Most people average two or three colds a year with the risk increasing during the winter months but instead of falling prey to one of these energy sappers, bolster your immune system with essential nutrients to help keep your defenses high.
The shorter daylight hours of winter and lack of sunlight make make many people depressed but moods can be lifted by certain foods.
Remember also to keep portion sizes small otherwise you'll be left feeling sluggish as your body works to digest the extra food.
If you need to snack between meals, fresh winter vegetables, such as radishes, broccoli and cauliflower or low-fat yoghurt flavoured with chillis and lime, make a good snack at work.
Here's some further suggestions from dorunning to help beat the winter blues for next time you head to the shops
Fish
Omega-3 acids, which make up a substantial portion of each brain cell, are found in fatty fish, particularly salmon. People who consume a lot of fish have been shown to have dramatically lower rates of depression than countries which eat less.
Steak
The trace mineral selenium has been shown to lift people's spirits and is found in lean sirloin steak
Other good sources include nuts, oatmeal and seafood. The mineral can be toxic in amounts which are too much more than the Recommended Daily Amount so it's important to obtain the mineral from foods rather than a supplement.
Shellfish
Large amounts of zinc are found in shellfish which help to keep your white blood cells working properly. Shellfish are ideal in soups, pasta sauce or jacket potatoes. Other foods containing zinc include lean meats, beans and wheat germ.
Whole grains (cereal, bread and pasta)
The carbohydrates from these foods help trigger the release of insulin in your body which encourages reactions from your body which lifts your mood. Aim to include carbohydrates in every meal and snack and at least five servings of fruit and vegetables.
Vegetables
Butternut squash
This is packed with beta-carotene which is converted into vitamin A in your body. Protective tissues such as your skin, sinus passages and the lining of your lungs rely on this vitamin for their proper texture and suppleness - cracks in these tissues allow unwanted bacteria, germs and viruses to enter your body. Butternut squash is great roasted.
Onions
Onions are an antioxidant and act on invading bacteria. They are great added to soups, stir fries, casseroles and chilli. The rest of the allium family - garlic and leeks are also good antioxidants as are grapes, tea and berries.
Artichokes
Artichokes taste great steamed, and they also contain a good supply of vitamin C, fibre and folic acid, as well as potassium and copper to your body.
Cabbage
The cabbage family is a great source for vitamin C and carotenes. Cabbage works well added to a stir fry or steamed and serving with chicken or fish.
Chestnuts
Roasted chestnuts are a source of vitamin C. They work equally well eaten separately or added to a stuffing mix.
Sweet potatoes
Sweet potatoes are great roasted, baked or mashed and are a source of the vitamins B6 and C, as well as beta-carotenes, potassium and copper.
Fruit
You've enjoyed picking your own raspberries and strawberries during the summer, but there are many other fruits available in the winter that taste just as delicious.
Bananas
Bananas contain vitamin B6 which helps to boost your body's production of serotonin - this helps to elevate your mood and give you a positive feeling. Eat a banana for a mid-morning snack or slice one over your cereal Give your porridge more flavour and cook a banana with it. B6 is also found in chicken, nuts beans and avocados.
Oranges
Oranges are full of vitamin C, folic acid and fibre which help to boost your immune system.
Aim to eat at least two vitamin-C rich fruits or vegetables a day - clementines or satsumas are perfect for a quick snack. If you're not so keen on citrus fruits, try kiwi fruit, berries, broccoli and tomatoes. Or pomegranates are another good source. Stir the seeds into yoghurt with some honey for your desert.
Cranberries are a great source of fibre, potassium and vitamin C and can be sweetened with honey or used to make a sauce for turkey or even fish.
Drink up
Don't forget that you still need to drink during the winter as well as the summer in order to combat the dryness of air conditioning and central heating.
Keep a bottle of water with you at work, or for a more tasty drink, try a low-calorie flavoured water to help you stay hydrated.
Don't drink too much caffeine to stay awake. If you do find yourself drinking coffee all day, cut back slowly otherwise you'll suffer from fatigue and headaches.
