Welcome to the May 2020 edition 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. Our medical team, which includes NDs, MDs, PhDs, RDs, an MS, and an LAc, has summarized the essence of several of the most interesting studies.

Research summaries in this month’s issue include: (1) vitamin D and mobility, (2) diet and the microbiome, (3) exercise and breast cancer survival, and (4) pycnogenol for dry mouth.

Vitamin D and Mobility

An important aspect of healthy aging is the ability to have and maintain good mobility. Hip fracture is both a serious injury in older adults and a leading cause of immobility, especially in women. According to the CDC,1 over 300,000 U.S. adults are hospitalized for hip fractures every year, with three-quarters of them being women.

A 2004 study first examined the relationship between vitamin D levels and mobility in older adults. This is important because vitamin D status has long been known to be important for maintaining both bone and muscle health, and having healthy levels can reduce the risk of falling.*2

A new study3 analyzes vitamin D status relative to the ability to walk unassisted in 290 subjects who were part of the FOCUS Trial (Functional Outcomes in Cardiovascular Patients Undergoing Surgical Hip Fracture Repair. Forty-six percent of participants had a low level of vitamin D (<20 ng/mL), and 76 percent were categorized as being “at nutritional risk” based on the Geriatric Nutritional Risk Index4 (GNRI, a calculation from body weight and reduced albumin concentrations). Both low vitamin D status and low GNRI were associated with reduced mobility.

Overall, the authors conclude that having adequate vitamin D status is important to regaining mobility after hip fracture, and that nutritional status as measured by GNRI might also be associated. This study adds to our knowledge of the critical role that vitamin D plays in the overall health of the musculoskeletal system in aging.

Contributed by Jacqueline Jacques, ND

References

  1. Hip fractures among older adults | Home and recreational safety | CDC Injury Center. https://www.cdc.gov/homeandrecreationalsafety/falls/adulthipfx.html [Accessed April 21, 2020]
  2. Bischoff-Ferrari H, Dawson-Hughes B, Willett W, et al. Effect of vitamin D on falls: a meta-analysis. JAMA 2004;291(16):1999. doi:10.1001/jama.291.16.1999
  3. Hao L, Carson J, Schlussel Y, et al. Vitamin D deficiency is associated with reduced mobility after hip fracture surgery: a prospective study. Am J Clin Nutr 2020 Feb. doi:10.1093/ajcn/nqaa029 (The current study)
  4. Bouillanne O, Morineau G, Dupont C, et al. Geriatric Nutritional Risk Index: a new index for evaluating at-risk elderly medical patients. Am J Clin Nutr 2005;82(4):777-783. 

Dietary changes can alter the gut microbiome in four days

Two commonly studied diet types include the Mediterranean diet (rich in whole foods, such as fresh fruits and vegetables, whole grains, olive oil, nuts, and fish) and the Western diet (rich in red meat, saturated fats, and simple sugars). Significant evidence links the Mediterranean diet to decreased risk of several diseases and conditions, including obesity, cardiovascular disease, and type 2 diabetes, while the Western diet is linked to increased risks for these very same conditions.

Research has also shown the gut microbiome to be strongly affected by diet type, and the types of microbes present in the gut affect disease risk. A high-fiber diet, such as the Mediterranean diet, is associated with a diverse gut microbiome made up of fiber-consuming microbes that are beneficial to health.

A research team considered whether dietary changes can affect the microbiome in just four days, including changes in metabolites produced by the bacteria associated with health effects. In this study, 10 healthy men and women consumed either a Mediterranean diet or a fast food (Western type) diet for four days. Following a washout period (no specific diet), the participants then switched diets for four more days. The gut microbiome was measured with stool testing, and metabolites were measure by blood tests.

After the two dietary changes, each participant’s microbiome remained similar to initial testing, although several significant differences did occur. Fiber-consuming bacteria increased and bile-tolerant bacteria decreased on the Mediterranean diet. Conversely, the fast food diet resulted in decreased fiber-consuming bacteria and increased bile-tolerant bacteria.

In addition, several changes in metabolites associated with health were reported following each diet type. The Mediterranean diet was associated with metabolite changes positively affecting health, while the fast food diet resulted in metabolite changes with negative health effects.

This study indicates that in just four days dietary changes can shift the microbiome of the gut and associated metabolites toward a pattern associated with chronic disease or toward one with health benefits.

Learn more about the Mediterranean diet.

Contributed by Jennifer L. Greer, ND, MEd

References

  • Zhu C, Sawrey-Kubicek L, Beals E, et al. Human gut microbiome composition and tryptophan metabolites were changed differently by fast food and Mediterranean diet in 4 days: a pilot study. Nutr Res 2020;77:62-72. 

Exercise is associated with breast cancer survival advantages 

Safe and effective strategies to improve breast cancer survival are in high demand. Inexpensive and accessible strategies are of particular interest. A recent study investigated how patterns of exercise before, during, and after chemotherapy treatment correlated with cancer recurrence and survival outcomes in high-risk breast cancer patients.1

Participants completed questionnaires regarding their exercise habits at study enrollment (for the month before), at six months after enrollment (approximate end of treatment), and again at one- and two years post-enrollment. Using the Physical Activity Guidelines for Americans2 for quantifying recreational physical activity, participants were divided into categories based on duration and intensity of regular, weekly exercise. These included inactive, low active, moderate active (minimum recommended), and high active exercise patterns.   

Any regular physical activity prior to diagnosis correlated with reduced hazard of recurrence and mortality, but only the moderate active group reached statistical significance. Meeting the minimum guidelines for exercise (moderate active) at the 2-year mark but not prior to diagnosis corresponded with significantly reduced risk for recurrence and mortality, suggesting that beginning exercise after diagnosis can still confer benefits. 

The high active group experienced the greatest reduction in mortality hazard, although significant benefits were achieved at lower levels. Participants meeting the minimum guidelines for exercise both before and after diagnosis had the lowest risk of recurrence and mortality, with more than 50-percent lower relative risk compared to participants not meeting the guidelines.

In combination with prior work, these results suggest that exercise, even at lower levels, is an important aspect of pre-diagnosis health and post-diagnosis breast cancer survivorship.  

Contributed by Sheena Smith, MS MA

References

  1. Cannioto R, Hutson A, Dighe S, et al. Physical activity before, during and after chemotherapy for high-risk breast cancer: relationships with survival. J Natl Cancer Inst doi:10.1093/jnci/djaa046 (Current study)
  2. U.S. Department of Health and Human Services. Physical activity guidelines for Americans, 2nd edition. 2018. https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf. [Accessed April 30, 2020.]

Pycnogenol® can benefit dry mouth

Pycnogenol, the patented name of a bark extract from French maritime pine (Pinus pinaster), has been widely studied for decades and has broad application for support of the cardiovascular system, women’s health, skin health, and more. French maritime pine, as the name implies, is grown in the coastal regions of southern France. The extract is standardized to contain at least 70 percent procyanidin flavonoids. Pycnogenol has been the subject of approximately 160 studies. This recent study examined its effect for dry mouth.

Dry mouth occurs when the salivary glands don’t produce enough saliva to keep the mouth moist. It can be caused by sleeping with the mouth open, acute stress, certain medications, aging, and some disease conditions (including diabetes). It can result in tooth decay, bad breath, and interference with taste and digestion (because saliva contains digestive enzymes).

In this 2-week study, 48 participants (ages 45-55) were divided into two groups: 150 mg Pycnogenol daily plus standard care (n=24; 12 diabetics/12 non-diabetics) or standard care only (n=24; 12 diabetics/12 non-diabetics). Salivation changes were measured by salivary gland ultrasound and by a chewing test that stimulated salivation. After two weeks both diabetics and non-diabetics in the Pycnogenol experienced improvements: 

  • Saliva production improvement: 82 percent in non-diabetics taking Pynogenol; no change in control group; 70 percent in diabetics taking Pycnogenol; no change in control group.
  •  Mouth dryness improvement: 66 percent in non-diabetics taking Pycnogenol; 3 percent in control group; 63 percent in diabetics taking Pyncogenol; 6 percent in control group.
  • Reduced incidence of mouth sores related to dry mouth: 69 percent in non-diabetics taking Pycnogenol; 3 percent in control group; 58 percent in diabetics taking Pycnogenol; 12 percent in control group.

Overall, Pycnogenol significantly improved salivary production, mouth dryness, and mouth sore incidence in diabetics and non-diabetics.

Contributed by Kathi Head, ND

References