What are the top 10 best direct marketing agencies for nutritional products?

A direct marketing agency is one that advertises directly to consumers
using TV, print, radio, or the internet. The consumer then responds to
the ad via phone, e-mail, mail, etc. These agencies are different
from advertising agencies that use the same media but the products are
sold through stores, e.g. Supermarkets, WalMart. Nutritional products
are supplements like vitamins, minerals, and herbs. What I am looking
for is the largest agencies who have major success with nutritional
products. I am especially interested in agencies in So. California.