Research regarding the addition of umami compounds on the palatability of foods reports mixed results. Some studies report no significant differences in palatability based on the addition of monosodium glutamate at levels ranging from 0.1% to 2.0%, while other research reports increased preference, liking, pleasantness and savory character of foods with added MSG and inosinate 5'-monophosphate (IMP-5).

• Grade I means there is Good/Strong evidence supporting the statement;
• Grade II is Fair;
• Grade III is Limited/Weak;
• Grade IV is Expert Opinion Only;
• Grade V is Not Assignable.
• High (A) means we are very confident that the true effect lies close to that of the estimate of the effect;
• Moderate (B) means we are moderately confident in the effect estimate;
• Low (C) means our confidence in the effect estimate is limited;
• Very Low (D) means we have very little confidence in the effect estimate.
• Ungraded means a grade is not assignable.