Immune function declines with age, and this decline is said to be largely influenced by the composition of a person’s gut microbiota. The gut microbiota protects the digestive system from external pathogens by modulating immune responses. However, aging reduces the diversity of the gut microbiota, and this leads to unfavorable conditions, such as frailty, increased susceptibility to infections, inflammatory diseases and increased morbidity. Fortunately, researchers have found a way to slow or reverse age-related changes in immune function.
In a recent study published in the journal Nutrition Research, researchers from Finland and the US looked at the effects of probiotic supplementation on the cellular innate activity of healthy older adults. They found that taking probiotic supplements, even for a short time, improves immune cell function, specifically the activity of polymorphonuclear (PMN) cells and natural killer (NK) cells. These cells are involved in the body’s immune response to infections.
Probiotics can help raise the immunity of older adults
According to studies, the most crucial age-related changes that occur within the innate immune system involve two types of immune cells, the PMN cells and the NK cells. PMN cells are mature white blood cells whose functions are important during infections and allergic reactions. PMN cells have a variety of antimicrobial mechanisms that are activated by bacterial products and inflammatory signaling molecules. NK cells, on the other hand, are critical components of the innate immune system. These cells are involved in the body’s response to tumors and viral infections.
Although the amount of NK cells increases with age, many of their abilities decline, resulting in a decrease in their function. PMN cells also suffer losses because of age and exhibit decreases in phagocytic activity — the ability to devour foreign particles — as well as mobility. Because of the consequences of these changes, scientists believe that restoring function to PMN and NK cells is a promising strategy to combat age-related immune function decline.
The researchers hypothesized that probiotic supplementation could enhance immune function in older adults. To test this hypothesis, they conducted a systematic review and meta-analysis of controlled trials that focused on PMN cell phagocytic capacity or NK cell tumoricidal activity following short-term probiotic supplementation in the elderly.
The researchers found 17 prospective controlled studies that involved a total of 733 participants. The duration of probiotic supplementation in the studies ranged from three to 12 weeks. The researchers reported that probiotic supplementation increased PMN phagocytic capacity and NK tumoricidal activity. They cited short-term supplementation duration as one of the limitations of their study.
The researchers concluded that short-term probiotic supplementation enhances cellular immune function in healthy older adults. (Related: Prebiotics improve digestion and reduce risk of cancer.)
The health benefits of probiotics
Probiotics are live microorganisms that can be found in fermented foods, such as yogurt, sauerkraut and tempeh. These beneficial microbes not only help balance the composition of the gut microbiota, they also promote digestive health and improve immune function. Here are other health benefits associated with probiotics consumption. (h/t to Healthline.com)
- Helps prevent and treat diarrhea
- Helps improve some mental health conditions (e.g., anxiety, depression, autism)
- Helps keep the heart healthy
- Reduces the severity of certain allergies and eczema
- Helps relieve the symptoms of certain digestive disorders
- Helps boost the immune system
- Helps with weight loss by reducing belly fat
The most common sources of probiotics are fermented dairy products and vegetables. But if these foods aren’t to your liking, you can opt for probiotic supplements. Just make sure they are of high quality and come from trusted sources. Check the label for proper dosage or consult your health care provider to get the most out of your supplement.