Researchers at the University of Alabama at Birmingham have found the secret ingredient in garlic that makes it good for the heart—allicin.
Allicin is also what makes your breath smell so bad after eating garlic. This could also mean that non-smelly garlic products aren't as good for you as whole natural garlic.
Which just goes to show that supplements and extracts and whatnot just can't beat the real thing. It's the same as with green tea: When it comes to understanding why things like green tea and garlic are good for us, science is only beginning to scratch the surface. So it only makes sense to take the whole package, instead of a pill containing the one or two substances we think are what's so good for us.
After all, who are we to second-guess Mother Nature?
Garlic's distinctive smell is a sign of how good for you it is.