Higher dietary intake of alpha-linolenic acid is associated with lower insulin resistance in middle-aged Japanese

Muramatsu, Takashi; Yatsuya, Hiroshi; Toyoshima, Hideaki; Sasaki, Satoshi; Li, Yuanying; Otsuka, Rei; Wada, Keiko; Hotta, Yo; Mitsuhashi, Hirotsugu; Matsushita, Kunihiro; Murohara, Toyoaki; Koji, Takehiko

doi:10.1016/j.ypmed.2010.02.014

Cited by 42 publications

(29 citation statements)

References 42 publications

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“…We observed no clear associations of marine fatty acids intake with prevalence of impaired glucose metabolism and insulin resistance in a Japanese population. Our finding agreed with that of a cross-sectional study in Japan showing no significant associations of EPA+DHA with insulin resistance [28]. Similarly, a recent meta-analysis of randomized control trials during 2 months to 6 months showed n-3 PUFA had no effects on insulin sensitivity [30].…”

Section: Discussionsupporting

confidence: 92%

“…As regards insulin resistance, we found no clear association between ALA and HOMA-IR. In contrast, a Japanese study of middle-aged employees showed that higher ALA intake was significantly associated with a lower prevalence of insulin resistance among normal weight subjects [28]. Although ALA might be related to lower risk of type 2 diabetes, the underlying mechanism should be clarified.…”

Section: Discussionmentioning

confidence: 91%

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Plant Oils Were Associated with Low Prevalence of Impaired Glucose Metabolism in Japanese Workers

Kurotani

Kochi²,

Nanri³

et al. 2013

PLoS ONE

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Fatty acid has been suggested to be involved in development of diabetes. However, its association is unclear among Japanese populations, which consume large amounts of fish rich in n-3 polyunsaturated fatty acids. The present cross-sectional study examined the association of individual dietary fatty acids and dietary fatty acid patterns with abnormal glucose metabolism among 1065 Japanese employees, aged 18–69 years. Impaired glucose metabolism is defined if a person has a history of diabetes, current use of anti-diabetic drug, fasting plasma glucose of 110 mg/dl (≥6.1 mmol/L) or greater, or hemoglobin A1C of 6.0% (≥42 mmol/mol) or greater. Dietary intake was assessed with a self-administered diet history questionnaire. Dietary fatty acid patterns were extracted by principal component analysis. Odds ratios of impaired glucose metabolism according to tertile categories of each fatty acids and dietary fatty acid patterns were estimated using logistic regression with adjustment for potential confounding variables. A higher intake of polyunsaturated fatty acid, n-6 fatty acid, linoleic acid, and oleic acid were significantly associated with a decreased prevalence of impaired glucose metabolism (P for trend = 0.03, 0.01, 0.02, and 0.04, respectively). Alpha-linolenic acid was marginally significantly associated with a decreased prevalence of impaired glucose metabolism (P for trend = 0.12). Of three fatty acid patterns identified, a higher plant oil pattern score, which characterized by high intake of alpha-linolenic acid, linoleic acid, and oleic acid, was associated with a decreased prevalence of impaired glucose metabolism (P for trend = 0.03). No association was observed for other patterns. In conclusion, plant source fatty acids might be protectively associated with development of diabetes in Japanese adults.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 91%

Plant Oils Were Associated with Low Prevalence of Impaired Glucose Metabolism in Japanese Workers

Kurotani

Kochi²,

Nanri³

et al. 2013

PLoS ONE

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“…Human studies provide evidence that dietary ALA supplementation by means of flaxseed oil and/or walnut consumption increases serum EPA and DHA concentrations [33–35], indicating conversion of ALA into longer chain fatty acids in vivo. Provided adequate amount and duration of consumption, dietary ALA may also reduce inflammation [35–37] and improve insulin resistance [38,39], i.e., two factors involved in colorectal cancer progression [2]. Flaxseed oil provides more than five times more ALA than walnuts [35] and, in our study, led to an inversed n-6/n-3 ratio in the diet (1:5), which was much different than that of the walnut diet (6.4:1).…”

Section: Discussionmentioning

confidence: 99%

Dietary walnuts inhibit colorectal cancer growth in mice by suppressing angiogenesis

et al. 2012

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Objective Animal studies have demonstrated that dietary supplementation with flaxseed oil inhibits colorectal cancer growth. Recent data indicate that walnuts have strong antiproliferative properties against colon cancer cells in vitro but no previous study has assessed the effects of walnuts in vivo or performed a joint evaluation of flaxseed oil and walnuts. The aim of the present study was to examine the effect of dietary walnuts on colorectal cancer in vivo and to comparatively evaluate their efficacy in relation to flaxseed oil. Methods HT-29 human colon cancer cells were injected in 6-wk-old female nude mice. After a 1-wk acclimation period, mice (n = 48) were randomized to diets containing ~ 19% of total energy from walnuts, flaxseed oil, or corn oil (control) and were subsequently studied for 25 d. Results Tumor growth rate was significantly slower in walnut-fed and flaxseed-fed mice compared with corn oil-fed animals (P < 0.05) by 27% and 43%, respectively. Accordingly, final tumor weight was reduced by 33% and 44%, respectively (P < 0.05 versus control); the differences between walnut and flaxseed diets did not reach significance. We found no differences among groups in metabolic and hormonal profile, serum antioxidant capacity, or inflammation (P > 0.05). However, walnuts and flaxseed oil significantly reduced serum expression levels of angiogenesis factors, including vascular endothelial growth factor (by 30% and 80%, respectively), and approximately doubled total necrotic areas despite smaller tumor sizes (P < 0.05 versus control). Dietary walnuts significantly decreased angiogenesis (CD34 staining; P = 0.017 versus control), whereas this effect did not reach significance in the flaxseed oil group (P = 0.454 versus control). Conclusion We conclude that walnuts in the diet inhibit colorectal cancer growth by suppressing angiogenesis. Further studies are needed to confirm our findings in humans and explore underlying mechanisms.

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“…Conversely, certain n-3 PUFA such as α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to improve glucose homeostasis and provide protective effects against the development of IR by increasing production of insulin-sensitizing adipokines (e.g. adiponectin) and reducing the pro-inflammatory state of adipocytes and macrophages [9-11]. This reinforces that the associations between individual FA and the development of IR are distinct.…”

Section: Introductionmentioning

confidence: 99%

Ethnic- and sex-specific associations between plasma fatty acids and markers of insulin resistance in healthy young adults

et al. 2013

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BackgroundAlthough evidence indicates that fatty acids (FA) can affect insulin resistance (IR), not all FA contribute equally to the process. Indeed, monounsaturated FA (MUFA) and polyunsaturated FA (PUFA) are reported to reduce IR, whereas saturated FA (SFA) and trans FA appear to increase IR. However, it is not yet clear how individual FA are associated with markers of IR, and whether these relationships are influenced by ethnicity and/or sex. Therefore, the goal of this study was to examine the ethnic- and sex-specific relationships between plasma FA and markers of IR in a cohort of healthy young Caucasian, East Asian, and South Asian adults.MethodsGas chromatography was used to quantify fasting plasma FA from young Canadian adults (22.6 ± 0.1 yrs) of Caucasian (n = 461), East Asian (n = 362), or South Asian (n = 104) descent. Linear regression models were used to investigate associations between plasma FA and markers of IR (i.e. fasting insulin, glucose, and HOMA-IR) according to ethnicity and sex.ResultsNumerous significant associations (P < 0.05, adjusted for multiple testing) were identified between individual FA and markers of IR, with the majority identified in Caucasians. For SFA, positive associations were found between 14:0 and fasting insulin and HOMA-IR in Caucasian and East Asian populations, and 18:0 and fasting glucose in Caucasians only. Several positive associations were also found for specific MUFA (18:1t11 and 18:1t6-8 with HOMA-IR, and 18:1c9 with fasting glucose) and PUFA (18:2n6 with fasting glucose and 18:2c9t11 with HOMA-IR) in Caucasian adults only. Most of the aforementioned associations were stronger in males compared to females. Interestingly, no significant associations were found between FA and markers of IR in South Asian adults.ConclusionsWe report numerous associations between plasma FA and markers of IR in Caucasian and East Asian populations, but not in South Asian individuals. Furthermore, these associations appeared to be more robust in men. This demonstrates the importance of investigating associations between FA and markers of IR in an ethnic- and sex-specific manner in order to better understand the contribution of plasma FA to the development of IR and type-2 diabetes.

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Higher dietary intake of alpha-linolenic acid is associated with lower insulin resistance in middle-aged Japanese

Cited by 42 publications

References 42 publications

Plant Oils Were Associated with Low Prevalence of Impaired Glucose Metabolism in Japanese Workers

Plant Oils Were Associated with Low Prevalence of Impaired Glucose Metabolism in Japanese Workers

Dietary walnuts inhibit colorectal cancer growth in mice by suppressing angiogenesis

Ethnic- and sex-specific associations between plasma fatty acids and markers of insulin resistance in healthy young adults

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