A double - blind placebo study found that regular use increases natural killer cell activity and early inflammatory response. (wellnessmama.com)
A 1994 study confirmed that the compounds in ashwagandha stimulate immune cells, and a more recent study found that an herbal tea containing ashwagandha increased natural killer cell activity in healthy volunteers with recurrent coughs and colds. (annmariegianni.com)
For more on the health benefits of blueberries, check out: How to Slow Brain Aging by Two Years Boosting Natural Killer Cell Activity Best Berries Dietary Treatment of Glaucoma (nutritionfacts.org)