Can diet help ‘boost’ our immune system to fight COVID-19?
While it is true that poor nutrition can hamper your ability to fight off illness and infection, it is misleading to think that a special food, nutrient or supplement can “boost” your immune system. There are many products being heavily promoted as “immune boosters”, however immunology is complex and there are no supplements or natural health products approved to treat or protect against the COVID-19 virus.
Alongside a healthy sleep pattern, regular physical activity and stress management strategies, now more than ever is a good time to develop a healthy eating routine.
A Balanced Diet
Following the key points below for a healthy balanced and varied diet with adequate energy and protein intake is important to best support your immune system and overall heart health.
- Aim for 5 – 7 portions of fruit and vegetables per day (aim to include at every meal)
- Choose brown and wholegrain versions of carbohydrates
- Include 2 servings of lean protein per day e.g. fish, lean red meat and poultry, peas, beans, lentils and eggs)
- Stay hydrated with water as your main fluid source
- Limit high sugar/fat/salt foods to a few times per week
Below, we will take you through some of the key nutrients found in a balanced diet one and highlight the role they pay in supporting your immune system to work properly.
7 key nutrients for a healthy immune system
Protein is important for many bodily functions such as healing and repair and maintaining healthy muscle mass. It also has a role in the formation of antibodies that fight infection and disease. Protein foods can be animal based such as meat, fish, poultry, eggs and dairy or plant based such as peas, beans, lentils, tofu and nuts. Vary your protein sources, choose lean meats and poultry and limit processed red meats to keep your diet low in saturated fat. Include fish twice a week one of which is oily such as salmon, mackerel, trout or sardines (tinned or fresh).
This vitamin is ace at supporting your immune system! It helps maintain the structure of the cells in the skin, respiratory tract and gut. It acts as an anti-oxidant which is kind of like anti-rust protection for our bodies cells, keeping them strong and ready to fight infection. Beta-carotene which is converted to vitamin A in the body is found in leafy greens, yellow and orange vegetables like pumpkin and carrots.
Vitamin E is also a powerful anti-oxidant and is found in green leafy vegetables such as spinach and broccoli. It is also found in avocados and vegetable oils such as sunflower and rapeseed oil and nuts and seeds including: almonds, hazelnuts and pumpkin. Why not try adding a handful of nuts or seeds to your cereal or using rapeseed oil in cooking and salad dressings.
Habitual vitamin C supplementation may help with the common cold by reducing severity and duration (>200mg/day) however we don’t know if this transfers to viruses. The recommended daily allowance (RDA) of vitamin C for most adults is 80mg which is easily achieved through a balanced diet. Foods rich in vitamin C include bell peppers, citrus fruits, broccoli, Brussels sprouts and berries. Fresh and frozen are equally as nutritious. While vitamin C supplementation up to 1000mg/day won’t do you any harm, excess consumption can result in stomach pain and diarrhoea.
Vitamin D works with calcium and phosphorus for healthy bones, muscles and teeth. Vitamin D also helps to regulate our immune responses and a recent review of the research found that vitamin D supplements can help protect against acute respiratory infections, particularly among people who are deficient.
This is one vitamin where supplementation is recommended, although we can make vitamin D in the skin through direct sunlight, in Ireland the sunlight isn’t strong enough between March and October. We can get some vitamin D from diet as it is found in foods such as eggs, salmon and fortified milk but typically we don’t consume enough of these foods to meet our needs. Taking a 10 micrograms per day supplement is recommended for adults and children over the age of one year. With the social isolation precautions our time outdoors may be restricted a bit more and so supplementation is more important than ever.
Zinc helps the immune system to work properly and plays a role in wound healing. The immune system works well when we consume the recommended daily allowance of zinc which is 10mg / day. It is rare to be deficient in zinc as it is present in a wide range of foods including; lean meat, poultry, seafood, milk, whole grain products, fortified breakfast cereals, beans, seeds and nuts.
Selenium is involved in the normal function of the immune system. Good sources include Brazil nuts (5-6 Brazil nuts provide an adults daily needs) fish and seafood, brown rice, baked beans, sunflower seeds and oats are also good sources.
Most importantly, please remember that correct and frequent hand washing is your first line of defense and to continue to physically distance yourself as much as possible to break the chain of transmission. For more information check out the HSE website.