Research Extracts: How a Vegan Diet Can Benefit Biological Age
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Welcome to the September 2024 issue of Research Extracts. “The Extracts” is designed to keep busy practitioners and savvy consumers up to date on the latest research on diet, nutrients, botanicals, the microbiome, the environment, and lifestyle approaches to good health and wellness. Our medical team, including NDs, MDs, PhDs, RDs, an MS in clinical nutrition, an MS in biology, and an LAc, summarizes the essence of several interesting recent studies.
In this issue: (1) health benefits of ginger, (2) prebiotic support for sleep and cognition, (3) effect of sweet or salty taste on eating behavior, and (4) vegan versus omnivorous diet and biological age.
Effect of Ginger Consumption on Eye Fatigue and Shoulder Stiffness
Used in both culinary and medicinal practices, ginger is believed to offer a variety of health benefits. In traditional practices, ginger is considered a warming herb, suggesting it promotes blood flow throughout the body. A recent study investigated the effects of ginger consumption on eye fatigue and shoulder stiffness.
This randomized, double-blind, placebo-controlled trial included 100 healthy adults (ages 20-75) who received either placebo or 100 mg of ginger extract daily for eight weeks. Participants maintained their normal lifestyles and diets, kept a record of food, beverage, supplement, and medication intake, and were asked not to start any new dietary supplements during the study period.
Study measures included changes in ocular blood flow measured at the macula and optic disk areas of the eye, peripheral blood flow measured at the forearm, firmness of shoulder muscles (measured using a muscle hardness meter), and a visual analog scale (VAS) for assessment of eye fatigue, shoulder stiffness, and body warmth.
In females younger than 51, ginger consumption enhanced peripheral blood flow mainly in deep blood vessels. This group also reported benefits to eye fatigue and shoulder stiffness. The authors suggested these effects are likely related to enhanced blood flow and that ginger could be a safe strategy for improving such self-reported concerns in younger women. Noted limitations of the study included a small number of male participants, variability in ocular blood flow testing, and a higher baseline VAS score for eye fatigue in the ginger group.
Note: Thorne’s Phytoprofen® contains 250 mg each of ginger extract, curcumin phytosome, Boswellia extract, and bromelain per two-capsule serving.
Contributed by Jennifer L Greer, ND, MEd
Reference
Can Prebiotic Fiber Help Support Memory and Sleep?
A growing body of research connects the gut microbiome to brain and mood health. A 2023 study found that the prebiotic fiber partially hydrolyzed guar gum (PHGG) improved gut health, sleep, and motivation among healthy adults.1
As a follow up, researchers enrolled 61 healthy, older adults (31 men and 30 women; average age 67) in a double-blind, placebo-controlled trial to receive either 5 grams of PHGG (SunFiber®) (n=30) or placebo (n=31) dissolved in water daily at breakfast for 12 weeks.2 Participants underwent cognitive and quality of life (QOL) evaluations at the start of the trial, at eight weeks, and at the end of the trial. Participants were advised to refrain from alcohol and avoid making any lifestyle or dietary changes.
Cognitive function was assessed using the Cognitrax Test − a computer-based assessment that includes tests for verbal memory, visual memory, processing speed, reaction time, simple attention, and sustained attention. The scores of each test were compared to age-matched “norms” and assigned a standardized score accordingly.
Quality of life questionnaires were used to assess measures of sleep and mood. An OSA-MA questionnaire was used for quality of sleep, which included 16 questions about “sleepiness on rising,” “initiation and maintenance of sleep,” “sleep length,” “frequent dreaming,” and whether sleep was “refreshing.” A profile of mood states questionnaire (POMS-2) utilized 65 questions to assess emotional state (e.g., feelings of “vigor-activity,” “friendliness,” “anger-hostility,” etc.).
The study reported that after 12 weeks, the participants consuming PHGG scored significantly higher in visual memory compared to their baseline measures and the placebo group. The PHGG group also scored significantly higher in simple attention compared to both baseline and placebo at the eight-week assessment.
The results of the OSA-MA found that the PHGG group had statistically significant improvements in their “sleepiness on rising” scores compared to both placebo and baseline.
Overall, researchers concluded the PHGG supplementation seemed to support visual memory and overall attention, as well as improved sleep quality. Although not all the assessed outcomes yielded statistically significant changes, supplementation with PHGG appeared to trend toward improvements across all measures compared to placebo and baseline, indicating that longer studies might be needed to fully assess the benefits of this prebiotic fiber.
Note: Thorne’s FiberMend® features 8 grams of PHGG (SunFiber®) per scoop alongside green tea phytosome and other beneficial prebiotic fibers. You can also find 1 gram of SunFiber in each serving of EnteroMend®.
Contributed by Carina Toledo, MS, MHI, CNS
References
- Abe A, Morishima S, Kapoor MP, et al. Partially hydrolyzed guar gum is associated with improvement in gut health, sleep, and motivation among healthy subjects. J Clin Biochem Nutr. 2023;72(2):189-197. doi:10.3164/jcbn.22-75
- Abe A, Kapoor MP, Morishima S, et al. Effectiveness of partially hydrolyzed guar gum on cognitive function and sleep efficiency in healthy elderly subjects in a randomized, double-blind, placebo-controlled, and parallel-group study. Nutrients. 2024;16(8):1211. doi:10.3390/nu16081211
Does Sweet or Salty Flavor Recognition Impact Eating Behavior?
Sweet and salty ingredients lead to increased palatability of foods and have been thought to trigger uncontrolled eating and use of food as rewards; these eating patterns may contribute to overconsumption and metabolic health concerns. Because taste recognition differs among individuals, the present study explored the impacts of sweet and salty taste recognition on use of food rewards and uncontrolled eating behaviors. The study included 38 adults (ages 22-67) who were participants in the Obese Taste Bud Study in Germany.
To measure taste recognition, test strips with varying intensity of flavors of sweet, sour, salty, and bitter were placed on participants’ tongues, with sweet and salty being the focus of this study. The participants were asked to identify the strip flavor, and accuracy of their taste recognition was measured. The Leeds Food Preference Questionnaire (LFPQ-G) was used to assess the liking and wanting of foods in four categories: high-fat savory, low-fat savory, high-fat sweet, low-fat sweet. Another tool, the Power of Food Scale (PFS), was used to measure appetite motivation, which provides insight into uncontrolled eating patterns.
The results for taste recognition and food reward showed a significant association between salty taste recognition and implicit desire for high-fat savory foods, with an increased motivation for consumption of these foods even when not hungry. Sweet taste recognition had an inverse association with low-fat savory foods. The results also showed that those with higher uncontrolled eating scores had significantly better salty taste recognition, but not sweet recognition, compared to low scorers. There were no significant differences in taste preferences between normal weight and obese participants.
Note: If you notice food cravings interrupting your wellness goals, consider Thorne’s Craving and Stress Support*.
Contributed by Carly Duffy, MPH, RD
Reference
A Vegan Diet Versus an Omnivorous Diet and Their Effects on Biological Age
A twin study registered 21 pairs of twins (mean age 40) from the Stanford Twin Registry and other databases. One member of the pair was assigned to an omnivorous diet with specific animal protein requirements, while the other twin was assigned to a total vegan diet – for eight weeks.
Food intake was assessed via diet logs and unannounced 24-hour recalls at baseline, four weeks, and eight weeks. Blood was tested for telomere length, DNA methylation, several epigenetic clocks, and the biological age of 11 different organ systems: heart, lung, kidney, liver, brain, immune, inflammatory, blood, hormone, metabolic, and musculoskeletal.
A vegan diet resulted in a decrease in biological age as measured by several epigenetic clocks (click on full text below for more detail). Also, a decrease in biological age was seen in five of 11 organ systems: inflammation, heart, hormones, liver, and metabolic. There were no significant changes seen in the omnivore group. The authors concluded: “Taken together, these findings suggest that the observed DNA methylation changes may contribute to the overall decreases in epigenetic age in response to a vegan diet, which is not observed among omnivores.”
In evaluating telomere length, the average length was significantly longer in the vegan group at the end of the study compared to baseline; no such increase was seen in the omnivore group. Also, overall telomere length in the vegan group was longer than in the omnivore group.
Note: Thorne’s Biological Age Test employs machine learning to evaluate blood biomarkers to determine how lifestyle, diet, illness, and genetics have affected your biological age of several organ systems and ultimately your overall biological age.
Contributed by Kathi Head, ND
Reference