[araneae]

A major problem with this graph is that it mixes data from substance-deficient groups with data from normal groups, despite claiming that it shows benefits when taken by "an adult with a healthy diet."

For instance, the data on creatine found an increase in cognitive ability in vegetarians. Since creatine is found primarily in muscle tissue, it makes sense that the vegetarians (who were most likely to be deficient in this substance) would see improvement. However, when they tested the supplement in normal adults, there was no improvement. Yet creatine is above the "worth it" line.

Contrast that with vitamin C. It's below the "worth it" line, and it probably is for any normal person. However, if you were to test it on sailors who had eaten nothing besides canned meat for the last 6 months, it would probably be at the top.

Sure, we can assume that most of us are not vitamin C deficient, but we can also assume that most of us are also not vegetarians and therefore not creatine deficient.

(Maybe they considered vegetarianism a "healthy diet"? But it should be obvious that it's not, since it's almost impossible to get many of the top nutrients on this chart from your diet. For instance, if you want to get omega-3 fatty acids from a vegetarian diet the only way is consume supplements extracted from algae.)