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Q: I've noticed I'm getting more colds as I get older. What can I do to give my immune system a boost?
A: Like the rest of your body, your immune system ages, too. This contributes to higher rates of illnesses such as respiratory infections. Scientists haven't found strong data to support any one pill or supplement to prevent this - or give our immune systems a "boost."
But they have conducted plenty of research on how we can keep our immune systems healthy as we age. Much of that requires going back to basics: staying up to date on vaccines, getting regular exercise and good sleep, eating healthfully and reducing stress.
You might also be surprised to learn about another lifestyle intervention: social connection. Social isolation and loneliness might impair your immune system, and social connection may actually have benefits. For example, one large study of more than 450,000 participants in the United Kingdom and Finland found that loneliness was associated with a higher risk of severe infection requiring hospitalization.
There's lots of theories as to why this happens. In part, it could be because loneliness might ramp up our sympathetic nervous system, which is responsible for our "fight or flight" response. This may influence our gene expression to preferentially express more bad inflammatory genes and decrease the expression of infection-fighting proteins.
There's no precise prescription or dosage for how much social connection is enough. But we know that many older adults live alone, and staying engaged with others is important, just like it is for other aspects of well-being beyond immunity.
As we look ahead to a new year, many people focus on improving their diet and exercise regimens. But it's important to also think about ways to foster more connections. Consider taking a class, joining a book club, volunteering or reaching out to an old friend.
Here are a few other ways to take care of your immune system as you age.
• Eat microbiome-friendly foods
Eating a diet filled with fruits, vegetables, legumes, whole grains and healthy fats like olive oil, while minimizing red meat, may help reduce inflammation and preserve a healthy gut microbiome, which in turn may help the immune system. By the same token, eating a diet high in ultra-processed foods has been associated with dysregulation of the immune system, though the exact reason is unclear.
There's lots of interest in the interaction between the gut microbiome and the aging immune system. There's even research into whether interventions targeting the gut microbiota - such as exposure to "younger" microbiomes - could help the immune system. These interventions are still far from prime time. And it's important to remember that this doesn't necessarily mean you should start taking probiotic supplements: The evidence supporting interventions like probiotics to help your immune system is inconsistent.
Be wary about supplements in general. While certain vitamins are important in a healthy immune system, the jury's still out on whether supplementing beyond normal levels is helpful - and over-supplementation can even be harmful. That being said, it can be particularly challenging for older adults to get adequate amounts of micronutrients by diet alone, so certain supplements, such as vitamin D and B12, may be recommended after consulting with your doctor.
• Find joyful ways to exercise
Exercise stimulates the immune system, reduces "immunosenescence" - which is the aging of the immune system - and can even enhance the body's response to vaccines, which declines as we age. In fact, one study showed that higher rates of physical activity were associated with a lower chance of community acquired pneumonia in women.
And exercising before you get older also can help: Studies have shown that exercising throughout adulthood was associated with improved immune function as people aged.
Overall, the party line is that regular, moderate exercise - particularly aerobic - is good for a well-functioning immune system in most people, though more research is needed to better understand the mechanisms, as well as the optimal types of exercise or duration of exercise needed.
We do know a few things. Any exercise is better than no exercise. The Centers for Disease Control and Prevention recommends 150 minutes of moderate exercise per week, such as brisk walking, or 75 minutes of vigorous exercise per week, such as jogging, as well as at least two days of strength training per week.
But this may feel too hard if you're just starting out. In general, the most important thing is consistency, so try to prioritize exercise that brings you joy and you will stick to, whether that's cardio, like taking a 30-minute walk every day, or resistance training, like joining a weightlifting class.
• Prioritize a good night's sleep
We know that sleep deprivation decreases the body's ability to fight infections. Older adults are even more susceptible to the effects of lack of sleep, and older people who don't sleep enough tend to have a blunted immune response compared with young people.
Older adults are also more likely to have sleep disturbances at baseline, whether that's nighttime urination or even insomnia.
Older adults are also more likely to have sleep disturbances at baseline, whether that's nighttime urination or even insomnia.
Try to get seven to eight hours of sleep a night, which may be easier said than done. There are certain strategies that can help, like resetting your body clock to stay awake a bit later to avoid those irksome middle-of-the-night wakeups, and strategic napping, such as capping your nap at an hour. If you find you're waking up a lot at night, talk to your doctor for help and to rule out conditions such as sleep apnea.
Netana Markovitz, MD, is a resident physician in internal medicine at Beth Israel Deaconess Medical Center/Harvard Medical School in Boston.