Foods for Stimulating the Immune System

Whether you have a condition that would benefit from stronger immune function or simply want to be on top of things, you should consider eating more foods that will help boost your immune system. Some may proclaim certain foods allegedly enhance immune function, but unless they have evidence to back them up, you may want to stick with foods with research behind them, such as the ones found below.

Mushrooms

White button mushrooms, typically cooked or eaten raw, are full of bioactives like beta-glucan—a dietary fiber that stimulates immune function. One study in Australia’s University of Western Sydney studied 20 volunteers who either ate a regular diet that included white button mushrooms or one that didn’t. To test whether immune function was affected, two antibodies (IgG and IgA) were measured from the participants’ saliva, as elevated levels indicate immune activation. The participants showed increased IgA levels—55 percent after a week of consuming mushrooms and then 58 percent after two weeks. The mushrooms seem to activate the gut, thereby stimulating the production of the antibodies by the immune system.

Aged Garlic

Garlic is known for its value as a cooking ingredient and its health benefits. Once aged, garlic is said to retain potent bioactives like apigenin, which may influence immune function. The effects of aged garlic were studied at the Gainesville campus of the University of Florida via 120 participants during flu/cold season. While receiving placebos or aged garlic extracts for three months and having blood analyzed for immune response, the participants kept daily illness journals for any symptoms, such as head congestion, body aches, cough, fever, or sore throat.

The garlic-consuming participants had more immune T-cells in their blood than the placebo group. Curiously, these resulting T-cells were supercharged, meaning they replicated eight times as fast as those in the placebo group. The journals showed that the garlic group had 20 percent fewer flu/cold symptoms, 58 percent fewer work days missed, and 60 percent fewer instances of sickness that led to cancelled activities.

Broccoli Sprouts and Raw Honey

Perfect for salads or being sautéed with raw honey, broccoli sprouts contain potent bioactives called sulforaphanes—in fact, broccoli sprouts have as much as 100 times more sulforaphanes than fully-matured broccoli. The chewing motion you create when you eat broccoli sprouts is actually important for promoting immune function, as it ruptures plant cell walls and releases myrosinase, an enzyme that converts sulforaphane (inactive in plants) into an active form.

Researchers with Stanford University, the University of North Carolina in Chapel Hill, and Switzerland’s University Children's Hospital Basel studied how consuming broccoli sprouts affects immune function by conducting flu vaccine clinical trials. They hoped to learn if broccoli sprouts helped boost the body’s immune response post-vaccination.

Twenty-nine volunteers were given a broccoli-sprout blended shake or a placebo version to drink every day for several days. On day two, both volunteer groups got a flu vaccine, with the results showing the broccoli group’s blood had over 20 times more natural killer T-cells compared to the placebo group, indicating greater activity from the immune system. The broccoli group also had less of the flu virus in their noses, showing their bodies cleared it more effectively.