Should Our Dietary Fats Be More Saturated Or Unsaturated?

The jury’s still out, but the editors at The Evolution and Medicine Review discuss dietary fat effects on gut microbiota and systemic inflammation.  The authors tend to favor unsaturated fats at this point.

2 responses to “Should Our Dietary Fats Be More Saturated Or Unsaturated?

  1. This is the high-fat diet the mice were fed by Mujico et al.
    Casein 265.0 􀁺
    L-Cystine 4.0 􀁺
    Maltodextrin 160.0
    Sucrose 90.0
    Lard 310.0
    Soybean Oil 30.0
    Cellulose 65.5
    Mineral Mix, AIN-93G-MX (94046) 48.0
    Calcium Phosphate, dibasic 3.4
    Vitamin Mix, AIN-93-VX (94047) 21.0
    Choline Bitartrate 3.0
    Blue Food Color 0.1

    Processed food, 100%, in other words.
    the Alcock paper says “modern dietary habits – including overnutrition and exposure to certain nutrients and processed foods – contribute to chronic inflammatory diseases”.
    But the Mujilo paper makes no attempt to separate “processed foods” from “certain nutrients”. All carbs, fats, protein are presented as extrinsic nutrients, as are fibre, vitamins and minerals. There are zero phospholipids, instead a mixture of trigycerides and choline is substituted.

    Is it never possible to compare foods as they are eaten?
    This menu resembles a convenience diet (such as baked goods made with shortening, fortified flour and dairy) more closely than it resembles a high-fat paleo diet, methinks.


    (Again with the processed food and extrinsic nutrients)

    Controversies have emerged regarding the beneficial v. detrimental effects of dietary n-6 PUFA. The alteration of the intestinal microbiota, a phenomenon termed dysbiosis, occurs during several chronic inflammatory diseases, but has not been well studied in an aged population. With present ‘Western’ diets predominantly composed of n-6 PUFA, we hypothesised that PUFA-rich diets cause intestinal dysbiosis in an aged population. C57BL/6 mice (aged 2 years) were fed a high-fat (40 % energy), isoenergetic and isonitrogenous diet composed of rapeseed oil, maize oil or maize oil supplemented with fish oil. We examined ileal microbiota using fluorescence in situ hybridisation and stained tissues by immunofluorescence for the presence of immune cells and oxidative stress. We observed that feeding high-fat diets rich in n-6 PUFA promoted bacterial overgrowth but depleted microbes from the Bacteroidetes and Firmicutes phyla. This corresponded with increased body mass and infiltration of macrophages and neutrophils. Fish oil supplementation (rich in long-chain n-3 PUFA like DHA and EPA) restored the microbiota and inflammatory cell infiltration and promoted regulatory T-cell recruitment. However, fish oil supplementation was associated with increased oxidative stress, evident by the increased presence of 4-hydroxynonenal, a product of lipid peroxidation. These results suggest that an n-6 PUFA-rich diet can cause dysbiosis and intestinal inflammation in aged mice. However, while fish oil supplementation on an n-6 PUFA diet reverses dysbiosis, the combination of n-6 and n-3 PUFA, like DHA/EPA, leads to increased oxidative stress, which could exacerbate gastrointestinal disorders in the elderly.