June/July 2020 Issue

Functional Foods & Cognitive Health
By Mindy Hermann, MBA, RDN
Today’s Dietitian
Vol. 22, No. 6, P. 40

Despite promise, further research is needed.

In recent years, consumer perception of health has moved away from conventional chronic disease prevention and treatment toward a more holistic approach. Consumers are defining health by how they feel rather than by clinical measures.

The IFIC Foundation 2019 Food and Health Report, based on survey results, helps substantiate this shift. Clean eating and intermittent fasting were named as top diets consumers follow, while the Dietary Approaches to Stop Hypertension, or DASH, diet ranked near the bottom.

In the report, the motivator to follow a specific eating pattern over the previous year was “to feel better and have more energy,” which ranked second, followed by weight loss, health improvement, and disease prevention. Energy ranked just below weight management as a top desired health benefit from food; digestive health was more sought after than heart health, and brain function ranked higher than bone health.

A major component of holistic health is boosting brain function, which involves improved memory, mood regulation, and decreased anxiety and depression. To that end, many people are turning to functional foods for assistance. The field of functional foods has evolved to incorporate a growing number of foods that promise improved feelings of health. Although functional foods have many definitions—and one could argue that all foods are functional in some way—the Academy of Nutrition and Dietetics (the Academy) defines them as “whole foods along with fortified, enriched, or enhanced foods that have a potentially beneficial effect on health.”1

Functional foods, however, shouldn’t be relied on as a single strategy to improve feelings of health. The Academy position paper qualifies that the benefits of functional foods depend on consumption “as part of a varied diet on a regular basis at effective levels based on significant standards of evidence.”1 Truth is, strong evidence doesn’t yet support the purported benefits of many functional foods.

Products developed to enhance brain function claim to prevent dementia and improve cognition, focus, and mood. Some boast the word “nootropic,” referring to targeted improvements in cognitive function, executive function, memory, creativity, and motivation. Most brain-related benefits haven’t been scientifically supported in a way that meets FDA standards for package claims, which is why benefit claims typically appear on websites and in promotional materials rather than on product packaging. Statements tend to suggest improvements related to brain health—for example, “Lower your stress levels and start your day with a calm mind.”

When discussing functional foods with RDs, clients are more likely to bring up subjective feelings related to brain health, such as mood, anxiety, and concentration, rather than objective test results evaluating memory, cognition, focus, and other brain functions. This article discusses the association between food and mood and examines some of the key ingredients added to foods and beverages that have been associated with memory, anxiety, and other aspects of brain health.

Food and Mood
Client reports of mood and mood changes are highly subjective. In addition, improvements in mood and brain function that may be attributed to food could result from numerous factors unrelated to diet changes. Dietetics practitioners can work with clients, however, to try to connect the dots between diet and specific food choices and improvements in various body functions and mood.

“Our food choices most definitely contribute to mood and regulation of the circadian rhythm,” says Monique Richard, MS, RDN, LDN, FAND, RYT-200, owner of Nutrition-In-Sight, a nutrition business specializing in MNT, consulting, communications, and corporate wellness in Johnson City, Tennessee; past chair of the Dietitians in Integrative and Functional Medicine Dietetic Practice Group; and president of the International Affiliate of the Academy. “The more we lean on higher-quality ingredients that support those pathways, the more benefits all around. For example, nutrients such as melatonin support pathways in sleep patterns but also neurotransmitter conduction related to mood and cognitive processes.”

Many functional foods for brain and mental health benefits already are part of a healthful diet. “Adequate fruit and vegetable consumption is associated with quality and duration of sleep,” Richard says. “Lutein and zeaxanthin in leafy greens, avocado, and egg yolk play key roles in cognitive function throughout the lifespan. The more common functional foods, including whole grains, lettuce, cherries, walnuts, and milk may be easier to come by than less common products, such as barley grass powder, asparagus powder, or lingzhi, also known as reishi mushroom, which are touted for their bioactive components that aid in sleep.

“I think the term ‘functional foods’ can be misleading,” Richard continues. “All whole foods offer functional properties due to their bioactive compounds and nutrients and aid in a multitude of reactions and cellular health throughout the body.”

Despite these benefits, Richard also recommends caution in the use of products with high concentrations of bioactive ingredients, particularly for people who are taking prescription medications for mental health. “Focusing on one particular ingredient or an excess thereof without assessing current health status, medication intake, drug-nutrient interactions, or overall nutrient intake can be harmful,” Richard says. “People on medications for depression, anxiety, hyperactivity, or sleep, as well as those with a heart condition or [who] have altered renal or liver function, may be especially vulnerable to increased food-drug interactions if consuming concentrated amounts of bioactive foods and ingredients that are isolated from their natural state.”

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The following is a sampling of the more popular functional food ingredients that are promoted to improve mood, focus, and brain health. Many of the benefit statements are worded by manufacturers as structure-function claims that the FDA hasn’t validated.

Ashwagandha
Ashwagandha (Withania somnifera), a plant in the nightshade family, is an important element in the alternative medicine practice of Ayurveda. Described as the “Prince of Herbs,” ashwagandha is promoted as an adaptogenic herb that helps the body successfully adapt to various stressful conditions, reduce stress and anxiety, and enhance memory and cognition.2 A recent review on the neuroprotective compounds in ashwagandha—sitoindosides, withaferin A, withanosides IV, withanols, withanolides, anaferine, and beta-sitosterol—notes its potential for use in brain disorders and calls for additional studies.3 A concentrated ashwagandha extract was shown to reduce a test score measuring the severity of general anxiety symptoms compared with placebo.4 Ashwagandha typically is incorporated into teas, coffees, and smoothie powders.

Ginkgo
Ginkgo (ginkgo biloba), also known as the maidenhair tree, is one of the oldest tree species in the world. Ginkgo nuts have a long history of use in Chinese medicine to treat cognitive dysfunction and other aspects of brain health.5 As with many botanicals used to improve brain health, the efficacy of ginkgo hasn’t been scientifically validated. The long-term Ginkgo Evaluation of Memory study, a randomized, double-blinded, placebo-controlled clinical trial involving 3,069 older adults followed over approximately six years, looked at various benefits attributed to ginkgo. Ginkgo supplementation wasn’t associated with less cognitive decline in older adults who began the study with normal cognition or with mild cognitive impairment.6 Ginkgo most often is added to sports nutrition products, soft drinks, and tea, including kombucha.

Melatonin
The naturally occurring hormone melatonin modulates the body’s circadian rhythms and sleep patterns.7 Brain-related benefits associated with melatonin include recovery from jet lag, correction of certain sleep-wake disorders, and anxiety reduction before surgery. In a group of hospitalized patients, melatonin and the sedative zolpidem (Ambien) had similar effects on patients’ perceptions of sleep effectiveness, sleep disturbance, and adverse effects.8 Studies on the benefits of melatonin supplementation currently are inconclusive because of differences in methodology and analysis.9 Melatonin has been added to a handful of food and beverage products, such as chocolates, waters, and ready-to-drink lattes, but is more widely available as a supplement.

Mushrooms
Mushrooms have a long history of medicinal use in Eastern, Western, and indigenous cultures. Today, the mushroom species cordyceps, lion’s mane, chaga, and reishi are promoted individually or in combination for immune support and brain-related benefits. Lion’s mane in particular is said to improve memory, cognitive function, and mood. Studies to date on functional mushrooms have been conducted primarily in vitro or in laboratory animals and suggest that mushrooms may benefit cognitive function.10 More research is needed. In addition to supplements, functional mushrooms can be found in sports powders with nootropic benefits, protein powders, beverages, and snack bars.

Omega-3 Fatty Acids
The omega-3 fatty acids alpha-linolenic acid, EPA, and DHA often are promoted to enhance brain health and prevent cognitive decline because of their role as components of phospholipids in the brain. A summary of studies from the National Institutes of Health Office of Dietary Supplements on consumption of omega-3s as supplements and in fish notes that omega-3 supplementation hasn’t been shown to affect cognitive function in healthy older adults or in people with Alzheimer’s disease compared with placebo but may improve certain aspects of cognitive function, including attention, processing speed, and recall, in people with mild cognitive impairment, pending further study.11 Numerous studies suggest that consumption of omega-3 fatty acids, or fish containing omega-3s, reduces depression, but a 2019 review didn’t find adequate substantiation.12 Omega-3 fatty acids occur naturally in foods such as fish and walnuts but can be added to fortify foods and beverages such as eggs, milk, and other animal-based foods through fortified feed.

Prebiotics/Probiotics
Research on the gut-brain axis suggests that improving gut health with the use of prebiotic fibers and probiotics positively impacts the central nervous system; brain diseases such as multiple sclerosis, Parkinson’s disease, and Alzheimer’s disease; as well as mood and anxiety.13 Signaling between the gut and the brain is thought to occur directly via the enteric nervous system, gut bacteria metabolites, the immune system, and neurochemical signaling.14

Gut health is thought to have a connection to both inflammation and mood. “We know that poor gut health leads to inflammation within the body, and inflammation has been shown to be connected to anxiety and depression; this is referred to as the science of psychobiotics,” explains Kara Landau, APD/AN, founder of Uplift Food, a New York City–based company touted on its website as “the world’s first functional food brand to focus exclusively on the Mood Supportive Benefits of PREbiotic Gut Healthy Foods.”

Landau continues: “Consuming a gut-healthy diet filled with prebiotic-rich foods, including both prebiotic soluble fibers and resistant starches, can nourish the diverse range of probiotics naturally found within the gut, helping to reduce inflammation and thereby playing a role in mood regulation.”

Richard emphasizes the importance of key dietary components for a healthy gut. “Since the health of the microbiome is critical for serotonin production, nourishing gut bacteria with soluble (prebiotic) and insoluble fiber, probiotics, polyphenols from fruits and vegetables, and fermented foods is essential, along with limiting foods that contribute to oxidative stress in the body.” A growing number of products, including yogurts, contain prebiotics and probiotics, but few promote brain health benefits.

L-Theanine
L-theanine, also known as gammaethylamino-L-glutamic acid and found in the leaves of the tea plant (Camillia sinensis), increasingly is promoted to improve sleep, cognition, and mental alertness, as well as relieve anxiety.15 Additional applications include stress relief, treatment for depression and attention-deficit-hyperactivity disorder, and improving mental performance and attention. L-theanine also is touted to induce relaxation without causing drowsiness. It’s typically added to tea-based beverages and chocolates that are sold as prebedtime snacks. While L-theanine may help improve attention span, its other effects haven’t yet been substantiated.16

— Mindy Hermann, MBA, RDN, is a food and nutrition communications consultant based in metro New York.

References
1. Crowe KM, Francis C; Academy of Nutrition and Dietetics. Position of the Academy of Nutrition and Dietetics: functional foods. J Acad Nutr Diet. 2013;113(8):1096-1103.

2. What is ashwagandha? KSM-66 Ashwagandha website. https://ksm66ashwagandhaa.com/ashwagandha/

3. Zahiruddin S, Basist P, Parveen A, et al. Ashwagandha in brain disorders: a review of recent developments. J Ethnopharmacol. 2020;257:112876.

4. Fuladi S, Emami SA, Mohammadpour AH, Karimani A, Manteghi AA, Sahebkar A. Assessment of Withania somnifera root extract efficacy in patients with generalized anxiety disorder: a randomized double-blind placebo-controlled trial [published online April 13, 2020]. Curr Clin Pharmacol. doi: 10.2174/1574884715666200413120413.

5. Ginkgo. National Institutes of Health, National Center for Complementary and Integrative Health website. https://www.nccih.nih.gov/health/ginkgo. Updated September 2016.

6. Snitz BE, O’Meara ES, Carlson MC, et al. Ginkgo biloba for preventing cognitive decline in older adults: a randomized trial. JAMA. 2009;302(24):2663-2670.

7. Melatonin: what you need to know. National Institutes of Health, National Center for Complementary and Integrative Health website. https://www.nccih.nih.gov/health/melatonin-what-you-need-to-know. Updated October 2019.

8. Stoianovici R, Brunetti L, Adams CD. Comparison of melatonin and zolpidem for sleep in an academic community hospital: an analysis of patient perception and inpatient outcomes [published online June 25, 2019]. J Pharm Pract. doi: 10.1177/0897190019851888.

9. Posadzki PP, Bajpai R, Kyaw BM, et al. Melatonin and health: an umbrella review of health outcomes and biological mechanisms of action. BMC Med. 2018;16(1):18.

10. Wong KH, Ng CC, Kanagasabapathy G, Yow YY, Sabaratnam V. An overview of culinary and medicinal mushrooms in neurodegeneration and neurotrauma research. Int J Med Mushrooms. 2017;19(3):191-202.

11. Omega-3 fatty acids: fact sheet for health professionals. National Institutes of Health, Office of Dietary Supplements website. https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/. Updated October 17, 2019.

12. Deane KHO, Jimoh OF, Biswas P, et al. Omega-3 and polyunsaturated fat for prevention of depression and anxiety symptoms: systematic review and meta-analysis of randomised trials [published online October 24, 2019]. Br J Psychiatry. doi: 10.1192/bjp.2019.234.

13. Cryan JF, O’Riordan KJ, Cowan CSM, et al. The microbiota-gut-brain axis. Physiol Rev. 2019;99(4):1877-2013.

14. Long-Smith C, O’Riordan KJ, Clarke G, Stanton C, Dinan TG, Cryan JF. Microbiota-gut-brain axis: new therapeutic opportunities. Ann Rev Pharmacol Toxicol. 2020;60:477-502.

15. L-theanine. Drugs.com website. https://www.drugs.com/npp/l-theanine.html. Updated October 22, 2019.

16. Theanine. WebMD website. https://www.webmd.com/vitamins/ai/ingredientmono-1053/theanine