People who ate flavonoids also had fewer sick days, she said.
"These findings show that if you're generally healthy, eating flavonoids found in lots of fruits and vegetables can help stave off the bugs over winter," Dr Braakhuis said.
"Make sure your dinner plate is at least half full of vegetables, sip green tea over winter and enjoy the occasional red wine."
Dr Braakhuis said further research was needed to find out whether food or supplements was a better source of flavonoids, or what an ideal dose would be.
"At this stage we would recommend about 0.5g of flavonoids from a variety of sources such as red cabbage, red onion, eggplant, blueberries and oregano," she said.
Wellington GP Dr Samantha Murton said eating a healthy diet including of a range of fruits and vegetables was essential to stave off the common cold, regardless of a food's flavonoid content.
"As far as a GP is concerned, when it comes to trying to protect yourself from coughs and colds, eating a healthy diet is really important. Eating more coloured fruit and vegetables is really critical," she said.
New Zealand Nutrition Foundation chief executive Sue Pollard said it was better to maintain a balanced diet rather than focus on specific nutrients.
"If you are eating a well-balanced diet, you are going to get flavonoids and you are going to get a lot of other things you need."
What to eat
• Flavonoids are phytonutrients in plant-based foods which contribute to their colour.
• Berries: Many have a high flavonoid content, particularly red, blue and purple berries. Riper and darker berries tend to contain more flavonoids.
• Red wine: Is high in flavonoids as it carries many of the benefits of red grapes.