When you have the flu, it’s bad enough to be laid up in bed, uncomfortable, exhausted and in pain. These are reasons enough for someone to do everything they can to maintain a strong immune system, but emerging research suggests there might be a far more serious one: increased risk for stroke or neck artery tears after contracting the flu or a flu-like illness.  

According to a press release from the American Heart Association, findings from researchers at Columbia University’s Vagelos College of Physicians and Surgeons presented at the American Stroke Association’s International Stroke Conference a few weeks ago indicates there’s an increased risk of tearing neck arteries within one month of battling a flu-like illness. If you’re uncertain what the link might be between a torn neck artery and stroke, “non-traumatic cervical artery dissection is a leading cause of ischemic stroke in patients 15- to 45-years old.”

In studying nearly 4000 patients with a first non-traumatic cervical artery dissection, researchers found 113 cases of influenza and 1,736 instances of flu-like illness during the three years preceding cervical artery dissection. Cervical artery dissection was more likely to have occurred within 30 days of contracting such illnesses compared to the same time one and two years prior. The study’s lead author did not mince words: “This trend indicates that flu-like illnesses may indeed trigger dissection.”

If increased risk for stroke is a possibility, then if someone contracts the flu or a flu-like illness, lost work time and missing out on fun with friends and loved ones are the least of the downsides. For those whose health is already compromised, flu may increase risk for bronchitis, sinus and ear infections, bacterial pneumonia, and worsening of existing heart problems.

Being that the increased risk for stroke or neck artery tears is tied to proximity of having the flu, the lead author noted that “results suggest that that the risk of dissection fades over time after the flu.” Unfortunately, waiting it out and hoping for the best isn’t an ideal strategy. A better way to go about things is to support the immune system and bolster immune function to reduce risk for contracting flu in the first place.

There may be a place for flu shots, and indeed, some professional environments—particularly in the medical profession—require employees to receive flu vaccines. But whether someone gets a flu shot or not, it’s important to take measures to support a healthy immune system, and not just during flu season.

While we typically think of winter as being prime-time for flu outbreaks, it may be too late if people wait until cold weather sets in to start thinking about colds and flu. Some years, influenza activity starts as early as October. According to the CDC, “Most of the time flu activity peaks between December and February, although activity can last as late as May.”

Maintaining a strong immune system at all times is important because people can spread flu to others before they even know they’re infected. Symptoms can begin anywhere from 1 to 4 days after the virus enters the body, so people can be infected with the flu virus but have no symptoms. With people going about their usual activities for a few days before they realize they’re sick—going to the office, the gym, taking mass transit—it’s no wonder flu can spread so quickly.

Supporting the immune system isn’t much different than supporting overall health—after all, a healthy body is robust and resilient. To this end, Harvard Medical School recommends getting adequate sleep, staying hydrated, exercising regularly, minimizing stress, and consuming alcohol only in moderation. Functional medicine physician Amy Meyers, MD, includes all of these in her 10 tips for preventing cold and flu naturally, and adds to them frequent hand washing, optimizing vitamin D levels, maintaining a healthy gut (including drinking gelatin-rich bone broth), and taking immune-boosting supplements, such as turmeric and glutathione. There’s a reason old-time hospitals used to bring patients out into the sunlight when they could: vitamin D is essential for healthy functioning of both the innate and adaptive immune systems. (It’s likely not a coincidence that cold & flu season peaks when most people get the least amount of sun exposure.)

Vitamin C and zinc are the nutrients typically recommended with regard to immune support, but the Cleveland Clinic points out other vitamins and minerals not often recognized for enhancing immunity, but which do play important roles in this, such as selenium, vitamin E, folate and iron. Riboflavin, B6 and B12 are also “essential for immunocompetence,” as is the amino acid glutamine. Macrophages, lymphocytes and neutrophils all have a high demand for glutamine, and a decrease in plasma glutamine availability is associated with impaired immune function in several clinical conditions.

All the key immune-supporting nutrients can be obtained from whole-foods omnivorous diets and carefully supplemented vegan diets. But beyond animal foods and plant foods, let’s not forget about the fungi kingdom—mushrooms. Various species of medicinal mushrooms are rich in beta-glucans, polysaccharides that stimulate the immune system. They’re also antibacterial, antiviral and antiparasitic, and should be welcomed into immune-boosting protocols.

For elderly individuals in particular, who have reduced immunity compared to younger people (and also poorer nutritional status), it’s recommended to optimize vitamin D and zinc status. Additionally, among the elderly, vitamin E intake above recommended amounts has been shown to enhance immune function and reduce risk for upper respiratory infections in nursing home residents.

Building a healthy immune system isn’t only for flu season. It’s a year-round endeavor that mirrors what people concerned about their health are already doing by consuming a nutritious, balanced diet and engaging in healthy lifestyle habits.