Re: Low-carb diet increased total and cardiovascular mortality



M

Matti Narkia

Guest
On Wed, 28 Mar 2007 23:04:06 +0300, "Juhana Harju" <[email protected]>
wrote:

>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
>women
>
>Lagiou P, Sandin S, Weiderpass E, Lagiou A, Mucci L, Trichopoulos D, Adami
>H-O
>
>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.
>
>Abstract
>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.
>
>http://tinyurl.com/2b39ml
>
>The full study is downloadable here:
>
>http://www.box.net/shared/7bjs4c452p


Remarks:

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
disease."


--
Matti Narkia