In order to meet the recommended nutritional needs of most people, the Nutrition Research Division of Health and Welfare Canada established the Recommended Nutrient Intakes or RNIs, for 9 vitamins, 6 minerals, protein, and energy.
Also the Nutrition Reasearch Division lists all the estimated safe and adequate intakes of two other vitamins and five minerals. To determine a specificRNI, nutritio scientists established a minimum value, below which deficiency develops, and the maximum amount, above which harm might occur. The RNI is set between these two values, with a margin of safety to ensure a reserve to carry a person through weeks or even months of inadequate intake.
Many people mistakenly assume that they must consume the full RNI of each nutrient daily. This of course is not true because each RNI is actually more than one person needs. For example the RNI for vitamin C (40mg) is really four times what the average person needs to prevent scurvy. It should be noted that in Canada, deficiency diseases are rare, occuring mostly among people with other disorders, for example, thiamine deficiency is common among long term alcoholics and seniors.