Effect of the amount and type of dietary fat on cardiometabolic risk factors and risk of developing type 2 diabetes, cardiovascular diseases, and cancer: a systematic review

Abstract

The effects of both the amount and quality of dietary fat have been studied intensively during the past decades. Previously, low-fat diets were recommended without much attention to the quality of fat, whereas there is general emphasis on the quality of fat in current guidelines. The objective of this systematic review (SR) was to assess the evidence of an effect of the amount and type of dietary fat on body weight (BW), risk factors, and risk of non-communicable diseases, that is, type 2 diabetes (T2DM), cardiovascular diseases (CVD), and cancer in healthy subjects or subjects at risk for these diseases. This work was performed in the process of updating the fourth edition of the Nordic Nutrition Recommendations from 2004. The literature search was performed in October 2010 covering articles published since January 2000. A complementary search was done in February 2012 covering literature until December 2011. Two authors independently selected articles for inclusion from a total of about 16,000 abstracts according to predefined criteria. Randomized controlled trials (RCT) and prospective cohort studies (PCS) were included as well as nested case–control studies. A few retrospective case–control studies were also included when limited or no data were available from other study types. Altogether 607 articles were quality graded and the observed effects in these papers were summarized. Convincing evidence was found that partial replacement of saturated fat (SFA) with polyunsaturated fat (PUFA) or monounsaturated fat (MUFA) lowers fasting serum/plasma total and LDL cholesterol concentrations. The evidence was probable for a decreasing effect of fish oil on concentration of serum/plasma total triglycerides as compared with MUFA. Beneficial effect of MUFA both on insulin sensitivity and fasting plasma/serum insulin concentration was considered as probable in comparisons of MUFA and carbohydrates versus SFA, whereas no effect was found on fasting glucose concentration in these comparisons. There was probable evidence for a moderate direct association between total fat intake and BW. Furthermore, there was convincing evidence that partial replacement of SFA with PUFA decreases the risk of CVD, especially in men. This finding was supported by an association with biomarkers of PUFA intake; the evidence of a beneficial effect of dietary total PUFA, n-6 PUFA, and linoleic acid (LA) on CVD mortality was limited suggestive. Evidence for a direct association between total fat intake and risk of T2DM was inconclusive, whereas there was limited-suggestive evidence from biomarker studies that LA is inversely associated with the risk of T2DM. However, there was limited-suggestive evidence in biomarker studies that odd-chain SFA found in milk fat and fish may be inversely related to T2DM, but these associations have not been supported by controlled studies. The evidence for an association between dietary n-3 PUFA and T2DM was inconclusive. Evidence for effects of fat on major types of cancer was inconclusive regarding both the amoun...

Misvisende om kosthold i ny nasjonal retningslinje for forebygging av hjerte- og karsykdommer

“…I forbindelse med NNR 2012 ble det gjort en systematisk kunnskapsoppsummering av litteratur fra januar 2000 til og med februar 2012 om fett og risikofaktorer og sykdomsendepunkter (hjerte-og karsykdom, diabetes type 2, kreft og overvekt), med henblikk på primaerforebygging. Sammenhengene mellom respektive eksponeringer og sykdommer ble klassifisert som «overbevisende», «sannsynlig», «mulig» og «usannsyn-lig» 16 .…”

“…Effekter av mettet fett på kausale risikofaktorer for hjerte-og karsykdom ble undersøkt i seks systematiske oversiktsartikler 16,157,[168][169][170] . I tillegg inkluderte vi en metaanalyse av Mensink som var publisert av WHO i 2016 147 .…”

“…4. Den ovennevnte systematiske oversikten av Schwab og medarbeidere 16 omhandlet også effekten av fett og fettsyrer på risikofaktorer. Totalt 45 studier som rapporterte effekter på blodlipider ble inkludert.…”

“…En årsakssam-menheng mellom totalt fettinntak og kreft totalt var usannsynlig. Mettet fett har videre en mulig sammenheng med økt risiko for eggstokkreft, ifølge Schwab og medarbeideres kunnskapsoppsummering fra 2014 for NNR 16 .…”

Mindre sitting – bedre helse?

“…Systematiske litteraturoversikter over intervensjonsstudier tyder på at en begrensning i kostens totale fettinnhold kan redusere risikoen for vektøkning (14), mens litteraturoversikter over befolkningsstudier tyder på at kostens totale fettinnhold ikke har noen sammenheng med kroppsvekten i befolkningen generelt (15). Kostens totale fettinnhold anbefales å utgjøre mellom 25 og 40 energiprosent.…”