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The flu is spreading all across the country, especially in California where the Department of Public Health reported that the influenza activity is more severe than last year.
We’ve all seen people proudly posting on Facebook or bragging at the office about how they “never” catch a cold or flu because they “have strong immune systems” or eat healthy foods or take certain supplements.
But can you really boost your immune system? Here are five things that the science shows do actually work:
1. Get enough sleep.
It really does work. Immune system signaling chemicals called cytokines are involved in sleep, and people who don’t get enough sleep are not only more prone to infections, but they do not get a good response to vaccines, either. Research has suggested that each night, adults need at least seven to eight hours of sleep.
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2. Eat enough fruits, vegetables and whole grains.
Fruits and vegetables give us not only the obvious vitamins, including A, C and E, but other nutrients and antioxidants whose roles are not fully understood. But beware of claims about magically effective “superfoods” or supplements made from concentrated food ingredients. While studies show a huge range of health benefits from eating a variety of fruits and vegetables, there’s not much evidence to show any particular fruit or product bestows special immunity. The key is variety, number and color — colorful fruits and vegetables tend to contain more vitamins and antioxidants such as lycopene and lutein.
3. Drink moderately, if at all.
A recent study found that people who downed the equivalent of four or five drinks in one session showed suppressed immune systems for several hours afterwards. Other studies show that people who chronically drink too much weaken their immune systems over time. People who abuse alcohol are more vulnerable to pneumonia, septicemia and hepatitis C.
4. Don’t smoke.
You can add a weakened immune system to the very long list of ills caused by smoking. Nicotine — found in traditional cigarettes and in e-cigarettes — skews the function of immune cells called macrophages. Various hydrocarbons found in cigarette smoke damage many different immune cells, including lymphocytes and macrophages.
5. Start moving.
But too much exercise can suppress the immune system, at least for a while. Studies of elite athletes show prolonged, intense exercise may lower some types of immunity, at least temporarily.
Here’s what has not been proven to boost your immunity:
Herbal products such as Echinacea: There’s way more research debunking Echinacea than supporting its use. Part of the problem is that different commercial products contain different amounts of the plant, and even vary on what plants they contain. Some plants, such as astragalus and licorice root, can be dangerous.
Probiotics: Yogurt, “prebiotics” and teas such as kombucha are all the rage and their popularity stems from solid science showing that gut bacteria can affect your weight, your risk of cancer and your susceptibility to infectious disease. The trouble is, no one’s been able to show yet which are the “good” bacteria and which are the “bad” ones. There’s also nothing definitive on whether eating or drinking any particular food can change the balance of gut bacteria. Probiotics fall squarely into the category of being good in theory, but the jury’s still out on which formula is best.
Eating organic: Go for it if you want to promote sustainable farming practices, but studies show organic food doesn’t contain more nutrients than conventionally produced foods.
Organic foods are also grown without use of artificial pesticides, but there’s not a lot of evidence yet to show that pesticides alter immune function — although high exposures, among farm workers for instance, are linked with neurological diseases such as Parkinson’s. It’s also not clear if most Americans ingest dangerous or health-altering levels of pesticides in food.
This updated story was originally published on Jan. 3, 2015.