Nicola Bates, Information Scientist, at the Veterinary PoisonsInformation Service (VPIS), advises...
Christmas food hazards are:
Chocolate contains theobromine, a chemical very similar to caffeine, which dogs do not tolerate very well. The amount of theobromine depends on the quality and type of chocolate. White chocolate contains very little and is generally not a risk but even a relatively small amount of dark chocolate (which is very high in theobromine) can cause agitation, hyperexcitability, tremors, convulsions and problems with the heart. Dogs will not unwrap chocolate and can eat a very large quantity. The wrappers are not toxic but could cause obstruction of the gut. If there are dogs in the household or are visiting over Christmas do not put any chocolate under or on the Christmas tree.
Onions (and garlic, leeks, shallots and chives)
Onions, garlic, leeks, shallots and chives all belong to the Allium species of plants. They can cause toxicity even when cooked. Initially there can be gastrointestinal signs with vomiting and diarrhoea but the main effect is damage to red blood cells resulting in anaemia.This may not be apparent for several days after ingestion. Foods to avoid at Christmas include sage and onion stuffing.
Grapes and dried fruits (currants, sultanas, raisins)
Grapes and their dried products (currants, sultanas and raisins) are toxic to dogs. Ingestion of even a small quantity can cause severe kidney failure. Don’t forget this will include food items that contain dried fruits such as Christmas pudding, Christmas cake and mince pies. Be aware that chocolate-coated raisins are available so there is the additional risk of chocolate toxicity with these.
Xylitol (food additive code E967)
Xylitol is a naturally occurring, sugar-free sweetener and is frequently found in sugar-free chewing gums and sweets, and some pharmaceuticals including nicotine replacement chewing gums. Xylitol is extremely harmful to dogs and can cause low blood sugar (hypoglycaemia) and liver damage.
Dogs may help themselves to any alcohol left unattended including wine and liqueurs and it can cause similar signs in them as it does in their owners when drunk in excess. Dogs can become wobbly and drowsy and in severe cases there is a risk of low body temperature, low blood sugar and coma.
Uncooked bread dough that has been left to prove can be hazardous to dogs. The dough expands in the warm, moist stomach and this can result in bloating and obstruction. Also the yeast produces alcohol and this can cause additional effects (see above).
Macadamia nuts can cause lethargy, increased body temperature, tremor, lameness and stiffness. Be aware that chocolate-coated macadamia nuts are available so there is also a risk of chocolate toxicity with these.
If there is any food left over at Christmas, be careful to dispose of it promptly and appropriately. Mouldy food (including yoghurt, bread and cheese) can contain toxins produced by the mould that cause rapid onset convulsions in dogs.
**Ed’s note – the toxicity mechanism regarding grapes/raisins and dogs is not fully understood by scientists. This means any amount could be fatal to a dog of any size. The advice from the world’s top scientists is NOT to give you dog any grapes, raisins, sultanas, or any products containing them such as Christmas cake, pudding, and/or mince pies. Even if dogs have been fine eating these products before, because the science is not understood, it is not safe to say that these dogs will be ok with the next grape they eat. Please avoid these foods to avoid tragedy this Christmas.