Various method dietary assessment
Introduction
The usage for accurate pacific dietary assessment is ever increasing. High quality data is required to develop diet-disease relationship and to understand the diverse dietary pattern. Consequently, continuous effort are being made to improve the exiting method as well as to develop advanced , innovative and accurate alternatives.
Factor that urged the development of new method are the errors of misreporting and estimation of portion size in traditional method (dietary recall and food record etc.) since they rely completely on the respondent's memory.
Utilization of innovative communication tools such as personal digital assistant, mobile phone and computer software for dietary assessment overcame the burden of recording by pen and paper and helped in obtaining reliable information. These techniques caused reduction in cost of data entry, coding and processing.
New techniques have several advantages in comparison to traditional methods; they do not depend on the respondent's memory, can process the data automatically and give personalized dietary advice. However, there are some associated disadvantages i.e. difficulty in implementation in rural areas and in low literacy populations.
Personal digital assistant
Image assisted methods
Computer and web- based methods
Scan and sensor-based methods
Mobile based method
Personal digital assessment (PDA)
PDA is a small and easy to carry gadget that can be used for several purposes. To assess food consumption , specially designed software is installed in PDA that can self-record the dietary intake.
It assists in real and accurate data collection and is used to evaluate dietary intake for short term. Before starting the assessment, the participants are given training for appropriate handling of device. Participants are required to record their food consumption right after eating it by selecting the appropriate food from the predefined list in the device.
PDAs from ancient times had a list of almost 180 foods but advanced
PDAs carry a list of approximately 400-4000 food item. However, usage of PDAs can be burdensome for some respondents due to selection of food from an extensive list when compared to pen and paper method.
PDAs make it easy to measure the portion size with the help of food photographs, electronic prompts, food models, picture books and common household measures. This feature enables participants to measure the quantity of foods they had eaten.
For example when person selects the food, PDA may display the colored images of food with default scale i.e. in grams but participants can adjust the scale before adding the foods to correct the amount consumed. The added data is then directly used to estimate nutrient intake with the help of food composition databases.
Strengths
1) Portable device and easy to everywhere
2)Facilitates collection, entry and coding of data
3)Alerts can set to remined the participants that they have to
record their food intake
Limitations
1)Training of participations is needed
2)Details of food reparation are not recorded
3)High burden on respondent partly due to extensive food list
4)Accuracy dependent upon literacy of participations
Image-assisted dietary assessment methods IADAM
IADAM is referred to assessment method that uses images in the form of photography or videos of the foods captured at the time of eating to reduce burden of respondent to memo dent the foods, thereby improving the accuracy of data collected.
Image keep the primary record of food intake and assist in self-reporting traditional methods i.e. self- reported 24- hour recall.
To use IADAM participant are required to carry cameras or handheld devices to capture image of the foods before and after consumption. It is recommended for participants to use straight maker i.e. spoon, fork or tablecloth placed close to or below the plate before capturing the image.
This will help in accurate estimation of portion size. foods not visible through images can be recorded via verbal or written from particularly with obscured images or in food mixes. Alternatively, to obtain such information and further details i.e. cooking method etc. a 24 - hour recall can be conducted.
In places where internet facility is available, the respondents are asked to send the pictures collected directly to the nutritionists/ dietitians. Portion sizes can be estimated by comparing those images with reference portions of known quantity displayed on computer screen or printed images from food atlas.
Nutrient intake is estimated using food composition databases. For more accuracy of image assisted methods, combined 24-houre recall is recommended to account for any misreporting .
Strength
1)Easy to use, even for low literacy population
2)Reduces errors of under - reporting
3)Suitable for people with memory loss issues and children
Limitations
1)Participants may forget to capture images
2)A single image is not enough to provide complete information
3)Does not provide information about food preparation and cooking method
4)Still written records may be needed for obscured images
Mobile-Based Technologies
Mobile-based technologies are increasing becoming accessible can potentially address the problems associated with accurate collection of dietary data. It allow the respondent to take image or keep voice recording of what they are eating.
This can be an appealing approach for dietary assessment of children and adolescent who take more interest in using technology. Mobile - based technologies are useful short-time assessment purposes. Respondents are advised to take images, make videos or voice recording of all drinks and foods they are eating at any occasion.
Portion size estimation from the images can be carried out by nutritionist/dietitian or professionals involved. Markers i.e. spoon, fork or table cloth, are used while capturing image as measurement references which helps to estimate volume of drinks and foods eaten.
Images should be taken before and after the meal intake to in account to obtain more accurate information.
Strength
1)Controlled and high - quality data is obtained
2)Remembers can be set to take image at meal time
3)Instant images can be sent to dietitians by facilities thus reduces systematic errors
Limitations
1)Does not provide details about preparation methods
2)Accuracy depends upon respondent 's literacy and skills to use technology
Strength
1)Controlled and high - quality data is obtained
2)Remembers can be set to take image at meal time
3)Instant images can be sent to dietitians by facilities thus reduces systematic errors
Limitations
1)Does not provide details about preparation methods
2)Accuracy depends upon respondent 's literacy and skills to use technology
Interactive computer and web-based technologies
Interactive computer and web-based technologies involve utilization of interactive assessment programs that are installed on computer devices and ''web based'' term infer that these computers are connected to internet.
These devices are used to gather dietary intake from specific time period i.e. recently eaten or consumed in distant past period. This methods is derived from the traditional pen and paper methods which are introduced in computer programs alongside some multimedia features such as food photographs and colors, food atlas, audio recordings, animated guides and webcams.
Several such methods have been developed based on traditional assessment method such as 24 hour recall, FFQs or food records etc. to collect data by using this method, respondents are asked to make record of what they have eaten in particular time period and add this information on computer software.
Software are designed with such comprehensive system that they may probe forgotten items. Once data entry and coding are done, system calculates nutrient intake by means of multimedia features. Web- based technologies also include some software that can accurately estimate portion size by adjusting images.
For example, ''Novel Assessment of nutrition and Ageing (NANA) based on touch screen computer-based food record and webcam (to capture images) is software specially designed for assessment of elderly. Another example of such software is web-based Automated Self-Administered 24- hour recall (ASA24).
This system present the series of audio-visual aids during data entry that helps the respondent in recalling accurately. Results obtain from this method have been found more accurate them interview base 24-hour recall. However, these web-based technologies require high speed internet access and high literacy level for their optimum performance .
Strength
1)Controlled and high-quality data is obtained
2)Reminder can be set to take images at meal time
3)Helps in data entry with visual and /or audible aids
4)Provide personalized feedback dietary advise
Limitation
1)Does not provide details about preparation methods
2)Require access to high speed internet
3)Adaptation of software is needed according to local
4)Accuracy depends upon respondent' s literacy and/or computer skill
Scan and sensor-based technologies
In scan-based technologies foods are assessed by scanning barcodes on their labels, but their use is limited to commercial and institutional settings. A similar yet innovative is sensor-based technique which is entirely passive to use and is independent of participate 's memory.
This approach has less interference with participant' s usual eating habits. Mostly used sensor-based technology namely e-Button comprises small device that records food consumption automatically. The device contains a microphone, mini camera, memory card and many other sensors. Participants are asked to wear the device around their neck before eating food.
The device capture the foods participants are eating and store their images in its memory card. These images are them directly sent to dietitian 's computer for further analysis.
Portion size estimated using two methods; firstly, by capturing the images of foods eaten at home with the help of straight marker i.e. spoon, fork or table cloth placed near to or below the plates. Secondly, for foods eaten away from home, device emits light (small beams from laser diode) that convert dimensional referent in to visible from which helps to calculate the portion size.
Once data about food consumption and portion size is recorded , the system is liked to food composition databases to estimate nutrient intake. Sensor based devices have been decorated incorporated with feature to count the chewing and swallowing. This involves accurate measurement of biological related movement related to eating and is considered the latest methods to quantify food intake.
Strength
1)Reduces participants burden
2)Does not rely on literacy of participants
3)Allows automatic identification of food by scanning barcodes
Limitation
1)Scanning barcodes is limited for packed foods only
2)Only applicable in controlled setting
3)Devices are expensive
All these techniques help in more specific and accurate dietary assessment. They are promising alternatives to overcome the drawbacks of traditional dietary assessment methods. However , the implementation in different setting.
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