Final answer:
Individuals with phenylketonuria (PKU) should avoid the nonnutritive sweetener aspartame. Therefore, the correct option is A.
Step-by-step explanation:
Aspartame is a nonnutritive sweetener that should be completely avoided by those who have phenylketonuria (PKU). Phenylalanine, an amino acid found in aspartame, is improperly metabolised by people with PKU. Phenylalanine builds up in the blood due to a hereditary illness called PKU, which prevents the body from breaking it down.
This condition may result in intellectual difficulties and other health problems. Consequently, aspartame, which is converted into phenylalanine, should be severely limited in the diets of people who have PKU.
When taken in moderation, nonnutritive sweeteners such as saccharin, neotame, sucralose, and xylitol are thought to be safe for people with PKU because they do not contain phenylalanine.
Therefore, the correct option is A.