Wednesday, January 20, 2010

Minimum vs Optimum

Most people are familiar with the RDA, the Recommended Dietary (Daily) Allowance of various nutrients. Many people assume that an RDA is, well, a recommended allowance for those nutrients. The amount we should be consuming each day. It turns out that this is almost but not quite true.

The RDA were first developed in 1941 to establish minimum nutritional standards for the US military and for civilian populations requiring food relief. The standards were set so as to provide guidance as to the minimum requirements necessary to avoid deficiency diseases such as rickets or scurvy. The RDA became the required US standards for nutrition labeling in 1973 and remained so until 1995, when they were replaced by the Percent Daily Value (%DV). In turn, these were based upon an updated version of the RDA called the Reference Daily Intake. Like the RDA, the RDI set minimum standards for generally healthy people, with a "fudge factor" of about 60% built in.

In 1997 a new standard was introduced called the Dietary Reference Intake. Unlike its predecessors, the DRI goes beyond "minimum" and reflects the amount of various nutrients required by a generally healthy person to maintain optimum health. Twelve years later, for reasons known only to the FDA, Congress and a cohort of food producer lobbyists, nutrition labeling requirements are still based on the older, minimums-based %DV system.

If you find all this confusing, join the club. Perhaps its meant to be confusing. I will leave it to you to determine who might benefit from that. In the meantime, here is a great article on translating nutrition labels into English. Just remember that, for now, it is all based on the minimum you need to avoid a nutritional deficiency diseases. Not on the optimum nutrition you require to be healthy and well.

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