You might be wondering which nutrients are important to help you avoid catching a cold or the flu during the colder months. This article will outline some key nutrients to include in your diet or through supplementation, to help you stay well this winter.
How to keep a cold or flu at bay:
Adequate intake of vitamin D is crucial for a healthy, well-functioning immune system. Our skin can create its own vitamin D when exposed to sunlight, however this is reduced during the winter months. Vitamin D deficiency is associated with an increased risk of respiratory tract infections, therefore it is important to ensure you get enough of this vitamin. Current UK advice is that we need 10 micrograms of vitamin D per day to maintain good health. We can usually obtain sufficient amounts from sun exposure and diet between April and the end of September. Food sources include oily fish, eggs, sun-enriched mushrooms and some fortified foods. However, during autumn and winter it is recommended that you take a 10 microgram vitamin D supplement to avoid depletion.
You may have an increased risk of vitamin D deficiency if you:
- Do not go outside often
- Are housebound
- Do not expose your skin to the sun when outdoors
- Have dark skin
- Do not consume oily fish or eggs
If you fit into one of these categories, it may be helpful to speak to your doctor about a vitamin D blood test. If you are deficient then you will likely need a much higher dose than 10 micrograms for a short amount of time, which your doctor can advise you on.
This nutrient plays an important role in supporting a healthy immune system. It also acts as an antioxidant, helping to protect cells from damage and inflammation.
Studies suggest that vitamin C supplementation may slightly reduce the duration of the common cold. Food sources include bell peppers, fresh parsley, thyme, kiwi, citrus foods, strawberries, broccoli, tomatoes, kale and berries.
Vitamin A helps our immune cells to fight off infection and is important for keeping cells in the respiratory system healthy. Foods such as carrots, butternut squash, sweet potatoes, bell peppers and spinach contain beta-carotene which the body converts into vitamin A. Direct sources of vitamin A include cheese, eggs and oily fish. Unless deficient, vitamin A supplementation should be avoided as excessive amounts of vitamin A may negatively affect the immune system.
Iron is a component of several proteins and enzymes involved in the immune response to fight off infection. Good food sources include red meat, fish, shellfish, organ meats, cooked spinach, cooked beans, nuts, dried fruit, tofu and pumpkin seeds. Both iron deficiency and iron excess may increase the susceptibility to infection therefore it is important not to consume too much or too little iron.
Selenium helps to protect cells from inflammation which can occur during viral infections. It is also involved in several biological processes that support immunity. Food sources include Brazil nuts, fish, meat and eggs.
Zinc is important for the production and function of white blood cells such as neutrophils, natural killer cells and T-cells which fight off infection. Food sources include oysters, beef, pork, firm tofu, chicken, shiitake mushrooms, yoghurt, nuts, beans, peas, lentils, pumpkin seeds and hemp seeds.
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