is best, of course. If your body is in good condition you won't catch a cold, even if your spouse is infected.
There are various ways to try and achieve this.
Consume enough vitamins and minerals, ideally in real foods. Eating an apple, for instance, is much better than taking a vitamin C tablet. The apple contains fiber, potassium, vitamins A, B1, B2, B3, B5, B6, E and K, manganese, magnesium, phosphorus, copper, folate, calcium, iron, protein quercetin and pectin: all in a form that is ideally suited to make best use of this vitamin C.
Rule 1: eat more FRESH VEGETABLES and FRUIT, healthy proteins and whole foods.
Particularly important to prevent or lighten a cold, are the following:
Zinc, in: meat, shellfish, yoghurt, beans, whole grains, peas, milk, nuts, seeds, mushrooms.
Vitamin C: oranges, grapefruit, strawberries, tomatoes, red peppers, broccoli, potatoes.
Selenium: nuts especially brazils, mushrooms, meat, whole cereals.
Vitamin E: sunflower seeds, almonds.
Probiotics boost the immune system. Live yoghurt is by far best: 'probiotic supplements' rarely work . Or take miso, sauerkraut, or properly fermented pickles. 
Useful foods are for instance:
Garlic: it's health effects are strongest if you cut or squash it 5 minutes before use, and then don't cook it for longer than 15 minutes . For the full effect, eat it raw: I used to give it to my kids in a spoonful of honey .
Grapefruit: best of the citrus . But beware, for grapefruit may interact with prescription medications .
Mushrooms contain beta-glucans for the immune system; plus anti-oxidants, vit B2 and B3.
Spinach contains vitamin C, E and zinc.
Rule 2: hydration. DRINK REGULARLY. This will keep your mucous membranes soft and moist, preventing tiny cracks that allow viruses and bacteria to enter
Other things you can do to build up your immune system are: get enough sleep and rest; take regular exercise (preferably outdoors) and, maybe hardest of all: control your stress levels. 
ONCE YOU HAVE IT
lots of hot! drinks:
Drink plenty of warm water with a pinch of sea salt. This should be as warm as possible, yet not hot. The water will relieve soreness in the throat and the sea salt (not table salt) helps break up accumulating mucus and congestion in the chest.
However, plenty of warm, soothing liquids such as tea, broths, soup are all good. Drink something every hour while awake if possible. 
Spicy foods may also reduce congestion associated with the common cold. For this reason, hot peppers, miso and spicy international dishes such as Indian or Thai curries and Asian stir-fries may prove helpful.
Chicken soup is often mentioned as a tasty and healing comfort during a cold. It is - but especially if homemade. For the proper way to make it, see , or for a simpler recipe, .
Once made, freeze in batches and enjoy whenever you feel the need.
A recipe mentioned by many is the following: take a tablespoon lukewarm honey with 1/4 spoon cinnamon powder daily for three days. This process should cure most chronic coughs and colds, and will clear the sinuses. 
ginger tea 
quercetin, a powerful antioxidant which reduces inflammation, contains natural anti-histamine and anti-inflammatory properties. In onions, apples w. skin, blueberries, grapes, black beans, red cabbage, and ginger. 
Try to avoid:
sugary foods/drinks; mucus-forming dairy esp. milk; junk food; heavy, high-fat food; alcohol and tobacco. Fruit juice is not ideal either, as it contains too much sugar, though fruit itself is of course excellent.
And keep warm! 
PS Did you know that Scandinavians have been taught to sneeze and cough in their elbows? That way you don't pass on the germs so easily.
PPS Sugar = poison. I’ve said it before and I say it again. Read the interview with ‘maverick scientist’ Robert Lustig in last month's Guardian. 
Veg: celeriac, turnip, beet, broccoli, cabbage, calabrese, carrots, cauliflower, chard, fennel, kohlrabi, runner beans, salsify/scorzonera, spinach, tomatoes, Jerusalem/globe artichokes, brussels', chicory, endive, swede, celery, corn salad, leek, peas/mange tout, courgettes, marrow, pumpkin/squash, (white) radish, rocket, spring onions, watercress, sweetcorn.
Meat: rabbit, goose, grouse, guinea fowl, partridge, pheasant, wood pigeon, duck, venison, squirrel.
Fish: crab, clam, cuttlefish, lobster, mackerel, mussels, scallop, sprats, cockles, black bream, gurnard, winkle, pollack, grey mullet, American signal crayfish.
broad beans, land cress, round seeded peas, winter lettuce, corn salad, Chinese leaves. Field beans are the only green manure you can still sow in October.
Plant rhubarb sets; garlic; autumn onion sets if the weather is good. The garlic should be suited for autumn planting. Don't use old cloves! Plant out spring cabbage and, in the South, cabbages and winter/spring lettuce.
CHICKEN SOUP for BEGINNERS
Put chicken in a pot with water to cover. Bring to boil and add, for instance: 1 onion, 1 potato, 1 parsnip, 1 turnip, 5 carrots. Cook on low fire for about 1½ hours. Add seasalt. Then add 3 ribs of celery and a bunch of parsley; cook till all the veg are very soft. Remove the chicken and use elsewhere. Blend, season. Once made, you can freeze it in batches.
GINGER TEA: traditional Thai cold remedy.
5cm piece fresh ginger, 2 stalks lemongrass, 1.5l water, 3 tblsp honey, (1 tsp chilli)
Peel ginger, slice thinly. Trim and cut lemongrass. Bring ginger, lemongrass, and water to a boil. Remove from heat, add honey, stir. Let steep partially uncovered for 15 mins. Strain, serve immediately.
WARM APPLE-CABBAGE SLAW
360ml shredded cabbage, 1 sliced apple, 1/4 cup broth or water, cider (or other nice) vinegar, seasalt. Herbs/spices as liked (such as coriander, cumin, caraway, fennel, bay, juniper, thyme, paprika powder, savory, thyme, marjoram)
Cook cabbage and apple in the liquid until soft. Stir in vinegar and salt.
FRIED MARROW, CARROT and ONION with SOUR CREAM
1/2 - 1 marrow, 1 carrot, 1 onion, 2-3 tblsp sour cream, parsley, salt, pepper
Peel and cube marrow, add salt and fry for 15 mins. Cut carrot very fine, onion too, add salt, fry these separate from the marrow for 10 mins. Mix all together, add pepper, fry 5 mins. Switch off fire, add sour cream. Serve with parsley on top.
SWEET and SOUR CABBAGE
1/2 kg firm white or red cabbage, 1 cooking apple, 1 tblsp butter, 1 tblsp flour, 1/2 tsp salt, 1/2 tsp caraway seeds, 1/4 litre cold water, (1 tsp honey, 1/2 tblsp vinegar).
Mix spices with the flour. Shred cabbage. Slice apple. Heat butter and add cabbage, apple, flour/ spices in layers. Pour cold stock over all this. Cover and cook until cabbage has become tender. Shake now and then, but don’t stir. Add liquid if it becomes dry, and more seasoning if necessary. Lovely with ham and pork.
SPICY STEW of LAMB or MUTTON (or any other meat, if need be)
1k diced mutton, and as much of the following as you have: cayenne/chili, ginger, coriander, turmeric, cumin, ground cloves, cardamom, cinnamon, salt, onions, thyme, curry, bay leaf, rosemary, tomato puree, masala, garlic.
Mix meat with salt, pepper, thyme, chopped onions, ginger, garlic, other spices and some olive oil. Cover, chill at least 1 hr or overnight. Put in pan, cook 30-60 mins. If more cooking is needed, pour 60 ml water at a time down the sides of the pot, not directly on to the meat, and give it a bit longer. If there's not enough sauce, add another 60ml water and simmer for 5-10 more minutes, stirring occasionally.
SAUTEED SPINACH with GARLIC and WHITE WINE, serves 2.
250g spinach, 3 minced garlic cloves, 2 tblsp olive oil, 130ml (cheap) white wine
Heat oil: when hot but not smoking, toss in garlic and move it around constantly. Once it becomes fragrant (very quickly), drop all the spinach into the pan and stir. Once it begins to wilt slightly, pour wine over it. Don't cook it for too long – you want the leaves to still be bright green when you take it off.
SPAGHETTI with ANCHOVIES, CHILLI and GARLIC, serves 2.
200g spaghetti (or linguine or tagliatelle), extra-virgin olive oil,, 6-8 anchovy fillets in oil (or 10-12 if you love them), 1 red chilli, deseeded and finely chopped or chilli powder, 2 sliced cloves garlic, salt, lots of parsley
Cook spaghetti al dente. Meanwhile, heat oil very gently in a heavy-bottomed small deep pan (you can use oil from the anchovy tin). Add anchovies and chilli and cook for 2 mins, crushing the anchovies. Add garlic, cook for 30-60 secs: don't let it colour. Mix in the drained pasta. Transfer to warmed dishes. Give the pasta some extra oil and freshly ground pepper, and serve with the chopped parsley on top.
 The same holds for onions, only onions need to wait 10 minutes after being cut up.
Or if you prefer a video: www.youtube.com/watch?v=4w9RJrXe9zw
There are innumerable websites devoted to the common cold. Here are some of the better ones:
NEXT TIME: THROATS