Re: Low-carb diet increased total and cardiovascular mortality

Discussion in 'Food and nutrition' started by Matti Narkia, Mar 28, 2007.

  1. Matti Narkia

    Matti Narkia Guest

    On Wed, 28 Mar 2007 23:04:06 +0300, "Juhana Harju" <>

    >A low carbohydrate and high protein diet increased total and cardiovascular
    >mortality among Swedish women.
    >Low carbohydrate-high protein diet and mortality in a cohort of Swedish
    >Lagiou P, Sandin S, Weiderpass E, Lagiou A, Mucci L, Trichopoulos D, Adami
    >University of Athens Medical School, Goudi, Athens, Greece; Karolinska
    >Institutet, Stockholm, Sweden; The Cancer Registry of Norway, Montebello,
    >Oslo, Norway; Athens Technological Institute (TEI), Akadimia Platonos,
    >Greece; Harvard School of Public Health, Boston, MA, USA; Harvard Medical
    >School, Boston, MA, USA.
    >J Intern Med 2007; 261:366-374.
    >Objective. The long-term health consequences of diets used for weight
    >control are not established. We have evaluated the association of the
    >frequently recommended low carbohydrate diets - usually characterized by
    >concomitant increase in protein intake - with long-term mortality.
    >Design. The Women's Lifestyle and Health cohort study initiated in Sweden
    >during 1991-1992, with a 12-year almost complete follow up.
    >Setting. The Uppsala Health Care Region.
    >Subjects. 42 237 women, 30-49 years old at baseline, volunteers from a
    >random sample, who completed an extensive questionnaire and were traced
    >through linkages to national registries until 2003.
    >Main Outcome Measures. We evaluated the association of mortality with:
    >decreasing carbohydrate intake (in deciles); increasing protein intake (in
    >deciles) and an additive combination of these variables (low
    >carbohydrate-high protein score from 2 to 20), in Cox models controlling for
    >energy intake, saturated fat intake and several nondietary covariates.
    >Results. Decreasing carbohydrate or increasing protein intake by one decile
    >were associated with increase in total mortality by 6% (95% CI: 0-12%) and
    >2% (95% CI: ?1 to 5%), respectively. For cardiovascular mortality, amongst

    Should be CI: -1 to 5%, check the abstract from the link below.

    >women 40-49 years old at enrolment, the corresponding increases were,
    >respectively, 13% (95% CI: ?4 to 32%) and 16% (95% CI: 5-29%), with the

    and here should be (95% CI: -4 to 32%). There's obviously been some
    kind of error in copy/paste, which caused minus-signs to be converted
    to question marks. I mentioned this error to you, when you posted the
    same abstract into a Finnish newsgroup. Why didn't you correct the
    error before posting the abstract here?

    >additive score being even more predictive.
    >Conclusions. A diet characterized by low carbohydrate and high protein
    >intake was associated with increased total and particularly cardiovascular
    >mortality amongst women. Vigilance with respect to long-term adherence to
    >such weight control regimes is advisable.
    >The full study is downloadable here:


    1) As seen from the 95% confidence intervals, only one of the elevated
    risks was clearly stastically significant.

    2) These results conflict with the earlier Harvard's Nurses' Health
    Study's results.

    3) If the results are real, they probably reflect more of the choice
    of the food items than the relative portion of carbohydrates in the
    diet. In other words, low amount of carbohydrates is often a marker of
    an unhealthy diet, where amount protein is increased by eating more
    various meat products at the expense of vegetable and fish protein.
    Too little vegetables and fish may increase the risk of health
    problems. There is, however, no need to eat unhealthily, when reducing
    carbs. There are plenty of good relatively low carb vegetable protein
    sources for example, and fish is healthy and has no carbs. Also, the
    fat coming with protein may affect the outcome one way or other
    depending of the type and the quality of the fat. In the editorial of
    the same issue of Journal of Internal Medicine (Volume 261 Issue 4,
    April 2007) Harvard's Walter C. Willett seems to agree with this. I
    quote below his summary and conclusions:

    "[...] the most likely interpretation of the superficially
    inconsistent Swedish and US findings is that both are correct
    within the context of their respective populations and their
    diets. Within the relatively lean and younger Swedish women,
    replacement of largely whole grains with the protein packages
    consumed in that population probably have an adverse effect
    on cardiovascular disease. In contrast, within a heavier and
    older population of US women, replacement of mainly refined
    starch and sugar with almost any source of calories is not
    likely to increase the risk of cardiovascular disease. This
    conclusion emphasizes the most fundamental conclusion of
    research into diet and cancer during the last decade: it is
    the type of fat and type of carbohydrate rather than the
    total amounts of either that influence risk of cardiovascular
    disease. Thus, in the Nurses' Health Study, a low-
    carbohydrate pattern that emphasized vegetable sources of
    protein and fat was associated with a significantly lower
    risk of coronary heart disease [2]. This finding is
    reinforced by the results from a recent large controlled
    feeding study in which replacement of complex carbohydrates
    with either protein or monounsaturated fat reduced
    cardiovascular risk factors [10]. Thus, there is every reason
    to believe that a moderately low carbohydrate intake
    (approximately 30-40% of energy) can result in low risk of
    cardiovascular disease if the proteins and fats are mainly
    from plant sources (but do not include hydrogenated oils) and
    the remaining carbohydrates are from whole grains, fruit and
    vegetables. However, the findings of Lagiou et al. suggest
    that most Swedish women who reduce their carbohydrate intake
    may not be adopting this version of a low-carbohydrate diet
    and are adversely affecting their risk of cardiovascular

    Matti Narkia

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