Depends on your preferences. I prefer fruits and vegetables to increase immunity. Then I would definitely recommend to have at Shilajit, check out here
. The thing is that, it is a naturally occurring biogenic stimulant made from medicinal plants. Also it can improve your sleep by helping your body naturally recalibrate its circadian rhythm. Plus, it will help you feel more grounded, calm, and tuned. I have been taken it for a month already and should admit its positive effects on my body.