Clinical Health Updates

High-protein, low-carb diet associated with increased mortality in women

Clinical Question:
Is a diet high in protein and low in carbohydrates beneficial to women’s health?

Bottom Line:
There is an association between women?s mortality risk and a diet that is low in carbohydrates, high in protein, or both. The strength of this association is reinforced by a dose-response gradient in the observations, as well as the additive effects of low carbohydrates and high protein.

Lagiou P, Sandin S, Weiderpass E, et al. Low carbohydrate-high protein diet and mortality in a cohort of Swedish women. Journal of Internal Medicine 2007;261:366-374.

Study Design:
Cohort (prospective)

The long-term health consequences of diets used for weight control are not established. They evaluated the association of the frequently recommended low carbohydrate diets – usually characterized by concomitant increase in protein intake – with long-term mortality. The Women’s Lifestyle and Health cohort study initiated in Sweden during 1991-1992, with a 12-year almost complete follow up. The study was done in The Uppsala Health Care Region. Included were 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. They 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. 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 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 additive score being even more predictive.