Q: I know that the Department of Health has told us to forget old wives' tales when it comes to protecting ourselves against catching flu, but is there anything I can do to lower my chances of picking up a common cold and boost my immune system this winter?

A: There is no fail-safe way of stopping yourself from picking up a cold, nor a definitive cure if you do fall ill. That said, simple things such as washing your hands frequently, especially when around others with colds, can help to reduce the risk of infection. When it comes to what you eat, things are less clear. Not surprisingly, the bedrock of a robust immune system is a balanced diet and a fit body, but cold viruses can overcome the healthiest of individuals.

At this point, taking vitamin C may be worth considering. Mega doses will not prevent a cold, but having 500mg three times a day may, according to some experts, reduce the severity of and the length of time that symptoms hang around when taken for a short, sharp spell, although I wouldn't recommend this if you have a tendency to get kidney stones.

Good foods for vitamin C are peppers (240mg per small pepper), papaya (120mg per two slices); citrus fruit (54mg per orange), frozen berries (around 60mg per big serving) and green leafy vegetables (60mg per serving of spinach).

The Department of Health rightly dismissed the advice from the Middle Ages that carrying around a clove of garlic can ward off flu. But for thousands of years it has been recognised for its therapeutic powers. It appears that allicin in garlic may help to block enzymes that give viruses (and bacteria and fungi) the ability to enter and damage tissues. The problem is, cooking inhibits the action of allicin so you do have to eat it raw to get any potential cold-beating benefits.

I have never been convinced by the cold-busting properties of echinacea, but herbal experts tell me that it may genuinely also help by stimulating your immune system to attack invading cold viruses and again, reduce symptoms if you do catch a cold. You need to look for products that contain at least 3.5 per cent of “echinacosides” which are the active substances in this herb, and to aim for 200mg five times a day. That said, you should not take echinacea for more than three weeks at a time.

We all have our own pet ideas about the best way to stave off a cold and mine happens to be a daily supplementation with Multibionta Immune Support Probiotic Multivitamin, which contains an immune-boosting probiotic “good” bacteria called Tribion harmonis, which the makers say has been proven to help to support our immune systems.

When I feel a sniffle coming on I grab a bottle of Immune Tincture made by The Organic Pharmacy (www.theorganicpharmacy.com). Knock back 15 drops in water three times a day. Containing echinacea, goldenseal, olive leaf and cat's claw, it has not been scientifically tested, so heaven knows if it really works, but I believe it does.

Catching the virus: danger factors

Research from Harvard Medical School shows that smokers are more likely to have prolonged symptoms of a cold. Passive smokers are more likely to catch a cold and have symptoms hanging around for longer than non-smokers.

It is likely that genetics play a role in determining whether a cold virus will or will not turn into a full-blown cold in different individuals.

Research suggests that people who are stressed are more likely to develop a cold. This may be because their immune systems are weakened through an increase in corticosteroid hormones.

If you have nutrition questions for Amanda, e-mail her at amanda.ursell@thetimes.co.uk