Salmon is one of many foods naturally rich in magnesium. Magnesium for arthritis can be taken as an oral supplement and often comes in combination form with calcium and potassium. Nuts are typically good sources of magnesium. Tofu is rich in magnesium.
ACE stands for the U.S. Customs and Border Protection's (CBP) Automated Commercial Environment, which is the primary system the trade community will employ to report imports and exports to the government to determine admissibility.
What and how much you can bring into the United States is controlled by the U.S. Customs office (www.cbp.gov), which basically views you as a small-time importer/exporter. Importers have to pay a governmental duty (tax) on any foreign-made item they bring into the country.