Kryptonite immobilizes Superman. Spider-Man's archenemy, Venom, changes from predator to weakling at the sight of a flame.

And you? Well, it turns out certain foods have the power to weaken your immune system, transforming you from super-germ fighter to a target for everything from the common cold to COVID-19.

The most immune-weakening consumables are:

• Excess alcohol. Whether it's a daily overdose or you binge once a week, you're increasing your risk for pneumonia and acute respiratory stress syndromes by drinking too much. That could potentially impact the outcome of a COVID-19 infection. It also leads to slower recovery from other infections and post-operative complications. 

• Too much salt. This causes a cascade of events, starting with the kidneys excreting excess sodium and ending with a reduction in your body's ability to fight bacterial infections. As little as 6 extra grams a day can set off the chain reaction. Your daily average should be below 3 grams a day.

• Added sugar. As little as 3.5 ounces (that's in a 16-ounce Coke, a Big Mac, and a slice of pecan pie) can reduce the ability of immune cells to neutralize bacteria for up to five hours.

• Highly processed foods. Stripped of fiber, these foods alter the mix of microbes in your gut biome, where 70% to 80% of immune cells hang out. That makes them less able to battle viruses. Getting adequate fiber (25 to 30 grams daily) has been shown to strengthen your flu-fighting powers. Whole cereals, veggies, fruit, and beans are go-to sources — plus they supply vitamins A and C, folate, and bioactive compounds that further boost immune health.