and in superphosphate fertilisers. Usually found in conjunction with zinc, the ratio of cadmium to zinc is much higher in refined flour and white bread than in the same wholewheat products. Eating wholewheat products and not smoking reduce exposure to cadmium. Vitamin C, glutathione and the trace element selenium all help to alleviate cadmium toxicity.
Mercury is another highly poisonous metal. Apart from pollution of the environment, the consumption of seafoods and fish is a major source of mercury. Mercury is concentrated in algae in the ocean and becomes progressively more concentrated as it progresses up the food chain. Selenium is a natural defence against mercury. It is found in wheat which is grown in selenium rich soils.
During the 1970s evidence emerged that aluminium could be harmful to humans when people in Scotland using home dialysis for kidney failure suffered a type of dementia which was traced to the town water supply which was being used in the dialysis and which had been clarified with alum. There has been some evidence to link aluminium with Alzheimer’s disease, but this is still controversial. The consumption of aluminium is increased when food is prepared in aluminium utensils.
Some herbs can cause poisoning when taken in large amounts. It is therefore important to consult a qualified herbal practitioner when taking herbal remedies.
Water contamination by algal blooms, becoming more common with the pollution of our freshwater lakes and rivers, is another source of poisoning. Microcystis, a type of blue-green algae, produces hepatotoxins which cause bleeding and breakdown of the liver, sometimes inducing tumours. In 1981 several people in Armidale, New South Wales, showed signs of liver problems after drinking water from a reservoir contaminated by microcystis blooms.