Eating for a healthy immune system

Summer and winter, we are exposed to extreme temperature fluctuations as we move between heated or air-conditioned environments and the outdoors. Cold air, both natural and artificial, contains less moisture and dries out our mucous membranes, exposing us to viruses that can cause colds. Before you know it, your forehead feels feverish, your throat is sore, and your nose is dripping like a leaky faucet.

This is where the immune system comes into play. When it’s strong, it attacks and kills bacteria, viruses, and other invaders—so we can be exposed to germs and still not become sick. But the immune system can be weakened or compromised with aging, excessive stress, and sudden or intense physical activity. Then the germs win. Moderate exercise is an excellent way of boosting the immune system. So is eating a balanced diet featuring a variety of foods.

In the US, health-conscious parents are likely to give their families chicken soup in the wintertime. It’s not only nutritious and raises core body temperature but also rich in high-quality proteins needed to build the protective mucous membranes of the nose and throat. Found in other meats as well as beans and tofu, these proteins contain cystine, an amino acid. When cystine is ingested, it’s eventually broken down into a component of glutathione, important to all living organisms for detoxification and antioxidation. Unlike adults, infants cannot synthesize cystine in the body so they must get it from food.

In Japan, drinking green tea is what families swear by during cold season. The amino acid theanine accounts for more than half of the amino acids found in tea and is especially plentiful in the first harvest of young leaves, and in gyokuro, a shade-grown Japanese green tea. Like cystine, theanine contributes to the production of glutathione, plus it counterbalances the stimulative effect of caffeine, helping you sleep better and reducing stress.

In clinical trials, Ajinomoto Group researchers first discovered that taking the amino acids cystine and theanine together can reverse immunodepression triggered by stress or lack of sleep; boost the effectiveness of the flu vaccine; and, once you get sick, reduce the severity and duration of cold symptoms like fever, sore throat, and runny nose. Regularly ingesting both cystine and theanine might even help strengthen the immune system, reducing your chances of getting sick.

The Ajinomoto Group is working to further explore the mechanisms and health benefits of cystine and theanine. If you’d like to add a bit more to your diet, try our delicious, nutritious recipes featuring cystine-rich foods such as chicken and tofu. And don’t forget to wash it down with a cup of green tea. You’re sure to make mom and dad proud.