In its new report entitled Direct Selling in the Nutrition Industry VIII, NBJ values the market at $12.2bn as of 2007 - 7.7 per cent growth on the previous year.
It classes nutritional products as dietary supplements, functional foods, natural organic products, including natural and organic personal care and household products.
The report indicates that there is strong potential for product marketers in pursuing direct selling options.
They pointed out, however, that the growth curve is still behind that of the retail market, which say sales growth of 11.1 percent last year.
Two direct sales channels were identified as being particularly popular, however: Internet sales and sales via the health practitioner.
Interestingly, and especially given the emphasis on science in the nutrition field, in some respects these two channels could be seen as opposing.
Consumers tend to place a high level of trust in the advice of their health practitioners, including doctors, nurses and chiropractors.
This market looks to have "risen steadily" in 2007.
While some products available over the internet do come with a solid backing and there are some useful products available online, the internet has also been vilified as a source of ineffective, and sometimes down right dangerous products.
Despite this reputation, which should make some consumers wary, internet sales experienced growth of more than 20 per cent, NBJ's research found that nutrition products by e-commerce were worth some $1.1bn in 2007.
Its explanation came from the lips of Patrick Rea, publisher and editorial director, who said: "Increasingly, nutrition industry entrepreneurs are turning to the direct channels to launch new businesses and products via direct-to-consumer sales channels because of their low barriers to entry and favorable economics."
The indication is, then, that consumers could be recognising that the internet and other direct sales channels (such as mail order, direct response TV, radio channels and network/multilevel marketing companies) are the places where the latest products and innovations have their first airings.
NBJ has identified some of the nutrition companies active in direct-to-consumer channels as being Amway, Atrium, Bodybuilding.com, Enzymatic Therapy, Herbalife, Mannatech, Metagenetics, NBTY, NuSkin Enterprises, Shaklee Corp and XanGo.