Other than masks, immunity-boosting supplements are probably the next most-coveted items in the pharmacy aisles these days. And it makes sense, doesn’t it? Your immune system is probably taking a beating from the stress of returning to work or getting Junior settled into the new school term. Boost your immune system and you’re less likely to pick up an infection, whether it’s the Wuhan coronavirus or the common cold, right?
There is some evidence that micronutrient deficiencies such as zinc and folate, as well as Vitamins A, B6 and C, may alter immune responses in lab tests on animals, according to an article by Harvard Medical School. But to make up for the shortfall, you may be better off eating the right foods instead of popping supplement tablets.
That’s because the nutrients from food are the “most potent” and “are accompanied by many non-essential but beneficial nutrients, such as hundreds of carotenoids, flavonoids, minerals and antioxidants that aren't in most supplements," said Dr Clifford Lo, an associate professor of nutrition at the Harvard School of Public Health. Furthermore, relying on pills may cause you to overdose without realising it.
Here’s a look at some of the foods to consider adding to your meals.
1. BELL PEPPER
Oranges aren’t the only food packed with Vitamin C, that nutrient widely known for keeping infection at bay. Red bell peppers are a strong contender, and in fact, contain twice as much Vitamin C as citrus fruits. One medium-sized red bell pepper provides 169 per cent of your daily requirement (90mg for men and 75mg for women per day), wrote UK-registered dietitian Caroline Hill on Healthline.
The red ones are the most nutritious because they've been on the vine the longest. Compared to the green peppers, reds contain 1.5 times more Vitamin C, eight times more Vitamin A and 11 times more beta carotene, according to the University of the District of Columbia’s Center for Nutrition, Diet and Health. As for the yellow ones, their nutritional values are in between.
Zinc is present in every cell and is especially important for the development and function of immune cells. Animal sources of zinc such as chicken are better absorbed than plant ones such as legumes (chickpeas, lentils, kidney beans) and wholegrains (oat, quinoa, brown rice). This is because plants contain phytates that inhibit the absorption of zinc, according to the US Department of Health & Human Services.
You don't need a lot of the mineral: 8mg for women and 11mg for men daily. An 85g-serving of chicken (about the size of a deck of cards) can provide about 2.4mg of zinc, according to Medical News Today. For the most nutritious cuts, choose skinless, lean meats with any visible fat removed.
Your immune system works best when there is sufficient glutathione to protect and help the cells in the immune system, such as the white blood cells, function. This potent antioxidant is produced by your body but with age, its level can drop, according to a study published in Integrative Medicine: A Clinician’s Journal.
Eating mushrooms is one way to top up your glutathione levels as certain species such as the porcini and white mushroom contain high quantities of the antioxidant. Fungi also have high levels of ergothioneine, an immune system-stimulating antioxidant, according to a study by Pennsylvania State University researchers that was published in Food Chemistry. Include a serving of mushrooms as part of your two servings of vegetables a day.
Spinach made the list not just because it's rich in Vitamin C, it's also packed with antioxidants such as kaempferol and quercetin, which increase the infection-fighting ability of your immune system, according to Healthline.
But make sure the leafy vegetable you’re ordering from the economy rice stall isn’t overcooked as the nutrients are easily destroyed by heat. Light cooking is all it takes to enhance its Vitamin A and allow other nutrients to be released from its oxalic acid. How much spinach to eat a day? A portion in your cai fan should be sufficient.
You probably don’t eat a lot of papaya when you have exotic fruits such as acai and dragonfruit to choose from these days. It may be time to rethink the tropical fruit, which has 157 per cent of the daily recommended amount of Vitamin C in a single small fruit, according to US-registered dietitian Franziska Spritzler on Healthline.
Papayas also have a digestion-friendly enzyme called papain that has anti-inflammatory effects, and not to mention, folate, B vitamins and Vitamin A in the form of carotenoids for the proper functioning of a healthy immune system. If you're not a big enough fan of papaya to finish a small, whole fruit by yourself, order a wedge from the fruit stall to cap off your meal instead.
Ok, so you've caught the cold despite your best efforts. Time for some yoghurt. This cold (a welcomed comfort when you have a fever), creamy treat is not only good for digestion, it is also great for lessening the severity of colds. Studies have shown that the probiotics in fermented foods help to improve the body’s immune response, according to the Mayo Clinic. It also contains zinc, Vitamin A, calcium, potassium and carbohydrates to fuel your body and help you recover.
Look for labels that say "live and active cultures" and for added Vitamin D as individuals with low Vitamin D levels may be more likely to get the cold or flu.