Winter is on its way bringing the increased potential for colds and flu. However nature is currently providing a number of seasonal foods that we need to increase nutrients vital for building our immunity. There are a couple of key vitamins and a mineral that we should look at specifically for preventing colds and flu. These are Vitamin A, Vitamin C and Zinc. Below I have explained why these nutrients are important and what foods they can be found in at the moment. So make sure you stock up whilst you can and get ready for a healthy winter!
Vitamin A
Why is it important?
This vitamin is important for keeping the mucus membranes in the nasal cavity healthy; to provide good defensive barriers against inhaled germs. Vitamin A also boosts the production of white blood cells, which are the cells that help us fight infection. Vitamin A also stops virus replication, so in a way stops them in their tracks. Low vitamin A is linked with poor wound healing, repeat infections and night blindness.
Which seasonal foods are rich in vitamin A?
Vitamin A is found in many yellow, orange and red foods, in the form of beta-carotene. Beta-carotene is converted to vitamin A in the digestive system. At the moment there are an abundance of root vegetables this colour such as carrots, pumpkin and golden kumara. So your mum was not lying when she said carrots could help you see in the dark. Also persimmons are orange in colour and a good source. We are not just looking at orange foods though. There are a number of green vegetables high in Vitamin A. You may be interested to know that these vegetables would be orange if they did not contain chlorophyll. Good sources around at the moment are spinach, cabbage, kale and other green leafy vegetables and brussel sprouts, broccoli, capsicum and celery.
High sources available all year round are eggs and oily fish.
Vitamin C
Why is it important?
Most people are aware that vitamin C can help prevent colds. The reason being is that it is used in every cell in the body and in this way is important for the immune system. If we become ill it is quickly depleted as it is a major component of white blood cells and it also stimulates white blood cell production. As mentioned before white blood cells are the army that protects your body from invasion, so you can see how important vitamin C is. It is worth noting that Vitamin C is depleted by alcohol, certain medications (for example the oral contraceptive pill) and most significantly by smoking. So people taking medicines or smoking and drinking regularly will need more vitamin C than others.
Which seasonal foods are rich in vitamin C?
Vitamin C can be found in most green vegetables, so we have double the reason to be enjoying the green leafy vegetables and others mentioned previously. Kiwifruit are an excellent source as are feijoas and persimmons. The other major fruit category is citrus fruits, so start enjoying those tangerines, oranges and lemons!
It is also worth noting that vitamin C is easily killed by heat. Therefore eat some fruit and vegetables raw and try to steam rather than boil when cooking.
Zinc
Why is it important?
Zinc, has antiviral properties and is released into the saliva to help kill any ingested bacteria and viruses. Like vitamin A it strengthens the barriers in the mucous membranes and it is used extensively by the immune system. Studies show a 50% reduction in cold duration when taking zinc.
Which seasonal foods are rich in Zinc?
When you are enjoying those pumpkins for their vitamin A, don’t throw away the seeds as they are a rich source of zinc. In fact most nuts and seeds are a good source of zinc. Beans, lentils and grains are good sources, so start making those hearty winter soups.
Finally the Bluff Oyster season is still going – and Oysters are the highest source of zinc!
