Nutrition Frontiers - Summer 2019

Date Posted: 

Thursday, July 25, 2019

Volume 10, Issue 3

Dear Nutrition Enthusiast,

The summer issue of Nutrition Frontiers showcases results of the VITAL trial – the Vitamin D and Omega-3 Trial, along with how cooked meat carcinogens affect prostate cancer. Meet our spotlight investigator, Dr. Piyali Dasgupta, and her research on capsaicin and small cell lung cancer therapy. Learn how dandelion greens give the lion’s share of nutrients, upcoming announcements and more.

RESEARCH UPDATE: ON THE CLINICAL FRONT

Vitamin D Supplements and Prevention of Cancer: the Vitamin D and Omega-3 Trial (VITAL)

A display of foods containing vitamin D3 and omega-3 fatty acids.Observational studies suggest that lower vitamin D levels are associated with a higher cancer risk. To evaluate whether vitamin D prevents cancer (and cardiovascular disease), Manson and colleagues conducted a nationwide, randomized, placebo-controlled trial using a two-by-two factorial design, of vitamin D3 (2000 IU/day) and omega-3 fatty acids (1 g/day) in 25,871 men and women. Over a median intervention period of 5.3 years, vitamin D had no effect on the primary end point of invasive cancer of any type or on the secondary end points of site-specific cancer or death from cancer. Effects did not vary according to baseline serum 25-hydroxyvitamin D levels. However, post hoc analyses to address latency suggested a 25% reduction in cancer deaths after exclusion of the first 2 years of follow up. Hypothesis-generating data of subgroup analyses raise the possibility of differential effects on invasive cancer incidence according to BMI, with normal-weight participants who received vitamin D having a lower cancer incidence than those who received placebo (p-value for interaction = 0.002). A 2-year postintervention follow-up is ongoing and will capture latency effects and increase statistical power to assess end points.

Announcements

Stars in Nutrition and Cancer lectures are available for viewing and approved by the CDR for CPE credit for RDNs.

Upcoming Events

July 29 – August 2, 2019
Causal Inference in Behavioral Obesity Research
Indiana Memorial Union
Indiana University
Bloomington, IN

July 31 – August 1, 2019
NIH Workshop on Metabolic Interactions between Folic Acid Excess and Vitamin B12 Deficiency
Bethesda, MD

August 7-8, 2019
Innovations in the Food System: Shaping the Future of Food – A Workshop, National Academies of Sciences, Engineering, and Medicine
Washington, DC or via webcast

Omega-3 Fatty Acids and Prevention of Cancer: the Vitamin D and Omega-3 Trial (VITAL)

A display of foods containing omega-3 fatty acids.The association of omega-3 fatty acids (n-3s) and cancer risk have been inconsistent. To evaluate whether n-3s prevent cancer (and cardiovascular disease), Manson and colleagues conducted a nationwide, randomized, placebo-controlled trial using a two-by-two factorial design, of vitamin D3 (2000 IU/day) and n-3 (1 g/day; EPA/DHA ratio = 1.3/1) in 25,871 men ≥ 50 years and women ≥ 55 years. Over a median intervention period of 5.3 years, n-3s had no effect on the primary end point of invasive cancer of any type or on the secondary end points of site-specific cancer or death from cancer. Exploratory analyses that excluded the first 2 years of follow-up suggested a non-significantly higher incidence of cancer in the n-3 group than in the placebo group but not a higher incidence of death from cancer. In subgroup analyses, the variable of sex may have modified the results regarding cancer incidence (lower hazard ratio in women than men) – and fish intake at baseline may have modified the effects of the intervention on all-cause mortality (lower hazard ratio in those with intake below, compared to above, the median). Overall, the results indicate a mostly neutral effect or slight but nonsignificant elevation in cancer incidence with n-3s.

RESEARCH UPDATE: WHAT’S NEW IN BASIC SCIENCE

Metabolic Activation of Cooked Red Meat Carcinogens

An image of a well-done cooked piece of red meat.Carcinogenic heterocyclic aromatic amines (HAAs) form in well-done cooked red meat. A DNA adduct of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) was detected in 13 of 54 human prostate biopsies, whereas DNA adducts of other HAAs were not detected. Bellamri and colleagues investigated cytotoxicity, metabolic activation, and DNA adduct formation of HAAs and their genotoxic N-hydroxylated metabolites in LNCaP cells, a well-characterized human prostate cell line. Only 2-hydroxy-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (HONH-PhIP), the reactive intermediate of PhIP, was cytotoxic. Moreover, HONH-PhIP formed DNA adducts at levels that were 20-fold higher compared to other HONH-HAAs. Mefenamic acid, a specific inhibitor of sulfotransferase (SULT1A1), decreased PhIP DNA adduct formation in LNCaP cells by 25%, and pretreatment of cells with Rhod-o-hp or pentachlorophenol, inhibitors of SULTs and N-acetyltransferases (NATs), decreased DNA binding of PhIP by 75%. These findings demonstrate that PhIP is a principal HAA in cooked red meat that induces DNA damage of the human prostate. Further research is needed to understand the role of xenobiotic enzymes involved in HAA metabolism and prostate cancer risk.

SPOTLIGHT INVESTIGATOR: PIYALI DASGUPTA

Portrait of Piyali Dasgupta, PhDPiyali Dasgupta, PhD, is an Associate Professor at the Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University.  Originally from India, Dr. Dasgupta came to the United States to pursue her postdoctoral studies at Columbia University and the Moffitt Cancer Center.  Dr. Dasgupta’s laboratory examines the anti-cancer activity of capsaicin, the spicy ingredient of chili peppers, in human small cell lung cancer (SCLC), particularly, how capsaicin robustly suppresses the growth and metastasis of human SCLC.  She observed that capsaicin sensitized human SCLC cells to the apoptotic activity of camptothecin.  Her laboratory also studies the anti-tumor activity of non-pungent capsaicin-like compounds, isolated from different varieties of chili peppers.  Dr. Dasgupta was selected for the prestigious ASPET-Astellas award in translational pharmacology in 2009. Marshall University has honored her with several awards including the Marshall University Distinguished Artists and Scholars Award, John and Francis Rucker Graduate Faculty Mentoring Award and the Dean’s Award for Excellence in Basic Research. Dr. Dasgupta is the recipient of an R15, Capsaicin and Small Cell Lung Cancer Therapy.

Read more about Dr. Dasgupta

Did you know?  Dandelion Greens Give the Lion’s Share of Nutrients

An image of the golden yellow dandelion.The golden yellow dandelion, Taraxacum officinale, is far from being just a bothersome weed! Dandelion has long been valued in folk medicine as a powerful herb to aid in digestion, purify the blood and act as a natural diuretic.  Dandelion originates from the French word, dent-de-lioun meaning ‘lion’s tooth,” possibly due to the plant’s distinct jagged leaves. Clearly, dandelion greens boast the lion’s share of nutrients ̶ one cup of dandelion greens provides 535% of the recommended daily value of vitamin K and 112% of the daily requirement of vitamin A.  Additionally, dandelion greens serve up a healthy dose of zeaxanthin, vitamins C and B6, thiamin, riboflavin, calcium, iron, potassium, folate, magnesium, manganese, phosphorus and copper, along with the soluble fibers, inulin and pectin.

This summer, venture to try something new such as this light dandelion green and citrus salad.  Add a few young tender dandelion leaves to your favorite sandwich or for a flavorful nutrient-punch try this peppery dandelion dressing on your salad of choice.  The endive-like bitter tinge of dandelion greens, particularly full-grown leaves, can be mellowed out by blanching, adding to a soup or sautéing the dandelion greens as done in this delicious pasta dish!