The colder months are the ideal time to support our immune systems with good nutrition. With winter approaching, which nutrients are particularly important and how can we make sure we get enough of them?

The following has been adapted from a feature by Bridget Smith in the Winter 2014-15 issue of Optimum Nutrition.

Many may wish they could snooze the dark and chilly months away, but winter is often a busy and stressful season when we need a steady supply of ‘oomph’ to cope with overloaded work schedules and to-do lists.

The last thing we want is illness – yet coughs and colds are often rife at this time of year. Which foods can help us keep well this winter?

Supporting immune function

The immune system is very complex, comprising of special cells with distinct roles that work hard all year round to keep us well.

Vitamins and minerals won’t stop you breathing in viruses, but a healthy immune system can help fight them off.

Supportive nutrients for good immune function include vitamin C, zinc, vitamins A and D, B-group vitamins and bioflavonoids.

Taking supplements of these nutrients might be worth considering for individuals with a depressed immune system, such as the elderly or infirm.

Vitamin C and zinc

Both vitamin C and zinc play important roles in immune function and help us resist infectious agents, so reducing the risk, severity, and duration of infectious diseases.

But contrary to popular belief, vitamin C can’t stop us from catching a cold and it can’t stop a cold in its tracks either.

What it does do, however, is aid the immune function in numerous ways, including promoting blood cell formation and excretion of heavy metals, as well as acting as an antihistamine and so reducing inflammatory reactions.

A group of nutrients called bioflavonoids, which are often present in the same foods as vitamin C, also support the immune system through their antioxidant, antimicrobial, anti-inflammatory and anti-allergic properties.

Zinc also plays a critical and multifunctional role in the body, ensuring cellular growth and development and proper functioning of the immune system, while protecting cells from oxidative stress and damage.

Vitamins A and D

Vitamins A and D have been shown to have crucial effects on the immune response.

These nutrients are involved in a broad range of immune processes such as lymphocyte activation and proliferation, the production of specific antibodies and regulation of the immune response.

In addition to supporting the immune system, vitamin D appears to have direct antimicrobial action against viruses, bacteria and other pathogens.

Getting enough vitamin D is easy in summer, because we produce a form of vitamin D (D3/ cholecalciferol) when our skin is exposed to strong ultraviolet-B (UVB) radiation from sunlight.

In winter we tend to hide away indoors; but even if we could sunbathe all winter long, in the UK the UVB rays just aren’t strong enough for us to make vitamin D between November and March.

This essential substance (actually more of a hormone than a vitamin) plays a key role in a wide variety of health functions, including calcium absorption and bone and muscle strength.

It may also help to ensure a normal immune response to pathogens such as viruses and bacteria, increase insulin sensitivity and improve cardiovascular function.

Very few foods are high in vitamin D; the best sources are cod liver oil and fresh, wild salmon.

Good amounts are also present in other fresh or canned oily fish (e.g. farmed salmon, tuna, mackerel and sardines), egg yolks and fortified foods such as cereals and dairy products.

Because vitamin D deficiency is widespread in the UK, you may wish to consider getting your levels checked and, if necessary, taking a supplement.

B vitamins and vitamin E

A sufficient intake of B-group vitamins, especially vitamin B6, is also important for immune support.

Vitamin B6 is needed for the immune system to produce various kinds of lymphocytes and antibodies to fight infection.

Vitamin E has been found to improve the function of immune system T-cells and to act as an immune modulator.

In particular, it helps to prevent the immune system’s natural inflammatory response from causing damage to body tissues.

Exercise and hydration

In addition to eating healthy, nutritious meals that support your energy and immunity, both exercise and adequate hydration continue to be important during the winter months.

It may be tough to keep to an exercise regime when it’s cold and wet outside, but try to find an activity that you enjoy doing and aim for least two and a half hours of moderate-intensity exercise per week (for example, walking, swimming or cycling).

Ensuring that you drink enough water is easier in summer, but we actually need to drink the recommended one and a half to two litres all year round for good kidney function and general health.

Home-made winter soups can help to keep you hydrated as well as supplying many of the nutrients mentioned above.

Some tips for immunity

For people with depressed immune systems and a low appetite, healthy eating at any time of the year may seem difficult or complicated.

Yet for these individuals, good nutrition is especially important and so it may be worth their seeking professional advice on nutritional supplements.

Simple steps, such as including some fruit, salad or vegetables with each meal, can also help to increase vitamin and mineral intake.

Eating a wide variety of seasonal foods during the winter months will not only help to ensure you get all the nutrients you need but has the extra benefit of providing good value for money.

Check out the Love British Food website for information on foods that are in season this time of year.

Your taste buds and health will be grateful.

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