So how can a good diet can support your immunity? The recent cool change is a good reminder to consider how to boost your immunity and reduce your risk of colds and flus this winter. A whole food diet rich with antioxidants, phytochemicals, vitamins and minerals strengthens immune function, protects our cells from damage and promotes healing.
Fruit and vegetables are the most potent form of these valuable nutrients but only 7% of Australians eat the recommended 5 serves of veges and 50% eat 2 serves of fruit per day.
So what changes can you make to have a healthier winter this year? Focus on increasing your intake of the following foods to boost immunity and your health in general.
VEGETABLES AND FRUIT
Vitamins A, C & E are powerful anti-oxidants that are essential for immune function and work best in combination. To maximise nutrients choose a variety of brightly coloured fruit and veg and eat the skin where possible.
Carrot, spinach, sweet potato, pumpkin are high in beta-carotenes that are converted to Vitamin A in the body. Vitamin A is needed for healthy cells in the immune, digestive and respiratory systems and is essential for iron transport and thyroid function.
Vitamin C stimulates the immune system, reduces infections and supports healing. Good sources are berries, citrus, capsicum, kiwifruit, and dark leafy greens like broccoli, spinach, bok choy and kale.
Wheatgerm, olive oil, seeds, nuts, oats and avocado contain vitamin E which has immune and anti-inflammatory properties. Garlic, onion, leeks and chives contain antibacterial and anti-viral compounds. Herbs and spices are also high in anti-oxidants and have immune boosting properties e.g. rosemary, turmeric and ginger.
Dose up now on fruit and veg to avoid reaching for the cold and flu meds later!
Where can you fit an extra serve in your day?
- Nourishing comfort foods like soups and stews are a good opportunity to add extra veges in the cooler weather and great for lunches or leftovers
- Tomato, spinach, avocado and mushroom go well with poached eggs for breakfast
- Hummus, pesto, guacamole and tahini are good snack options full of nutrients and flavour
Aim for 2-3 serves per week of salmon, sardines, mackerel or tuna for the immune boosting benefits of omega 3s (good fats) and vitamin D. Omega 3’s are needed to form immune cells and also reduce inflammation in the body. If you don’t eat fish regularly a supplement is recommended.
Vitamin D is also important for bone and muscle strength and associated with reduced risk of cancer, diabetes, allergy and other auto-immune conditions. Approx 15% of Queenslanders are vitamin D deficient (up to 50% in southern states in winter). Safe sun exposure is recommended to maintain levels but if you avoid the sun or are over 60 a supplement may be required.
Adequate protein is essential for production of the anti-bodies produced by the immune system to destroy bacteria and viruses. High protein foods such as red meat, liver, kidney and oysters also have the highest content of the immune promoting minerals zinc and iron. Other types of meat including fish, legumes, egg and dairy are lower in these minerals but a re still excellent sources of protein.
Over 50% of men over 50 years old and about 10% of women are zinc deficient. Zinc promotes healing and may reduce the duration of cold symptoms. It is also important for prostate function. In addition to red meat, zinc is also found in pumpkin and sunflowers seeds, chia, cashews and quinoa.
About 25% of women don’ t consume enough iron due to lower red meat intake. Low iron levels increase the risk of infection as well as causing exhaustion, poor concentration, weakness, pale skin, brittle nails and mouth ulcers. Vegetarian sources of iron include amaranth, quinoa, lentils and beans, nuts, dried apricots, spinach, and molasses however absorption is lower so greater quantities are required. Having vitamin C (e.g. a glass of orange juice) with these iron sources increases absorption.
The healthy bacteria in in our digestive tract are a vital part of the immune defence system. If the bacteria is out of balance we are at increased risk of illness. Probiotics can boost this good bacteria. In fact, taking a probiotic supplement has been shown to reduce the frequency of colds and gut infections by 40%. Natural probiotic sources include yogurt, kefir, kombucha, sauerkraut, miso and tempeh.
Eating a good range of fruit and vegetables provide the nutrients the good bacteria need to flourish and establish in our gut.
SAFETY WITH SUPPLEMENTS
While increasing natural food intake of nutrients is safe and highly recommended, caution is advised with supplements.
Some supplements can build up to toxic levels in the body
- Excessive vitamin D, iron or zinc supplements can damage the liver, heart and kidneys
- Vitamin A supplements should be avoided in pregnancy due to a risk of birth defects
Not all supplements are equal.
- Cheaper formulations are often in forms that are poorly absorbed (which can cause digestive upset) or in doses that are too low to have an impact.
Some minerals compete for uptake and other nutrients can interact with each other or prescription medications – the contraceptive pill, aspirin, blood pressure and reflux medications are some examples that can cause nutrient deficiencies.
If you would like more advice on how to boost your immunity this winter or a general diet check-up, book an appointment with our nutrition counsellor and dietitian