The second issue of Food Security is now published, and is free online. It documents some of the multiple causes of food insecurity.
Helium can be found in underground deposits in the earth. Helium can also be found in stars and other planets. The helium underground - and extracted from natural-gas - is a by-product of the natural radioactive decay of uranium, though is far too stable to be radioactive itself. It also occurs in very small amounts in the atmosphere.
The helium that is available commercially is extracted from oil and gas wells. Helium can be extracted from underground because it is trapped by the same sorts of impermeable rock layers that trap petrochemicals. That helium has had thousands or millions of years to accumulate in those rock formations, but we can empty them in a few decades.