August 2019 Issue

Ask the Expert: Functional Beverages
By Toby Amidor, MS, RD, CDN, FAND
Today’s Dietitian
Vol. 21, No. 8, P. 7

Q: My clients are asking about new functional beverages on the market that tout various health benefits, particularly for brain and immune health. Is there any legitimacy to these claims?

A: As health-conscious consumers turn away from carbonated and sugary drinks, many companies have responded with functional beverages boasting nutrients and compounds marketed as being health promoting. While some of these beverages offer a few potentially beneficial ingredients, many make unfounded claims about lesser-studied compounds. Functional beverages come with a wide array of health claims, but this article focuses on those with supposed benefits for brain and immune health.

Definition and Popularity
There’s no formal FDA regulatory category or legal definition for functional foods and beverages, so these products are regulated as conventional foods, dietary supplements, food for special dietary uses, medical foods, or drugs, depending on their intended use and nature of the manufacturers’ claims.1 The Academy of Nutrition and Dietetics defines functional foods as both whole and fortified/enriched foods that may benefit health when they’re consumed as part of a healthful diet, regularly and at levels high enough to impact health, and are rooted in significant evidence.2 Without a legal definition for the “functional” label, as with supplements, consumers are left to evaluate evidence for claims themselves.

In spite of the lack of regulation, the functional food industry is booming, especially functional beverages, which are expected to emerge as the fastest-growing product segment in the global nonalcoholic beverage category between 2018 and 2025.3

Brain Health
Functional beverage companies such as BrainGear, Brain Juice, and Synapse Natural Cognitive Boost typically claim their drinks boost mental performance and optimize memory function, focus, and mental clarity. The functional ingredients added to beverages vary from brand to brand; in the aforementioned brands, 12 functional ingredients are used in varying amounts. One ingredient that appears often for brain health is choline, which has been linked to better cognitive function in numerous studies.4 However, others, such as acetyl-L-carnitine, have weaker evidence—acetyl-L-carnitine has been linked to improved learning capacity only in aging rats.5

In addition to the inconsistency of functional ingredients listed between brands touting the same health improvement, there’s little or no scientific evidence on the health consequences of the combination of these functional ingredients (sometimes 10 or more).

Immune Support
According to Mintel, launches of functional beverages claiming to benefit the immune system increased 23% between 2013 and 2017.6 Products include CORE Organic, Blossom Water, Nootra Life, and Medlie Immunity Shot. Vitamin C, or foods that contain vitamin C, and probiotics tend to be common ingredients in many functional beverages boasting immune support, but functional ingredients differ between brands.

According to the National Institutes of Health, the results of controlled studies on vitamin C and its support against the common cold have been inconsistent.7 There’s a positive relationship between probiotics and immune health, but research is still emerging.8,9

Recommendations for Clients
With a vast array of functional beverages available, variable ingredient lists, and lack of regulation, it’s tough for both consumers and RDs to wade through the claims. RDs should advise clients that, although some evidence may exist for the health benefits of individual ingredients in these beverages, the ingredients’ collective effect hasn’t been studied. If clients are intent on drinking functional beverages for potential health outcomes, practitioners should consider the interactions ingredients may have with clients’ medications and/or health conditions.

— Toby Amidor, MS, RD, CDN, FAND, is the founder of Toby Amidor Nutrition ( and a Wall Street Journal best-selling author. Her four cookbooks are Smart Meal Prep for Beginners, The Easy 5-Ingredient Healthy Cookbook, The Healthy Meal Prep Cookbook, and The Greek Yogurt Kitchen. She’s a nutrition expert for and a contributor to U.S. News Eat + Run, Muscle&, and


1. Functional foods policy and regulations. Institute of Food Technologists website.

2. Functional foods. Academy of Nutrition and Dietetics website. Published July 5, 2017.

3. Nonalcoholic beverage market analysis by product (CSD, fruit beverages, bottled water, functional beverages, sports drinks), by distribution channel, and segment forecasts, 2018–2025. Grand View Research website. Published October 2017.

4. Poly C, Massaro JM, Seshadri S, et al. The relation of dietary choline to cognitive performance and white-matter hyperintensity in the Framingham Offspring Cohort. Am J Clin Nutr. 2011;94(6):1584-1591.

5. Kobayashi S, Iwamoto M, Kon K, Waki H, Ando S, Tanaka Y. Acetyl-L-carnitine improves aged brain function. Geriatr Gerontol Int. 2010;10(Suppl 1):S99-S106.

6. Nutrition and performance drinks — US — March 2018. Mintel website. Published March 2018.

7. Vitamin C: fact sheet for health professionals. National Institutes of Health, Office of Dietary Supplements website. Updated September 18, 2018.

8. Yan F, Polk DB. Probiotics and immune health. Curr Opin Gastroenterol. 2011;27(6):496-501.

9. Zhang H, Yeh C, Jin Z, et al. Prospective study of probiotic supplementation results in immune stimulation and improvement of upper respiratory infection rate. Synth Syst Biotechnol. 2018;3(2):113-120.