Your Winter Nutrition Guide
Department of Internal Medicine
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Building a Strong Immune System
The colder temperatures are here, the rain is falling, and there is snow in the forecast. What’s more, the heat has been switched on and we’ve been noticing more polluted days in Beijing recently. Spending more time indoors, with less ventilation and less humidity can lead to an uptick in some respiratory illnesses, including the common cold and the flu. During this time of year, keeping a healthy diet that is full of certain immune boosting nutrients is a great idea to help keep you active and fight off some winter time illnesses. Some immune boosting nutrients include:
Vitamin C: Vitamin C contributes to immune defense by supporting various cellular functions. It can also help to prevent and treat respiratory and systemic infections. This vitamin can often be found in leafy vegetables, peppers, fruits, and even potato skin. Numerous fruits and vegetables are good sources of vitamin C. Eating 2 kiwis or 1 cup of broccoli could easily help us meet the recommended daily requirement. It might be unnecessary to supplement vitamin C if you eat enough of fruits and vegetables and do not have absorption troubles.
Vitamin E: Vitamin E is an antioxidant that modulates immune functions and can help with the production of certain white blood cells. You can get vitamin E from eating nuts, natural oils, and meat fat, but watch out for the portions because too much oil or fat can also lead to weight gain.
Carotenoids: Carotenoids are pigments found in plants, algae, and other photosynthetic bacteria. These pigments are what produce the bright colors found in many fruits and vegetables. Carotenoids are antioxidants that can help your body fight against disease and boost your immune system. They often are essential for growth, immune function, and have even been associated with a reduced risk of cancer. Foods rich in carotenoids are mostly dark colored fruits and vegetables including yams, kale, spinach, carrots, and oranges.
Vitamin D: Vitamin D, in addition to its effects on calcium and bone health, also helps build innate and adaptive immune responses. It has both anti-inflammatory and immunoregulatory purposes and helps activate certain immune responses. There are not many food sources that help us to absorb as much vitamin D as 30 minutes of effective sun exposure can, but fatty fish such as salmon and trout are rich in vitamin D.
Folate: Folic acid plays a role in DNA and protein development, with folate deficiency contributing to frequent illness. Folate can be found in beans, eggs, and leafy greens.
Iron: Cells of the immune system, including macrophages and monocytes, are regulated by iron. Iron helps build and strengthen the body’s mechanisms for fighting off diseases. Meat, seeds, fish, and nuts are all good sources of iron. Iron from meat sources might be easier to absorb compared to plant based iron sources.
Selenium: Selenium is essential for the operation of many aspects of the immune system, acting as an anti-oxidant, reducing inflammation and other stressors in the body. Oysters, eggs, and sunflower seeds and plants that are grown from selenium rich soil are good sources.
Zinc: Zinc helps your immune system by aiding in the production of immune cells that your body uses to fight off diseases. Additionally, studies have shown that taking zinc at the onset of a cold can decrease the time you are sick. Meat, seafood, eggs, nuts, and beans are good sources of zinc.
Hello darkness my old friend
We previously learned that the colder and darker months can impact our mood, leading to signs of seasonal affective disorder. With the shorter, darker days we’re spending less time outside, which could lead to a lack of vitamin D and even food cravings.
Foods high in carbs and fats can trigger a release of dopamine, endorphins, and serotonin. Basically, the hormones in our brain that make us feel happy and lift our spirits. When the weather is bleak and our mood may mirror the outside temperatures, we may feel the extra need for these comfort foods to make us feel better. More so, when our body temperature drops, thanks to the cold Beijing winter, our body tends to crave carbohydrate-rich foods which can provide instant heat. Enjoy these foods, but in moderation.
To get enough vitamin D, you can eat a diet full of food sources like fatty fish, cheese, and mushrooms. Also, if the days are clean, try to get a few minutes of sunlight each day. This can help boost your vitamin D levels and as we learned above, help improve your immune system. If you are still struggling to get the appropriate amount of vitamin D, supplements may be useful. Consult with your dietitian or physician to see if it is necessary.
Avoiding those extra holiday pounds
The winter time also signifies the beginning of the holiday season. Though this is often a time of happiness and joy with such celebrations as Thanksgiving and Christmas, these festive times can lead to overindulgence in high caloric foods and sweets…not to mention alcohol! It can be hard during this time of year to avoid the extra parties and the extra calories. But some simple tips can help you keep you mindful and healthy throughout this time.
First, know your plan and stick to it. Eat your plate in order from low to high calories. For example, start by eating vegetables before moving on to the more carb-heavy entrees or sides. This can help fill you up a bit more and lead to less over eating of high caloric foods.
Next, try not to think in terms of “off limit” foods, as this could lead to unhealthy habits. Instead, try to eat in moderation, and try to choose drinks and desserts that are less sugary. If you have alcohol, perhaps limit to one or two glasses of wine, and stick to desserts with fruits. Avoiding “empty calories” can be a good trick to staving off some extra unwanted calories as well. For example, having some grapes instead of a honey bun, or an apple to replace that second candy bar could help set you on the right track for some healthier holiday eating. In general though, a balanced diet is really what it is all about. Make sure to get the recommended amount of fruits, grains, protein, vegetables, and dairy to keep you satiated.
Also, if exercise is a part of your routine, stick with it! While we understand the weather can be a deterrent during this time of year, keeping to a consistent work out plan can help balance out those extra cookies and mashed potatoes common with the holidays. What’s more, exercise has the added benefits of managing mental health and even preventing certain nutrition related diseases, such as osteoporosis. Experts recommend about 30 minutes of moderate exercise five days a week.
At the end of the day, the holidays are a time to gather with the ones you love. Eat wisely, get moving, and enjoy each day with each other.
Ms. Lynn Zhang received her master’s degree in Dietetics from Ohio University in the United States and completed her residency in central California. Ms. Zhang is a comprehensive clinical dietitian and her areas of interest include nutrition therapy for critical care, diabetes, cardiovascular diseases, cancer, trauma and burns, enteral/parental nutrition, weight management, obstetrics, and pediatrics well-being. Ms. Zhang is a Registered Dietitian and Nutritionist (RDN), licensed by both the US Academy of Nutrition and Dietetics (AND) and the Chinese Nutrition Society. To make an appointment with Ms. Zhang or another one of our Dietitians, please call our 24hr Service Center at 4008-919191 or book throughout our WeChat Patient Portal.