Whole flaxseeds but not sunflower seeds in rye bread reduce apparent digestibility of fat in healthy volunteers

Influence of Flaxseed (Linum usitatissimum) on Female Reproduction

This review describes the chemical composition of flaxseed (Linum usitatissimum) and its general health effects, as well as the currently available knowledge concerning its action on the female reproductive state, functions on the ovary and ovarian cells and reproductive hormones, as well as possible constituents and extra- and intracellular mediators mediating its effects on female reproductive processes. Flaxseed contains a number of biologically active molecules, which, acting through multiple signalling pathways, can determine numerous physiological, protective and therapeutic effects of flaxseed. The available publications demonstrate the action of flaxseed and its constituents on the female reproductive system - ovarian growth, follicle development, the resulting puberty and reproductive cycles, ovarian cell proliferation and apoptosis, oo- and embryogenesis, hormonal regulators of reproductive processes and their dysfunctions. These effects can be determined by flaxseed lignans, alpha-linolenic acid and their products. Their actions can be mediated by changes in general metabolism, metabolic and reproductive hormones, their binding proteins, receptors and several intracellular signalling pathways, including protein kinases, transcription factors regulating cell proliferation, apoptosis, angiogenesis and malignant transformation. Flaxseed and its active molecules are found potentially useful for improving farm animal reproductive efficiency and treatment of polycystic ovarian syndrome and ovarian cancer.

Dietary Ground Flaxseed Increases Serum Alpha-Linolenic Acid Concentrations in Adult Cats

We evaluated effects of dietary ground flaxseed on fecal and serum alpha-linolenic acid (ALA) concentrations, nutrient digestibility, and stool quality in female and male adult cats (n = 20 (8 males, 12 females); 3.95 ± 1.49 years of age (mean ± SD); 3.88 ± 0.82 kg BW). We hypothesized that adding ground flaxseed would increase serum ALA compared with feeding no flax, without changing nutrient digestibility. Cats were fed as-is 2.6% added-flaxseed (flax, n = 10) or no-flax (control, n = 10) diets (2.66 vs. 0.78% ALA of total fatty acids; crude protein 35%, fat 20%, fiber 3% as-fed) twice daily to maintain body weight for 28 days. Fecal collections were conducted on days 23−27 for total-tract nutrient digestibility, stool quality (scale 1−5; 1 = watery diarrhea, 5 = hard, dry, crumbly) and long-chain fatty acid (LCFA) analyses. Blood was collected on days 0, 14, and 28 for serum LCFA and chemistry analysis. Digestibility and fecal data were analyzed by ANOVA (SAS v9.4, Cary, NC, USA) and a repeated measures ANOVA for serum ALA. Flax-fed cats, compared with control-fed, had greater (p < 0.05) serum ALA after 14 days (4.00 vs. 0.71 µg/mL) and 28 days (7.83 and 3.67 µg/mL). No differences were observed in stool quality, and dry matter, protein, fat, and ALA digestibility. However, metabolizable energy was greater in the flax vs. control diet (4.18 vs. 3.91 kcal/g; p < 0.05). Overall, these data demonstrate that ground flaxseed added to cat diets increases serum ALA within 14 days, with no detriments to nutrient digestibility. We conclude that flaxseed can be used as a bioavailable source of ALA in cat diets.

Plant-Based Food By-Products: Prospects for Valorisation in Functional Bread Development

The industrial and small-scale processing of plant-based food materials is associated with by-products that may have a negative impact on the environment but could add value to bread-based products. The bioactivity of plant-based food by-products, their impact on the properties of functional bread, and their bioavailability/bioaccessibility leading to potential health effects when consumed was reviewed. Plant-based food by-products which may be added to bread include rice bran, wheat bran, corn bran, grape pomace/seed extract, tomato seed/skin, and artichoke stems/leaves. These by-products contain high concentrations of bioactive compounds, including phenolics, bioactive peptides, and arabinoxylan. Pre-treatment procedures, including fermentation and thermal processing, impact the properties of plant-based by-products. In most cases, bread formulated with flour from plant-based by-products demonstrated increased fibre and bioactive compound contents. In terms of the sensory and nutritional acceptability of bread, formulations with an average of 5% flour from plant-based by-products produced bread with acceptable sensory properties. Bread enriched with plant-based by-products demonstrated enhanced bioavailability and bioaccessibility and favourable bioactive properties in human blood, although long-term studies are warranted. There is a need to investigate the bioactive properties of other underutilised plant-based by-products and their potential application in bread as a sustainable approach towards improving food and nutrition security.

Flaxseed for Health and Disease: Review of Clinical Trials

BACKGROUND

Flaxseed (Linum usitatissimum) is an oil-based seed that contains high amounts of alpha-linolenic acid, linoleic acid, lignans, fiber and many other bioactive components which is suggested for a healthier life. Nowadays, flaxseed is known as a remarkable functional food with different health benefits for humans and protects against cardiovascular disease, diabetes, dyslipidemia, obesity and altogether metabolic syndrome.

METHODS

To review the bioactive components of flaxseed and their potential health effects, PubMed and Scopus were searched from commencement to July 2019. Keywords including: "flaxseed", "Linum usitatissimum", "metabolic syndrome", "obesity", "inflammation", "insulin resistance", "diabetes", "hyperlipidemia" and "menopause" were searched in the databases with varying combinations.

CONCLUSION

Consumption of flaxseed in different forms has valuable effects and protects against cardiovascular disease, hypertension, diabetes, dyslipidemia, inflammation and some other complications. Flaxseed can serve as a promising candidate for the management of metabolic syndrome to control blood lipid levels, fasting blood sugar, insulin resistance, body weight, waist circumference, body mass and blood pressure.

Flaxseed Supplementation Improves Anthropometric measurements, Metabolic, and Inflammatory Biomarkers in Overweight and Obese Adults

Abstract. Background: The aim of this study was to assess the effects of supplementation with flaxseed on anthropometric measurements, lipid profile, insulin resistance, and inflammatory biomarkers in overweight and obese adults.

Methods: Fifty overweight and obese adults with body mass index (BMI) of 30.72 ± 3.31 kg/m2 participated in this study. Participants were randomly assigned to take lifestyle advice or lifestyle advice plus 30 g/day milled flaxseed for 12 weeks. The primary outcome was body weight; secondary outcomes included other anthropometric parameters, lipid profile and inflammatory biomarkers.

Results: At the end of the study, the following significant mean differences were seen in flaxseed and control groups, respectively: weight [−9.36 vs. −3.09 kg; P < 0.001], BMI [−3.34 vs. −1.2 kg/m2; P < 0.001], triglyceride [−62.88 vs. −9.85 mg/dL; P < 0.001], total cholesterol [−32.2 vs. −14.95; P = 0.04], homeostatic model assessment (HOMA-IR) [1.25 vs. −0.32; P = 0.024], high sensitive- C reactive protein [−2.2 vs. −1.01 mmol/L; P < 0.001] and tumor necrosis factor-α [−1.34 vs. −0.14 Pg/mL; P = 0.005].

Conclusion: These results suggest that flaxseed supplementation in addition to lifestyle modification is significantly superior to lifestyle modification alone for weight loss. More studies with different dosages of flaxseed are needed to find the optimal dosage. This trial was registered at clinicaltrials.gov as NCT02410668.

Influence of food structure on dairy protein, lipid and calcium bioavailability: A narrative review of evidence

Beyond nutrient composition matrix plays an important role on food health potential, notably acting on the kinetics of nutrient release, and finally on their bioavailability. This is particularly true for dairy products that present both solid (cheeses), semi-solid (yogurts) and liquid (milks) matrices. The main objective of this narrative review has been to synthesize available data in relation with the impact of physical structure of main dairy matrices on nutrient bio-accessibility, bioavailability and metabolic effects, in vitro, in animals and in humans. Focus has been made on dairy nutrients the most studied, i.e., proteins, lipids and calcium. Data collected show different kinetics of bioavailability of amino acids, fatty acids and calcium according to the physicochemical parameters of these matrices, including compactness, hardness, elasticity, protein/lipid ratio, P/Ca ratio, effect of ferments, size of fat globules, and possibly other qualitative parameters yet to be discovered. This could be of great interest for the development of innovative dairy products for older populations, sometimes in protein denutrition or with poor dentition, involving the development of dairy matrices with optimized metabolic effects by playing on gastric retention time and thus on the kinetics of release of the amino acids within bloodstream.

Wholegrain rye, but not wholegrain wheat, lowers body weight and fat mass compared with refined wheat: a 6-week randomized study

BACKGROUND

Observational studies suggest inverse associations between wholegrain intake and body weight gain. Only few controlled intervention studies have supported this association and few compare effects of different grain varieties.

OBJECTIVE

To investigate how wholegrain wheat (WGW) and rye compared with refined wheat (RW) affect body weight and composition and appetite sensation.

DESIGN

Seventy overweight/obese adults participated in this 6-week randomized parallel study, in which they replaced their habitual cereal foods with RW, WGW or wholegrain rye (WGR). Further, a 4 h postprandial test meal challenge was completed with meals corresponding to diet allocation in the beginning and after the intervention. Body weight and composition, fasted blood samples, compliance and 4-day dietary intake were obtained before and after the intervention period. Appetite and breath hydrogen excretion was assessed during the postprandial test meal challenge.

RESULTS

Diet allocation affected body weight significantly (P=0.013) and tended also to affect fat mass (P=0.065). Both body weight and fat mass decreased more in the WGR group (-1.06±1.60 and -0.75±1.29 kg, respectively) compared with the RW group (+0.15±1.28 and -0.04±0.82 kg, respectively; P<0.01 and P<0.05, respectively). Further, the decrease in fat mass in the WGR group tended to exceed that in the WGW group (P=0.07). Overall, no effect of diet on appetite sensation was observed; however, energy intake from study products was ~200 kcal lower in the WGR group when compared with that in the RW group (P<0.05), although total energy intake did not differ between groups.

CONCLUSIONS

Our results support a role for WGR foods in body weight regulation, when provided ad libitum. The effect may be mediated by satiation reflected in a reduction in energy intake, mainly from the wholegrain products without compensation in other parts of the diets, despite no difference in appetite.

Supplementation with dairy calcium and/or flaxseed fibers in conjunction with orlistat augments fecal fat excretion without altering ratings of gastrointestinal comfort

Background

Orlistat is a lipase inhibitor which reduced absorption of dietary fat by ~30% thereby inducing a weight loss; however, side effects occur as a consequence of increased colonic fat content. To test the hypothesis that most gastrointestinal side events induced by treatment with orlistat could be prevented/ameliorated by concomitant use of natural dietary components, flaxseed fiber (FF) and/or dairy calcium (Ca), binding liquid fats to more solid complexes.

Methods

A randomized controlled dietary intervention study. Thirty-eight obese adults completed a 1-week run-in period, where all participants were treated with orlistat (60 mg t.i.d) and were hereafter randomized to 12 weeks dietary supplementation with/without 5 g FF (FF+/FF-) and/or 1200 mg dairy calcium (Ca+/Ca-) in conjunction with orlistat. All feces were collected for 3 days, and diet was recorded for 5 days, during run-in and week 4. The primary end-point, gastrointestinal symptoms, was assessed biweekly. At baseline and after 12 weeks, cardiometabolic risk markers and anthropometrics were evaluated as secondary end-points.

Results

Both FF and Ca increased fecal fat excretion (P = 0.02 and P = 0.04, respectively). Although fecal fat excretion increased by ~100% in the FF+/Ca + group, and only by ~12% in the FF-/Ca + group, no interaction between FF and Ca was present, suggesting an additive effect. The fecal fat excretion was ~10 g/d higher with FF and Ca (~25 g/d) compared to fecal fat excretion with orlistat alone (~15 g/d). Mean ratings of severity of diarrhea tended to increase with Ca (P = 0.03) but not with FF. No other gastrointestinal symptoms, or a composite score of symptoms, were affected by the dietary supplements. Body weight was reduced in all groups but did not differ between groups, whereas waist circumference was most reduced in the FF+/Ca + group. No effects of dietary supplements on cardiometabolic risk factors were observed, except a slight increase in diastolic blood pressure (P = 0.03) with FF, but not Ca.

Conclusions

Our results do not support an improvement in orlistat-induced gastrointestinal side effects by concomitant use of FF and Ca. However, fecal fat excretion was increased with both FF and Ca in the absence of a worsening of symptoms, warranting further studies powered to detect potential additive weight loss effects.

Trial registration

Ethical Committee of the Capital Region of Denmark reg. no. H-1-2010-110, 02-11-2010 database no. NCT01320228, 21-03-2011.

Electronic supplementary material

The online version of this article (doi:10.1186/s12986-017-0164-8) contains supplementary material, which is available to authorized users.

Dietary supplementation with flaxseed mucilage alone or in combination with calcium in dogs: effects on apparent digestibility of fat and energy and fecal characteristics

BACKGROUND

In humans, dietary supplementation with flaxseed mucilage and calcium decrease apparent digestibility of fat and energy. These supplements could prove useful for weight management in dogs.

OBJECTIVE

To examine dry matter, energy and fat apparent digestibility, and fecal characteristics following dietary flaxseed mucilage supplementation alone or in combination with calcium.

METHODS

A single-blinded crossover feeding trial was conducted on 11 privately owned dogs. During three consecutive 14-day periods, dogs where fed commercial dog food supplemented with potato starch (control diet), flaxseed mucilage or flaxseed mucilage and calcium. Feces from the past 2 days of each period were collected for analysis. Owners recorded fecal score (1-7: 1=very hard/dry feces, 2-3=ideal and 7=diarrhea).

RESULTS

Apparent digestibility of fat was lower in both flaxseed mucilage diet (94.5±0.8%), and flaxseed mucilage and calcium diet (92.9±0.9%) compared with control diet (96.9±0.2%, P<0.0001) with fat digestibility in flaxseed mucilage and calcium diet being significantly lower than the diet supplemented with only flaxseed mucilage. Dry matter and energy digestibility was not significantly affected by diet. Fecal wet weight, dry weight and dry matter percentage was not affected by diet despite a higher fecal score for test diets (3.7±0.3) compared with control (2.8±0.2, P<0.007).

CONCLUSION

In dogs, flaxseed mucilage decreased fat apparent digestibility and this effect was enhanced when combined with calcium. Dry matter and energy apparent digestibility was not affected. Decreased fecal quality may limit the acceptable level of supplementation. Further studies on incorporating flaxseed mucilage in pet food products for weight management are needed.

High-fiber rye diet increases ileal excretion of energy and macronutrients compared with low-fiber wheat diet independent of meal frequency in ileostomy subjects

Background

Whole-grain foods and cereal dietary fiber intake is associated with lower body weight. This may partly result from lower energy utilization of high-fiber diets.

Objective

In the present study, the impact on ileal excretion of energy and macronutrients in response to a rye bread high-fiber diet compared to a refined wheat low-fiber diet was investigated. Furthermore, the effect of meal frequency on apparent absorption of nutrients was studied for the first time.

Design

Ten participants that had undergone ileostomy consumed standardized iso-caloric diets, including low-fiber wheat bread (20 g dietary fiber per day) for 2 weeks followed by high-fiber rye bread (52 g dietary fiber per day) for 2 weeks. The diets were consumed in an ordinary (three meals per day) and a nibbling (seven meals per day) meal frequency in a cross-over design. Ileal effluents were collected during 24 h at the third day of each of the four dietary periods and analyzed for gross energy and nutrient contents.

Results

The results showed that intake of rye bread high-fiber diet compared to the refined wheat low-fiber diet caused an increase in ileal excretion of energy and macronutrients. The effect was independent of meal frequency. This suggests that a high intake of rye may result in lower availability of macronutrients for small intestinal digestion and absorption. A regular intake of rye may therefore have implications for weight management.

Linseed dietary fibers reduce apparent digestibility of energy and fat and weight gain in growing rats

Dietary fibers (DF) may affect energy balance, an effect often ascribed to the viscous nature of some water soluble DF, which affect luminal viscosity and thus multiple physiological processes. We have tested the hypothesis that viscous linseed DF reduce apparent nutrient digestibility, and limit weight gain, in a randomized feeding trial where 60 male, growing, Wistar rats, with an initial weight of ~200 g, were fed different diets (n = 10 per group): low DF control (C), 5% DF from cellulose (5-CEL), CEL + 5% DF from whole (5-WL) or ground linseed (5-GL), CEL + 5% DF from linseed DF extract (5-LDF), and CEL + 10% DF from linseed DF extract (10-LDF). Diets were provided ad libitum for 21 days. Feed intake and faecal output were measured during days 17-21. Faecal fat excretion increased with increasing DF content and was highest in the 10-LDF group. Apparent fat digestibility was highest with the C diet (94.9% ± 0.8%) and lowest (74.3% ± 0.6%) with the 10-LDF diet, and decreased in a non-linear manner with increasing DF (p < 0.001). Apparent fat digestibility also decreased with increased accessibility of DF (5-WL vs. 5-GL) and when the proportion of viscous DF increased (5-GL vs. 5-LDF). The 10-LDF resulted in a lower final body weight (258 ± 6.2 g) compared to C (282 ± 5.9 g), 5-CEL (281 ± 5.9 g), and 5-WL (285 ± 5.9 g) (p < 0.05). The 10-LDF diet reduced body fat compared to 5-CEL (p < 0.01). In conclusion, DF extracted from linseed reduced apparent energy and fat digestibility and resulted in restriction of body weight gain in growing rats.

Flaxseed dietary fibers suppress postprandial lipemia and appetite sensation in young men

BACKGROUND AND AIM

Dietary fibers (DF) are linked to a reduced risk of life-style diseases, which relate to their physiological effects in the gastrointestinal tract. The aim was to examine whether flaxseed DF-enriched meals suppress postprandial lipemia and reduce appetite.

METHODS AND RESULTS

Four different iso-caloric meals were tested in 18 young men in a double-blind randomized crossover design. Test meals were served after an overnight fast. DF content and source were: control (C): 1.4 g/MJ; whole flaxseed (WF): 2.4 g/MJ from whole flaxseeds; low-mucilage dose (LM): 2.4 g/MJ from flaxseed DF; high-mucilage dose (HM): 3.4 g/MJ from flaxseed DF. During the 7 h test day, subjective appetite sensation was assessed using visual analogue scales and appetite-regulating hormones, and lipemia and glycemia were measured, after which ad libitum energy intake was recorded. There was a significant time × meal effect on triacylglycerols (TG) (p = 0.02) and an 18% smaller area under the curve (AUC) for TG after meal HM compared to meal C was observed (p < 0.01). AUC for insulin was smaller after both LM and HM meals compared to C and WF meals. Higher mean ratings of satiety (p < 0.01) and fullness (p = 0.03) was seen following the HM meal compared to meal C. AUC for ghrelin, CCK and GLP-1 and ad libitum energy intake did not differ between meals, but ghrelin response exhibited a different response pattern after the mucilage-containing meals.

CONCLUSION

These findings suggest that flaxseed DF may suppress postprandial lipemia and appetite although subsequent energy intake was not affected.

Flaxseed dietary fibers lower cholesterol and increase fecal fat excretion, but magnitude of effect depend on food type

Background

Dietary fibers have been proposed to play a role in cardiovascular risk as well as body weight management. Flaxseeds are a good source of dietary fibers, and a large proportion of these are water-soluble viscous fibers.

Method

Here, we examine the effect of flaxseed dietary fibers in different food matrices on blood lipids and fecal excretion of fat and energy in a double-blind randomized crossover study with 17 subjects. Three different 7-d diets were tested: a low-fiber control diet (Control), a diet with flaxseed fiber drink (3/day) (Flax drink), and a diet with flaxseed fiber bread (3/day) (Flax bread). Total fat and energy excretion was measured in feces, blood samples were collected before and after each period, and appetite sensation registered 3 times daily before main meals.

Results

Compared to control, Flax drink lowered fasting total-cholesterol and LDL-cholesterol by 12 and 15%, respectively, (p < 0.01), whereas Flax bread only produced a reduction of 7 and 9%, respectively (p < 0.05). Fecal fat and energy excretion increased by 50 and 23% with Flax drink consumption compared to control (p < 0.05), but only fecal fat excretion was increased with Flax bread compared to control (p < 0.05).

Conclusion

Both Flax drink and Flax bread resulted in decreased plasma total and LDL-cholesterol and increased fat excretion, but the food matrix and/or processing may be of importance. Viscous flaxseed dietary fibers may be a useful tool for lowering blood cholesterol and potentially play a role in energy balance.

Trial Registration

ClinicalTrials.gov: NCT00953004

Effects of dietary fibre on subjective appetite, energy intake and body weight: a systematic review of randomized controlled trials

Dietary fibres are believed to reduce subjective appetite, energy intake and body weight. However, different types of dietary fibre may affect these outcomes differently. The aim of this review was to systematically investigate the available literature on the relationship between dietary fibre types, appetite, acute and long-term energy intake, and body weight. Fibres were grouped according to chemical structure and physicochemical properties (viscosity, solubility and fermentability). Effect rates were calculated as the proportion of all fibre-control comparisons that reduced appetite (n = 58 comparisons), acute energy intake (n = 26), long-term energy intake (n = 38) or body weight (n = 66). For appetite, acute energy intake, long-term energy intake and body weight, there were clear differences in effect rates depending on chemical structure. Interestingly, fibres characterized as being more viscous (e.g. pectins, β-glucans and guar gum) reduced appetite more often than those less viscous fibres (59% vs. 14%), which also applied to acute energy intake (69% vs. 30%). Overall, effects on energy intake and body weight were relatively small, and distinct dose-response relationships were not observed. Short- and long-term effects of dietary fibres appear to differ and multiple mechanisms relating to their different physicochemical properties seem to interplay. This warrants further exploration.