As we slide into November, your thoughts are likely turning to where the hell you put your cashmere beanie hat, which lip balm will actually heal your chapped, sore lips – and what to eat to prevent a cold.
Yep, cold and flu season is here and staving off the virus is pretty high up on most people’s winter agendas (missing the work Christmas party thanks to sniffles is no one’s idea of fun). The good news? What you choose to eat and drink can directly influence your immune health.
So what are the best foods that boost immunity? To get you the intel WH tapped up consultant dietician and head of nutritional research at Heights, Sophie Medlin, to find out her must-eat immunity-boosting foods to stave off the sniffles – plus, why our diet plays such an important role in keeping our immune system healthy.
Why are nutrients so important for our immune system?
Our immune system is complex and influenced by many factors, including sleep, exercise, stress and importantly, nutrition, explains Medlin. ‘It can be helpful to remember that our immune system uses up more nutrients when it is fighting an infection because vitamin C, zinc and others are essential to the functioning of our immune cells.’
‘While there is no one “superfood” which will fight illness on its own, what we put into our body truly is the foundation of our health, and eating a balanced, varied diet rich in plants makes a vital contribution to the function of the cells throughout our body, including our immune cells – 70% of which live in our gut. That’s why the health and diversity of our gut microbiome is one of the most important elements in determining the health of our immune system.’
How can food boost your immune system?
The right combination of vitamins and minerals helps to support our immune system in a multitude of ways, says Medlin – including; ‘working as antioxidants to protect healthy cells, supporting growth and activity of immune cells, and producing antibodies’.
As mentioned, our gut microbiome plays a key role in our immune function by stimulating immune cell activity. ‘Consuming a variety of vitamins and minerals through fruits, vegetables and whole grains is essential in supporting the growth and maintenance of these good gut microbes,’ she says.
Important nutrients for our immune system include zinc, vitamin C, vitamin D, selenium, iron and protein.
In our fast-paced lifestyles, we often rely on convenience foods and therefore struggle to get all of the nutrients we need from our diet. ‘We also neglect our diet more when we’re stressed and anxious which makes us more vulnerable,’ adds Medlin.
‘Taking a good quality supplement and probiotic can give you an insurance policy by ensuring the right nutrients are always available to help support your immune system even when your diet is less optimal in the short term. That said, as a well-supplemented dietitian sitting writing this with a cold… sometimes, it doesn’t matter how much effort you put in, the bugs will still get you if you’re run down so don’t blame yourself.’
How can supplements help bolster immune health?
The question of diet vs supplements is one which is asked a lot, says Medlin, ‘and the two are often polarised as two sides of a strict dichotomy. In reality, the relationship is much more nuanced. A balanced and varied diet is absolutely the best place to start – it’s the foundation of all nutritional health, and ideally, we would be able to get all of our nutrients from this.’
However, our busy modern lifestyles can sometimes make it difficult for us to stay on top of what we’re eating and to get the right combination of vegetables and whole foods that we need.
‘There are also environmental factors to take into account,’ she says. ‘Evidence suggests that deteriorating air quality and atmospheric pollution increases our nutritional requirements, as does poor gut health — an increasingly common problem. On top of that, decades of intensive factory farming have depleted the soil of nutrients. This means that the food we grow contains less nutritional value than it used to, making it even harder to get enough of the nutrients we need from diet alone. We also know that caffeine and alcohol deplete our nutrient stores.’
If you aren’t able to get all of your nutritional requirements from your diet, then nutritional supplementation is a simple, convenient and effective way to bridge the gap and ensure that you’re getting the vitamins and minerals you need for a healthy immune system.
But can you overdo it with supplements?
When choosing a supplement, Medlin recommends checking the quantity and making sure that any dose is within the safe upper limit (SUL); ‘it’s essential to make sure that the ingredients — the actual compounds that contain the micronutrients — are high quality and high-impact. That means you’re looking for active, bioavailable forms of the nutrient where possible.’
But unless you’re deficient in a certain nutrient, could you do more harm than good by taking supplements?
‘It is certainly possible to overdo it with nutrients,’ she says, ‘for example, during the pandemic, we saw people taking “megadoses” of things like vitamin C and D which makes your body have to work very hard to process and excrete these nutrients which in the end, causes more harm than good.
‘Some nutrients such as B vitamins and water-soluble and your body can easily take what it needs without causing harm whereas others like vitamin D, vitamin A and vitamin E can build up in your body causing harm.’
What are the best immune-boosting foods?
Here are nine nutrients which have been scientifically proven to specifically benefit your natural immunity. Each can be sourced through the foods listed, (but also found within supplements).
1. Vitamin A
Vitamin A is an anti-inflammatory, which provides essential support for your immune system by supporting the production of antibodies.
Good sources of vitamin A include:
- Red and yellow vegetables
- Leafy green vegetables
2. Vitamin B6
B Vitamins help to maintain a healthy immune system by supporting cellular function.
Good sources of vitamin B6 include:
- Oily fish
- Chicken breast
Vitamin B9, also known as folate or folic acid, is another nutrient you need for proper immunity.
You can get B9 from some food sources, such as:
4. Vitamin B12
Another B vitamin, this time B12. We only need small amounts of B12, which you can find in foods like:
5. Vitamin C
The most well-known vitamin for immunity is Vitamin C. It’s an antioxidant which means it protects your body from toxins which cause inflammation.
Good sources of vitamin C include:
- Citrus fruit
- Brussels sprouts
6. Vitamin D
While it’s true that we can get vitamin D from sunlight, there’s little to no chance of us getting enough exposure in the winter. For this reason, the NHS recommends everyone take a vitamin D supplement to counteract the lack of sunlight exposure we receive throughout the winter.
Some foods do contain vitamin D, including:
- Fortified eggs
- Mushrooms which have been treated with ultraviolet light
- Tinned fish
However, it should be pointed out that these foods aren’t long-term practical sources because the quantity of Vitamin D within them is so low.
Most people think of iron as something for your red blood cells, but it’s essential for maintaining your natural defences too. People often think first of red meat when it comes to meeting their iron intake, but you can actually get the trace element from a variety of vegetarian sources too, including:
Selenium is a lesser-known mineral, and it plays a key role in the healthy functioning of the immune system by protecting the immune cells from oxidative stress – a process which disrupts the body’s ability to rid itself of toxins. There aren’t many food sources that contain high levels of selenium, but some of the best are:
- Brazil nuts
Zinc supports so many healthy functions throughout the body, and is important for the development and regeneration of a specific type of immune cell. Zinc is also highly important for other bodily processes such as cognitive function, fertility and reproduction.
Good sources of zinc include:
- Pumpkin seeds
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