Contents © 2008, The LifeLine Group, Inc. All Rights Reserved

Compendium of Alaska Traditional and Subsistence Dietary Files - Features

Approach and Principles

The ability to more closely define the diets of unique populations and have them considered in state-of-the-art risk assessment models raises the need to assure the quality of the data used. The following principles were used by The LifeLine™ Group in building the Compendium of Alaska Traditional and Subsistence Dietary Files and are extensively documented.

• Best available information is used when creating a dietary file
   
  • Outline the standards selected for determining best available evidence.
  • Use statistically strong, current, and relevant measurements.
  • Files may contain data from more than one source.

• Data Quality is preserved by examining each piece of information to determine if it is :
   
  • Relevant: The data source must provide information about parameters which are important to the DRG™. This may include things such as what foods are eaten and in what form, probability of eating associated with different age groups, seasons, locations, amount eaten (portion size) and/or patterns (long term variability) associated with consumption of the food.
  • Representative: The data must provide information about the population under consideration. If not, a rationale for extrapolation should be documented.
  • Quantifiable: Ideally, the data will carry with it a quantitative component. This may consist of an actual measure of amount eaten or harvested, a total weight eaten, a per capita weight consumed, and percentages of people eating or using a resource or percent of resource used in a specific preparation method. In some cases this quantitative component is inferred.
  • Transparent: All data are referenced to their source. The DRG™ provides ample opportunity for extensive referencing. Transparency is especially important when using non-customary sources of data such as narratives, personal experience, assumptions based upon similar foods or manipulation of existing data from studies. This information may not have been exposed to familiar routes of scientific validation and thus may be more subject to debate than data provided from more customary sources such as large surveys.
• Dietary practices are reviewed by experts in the area to assure an accurate representation by each file of the regional diet simulated, as well as to expedite acceptance of the files among risk assessors and members of the population being described. In building the Compendium of Alaska Traditional and Subsistence Dietary Files , this review process was done simultaneously with the creation of the dietary files so that experts could review the development of each piece of the file on an ongoing basis. Determination of the population of interest, the relevant food list, and consumption parameters were intensively reviewed by credible experts.
• When creating a dietary file, the population being described should be defined based on considerations such as:
   
  • Available data quality
  • Feasibility
  • Defensibility of the decision to define the boundaries/population
• A relevant food list for the population under consideration is defined based on the following standards:
   
  • Foods eaten in large amounts
  • Foods eaten by a large number of people
  • Foods known to carry high concentrations of toxins.

 

Key Areas

The Five Ecological-Cultural Zones

There are five Ecological-Cultural Zones, to include the Arctic-Subarctic Coast/Yupik-Inupiaq, Aleutian Pacific/Aleut-Alutiiq, Subarctic Interior/Athabaskan, Southeast Alaska Coast/Tlingit-Haida and Urban-Urban Periphery (Alaska Department of Fish and Game, 2000).

Food List Construction

A universal food list to be used in each of the Ecological-Cultural Zones was developed relevant to the unique dietary profiles seen in Alaska. Three principles guided the development of the food list to be used in the Alaska dietary files. Every effort was made to include foods eaten by a large number of people in the population or foods eaten frequently, foods eaten in large amounts (even if they aren’t eaten by many people or frequently), and foods known to carry high levels of substances of interest regardless of the frequency or amount eaten (chemicals, toxins, etc.).

The process by which the food list was developed was first to identify data sources that were available regarding foods eaten in Alaska, and then to use expert advice and opinion to determine a relevant food list.

Acceptable Calorie Ranges

The Dietary Record Generator™ (DRG™) requires that an acceptable calorie range for each age range and season be entered in order to remove from the final dietary file unreasonable daily files which are created due to random variation inherent in this probabilistic application. The goal for setting up this calorie range is that it be narrow enough to eliminate unreasonable files and wide enough to allow for random variation seen in dietary intake. Variation due to differences in caloric intake between individuals as well as differences in caloric intake within the same individual due to day to day variability both need to be considered in this range of acceptable calorie intake.

Consumption Parameters

The portion size and probability of eating are the two main consumption parameters that are discussed in the Compendium.

Portion Size

Portion size is the estimate of how much food is eaten when it is eaten. Although there are no studies or resources describing portion sizes of foods eaten by Alaska Native communities there are data from the assessments done by the Centre for Indigenous Peoples’ Nutrition and Environment (CINE) about Yukon First Nations, Inuit and Dene/Metis dietary practices in Canada. These estimates are extrapolated for use in the Alaska Native population.

Probability of Eating

Probability of eating refers to the estimate of how frequently a food is eaten. On a given day in a specific season and age group, the probability of eating refers to the likelihood that a food will be eaten. These estimates are calculated from both harvest estimates and consumption estimates respectively from the Community Subsistence Information System (CSIS) and the Alaska Traditional Diet Project (ATDP).