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.
Some of the helium-3 found in the terrestrial atmosphere is also a relic of atmospheric and underwater nuclear weapons testing. Most of this comes from the decay of tritium (hydrogen-3), which decays into helium-3 with a half life of 12.3 years.