Does what we eat actually help prevent colds and infections?

Posted by for Nutrition

The benefits of a balanced diet, and the nutrients you need to know about, when it comes to avoiding winter colds. 

Winter brings with it a whole lot of nastiness, from dark mornings to icy weather. But one of the least favourable things about the season has to be the colds. The sniffles, tiredness and general run-down feeling seems to extend from November to March without much respite. 

Our bodies are constantly working hard to fight off those germs (and any other infection we might get) with our inbuilt immune system, mainly by the force of white blood cells that can destroy bacteria. But white blood cells can only be produced and function at their best with the support of essential nutrients.

What to feed your immune system

“There is no quick fix to supporting your immune system. However, eating a healthy and balanced diet does promote good immune function and mood,” says Nehal Keshwala, senior specialist dietician at The Princess Grace Hospital, part of HCA Healthcare UK. “A healthy balanced diet includes five portions of fruit and vegetables a day and good sources of protein, iron and calcium. Starchy foods (bread, pasta, rice and cereal) are also a part of that and can provide energy which can help fight off any brewing infections.”

Charlotte Bierens, head of nutrition at nutritionally-complete meal brand Jimmy Joy also notes the importance of having a well-rounded diet. “In order to stimulate the body’s capability of defending itself against pathogens, the body should be nourished with a balanced and complete diet,” she says. Charlotte also points out some key nutrients that you might want to pay attention to if avoiding a cold is at the top of your to-do list. 

Zinc

Cellular function, including the killing of harmful pathogens and cytokine (cell signalling molecules that aid cell to cell communication in immune responses) production, are dependent on zinc and are impaired due to zinc deficiency, according to a study published in the Nutrients journal. In fact, the study dubbed zinc the ‘gatekeeper’ to the immune system, which sounds too important to ignore. 

You need around 7mg a day, which the NHS says is doable from a well-balanced diet that includes sources of zinc such as:

  • Red meat
  • Milk
  • Chickpeas 
  • Wholegrains
  • Fortified cereals and alternative milks 
symptoms-zinc-deficiency
Cereal can be fortified with zinc

Vitamin C

Vitamin C is the most popular cold-fighting nutrient out there, and whether you get it from eating a ton of oranges or by supplementing, there’s a reason for its popularity. A study from the Nutrients journal concluded that vitamin C can both prevent and treat respiratory and systemic infections because of its roles in both supporting immune cells and killing bacteria.

The NHS advises 40mg of vitamin C a day, but states that any amount up to 1000mg is a safe dose. Anything over that can cause an upset stomach. High vitamin C foods include: 

  • Kale 
  • Peppers
  • Citrus fruits 

Vitamin D

Traditionally, this vitamin is associated with strong bones. But we now understand the huge impact that vitamin D has on a whole range of other functions in the body including mood and infection fighting. “Research has shown a decrease of 42% in the incidence of influenza infection by people taking vitamin D supplements, thought to be down to the function of so-called T-cells which destroy infected cells and stimulate antibody production,” explains Charlotte. 

You can get vitamin D from some foods, such as:

  • Oily fish
  • Eggs 
  • Fortified dairy products
  • Mushrooms

However, as the main source of vitamin D is sunlight, everyone should supplement during the winter months. 

Probiotics

As well as the vitamins and minerals, we need to think about the bacteria that our food contains. “Looking after your gut health will help protect immune function, particularly in the winter months,” says Nehal. “Including plenty of probiotic foods (that contain live bacteria) and prebiotic foods (to feed the live bacteria) will encourage the growth of good bacteria which help protect against gut microbes that could lead to infections.”

Good sources of probiotics include:

  • Live yogurt
  • Kefir
  • Fermented foods, such as sauerkraut and kimchi

Prebiotic foods include:

  • Leeks
  • Onions
  • Wholegrains 
  • Legumes

Ultimately, the best thing you can do to prevent getting an infection is eating a whole host of different foods, with a big focus on fruits and vegetables, and keep up good hygiene habits to avoid coming into contact with too many germs. 

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Images: Getty

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Chloe Gray

Chloe Gray is the senior writer for stylist.co.uk's fitness brand Strong Women. When she's not writing or lifting weights, she's most likely found practicing handstands, sipping a gin and tonic or eating peanut butter straight out of the jar (not all at the same time).