During a time when people are stocking up on hand sanitizer and face masks to bolster their external defenses against viruses and other pathogenic microbes, it’s also important to consider ways to reinforce the body’s internal immune defenses. 

Several lifestyle factors can play a significant role in immune function. Stress management, good sleep, healthy nutrition, and regular physical activity are key strategies everyone should consider in their immune health arsenal. 

Stress and Immune Function

Stress can increase an individual’s susceptibility to illness after exposure to infectious microbes, Stress can disrupt both humoral (antibody-mediated) and cellular (T-lymphocyte-mediated) immune responses. For example, studies show that “people with higher levels of perceived stress, emotional reactivity, recent stressful life events, and negative emotional styles” are all at greater risk of acute respiratory infections. 

Stress can be managed in various ways. Individuals should discern what works best for them. Two beneficial options that people can try from the comfort and safety of their home are mindfulness meditation and a gratitude practice. 

Mindfulness meditation can be as simple as taking time to focus on breathing in and out slowly for 15 minutes. When 138 middle-aged adults underwent a two-month training in mindfulness-based stress reduction, it produced a modest reduction in acute respiratory illness and was similar in effectiveness to accepted medical interventions. In addition, emerging research suggests meditation may support methylation-based epigenetic changes that benefit immune function.

Although we may intuitively suspect that "gratitude" practice may improves well-being and supports sleep, the research suggests it. To engage thoughts of gratitude, a person may simply write down five things they’re grateful for every day. Gratitude is linked to positive emotions, such as happiness and hope, and helps shift our focus away from stress and negative emotions.

Sleep and Immune Function 

Sleep is an essential contributor to our health that is often neglected. Interestingly, although humans can survive without food for more than a month, the longest recorded period a person has been able to go without sleep is just 11 days. However, the negative effects of sleep deprivation can begin within just one day of sleep deprivation. The immune system is one of the functions that are impacted.

As discussed in a previous blog, sleep disruption can impair both the innate and adaptive (acquired) branches of the immune system. In addition, human research has shown that stress hormones released in response to just one night of insufficient sleep can decrease the immune system’s release of natural killer (NK) cells. NK cells provide rapid, innate killing of virus-infected cells. They also help prime the activity of other immune cells to fight viruses.

Setting a relaxing bedtime routine and managing stress can go a long way toward promoting good sleep. In addition, several nutraceuticals, including melatonin, valerian root, and tryptophan (the precursor of serotonin), may promote normal sleep. These and other sleep-supportive nutritional and botanical ingredients may be offered in a single dietary supplement for ease of use.

Nutrition, Physical Activity, and Immune Function

A healthy diet and regular physical activity are interconnected due to their role in maintaining a healthy body weight. This is relevant to immune function because excess body fat and obesity have been associated with an increased risk for acute respiratory infections. 

Although we easily notice excess body fat in obese individuals, it is less recognized that up to 40% of normal-weight adults may have excess body fat that impairs their health. Challenges controlling body fat may be heightened during a pandemic because people may not be able to utilize the exercise options they normally would. Yet, encouraging exercise during this time is essential. 

Moderate exercise can help improve a person’s innate immunity and help provide protection against viral infections. Some exercise options include using exercise videos, joining a virtual exercise class, and utilize the outdoors while observing physical distancing guidelines

Nutritious dietary choices should also be emphasized, as they aid in weight management.  Healthy foods such as vegetables, nuts, and grass-fed meats provide nutrients that support immune function. For example, zinc, iron, B vitamins, vitamin C, and vitamin D play important roles in immune function. In some cases, targeted supplementation of such nutrients may be needed to meet individual requirements.

By Marsha McCulloch, MS, RDN, LN