NEWS | June 19, 2020

UC Davis Health expert: How to tune up your immune system during COVID-19 pandemic and beyond


One of the consistent warnings during the COVID-19 pandemic has been about the vulnerability of older people because they generally have weaker immune systems. But a UC Davis Health immunology expert says there are still things people of any age can do to support their own immune systems.

Eating well, exercising and laughing can help our immune systems stay strong as we age. Eating well, exercising and laughing can help our immune systems stay strong as we age.

Those include eating well, exercising, sleeping enough and – as difficult as it may be during a pandemic – reducing stress and keeping a positive outlook.

“What you do every day and how you manage your health matter,” said Satya Dandekar, a professor of microbiology and the chairperson of the Department of Medical Microbiology and Immunology.

The fundamentals of our immune system start with a simple fact of life: As we age, our bodies become slower and less adept at repairing and renewing themselves.

“At the molecular level and the cellular level, there is an ongoing process of tissue repair and renewal in our bodies,” Dandekar said. “We are increasing the numbers of our cells to perform physiological functions and to replace and replenish the loss of cells.”

But as we age, the renewal process slows. “One of the big challenges of aging,” Dandekar said, “is that our ability to replace and renew our immune system is decreased.”

That could also mean that a vaccine might not be as effective for some older people. When young people receive a vaccine, their bodies mount a strong immune response that includes producing antibodies that fight the pathogens. That response weakens over the years.

“Young people also have a tremendous capacity to create cytotoxic lymphocytes, the ones that identify and kill infected cells when you need them to,” Dandekar said. “As we age, we just don’t produce the same good immune response.”

Exercise helps

But there is good news for older folks, and, really, for everyone. We can help keep our immune systems in better shape by staying in shape. In short, a fit 70-year-old will likely have a stronger immune system than a 70-year-old who doesn’t exercise or eat well.

“There is absolutely a difference,” Dandekar said.

Exercise not only strengthens our core and our musculoskeletal system, it strengthens our cells’ capacity to improve our energy balance and oxygen supply. Plus, simply enough, exercise boosts our ability to breathe, which helps our immune systems and organs function well.

Vegetables, fruits, nuts and seafood protect your immune system

Eating well is another key to maintaining our immune system. Dandekar said the foods that have a positive effect are Mediterranean diets, seafood and fatty fishes such as salmon, and plant-derived foods and nuts – such as almonds, walnuts or peanuts, she said.

“Nuts are the seeds of the plants and contain all the nutrients,” Dandekar said. “They help your immune system and your body remain strong.”

She said there is no overstating the value of a balanced diet rich in plant-based foods.

“The quality of the food you eat influences the colonization and makeup of the bacteria in your gut,” Dandekar said. “And the gastrointestinal tract is where you harbor almost 80% of your immune system.”

Those healthy foods also help with the renewal and regeneration process in the gut at the molecular level, she said.

So, do vitamin supplements help? Maybe a little.

“If your diet is not well-balanced or complete, you can overcome some of the deficiencies with vitamins and supplements,” she said. “But overdoing vitamins or supplements is not helpful, and most of them are usually excreted out of our bodies. Eating a balanced diet is the best approach to health.”

Sleep matters

Although we tend to make sleep a relatively low priority in our busy lives, Dandekar said for anyone, old or young, it has a huge impact on our health and our ability to fight COVID-19 and other diseases.

“Sleep is very, very important,” she said. “That’s when all the biological forces get reset. That is when we do so much of our repair and regeneration.”

But here is something to lose sleep over: One reason many people don’t sleep well is because of their stress level, which also weakens the immune system.

Stress hits in many ways

“We are going through a devastating pandemic and an economy that has lost a tremendous number of jobs. People feel very vulnerable,” Dandekar said. “People are also seeing and experiencing challenges of racism, inequality and social injustice. How could we not feel stress in these times?” 

The emotional impact of stress is significant. So is the physical impact.

“The body’s response to stress, no matter what source it originates from, is the same,” she said. “The stress hormone levels increase and dampen the immune system.”

How do we deal with that? Staying socially connected in these isolated times is a good start.

“Human interaction is very therapeutic,” Dandekar said. “And try to find humor in your life.”

Also, try to be aware of the stress. Try to process it. Practice mindfulness or other actions so the stress doesn’t just build.

“Don’t let it simmer. Seek help from your primary care physician and support from family and friends,” Dandekar said. “Maintaining an optimistic and happy outlook towards life contributes to good health, both physically and mentally.”

It’s never too late

The good news, Dandekar said, is that we can have an impact on our health and our immune systems at any age by eating well and exercising, even if we never did those things before.

“If you had a poor diet at age 35, you are not doomed for life,” she said. “On the other hand, if you are healthy at 35, it doesn’t mean that you can start eating a high fat diet and smoking. It is encouraging that we can keep making a difference in our health one day at a time – at any age.”