Amino Acid Analysis Program

In 2011, National PKU News began working on a program to complement our dietitian-driven, ingredient-based food analysis with a lab based amino acid testing. We found in our initial trials that not all labs are capable of capturing accurate results for the small amounts of phenylalanine in diet appropriate foods. This was before the launch of How Much Phe, when all data was published in The Low Protein Food List for PKU.

We sought the help of industry experts were very fortunate to gain the support of Eurofins Laboratories Chief Scientific Officer, Lars Reimann. Mr. Reimann designed our methodology, helped gain the support from his industry contacts for our baseline sample studies (pro bono) and has assisted and advised as we put the methodology into commercial practice in 2014.

This methodology took several years to develop, but we now have a repeatable process for the testing of Phenylalanine across a host of food types.

What comes first: A robust process to allow users to request new additions to How Much Phe:

  • Users can fill out a Food Request Form, which puts the product(s) into the research queue for our dietitian, who will reach out and try to obtain unrounded protein values for the products.
  • The Food Request Form generates text that you can use to contact food companies to request unrounded protein. We've found that appeals from individual consumers are the most compelling, and have the best results.
  • Anyone (whether or not they are subscribers) can use that form to generate text to appeal to a manufacturer.
  • Manufacturers who provide unrounded protein are added to the Partnership For PKU and get other perks like social media announcements and the opportunity to provide coupons to our community

What happens when a manufacturer isn't cooperative, or just doesn't have the data we need?
We offer to allow them to sponsor unrounded protein testing. If a company declines to sponsor testing, we then decide how important their product is to the community, based on the number of food requests, whether it features a new ingredient we need values for, and how widely it is available. For many products whose ingredients we know the phe-to-protein ratio, we can order unrounded protein analysis, which is less expensive than the phe-optimized amino acid analysis.

When do we use Amino Acid Analysis?
The lab analysis process for phenylalanine content, described below, is comprehensive, costly, and requires significant staff time to select and prepare testing candidates, manage the testing process, and evaluate the results. For that reason, we reserve amino acid analysis for those products that fit these criteria:

  • Important to and suitable for the low-protein diet
  • Popular within the community (based on food requests, searches & other metrics)
  • Widely available
  • Unique enough that its makeup can't be easily inferred or estimated based on similar products
  • Without other sources of data from which we can estimate phenylalanine content

NOTE: Because many of the foods we test are very low in phenylalanine, we've worked with the labs to develop a process optimized for detection of phenylalanine, which therefore potentially reduces the accuracy of detected levels of other amino acids. We do not therefore authenticate other amino acid levels in this testing process.

Here's a brief overview of the testing methodology:

  • National PKU News analytical testing methodology includes baseline freeze-dryed control samples that have been analyzed in triplicate across six independent laboratories
  • Before shipping, we have a joint phone call with the labs to discuss the sample prep and shipping for each item to be tested
  • Next, each food sample is prepared as discussed and shipped to two independent laboratories for analysis along with the baseline control samples. Currently, all foods are tested with 100% crossover, meaning each lab tests all foods National PKU News then complies all results across labs
  • Next, the scientific teams together from both labs review the individual food results across labs for consistency and recommend any further testing as necessary before we publish to
  • All of this is coordinated by National PKU News so that the timing of testing of food samples is consistent across labs since protein values are not necessarily stable over time, particularly in fresh fruits and vegetables
  • All results are reviewed by our staff dietitian and Executive Director before publication, in consultation with Lars Reimann when necessary.