Older adults: Plant-based snacks boost plasma antioxidants and the microbiome

This article is part of our May 2022 Healthy Aging special issue. Download the full issue here.

Relation

Zhang JY, Lo HC, Yang FL, Liu YF, Wu WM, Chou CC. Plant-based snacks rich in antioxidants increase plasma antioxidant capacity and alter gut bacterial composition in older adults.Nutrients. 2021;13(11):3872.

Key to take away

A four-month intervention with whole plant-based smoothies combined with sesame seed-based snacks has positive effects on circulating antioxidant parameters in the elderly, as well as measurable effects on the microbiome.

Draft

Open, single-arm intervention

Participant

Healthy and subhealthy older adults (N = 42, mean age 79.7 ± 8.6 years) in 2 senior living facilities operated by Yonghe Cardinal Tien Hospital, New Taipei City, Taiwan

Inclusion criteria

age 65 years or more; residents of the facility for 2 or more months; Healthy or sub-healthy diagnosis by a doctor. Subhealth was defined as no existing pathology but existing prehypertension, overweight or underweight, serum lipids above the limit, and/or suboptimal renal or liver health.

Exclusion criteria

Cancer, chronic obstructive pulmonary disease, severe disability or dementia

Instruments

Anthropometric measurements (weight, height, waist and hip circumference), body mass index (BMI), waist-hip ratio, complete blood count (CBC) with differential, lipid panel, blood urea nitrogen (BUN), creatinine, high sensitivity C-reactive protein (hs-CRP), antioxidant enzymes in Plasma and erythrocytes (thiobarbituric acid-reactive substances, reduced glutathione, oxidized glutathione, total sulfhydryl groups, protein-bound sulfhydryl groups, non-protein sulfhydryl groups), stool samples (short-chain fatty acids [SCFA], acetic acid, propionic acid, butyric acid, total bacterial DNA, operational taxonomic units, alpha diversity, beta diversity). Investigators performed measurements at baseline, 2 months, and 4 months.

intervention

There were 4 different plant-based smoothies with orange, green, dark green and purple color. The researchers used the following processes for each: “cleaning, preparation, blanching, microprocessing, packaging and frozen storage at -30 C.”

Each smoothie, 150 g, contained 1 replacement of vegetables (2 types), 1 replacement of fruits (2 types) and 1 replacement of nuts (145-186 kcal, 21-29 g carbohydrates, 4-5 g protein, 7 g fat, 2.7-4.7 g fiber and various minerals, vitamins and phytochemicals, low in saturated fats, none Cholesterol, low sodium, low sugar and 10%-15% of the recommended daily intake of vitamins A, C, B₁, potassium, calcium and magnesium). Also snacks made from sesame powder and spread (10 g each) with 57.6 kcal and 63.3 kcal, 2.1 g and 2.5 g carbohydrates, 1.6 g and 1.3 g protein, 5.5 g and 5.7 g lipids, each with various vitamins and minerals provided to increase the absorption of calcium, polyunsaturated fatty acids, vitamin E and secondary plant substances.

Each week for 4 months, participants received 1 serving of each type of smoothie (4 types total) and one 5^thPortion of your choice (5 servings in total per week) and 3 portions of the sesame snack. Compliance and consumption were recorded.

Results

Investigators recruited 59 older adults, with 30 women and 12 men participating in the intervention and blood collection. One woman and one man refused to provide stool samples after the 4-month intervention. Women were 77.7 years old+7.6 years; Men were 85.3 years old+8.4 years. There were no significant differences in BMI (baseline = 24.0 ± 2.8 kg/m²) or waist-hip ratio in women and men.

Compliance with smoothies and snacks was 88.0% for women and 92.5% for men. Body weight increased significantly after 2 months (P=0.028) and then decreased to about 1 kg above baseline, while BMI, waist and hip circumference and waist-hip ratio did not change significantly.

Red blood cells (RBC), hematocrit, albumin and urea decreased significantly after 4 months; Hemoglobin, cholesterol and high-density lipoproteins (HDL) also increased significantly, but the change in low-density lipoprotein (LDL) cholesterol was not significant. Reduced glutathione (P<0.001), total sulfhydryl (P<0.015), protein-bound sulfhydryl (P<0.019) and the total antioxidant capacity (P<0.015) increased significantly over the 4 months. Oxidized glutathione (P< 0.001) decreased significantly over the 4 months, while there was no significant change in thiobarbituric acid-reactive substances.

Fecal SCFAs were unchanged after 4 months, as were various SCFA levels. Bacterial species in feces were significantly reduced after 2 and 4 months. The 4 dominant phyla were Firmicutes, Bacteroidetes, Proteobacteria, and Verrucomicrobia throughout the study and accounted for 95% of the total bacterial count. Investigators identified 28 bacterial taxa at baseline and after 2 and 4 months. The older adults had declinedBacilli,Streptococcus, Ruminiclostridium, Deltaproteobacteria,Patescibacteriaand increasedLactobacilliafter 2 and 4 months compared to baseline. At 2 months there were increasedBacteroidetesandBacteroides thetaiotaomicronand increased after 4 monthsAgathobactercompared to baseline. A comparison of microbiota and total antioxidant capacity (TAC) was foundRuminiclostridium_5, Agathobacter, Bacteroidetes,andFusobacterianegatively associated with TAC (P=0.003).Lactobacillus salivariuswas positively associated with TAC (P=0.005). Sample sizes were found to be adequate to detect interactions between gut bacterial composition and antioxidant enzymes.

Key insights

Plant-based snacks and smoothies rich in antioxidants can improve antioxidant capacity and alter gastrointestinal microbiota in older adults over 4 months when consumed regularly.

Transparency: The authors disclose no conflicts of interest. Funding was provided by grants from the Ministry of Science and Technology, Taiwan.

Practice implications

A diet rich in vegetables, fruits, whole grains and nuts has an antioxidant, anti-inflammatory and therefore anti-aging effect and reduces frailty.^1.2Higher intake of flavonoids in fruits and vegetables is associated with less subjective cognitive decline in older American adults.³One of the unfortunate facts is that as adults age, their ability to chew, swallow, and digest decreases, an assumption made for this study population and therefore a factor in the design of this study.⁴

Active phytochemicals with antioxidant properties are associated with colorful foods: fruits, vegetables, nuts and seeds.⁵The question that doctors would like to have answered is: Which fruits, vegetables, nuts and seeds produce the most effective or problematic change in a patient's microbiome when they have prediabetes, cognitive impairment risk factors, cancer risk factors, etc.?⁶Here, clinical questions take precedence over scientific answers.

sesame seeds,Sesamum indicum,Believed to be native to sub-Saharan Africa and India, Pedaliaceae were the first human oilseed crop and were domesticated as a drought-tolerant plant more than 5,500 years ago.⁷Production in 2018 was more than 6 million tons. In 100 g or 3.5 ounces there are 573 calories, 5% water, 23% carbohydrates of which 12% fiber, 50% fat, 18% protein and 20% or more of the recommended daily value of several B vitamins, iron, magnesium, calcium, phosphorus and zinc.⁷Also present are phytic acid, a known binder of minerals that can reduce their absorption in the small intestine, as well as the lignans sesamolin, sesamin, pinoresinol and lariciresinol.⁸What sesame supports or reduces intestinal bacteria is largely unknown. Unfortunately, sesame is a common allergen at number 9^thin children and adults, and since November 2019 in Canada and the United States, it must be listed on the label if it is present in a food.⁹About 17% of children are allergic to sesame, with 20% to 30% expected to outgrow this allergy.⁸

Sesame is unfortunately a common allergen, ranking 9th in children and adults, and as of November 2019, it must be listed on the label in Canada and the United States if it is present in a food.”

This 4-month study found that it was a reasonable amount of time to evaluate some biome changes. Very limited data was provided on study participants; for example, I would have liked to know how many were classified as healthy versus sub-healthy adults and whether there were differences in results between the two groups. There was no indication whether the snacks were taste tested to make them palatable or attractive to study participants, a factor that could limit consumption. Likewise, there was no data on the selection of the 5th^thsmoothie and whether this was based on taste, color, both, or both. Information about the ingredients of the 4 smoothies was also not provided. Finally, the investigators described the foods as having been "textured altered," but we don't know whether this improved their ability to be chewed, swallowed, and digested, nor how the texture was altered, nor how well the subjects liked the smoothies and snacks. The study was generally well written, but not all subheadings matched the content of this section.

Plant-based, antioxidant-rich smoothies containing unknown vegetables, fruits, and nuts, as well as snacks prepared from sesame seeds, may improve antioxidant capacity and alter gastrointestinal microbiota in older, presumably Taiwanese, adults over 4 months of age when consumed regularly.