Chapter 1. Introduction to Nutrition
Understanding Daily Reference Intakes
There are several tools that can help you design a healthy diet. You can get in the habit of reading food labels and rely on the advice of Canada’s Food Guide. To better understand food labels and the nutrition facts tables, you must be familiar with the Dietary Reference Intakes (DRI). DRIs are the recommendation levels for specific nutrients and consist of a number of different types of recommendations. The aim of this value is to prevent and reduce the risk of developing chronic disease and promote optimal health.
Daily Reference Intakes: A Brief Overview
“Dietary Reference Intakes” (DRI) is an umbrella term for six reference values:
DRIs for most nutrients
- Estimated Average Requirement (EAR)
- Recommended Dietary Allowance (RDA)
- Adequate Intake (AI)
- Tolerable Upper Intake Level (UL)
The DRIs are not minimum or maximum nutritional requirements and are not intended to fit everybody. They are to be used as guides only for the majority of the healthy population.[1]
The DRIs are dietary standards for healthy people only; they are not appropriate for people who are ill or malnourished, even if they were healthy previously. They identify the amount of nutrient needed to prevent deficiency diseases in healthy individuals for a specific group (e.g., females aged 31-50), but also consider how much of this nutrient is required to reduce the risk of chronic diseases.
DRIs for Energy and Macronutrients
- Estimated Energy Requirement (EER)
- Acceptable Macronutrient Distribution Range (AMDR)
Determining Dietary Reference Intakes
There is a distinct difference between a requirement and a recommendation. For instance, the DRI for vitamin D is a recommended 600 international units each day. However, in order to find out your true personal requirements for vitamin D, a blood test is necessary. The blood test will provide an accurate reading from which a medical professional can gauge your required daily vitamin D amounts. This may be considerably more or less than the DRI, depending on what your level actually is.
Each DRI value is derived in a different way. See below for an explanation of how each is determined:
- Estimated Average Requirements (EAR): The EAR for a nutrient is determined by a committee of nutrition experts. These experts review the scientific literature to determine a value that meets the requirements of 50 percent of people in their target group within a given life stage and for a particular sex. The requirements of half of the group will fall below the EAR and the other half will be above it. It is important to note that, for each nutrient, a specific bodily function is chosen as the criterion on which to base the EAR. For example, the EAR for calcium is set using a criterion of maximizing bone health. Thus, the EAR for calcium is set at a point that will meet the needs, with respect to bone health, of half of the population. EAR values become the scientific foundation upon which RDA values are set.
- Recommended Daily Allowances (RDA): Once the EAR of a nutrient has been established, the RDA can be mathematically determined. While the EAR is set at a point that meets the needs of half the population, RDA values are set to meet the needs of the vast majority (97 to 98 percent) of the target healthy population. It is important to note that RDAs are not the same thing as individual nutritional requirements. The actual nutrient needs of a given individual will be different than the RDA. However, since we know that 97 to 98 percent of the population’s needs are met by the RDA, we can assume that if a person is consuming the RDA of a given nutrient, they are most likely meeting their nutritional need for that nutrient. The important thing to remember is that the RDA is meant as a recommendation, and meeting the RDA means it is very likely that you are meeting your actual requirement for that nutrient.
- Adequate Intake (AI): AIs are created for nutrients when there is insufficient consistent scientific evidence to set an EAR for the entire population. As with RDAs, AIs can be used as nutrient-intake goals for a given nutrient. For example, there has not been sufficient scientific research into the particular nutritional requirements for infants. Consequently, all of the DRI values for infants are AIs derived from nutrient values in human breast milk. For older babies and children, AI values are derived from human milk coupled with data on adults. The AI is meant for a healthy target group and is not meant to be sufficient for certain at-risk groups, such as premature infants.
- Tolerable Upper Intake Levels (UL): The UL was established to help distinguish healthful and harmful nutrient intakes. Developed in part as a response to the growing usage of dietary supplements, ULs indicate the highest level of continuous intake of a particular nutrient that may be taken without causing health problems. When a nutrient does not have any known issue if taken in excessive doses, it is not assigned a UL. However, even when a nutrient does not have a UL, it is not necessarily safe to consume in large amounts.
This graph illustrates the risks of nutrient inadequacy and nutrient excess as we move from a low intake of a nutrient to a high intake. Starting on the left side of the graph, you can see that when you have a very low intake of a nutrient, your risk of nutrient deficiency is high. As your nutrient intake increases, the chances that you will be deficient in that nutrient decrease. The point at which 50 percent of the population meets their nutrient need is the EAR, and the point at which 97 to 98 percent of the population meets their needs is the RDA. The UL is the highest level at which you can consume a nutrient without it being too much—as nutrient intake increases beyond the UL, the risk of health problems resulting from that nutrient increases. [2]
DRIs for Energy and Macronutrients
- Estimated Energy Requirement (EER): The EER is the average dietary energy intake that is predicted to maintain energy balance in healthy adults. This value is defined by a person’s age, gender, weight, height and level of physical activity that is consistent with good health. See below for how to calculate your EER.
- Acceptable Macronutrient Distribution Range (AMDR): The AMDR is the calculated range of how much energy from carbohydrates, fats, and protein is recommended for a healthy diet adequate of the essential nutrients and is associated with a reduced risk of chronic disease. The ranges listed in Table 1.4 “Acceptable macronutrient distribution ranges (AMDR) for various age groups” allow individuals to personalize their diets while taking into consideration that different subgroups in a population often require different requirements. The DRI committee recommends using the midpoint of the AMDRs as an approach to focus on moderation.[3]
Age Group | Carbohydrates (%) | Protein (%) | Fat (%) |
Children (1–3) | 45–65 | 5–20 | 30–40 |
Children and Adolescents (4–18) | 45–65 | 10–30 | 25–35 |
Adults (>19) | 45–65 | 10–35 | 20–35 |
Data Source: (“Dietary Reference Intakes,” 2002)[4] |
Example: Calculating an AMDR
Min, who is 25 years old, has recently calculated that they need to consume 2100 kcal per day. Based on this, how many kcal and grams of carbohydrates, fats and protein should they consume to fall within the recommended AMDR?
- Step 1: Remind yourself of the AMDR for carbohydrates, proteins, and fats.
- Carbohydrates: 45-65%
- Protein: 10-35%
- Fat: 25-35%
- Step 2: Convert the percentages above to a decimal. To do this, divide them by 100.
- Carbohydrates: 0.45-0.65
- Protein: 0.1-0.35
- Fat: 0.25-0.35
- Step 3: In kcal, calculate the range of carbohydrates that Min should consume. Use the following equations:
- Total kcal required per day X lower range decimal = lower range value
- 2100 X 0.45 = 945
- Total kcal required per day X upper range decimal = lower range value
- 2100 X 0.65 = 1365
- To stay within the AMDR for carbohydrates, Min should consume 945-1365 kcal of carbohydrates per day.
- Total kcal required per day X lower range decimal = lower range value
- Step 4: In grams, calculate the range of carbohydrates that Min should consume.
- Remind yourself how many kcal of carbohydrates are contained in 1 g.
- 4 kcal
- Divide the lower and upper kcal ranges by the number of kcal contained in 1 gram of carbohydrates (e.g., 4).
- 945/4 = 236.25
- 1365/4 = 341.25
- To stay within the AMDR for carbohydrates, Min should consume 236.25-341.25 g of carbohydrates per day.
- Remind yourself how many kcal of carbohydrates are contained in 1 g.
- Step 5: Complete steps 3 and 4 for protein and fat.
Exercise: Calculating your own AMDR
Exercise 1:
Let’s assume that you need to consume 2300 kcal per day. Calculate your AMDR for carbohydrates, proteins and fats.
Exercise 2:
Below, you will have the opportunity to calculate your daily estimated energy requirement (EER), which estimates how many kcal you should consume per day. Once you have this value, try calculating your own AMDR.
Calculating your EER
To calculate an EER, you will need to know a person’s age, gender, weight, height and level of physical activity. The equations used to determine a person’s EER are as follows:
Infants and young children
- 0 to 3 months
- EER = (89 x weight [kg] -100) + 175
- 4 to 6 months
- EER = (89 x weight [kg] -100) + 56
- 7 to 12 months
- EER = (89 x weight [kg] -100) + 22
- 13 to 35 months
- EER = (89 x weight [kg] -100) + 20
Children and adolescents 3 to 18 years
Girls
- 3 to 8 years
- EER = 135.3 – (30.8 x age [y]) + PA x { (10.0 x weight [kg])+ (934 x height [m]) } + 20
- 9 to 18 years
- EER = 135.3 – (30.8 x age [y]) + PA x { (10.0 x weight [kg]) + (934 x height [m]) } + 25
Boys
- 3 to 8 years
- EER = 88.5 – (61.9 x age [y])+ PA x { (26.7 x weight [kg]) + (903 x height [m]) } + 20
- 9 to 18 years
- EER = 88.5 – (61.9 x age [y]) + PA x { (26.7 x weight [kg]) + (903 x height [m]) } + 25
Adults 19 years and older
Women
EER = 354 – (6.91 x age [y]) + PA x { (9.36 x weight [kg]) + (726 x height [m]) }
Men
EER = 662 – (9.53 x age [y]) + PA x { (15.91 x weight [kg]) + (539.6 x height [m]) }
Pregnancy
- 1st trimester
- EER = Non-pregnant EER + 0
- 2nd trimester
- EER = Non-pregnant EER + 340
- 3rd trimester
- EER = Non-pregnant EER + 452
Lactation
- 0 to 6 months postpartum
- EER = Non-pregnant EER + 500 – 170
- 7 to 12 months postpartum
- EER = Non-pregnant EER + 400 – 0
- [5]
Sedentary (PAL 1.0 to 1.39)
Typical daily living activities (for example, household tasks, walking to the bus) |
Low active (PAL 1.4 to 1.59)
Typical daily living activities plus 30 to 60 minutes of daily moderate activity (for example, walking at 5 to 7 km/h) |
Active (PAL 1.6 to 1.89)
Typical daily living activities plus at least 60 minutes of daily moderate activity |
Very active (PAL 1.9 to 2.5)
Typical daily living activities plus at least 60 minutes of daily moderate activity plus an additional 60 minutes of vigorous activity or 120 minutes of moderate activity |
|
---|---|---|---|---|
Boys 3 to 18 y |
1.00 | 1.13 | 1.26 | 1.42 |
Girls 3 to 18 y |
1.00 | 1.16 | 1.31 | 1.56 |
Men 19 y + |
1.00 | 1.11 | 1.25 | 1.48 |
Women 19 y + |
1.00 | 1.12 | 1.27 | 1.45 |
Data Source: (“Dietary Reference Intakes Tables,” n.d.)[6] |
Example: Calculating an EER
Prabjit is a 36-year-old female who weighs 55 kg and is 1.5 m tall. On most days, Prabjit walks briskly for 45 minutes. Based on this, what is Prabjit’s EER?
- Step 1: Find the correct equation
- Women: EER = 354 – (6.91 x age [y]) + PA x { (9.36 x weight [kg]) + (726 x height [m]) }
- Step 2: Input the information you know
- EER = 354 – (6.91 x [36]) + 1.12 x { (9.36 x [55]) + (726 x [1.5]) }
- Step 3: Review BEDMAS (or BIDMAS)
- When faced with a long equation, BEDMAS is an acronym that reminds us of the correct order of operations:
- Brackets First Priority
- Exponents (or Indices) Second Priority
- Division Third Priority
- Multiplication Third Priority
- Addition Fourth Priority
- Subtraction Fourth Priority [7]
- When faced with a long equation, BEDMAS is an acronym that reminds us of the correct order of operations:
- Step 4: Perform calculations in brackets
- EER = 354 – (6.91 x [36]) + 1.12 x { (9.36 x [55]) + (726 x [1.5]) }
- EER = 354 – (248.8) + 1.12 x { (514.8) + (1089) }
- Don’t forget to add 514.8 to 1089, as that’s in a bracket too.
- EER = 354 – (248.8) + 1.12 x { 1603.8 }
- Step 5: As there are no exponents in this equation, complete the division and multiplication.
- EER = 354 – (248.8) + 1.12 x { 1603.8 }
- EER = 354 – (248.8) + 1796.3
- Step 6: Complete the addition and subtraction
- EER = 354 – (248.8) + 1796.3
- EER = 1901.5
Exercise: Calculating your own EER
Using the example and equations above, consider calculating your own EER. If you want to check your work, you can use Omnicalculator online.
Tips for Using the Dietary Reference Intakes to Plan Your Diet
You can use the DRIs to help assess and plan your diet. Keep in mind when evaluating your nutritional intake that the values established have been devised with an ample safety margin and should be used as guidance for optimal intakes. Also, the values are meant to assess and plan average intake over time; that is, you don’t need to meet these recommendations every single day—meeting them on average over several days is sufficient.
- Deng S, West BJ, Jensen CJ. A Quantitative Comparison of Phytochemical Components in Global Noni Fruits and Their Commercial Products. Food Chemistry. 2010; 122(1), 267–70. http://www.sciencedirect.com/science/article/pii/S0308814610001111. Accessed December 4, 2017. ↵
- Source: Dietary Reference Intakes Tables and Application. The National Academies of Science, Engineering, and Medicine. Health and Medicine Division. http://nationalacademies.org/HMD/Activities/Nutrition/SummaryDRIs/DRI-Tables.aspx. Accessed November 22, 2017. ↵
- Dietary Reference Intakes Tables and Application. The National Academies of Science, Engineering, and Medicine. Health and Medicine Division. http://nationalacademies.org/HMD/Activities/Nutrition/SummaryDRIs/DRI-Tables.aspx. Accessed November 22, 2017. ↵
- Source: Food and Nutrition Board of the Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. http://www.nationalacademies.org/hmd/~/media/Files/Activity%20Files/Nutrition/DRI-Tables/8_Macronutrient%20Summary.pdf?la=en. Published 2002. Accessed November 22, 2017. ↵
- EER equation source: https://www.canada.ca/en/health-canada/services/food-nutrition/healthy-eating/dietary-reference-intakes/tables.html ↵
- Physical activity coefficient source: https://www.canada.ca/en/health-canada/services/food-nutrition/healthy-eating/dietary-reference-intakes/tables.html ↵
- Taken from: https://www.cemc.uwaterloo.ca/events/mathcircles/2013-14/Fall/Junior6_Oct8.pdf. ↵