The temperature is still good for picnics and parties but one can’t disregard that the combination of chilly winds and low temperatures may lead to croaky throat, runny nose and fever. This being the season for colds and flu, it’s a challenging time for one’s immunity. Our body also experiences changes in energy levels, metabolism and even food preferences. So what we choose to eat can play a crucial role in boosting immunity.

What is immunity?

It is our defence mechanism, which protects us from invasions by foreign substances. There are special processes that can destroy foreign substances — like bacteria, viruses, fungi, parasite — before they multiply and cause illness.

Who is at risk?

All of us are at risk. However, some of us need to take more care to keep our immune system working at its best. You are more prone to infections if you are…

• Recovering from any kind of illness
• Work in a place where you interact with a lot of people, such as schools, hospitals, call centres and banks, as you are more likely to be exposed to various infections
• Elderly
• Children
• If you’re taking medications which suppress the immune system, like corticosteroids or anticancer drugs
• Have poor health

The World Health Organisation (WHO) recommends increasing, during winter, the intake of vitamins A, C and E, which are antioxidants, and minerals, including selenium, zinc and magnesium as well as omega-3 and omega-9, which are fatty acids.

The immune system needs the right fuel to function efficiently. Certain food contain nutrients that are known to have potent immune-stimulating effects, which can be used to improve resistance to infection and keep diseases at bay. The following nutrients play a key role in boosting healthy immune function.

Beta carotene: It is converted into vitamin A and helps protect the immune system from the action of damaging free radicals. Vitamin A strengthens the skin and therefore acts as a first line of defence against viruses and bacteria.

Sources: It is found in high concentration in mango, papaya, watermelon, melon, apricot, sweet potato, carrot, red and yellow pepper. Drink plenty of carrot and watermelon juice.

Vitamin C: It stimulates our immunity by its ability to increase the production of antibodies and speed up the rate at which immune cells mature. Viruses cannot survive in a vitamin C-rich environment making it an incredible anti-viral agent. However, a megadose of vitamin C can cause diarrhoea and gastrointestinal disturbances. The US Food and Nutrition Board recommends a tolerable upper intake level for vitamin C of two grams daily.

Sources: Fruits like orange, sweet lime, grapefruit, kiwi, strawberry and Indian gooseberry (amla). Guavas have more vitamin C than orange, making them an excellent source of vitamin. Vegetables such as bell pepper, cabbage, broccoli, tomato and cauliflower also contain it.

Zinc: It is a crucial nutrient for the production and functioning of immune cells. Low levels of zinc have been shown to weaken the immune system.

Sources: Oysters, beef, lamb, shrimp, green pea, egg yolk, wholegrain, peanut, almond, cashew, pumpkin and flax seeds, and ginger root.

Valuable veggies

What better way to increase your intake of vitamins and minerals than vegetables? But it is not just enough to eat vegetables; we need to include all different hues, especially orange, yellow and red-coloured ones, such as squash, pumpkin, tomato, cherry, strawberry and orange, since they are rich in both vitamin C and beta carotene. Cruciferous vegetables like kale, broccoli, spinach and cauliflower have been shown to boost immunity and offer protection against cancer.

Besides eating them, the intake can come in the form of juices, vegetable soups, salads, stir fries and pasta sauce.

Things to avoid

Excessive sugar intake: As the level of sugar in the bloodstream goes up, the efficiency of the immune system goes down. Refined sugars have a negative impact on immunity levels. Reduce intake of sugar, sweets and sweetened drinks.

Alcohol: Binge-drinking leads to loss of immune cells. Alcoholics are more susceptible to infections and diseases.

Large fatty meals: When the body has to cope with fatty foods and large meals, its ability to combat infection is reduced. Avoid big meals containing large amounts of fat.

Remember…

• Regularly wash your hands; it minimises chance of contracting an infection by reducing your exposure to bacteria and viruses.
• Restful sleep helps your body recover and can make your immune system function more efficiently.
• Exercising during winter can help protect against illnesses and boost immunity. A study has shown that people who engage in moderate physical activity — about three hours a week — are 35 per cent less likely to catch a cold or flu.
• Eat breakfast because research has shown that people who skip breakfast are prone to common colds.

Hena Nafis is a consultant nutritionist and the owner of nutrition and lifestyle clinic Nutrience, and the health cafe, Eat Good Food