Rachel M. Cole

ω-3 Fatty acid supplements in women at high risk of breast cancer have dose-dependent effects on breast adipose tissue fatty acid composition

BACKGROUND Preclinical evidence of the preventive benefits of omega-3 (n-3) polyunsaturated fatty acids (PUFAs) in breast cancer continues to fuel interest in the potential role of dietary fat content in reducing breast cancer risk. The dose of fish-oil/omega-3 PUFAs needed to achieve maximal target tissue effects for breast cancer prevention remains undefined. OBJECTIVE To determine the dose effects of omega-3 fatty acids on breast adipose tissue fatty acid profiles, we conducted a study of 4 doses of omega-3 PUFAs in women at high risk of breast cancer. DESIGN In this 6-mo randomized open-label study, 48 women with increased breast cancer risk received 1, 3, 6, or 9 capsules/d of an omega-3 PUFA supplement that provided 0.84, 2.52, 5.04, and 7.56 g docosahexaenoic acid (DHA) + eicosapentaenoic acid (EPA) daily, respectively. Subjects made monthly visits, at which time pill counts were made and fasting blood samples were collected to determine fatty acid profiles; anthropometric measurements were made, breast adipose tissue samples were collected, and laboratory tests of toxicity (alanine aminotransferase, LDL cholesterol, and platelet function) were made at baseline and at 3 and 6 mo. RESULTS All doses led to increased serum and breast adipose tissue EPA and DHA concentrations, but the response to 0.84 g DHA+EPA/d was less than the maximum possible response with > or = 2.52 g/d. Body mass index attenuated the dose response for serum tissue DHA and EPA (P = 0.015 and 0.027, respectively) and breast adipose tissue DHA (P = 0.0022) in all of the treatment groups. The incremental increase in DHA and EPA correlated inversely with baseline fat and serum values. Compliance over 6 mo was 92.9 +/- 9.2% and was unaffected by treatment arm. No severe or serious toxicities were reported. CONCLUSIONS Daily doses up to 7.56 g DHA+EPA were well tolerated with excellent compliance in this cohort at high risk of breast cancer. Body mass index and baseline fatty acid concentrations modulated the dose-response effects of omega-3 PUFA supplements on serum EPA and DHA and breast adipose tissue DHA.

Erythrocyte linoleic acid, but not oleic acid, is associated with improvements in body composition in men and women

SCOPE Supplementation with linoleic acid (LA; 18:2Ω6)-rich oils increases lean mass and decreases trunk adipose mass in people. Erythrocyte fatty acids reflect the dietary pattern of fatty acid intake and endogenous metabolism of fatty acids. The aim of this study is to determine the relationship of erythrocyte LA, with aspects of body composition, insulin resistance, and inflammation. Additionally, we tested for relationships of oleic acid (OA) and the sum of long chain omega-three fatty acids (LC-Ω3-SUM), on the same outcomes. METHODS AND RESULTS Men and women (N = 139) were evaluated for body composition, insulin resistance, and serum inflammatory markers, IL-6, and c-reactive protein (CRP) and erythrocyte fatty acid composition after an overnight fast. LA was positively related to appendicular lean mass/body mass index and inversely related to trunk adipose mass. Additionally, LA was inversely related to insulin resistance and IL-6. While there was an inverse relationship between OA or LC-Ω3-SUM with markers of inflammation, there were no relationships between OA or LC-Ω3-SUM with body composition or HOMA-IR. CONCLUSION Higher erythrocyte LA was associated with improved body composition, insulin resistance, and inflammation. Erythrocyte OA or LC-Ω3-SUM was unrelated to body composition and insulin resistance. There is much controversy about whether all unsaturated fats have the same benefits for metabolic syndrome and weight gain. We sought to test the strength of the relationships between three unsaturated fatty acid in erythrocytes with measurements of body composition, metabolism, and inflammation in healthy adults. Linoleic acid, but not oleic acid or the sum of long-chain omega 3 fatty acids (w3), was associated with increased appendicular lean mass and decreased trunk adipose mass and insulin resistance.

Adipose tissue lipolysis and energy metabolism in early cancer cachexia in mice

Cancer cachexia is a progressive metabolic disorder that results in depletion of adipose tissue and skeletal muscle. A growing body of literature suggests that maintaining adipose tissue mass in cachexia may improve quality-of-life and survival outcomes. Studies of lipid metabolism in cachexia, however, have generally focused on later stages of the disorder when severe loss of adipose tissue has already occurred. Here, we investigated lipid metabolism in adipose, liver and muscle tissues during early stage cachexia – before severe fat loss – in the colon-26 murine model of cachexia. White adipose tissue mass in cachectic mice was moderately reduced (34–42%) and weight loss was less than 10% of initial body weight in this study of early cachexia. In white adipose depots of cachectic mice, we found evidence of enhanced protein kinase A - activated lipolysis which coincided with elevated total energy expenditure and increased expression of markers of brown (but not white) adipose tissue thermogenesis and the acute phase response. Total lipids in liver and muscle were unchanged in early cachexia while markers of fatty oxidation were increased. Many of these initial metabolic responses contrast with reports of lipid metabolism in later stages of cachexia. Our observations suggest intervention studies to preserve fat mass in cachexia should be tailored to the stage of cachexia. Our observations also highlight a need for studies that delineate the contribution of cachexia stage and animal model to altered lipid metabolism in cancer cachexia and identify those that most closely mimic the human condition.

Associations of erythrocyte ω-3 fatty acids with biomarkers of ω-3 fatty acids and inflammation in breast tissue

There is increasing evidence that chronic inflammation is associated with increased breast cancer risk. Long‐chain omega‐3 polyunsaturated fatty acids (LCω‐3PUFA) may reduce circulating biomarkers of inflammation; however associations of blood LCω‐3PUFA with breast tissue LCω‐3PUFA and breast tissue biomarkers of inflammation are not well understood. We conducted a cross‐sectional analysis of breast tissue and blood samples from n = 85 women with no history of breast cancer, who underwent breast reduction surgery. Fatty acids of erythrocytes and undissected breast tissues were analyzed by gas chromatography; C‐reactive protein (CRP), interleukin (IL)–6 and IL‐8 in plasma and tissue were measured by ELISA. Multivariable‐adjusted regression models were used to estimate associations between erythrocyte LCω‐3PUFA and breast tissue biomarkers. Women in the highest erythrocyte LCω‐3PUFA tertile had LCω‐3PUFA concentrations in the breast 73% (95% CI: 31–128%; p trend < 0.0001) higher than women in the lowest tertile. Associations for each individual LCω‐3PUFA were similar in magnitude. No significant association was found for the shorter ω‐3 PUFA, α‐linolenic acid. Although compatible with no association, women in the highest tertile of erythrocyte eicosapentaenoic acid had a nonsignificant 32% (95% CI: −23 to 62%) reduced breast tissue CRP. No correlation was observed between erythrocyte ω‐3 PUFA and tissue IL‐6 or IL‐8 concentrations. Our findings provide evidence that erythrocyte ω‐3 fatty acids are valid measures of breast tissue concentrations, and limited evidence that inverse associations from prospective epidemiologic studies of blood LCω‐3PUFA and breast cancer risk may be partly explained by reductions in breast tissue inflammation; however, these findings require replication.

Short-term food restriction followed by controlled refeeding promotes gorging behavior, enhances fat deposition, and diminishes insulin sensitivity in mice☆

Rodents are commonly used in food restriction refeeding studies to investigate weight regain. Mice that are rationed food every 24 h may consume all allocated food in a short time (gorge) and therefore undergo a brief well-fed period followed by an extended fasted period until the next days food allotment. These exaggerated metabolic states are not typical in mice fed ad libitum (nibbling). The aim of the current study was to elucidate the intraday and cumulative metabolic consequences of gorging (induced by food restriction) in mice during controlled refeeding. Accordingly, following a temporary food restriction, mice were fed rations similar to intakes of controls fed ad libitum. Temporary food restriction initiated gorging behavior that persisted during refeeding; consequently, metabolism-related measurements were obtained in the gorging mice during their daily fed and fasted metabolic states. Robust differences in adipose tissue lipogenic and inflammatory gene expression were found in the gorging mice by metabolic state (fed versus fasted). Additionally, despite a reduced cumulative food intake compared to mice fed ad libitum, restriction-induced gorging mice had increased intraabdominal fat accumulation, diminished hepatic and peripheral insulin sensitivity, and a gene expression profile favoring lipid deposition. Our findings highlight the intraday differences in gene expression in gorging mice before and after feeding that confound comparisons with mice fed ad libitum, or nibbling. The present study also provides evidence that weight regain following food restriction is associated with cumulative metabolic and behavioral abnormalities in mice.

Citrus flavonoid, naringenin, increases locomotor activity and reduces diacylglycerol accumulation in skeletal muscle of obese ovariectomized mice

SCOPE Estrogen deficiency has been associated with central obesity, muscle loss and metabolic syndrome in postmenopausal women. This study assessed naringenin accumulation in tissues and investigated the hypothesis that naringenin reverses diet-induced metabolic disturbances in obese ovariectomized mice. METHODS AND RESULTS In study 1, we measured naringenin concentrations in plasma, liver, perigonadal and subcutaneous adipose tissues, and muscle of ovariectomized C57BL/6J female mice after 11 weeks of naringenin supplementation. Naringenin accumulated 5-12 times more in mice fed a 3% naringenin diet than in mice fed a 1% naringenin diet. In study 2, ovariectomized mice were fed a high-fat diet (60 kcal% fat) for 11 weeks and half of the mice were then supplemented with 3% naringenin for another 11 weeks. Dietary naringenin suppressed weight gain, lowered hyperglycemia and decreased intra-abdominal adiposity evaluated by magnetic resonance imaging. Naringenin-fed mice exhibited elevated locomotor activity monitored by infrared beam breaks, maintained muscle mass and reduced muscle diacylglycerol content. Real-time PCR analysis in muscle revealed decreased mRNA level for genes involved in de novo lipogenesis, lipolysis and triglyceride synthesis/storage. CONCLUSION Long-term 3% naringenin supplementation resulted in significant naringenin accumulation in plasma and tissues, associated with attenuated metabolic dysregulation and muscle loss in obese ovariectomized mice.

Incorporation of eicosapentaenioic and docosahexaenoic acids into breast adipose tissue of women at high risk of breast cancer: A randomized clinical trial of dietary fish and n-3 fatty acid capsules

SCOPE The fatty acid profile of dietary lipids is reflected in mammary adipose tissue and may influence mammary gland biology and cancer risk. To determine the effects of fish consumption on breast adipose tissue fatty acids, we conducted a study of fish versus n-3 PUFA supplements in women at increased risk of breast cancer. METHODS AND RESULTS High risk women were randomized to comparable doses of marine n-3 PUFAs as canned salmon + albacore or capsules for 3 months. Pre- and posttreatment fatty acid profiles were obtained by GC. Dietary fish (n = 12) and n-3 PUFA capsules (n = 13) yielded increased eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in plasma (p < 0.0001), erythrocyte membranes (p < 0.0001), and breast fat (p < 0.01) at 3 months. Women taking capsules had higher plasma and erythrocyte membrane EPA changes (∼four versus twofold, p = 0.002), without significant differences in DHA. Increases in breast adipose EPA, DHA were similar for both groups. Higher BMI correlated with smaller changes in plasma, erythrocyte membrane EPA, and breast adipose EPA, DHA. Adherence was excellent at 93.9% overall and higher in the fish arm (p = 0.01). CONCLUSION Fish provides an excellent source of n-3 PUFAs that increases breast adipose EPA, DHA similar to supplements and represents a well-tolerated intervention for future studies of the impact of n-3 PUFAs and dietary patterns on breast cancer.

Omega-3 Fatty Acid Plasma Levels Before and After Supplementation: Correlations with Mood and Clinical Outcomes in the Omega-3 and Therapy Studies

OBJECTIVE To examine fatty acid profiles, their response to omega-3 fatty acid (Ω3) supplementation, and associations with clinical status and treatment response in youth with mood disorders. METHODS In a placebo-controlled 2X2 design, 7-14 year-olds (N = 95) in parallel pilot trials (depression N = 72; bipolar N = 23) were randomly assigned to 12 weeks of Ω3 supplementation (1.4 g eicosapentaenoic acid [EPA], 0.2 g docosahexaenoic acid [DHA], and 0.27 g other Ω3 per day); psychoeducational psychotherapy (PEP); their combination; or placebo (mainly oleic and linoleic acid) alone. Blood was drawn at baseline (N = 90) and endpoint (n = 65). Fatty acid levels were expressed as percent of total plasma fatty acids. Correlational and moderator/mediator analyses were done with SPSS Statistics 23. RESULTS At baseline: (1) DHA correlated negatively with alpha-linolenic acid (ALA) (r = -0.23, p = 0.029); (2) Arachidonic acid (AA, Ω6) correlated negatively with global functioning (r = -0.24, p = 0.022); (3) Total Ω3 correlated negatively with age (r = -0.22, p = 0.036) and diastolic blood pressure (r = -0.31, p = 0.006). Moderation: Baseline ALA moderated response to Ω3 supplementation: ALA levels above the sample mean (lower DHA) predicted significantly better placebo-controlled response (p = 0.04). Supplementation effects: Compared to placebo, 2 g Ω3 per day increased EPA blood levels sevenfold and DHA levels by half (both p < 0.001). Body weight correlated inversely with increased EPA (r = -0.52, p = 0.004) and DHA (r = -0.54, p = 0.003) and positively with clinical mood response. Mediation: EPA increase baseline-to-endpoint mediated placebo-controlled global function and depression improvement: the greater the EPA increase, the less the placebo-controlled Ω3 improvement. CONCLUSION Ω3 supplementation at 2 g/day increases blood levels substantially, more so in smaller children. A possible U-shaped response curve should be explored.

Polyunsaturated Fatty Acid (PUFA) Status in Pregnant Women: Associations with Sleep Quality, Inflammation, and Length of Gestation.

Mechanistic pathways linking maternal polyunsaturated fatty acid (PUFA) status with gestational length are poorly delineated. This study examined whether inflammation and sleep quality serve as mediators, focusing on the antiinflammatory ω-3 docosahexaenoic acid (DHA; 22:6n3) and proinflammatory ω-6 arachidonic acid (AA; 20:4n6). Pregnant women (n = 135) provided a blood sample and completed the Pittsburgh Sleep Quality Index (PSQI) at 20–27 weeks gestation. Red blood cell (RBC) fatty acid levels were determined by gas chromatography and serum inflammatory markers [interleukin (IL)-6, IL-8, tumor necrosis factor-α, IL-1β, and C-reactive protein] by electrochemiluminescence using high sensitivity kits. Both higher serum IL-8 (95% CI = 0.10,3.84) and poor sleep (95% CI = 0.03,0.28) served as significant mediators linking lower DHA:AA ratios with shorter gestation. Further, a serial mediation model moving from the DHA:AA ratio → sleep → IL-8 → length of gestation was statistically significant (95% CI = 0.02, 0.79). These relationships remained after adjusting for depressive symptoms, age, BMI, income, race, and smoking. No interactions with race were observed in relation to length of gestation as a continuous variable. However, a significant interaction between race and the DHA:AA ratio in predicting preterm birth was observed (p = 0.049); among African Americans only, odds of preterm birth decreased as DHA:AA increased (p = 0.048). These data support a role for both inflammatory pathways and sleep quality in linking less optimal RBC PUFA status with shorter gestation in African American and European American women and suggest that African-Americans have greater risk for preterm birth in the context of a low DHA:AA ratio.

Citrus flavonoid naringenin reduces mammary tumor cell viability, adipose mass, and adipose inflammation in obese ovariectomized mice

SCOPE Obesity-related metabolic dysregulation may be a link between obesity and postmenopausal breast cancer. Naringenin, a flavonoid abundant in grapefruits, displays beneficial effects on metabolic health and tumorigenesis. Here, we assessed the effects of naringenin on mammary tumor cell growth in vitro and in obese ovariectomized mice. METHODS AND RESULTS Naringenin inhibited cell growth, increased phosphorylation of AMP-activated protein kinase (AMPK), down-regulated CyclinD1 expression, and induced cell death in E0771 mammary tumor cells. Obese ovariectomized mice were fed a high-fat (HF), high-fat diet with low naringenin (LN; 1% naringenin) or high-fat diet with high naringenin (HN; 3% naringenin) for 2 weeks and then implanted with E0771 cells in mammary adipose tissue. Three weeks after tumor cell implantation, naringenin accumulation in tumor was higher than that in mammary adipose tissue in HN mice. HN decreased body weight, adipose mass, adipocyte size, α-smooth muscle actin mRNA in mammary adipose tissue, and mRNA of inflammatory cytokines in both mammary and perigonadal adipose tissues. Compared with mice fed HF diet, HN delayed growth of tumors early but did not alter final tumor weight. CONCLUSION Naringenin reduces adiposity and ameliorates adipose tissue inflammation, with a moderate inhibitory effect on tumor growth in obese ovariectomized mice.