A recent study suggested that women who regularly follow a low-carbohydrate, high-protein diet are at increased risk for CVD compared with women who do not follow the diet.
The population-based cohort study included more than 43,000 Swedish women who were followed for a mean of 15.7 years and generated about 680,000 person-years of follow-up. Researchers recorded 1,270 incident CV events in the women, of which 55% were ischemic heart disease, 23% ischemic stroke, 10% subarachnoid hemorrhage, 6% hemorrhagic stroke and 6% peripheral arterial disease.
Researchers used a scaled point system to measure the low-carbohydrate, high-protein diets of the women, with a score of 2 indicating a very high adherence to the diet and a score of up to 20 indicating a very low adherence to the diet.
According to the results, increasing incidence of CVD was associated with:
- A one-tenth decrease in carbohydrate intake (incidence RR=1.04; 95% CI, 1-1.08).
- A one-tenth increase in protein intake (incidence RR=1.04; 95% CI, 1.02-1.06).
- A 2-unit increase in the low-carbohydrate/high-protein score (incidence RR=1.05; 95% CI, 1.02-1.08).
After controlling for risk factors, as well as total energy and saturated/unsaturated fat intake, “women had a statistically significant 5% increase in the incidence of CV events per 2 unit increase in the 20-unit low-carbohydrate/high-protein score. In practical terms … a 20-g decrease in daily carbohydrate intake and a 5-g increase in daily protein intake could correspond to a 5% increase in the overall risk of CVD,” the researchers wrote.
The researchers found no heterogeneity in the association between diet scores and the five studied CV outcomes: ischemic heart disease, ischemic stroke, hemorrhagic stroke, subarachnoid hemorrhage and peripheral arterial disease.
All women participated in the Swedish Women’s Lifestyle and Health Cohort and were aged 30 to 49 years at the start of the study (1991-1992). Each participant completed an extensive dietary survey and answered questions on smoking, physical activity, alcohol use, BP and other risk factors.
“Having been generated from a cohort of relatively young women, the results of our study are directly relevant to a group that often resorts to weight control regimens that encourage restriction of carbohydrate with unavoidable increases in protein intake,” the researchers wrote.
They noted that these data “do not answer questions concerning possible beneficial short-term effects of low-carbohydrate or high-protein diets in the control of body weight or insulin resistance.” Rather, the data “draw attention to the potential for considerable adverse effects on CV health of these diets when they are used on a regular basis, without consideration of the nature of carbohydrates (complex vs. refined) or the source of proteins (plant vs. animal).”
Disclosure: The study was supported by grants from the Swedish Cancer Society and Swedish Research Council. The researchers report no relevant financial disclosures.