Seasonal influenza peak season is here! Eat more of these 5 immune-boosting summer foods

Seasonal influenza peak season is here! Eat more of these 5 immune-boosting summer foods

Seasonal influenza peak season is here! Eat more of these 5 immune-boosting summer foods



3  Mins Read

Some people may think you can only catch a cold during winter. Contrary to popular belief, it doesn’t have to be cold outside to catch a cold. According to the Centre for Health Protection of Hong Kong, seasonal influenza is more common in periods from January to March/April, and from July to August.

When it comes to immune-boosting foods, most people think of garlic and yogurt right away. In addition to these two foods, a bountiful of summer crops are also available.

Green tea

Both green and black teas are packed with flavonoids, a type of antioxidant. In addition to taste and color, they differ in the levels of epigallocatechin gallate, or EGCG, another powerful antioxidant. EGCG has been shown to enhance immune functions. As green tea is usually steamed and not fermented, EGCG can be preserved. Black tea, on the other hand, goes through fermentation. This process can destroy significant amounts of EGCG. A 2007 study showed that participants taking green tea extracts showed improved immune responses by secreting more virus-fighting T-cells.  Regardless of hot or cold green tea, it also has the function of strengthening the immune system.

Red bell pepper

If you think citrus fruits have the most Vitamin C of any fruit or vegetable, think again. Ounce for ounce, red bell peppers contain twice as much Vitamin C as citrus fruits. Vitamin C is one of the biggest immune system boosters of all. In fact, a lack of Vitamin C can make you more prone to getting sick. As your body doesn’t make or store Vitamin C, it’s best to eat foods rich in this vitamin every day (and even every meal).

Cherry tomatoes

Have you ever noticed that tomatoes seem to taste sweeter in the summer months? There are many varieties of these red gems to choose from: cherry, grapes, beefsteak, and roma, just to name a few. The smaller varieties like cherry tomatoes are just a perfect to-go snack that you can pack for outdoor trips. This means you don’t need to wait for meal times and can eat them a lot often. Tomatoes contain high amounts of Vitamins C and E, potassium, and all the powerful carotenoids such as beta-carotene and lycopene. These carotenoids are important immune-boosting nutrients; your body turns them into Vitamin A which has an antioxidant effect to fight off infection.


Beta-glucans, a type of soluble polysaccharides found in many foods have been identified as having an ability to boost immunity. In particular, beta 1,3/1,6 glucans from mushrooms have been shown to enhance macrophage activity, which is critical in warding off infection. Shitake, maitake and reishi varieties are reported to be most effective in boosting immunity, but everyday favorites like crimini and white button mushrooms are also healthy options.


When it comes to preventing sickness, Vitamin E also plays a key role in maintaining a healthy immune system. Vitamin E is a fat-soluble vitamin; it requires the presence of fat to be absorbed properly. So nuts are perfect in this regard as they are packed with both Vitamin E and healthy fats. Among all nuts, almonds rank the highest in Vitamin E content. A one-ounce serving (about 23 pieces of almonds) provides almost half of the recommended daily amount of Vitamin E. So enjoy almonds more often by making them an afternoon snack, or tossing extra in your summer salad dishes.

¹ Remarks:
Information of Centre for Health Protection:

Gloria Tsang - Registered Dietitian